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A Warning For Coolant Users...

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  • Ray Livingston
    Just in case anyone else is as stupid as I am.... I often use MDF as a spacer under my work, to protect the table. It s cheap, dimensionally stable, and
    Message 1 of 17 , Aug 27, 2008
      Just in case anyone else is as stupid as I am.... I often use MDF as
      a "spacer" under my work, to protect the table. It's cheap,
      dimensionally stable, and I've got lots of it. Unfortunately, I've
      just learned the hard way it has one major problem - if you use
      coolant, at least the KoolMist mist coolant I use, something appatently
      leaches out of the MDF that will stain your pretty, precision ground
      cast iron table black and splotchy. This just happened to my lovely
      brand new (well, 8 months ago...) knee mill. It happened a couple of
      years ago to my mini-mill, but in that case I assumed it was because I
      had left the wet MDF and fixture plate on the machine for about a
      week. This time, I removed them the instant the job was done, but it
      was already too late.

      I have yet to find a way to remove the stains. Someone suggested some
      rust/bluing remover from a gun shop. I'm going to give that a shot.

      Regards,
      Ray L.
    • Dan Mauch
      I have a similar problem where I have an aluminum tooling plate that is sometimes bolted to my mill for weeks on end. When I remove it the table is black. I
      Message 2 of 17 , Aug 27, 2008
        I have a similar problem where I have an aluminum tooling plate that is sometimes bolted to my mill for weeks on end. When I remove it the table is black. I use the 3M scoch pads that are availble at industrial supply stores. A few swipes with that and the table look like new.
        Dan Mauch
        economical 3D scanner software and kits
        low cost stepper and servo motors.
        cases for Gecko drives
        kits and assembled 3-4 axis drives
        www.camtronics-cnc.com
        www.seanet.com/~dmauch
        ----- Original Message -----
        Sent: Wednesday, August 27, 2008 4:13 PM
        Subject: [mill_drill] A Warning For Coolant Users...

        Just in case anyone else is as stupid as I am.... I often use MDF as
        a "spacer" under my work, to protect the table. It's cheap,
        dimensionally stable, and I've got lots of it. Unfortunately, I've
        just learned the hard way it has one major problem - if you use
        coolant, at least the KoolMist mist coolant I use, something appatently
        leaches out of the MDF that will stain your pretty, precision ground
        cast iron table black and splotchy. This just happened to my lovely
        brand new (well, 8 months ago...) knee mill. It happened a couple of
        years ago to my mini-mill, but in that case I assumed it was because I
        had left the wet MDF and fixture plate on the machine for about a
        week. This time, I removed them the instant the job was done, but it
        was already too late.

        I have yet to find a way to remove the stains. Someone suggested some
        rust/bluing remover from a gun shop. I'm going to give that a shot.

        Regards,
        Ray L.

      • Ray Livingston
        Dan, That won t do it on mine. I even tried Phosphoric acid and a Scotchbrite pad. It did almost nothing. Regards, Ray L. ... that is sometimes bolted to my
        Message 3 of 17 , Aug 27, 2008
          Dan,

          That won't do it on mine. I even tried Phosphoric acid and a
          Scotchbrite pad. It did almost nothing.

          Regards,
          Ray L.


          --- In mill_drill@yahoogroups.com, "Dan Mauch" <dmauch@...> wrote:
          >
          > I have a similar problem where I have an aluminum tooling plate
          that is sometimes bolted to my mill for weeks on end. When I remove
          it the table is black. I use the 3M scoch pads that are availble at
          industrial supply stores. A few swipes with that and the table look
          like new.
          > Dan Mauch
          > economical 3D scanner software and kits
          > low cost stepper and servo motors.
          > cases for Gecko drives
          > kits and assembled 3-4 axis drives
          > www.camtronics-cnc.com
          > www.seanet.com/~dmauch
          > ----- Original Message -----
          > From: Ray Livingston
          > To: mill_drill@yahoogroups.com
          > Sent: Wednesday, August 27, 2008 4:13 PM
          > Subject: [mill_drill] A Warning For Coolant Users...
          >
          >
          > Just in case anyone else is as stupid as I am.... I often use MDF
          as
          > a "spacer" under my work, to protect the table. It's cheap,
          > dimensionally stable, and I've got lots of it. Unfortunately,
          I've
          > just learned the hard way it has one major problem - if you use
          > coolant, at least the KoolMist mist coolant I use, something
          appatently
          > leaches out of the MDF that will stain your pretty, precision
          ground
          > cast iron table black and splotchy. This just happened to my
          lovely
          > brand new (well, 8 months ago...) knee mill. It happened a couple
          of
          > years ago to my mini-mill, but in that case I assumed it was
          because I
          > had left the wet MDF and fixture plate on the machine for about a
          > week. This time, I removed them the instant the job was done, but
          it
          > was already too late.
          >
          > I have yet to find a way to remove the stains. Someone suggested
          some
          > rust/bluing remover from a gun shop. I'm going to give that a
          shot.
          >
          > Regards,
          > Ray L.
          >
        • iqc4unme
          Ray, I have used the KoolMist spray setup for awhile now also & noticed the staining effect on that pretty cast iron table too. I always wipe down the table
          Message 4 of 17 , Aug 27, 2008
            Ray,
            I have used the KoolMist spray setup for awhile now also & noticed the
            staining effect on that pretty cast iron table too. I always wipe down
            the table after I am through with the mill for the evening. It`s hard
            to say what is in the MDF that is causing the black colored stains to
            appear but MDF has lots of chemicals in it anyway. I have used MDF in
            my past career job & so have lots of experience with it. A machinist
            warned me about the staining effect using the mist sprayers so I had a
            heads up on it when I bought the system. Like Dan, I keep 3M
            scotchbrite pads around the "shop" & occasionally use them on the mill
            table when I have a stain problem. They do seem to work good.
            Best Regards,
            Nat




            --- In mill_drill@yahoogroups.com, "Dan Mauch" <dmauch@...> wrote:
            >
            > I have a similar problem where I have an aluminum tooling plate that
            is sometimes bolted to my mill for weeks on end. When I remove it the
            table is black. I use the 3M scoch pads that are availble at
            industrial supply stores. A few swipes with that and the table look
            like new.
            > Dan Mauch
            > economical 3D scanner software and kits
            > low cost stepper and servo motors.
            > cases for Gecko drives
            > kits and assembled 3-4 axis drives
            > www.camtronics-cnc.com
            > www.seanet.com/~dmauch
            > ----- Original Message -----
            > From: Ray Livingston
            > To: mill_drill@yahoogroups.com
            > Sent: Wednesday, August 27, 2008 4:13 PM
            > Subject: [mill_drill] A Warning For Coolant Users...
            >
            >
            > Just in case anyone else is as stupid as I am.... I often use MDF as
            > a "spacer" under my work, to protect the table. It's cheap,
            > dimensionally stable, and I've got lots of it. Unfortunately, I've
            > just learned the hard way it has one major problem - if you use
            > coolant, at least the KoolMist mist coolant I use, something
            appatently
            > leaches out of the MDF that will stain your pretty, precision ground
            > cast iron table black and splotchy. This just happened to my lovely
            > brand new (well, 8 months ago...) knee mill. It happened a couple of
            > years ago to my mini-mill, but in that case I assumed it was
            because I
            > had left the wet MDF and fixture plate on the machine for about a
            > week. This time, I removed them the instant the job was done, but it
            > was already too late.
            >
            > I have yet to find a way to remove the stains. Someone suggested some
            > rust/bluing remover from a gun shop. I'm going to give that a shot.
            >
            > Regards,
            > Ray L.
            >
          • Ray Livingston
            Nat, Interesting.... I ve never had a problem with KoolMist staining, other than when MDF was involved. In fact, on my mini-mill, I did a job that had it
            Message 5 of 17 , Aug 27, 2008
              Nat,

              Interesting.... I've never had a problem with KoolMist staining,
              other than when MDF was involved. In fact, on my mini-mill, I did a
              job that had it swimming in coolant, and I just left it. There was
              no rust, except under the MDF. The rest of the table looks like new
              to this day. I usually try to run it dry enough that no significant
              moisture makes it to the table, but I Was doing steel and stainless,
              and doing some pretty aggressive cuts, so I needed a lot of coolant
              to keep the temperatures down.
              I sure hope the rust/bluing remover works. The table on my knee
              mill was a thing of beauty before this happened.

              Regards,
              Ray L.


              --- In mill_drill@yahoogroups.com, "iqc4unme" <bsthrottleup@...>
              wrote:
              >
              > Ray,
              > I have used the KoolMist spray setup for awhile now also & noticed
              the
              > staining effect on that pretty cast iron table too. I always wipe
              down
              > the table after I am through with the mill for the evening. It`s
              hard
              > to say what is in the MDF that is causing the black colored stains
              to
              > appear but MDF has lots of chemicals in it anyway. I have used MDF
              in
              > my past career job & so have lots of experience with it. A machinist
              > warned me about the staining effect using the mist sprayers so I
              had a
              > heads up on it when I bought the system. Like Dan, I keep 3M
              > scotchbrite pads around the "shop" & occasionally use them on the
              mill
              > table when I have a stain problem. They do seem to work good.
              > Best Regards,
              > Nat
              >
              >
              >
              >
              > --- In mill_drill@yahoogroups.com, "Dan Mauch" <dmauch@> wrote:
              > >
              > > I have a similar problem where I have an aluminum tooling plate
              that
              > is sometimes bolted to my mill for weeks on end. When I remove it
              the
              > table is black. I use the 3M scoch pads that are availble at
              > industrial supply stores. A few swipes with that and the table look
              > like new.
              > > Dan Mauch
              > > economical 3D scanner software and kits
              > > low cost stepper and servo motors.
              > > cases for Gecko drives
              > > kits and assembled 3-4 axis drives
              > > www.camtronics-cnc.com
              > > www.seanet.com/~dmauch
              > > ----- Original Message -----
              > > From: Ray Livingston
              > > To: mill_drill@yahoogroups.com
              > > Sent: Wednesday, August 27, 2008 4:13 PM
              > > Subject: [mill_drill] A Warning For Coolant Users...
              > >
              > >
              > > Just in case anyone else is as stupid as I am.... I often use
              MDF as
              > > a "spacer" under my work, to protect the table. It's cheap,
              > > dimensionally stable, and I've got lots of it. Unfortunately,
              I've
              > > just learned the hard way it has one major problem - if you use
              > > coolant, at least the KoolMist mist coolant I use, something
              > appatently
              > > leaches out of the MDF that will stain your pretty, precision
              ground
              > > cast iron table black and splotchy. This just happened to my
              lovely
              > > brand new (well, 8 months ago...) knee mill. It happened a
              couple of
              > > years ago to my mini-mill, but in that case I assumed it was
              > because I
              > > had left the wet MDF and fixture plate on the machine for about
              a
              > > week. This time, I removed them the instant the job was done,
              but it
              > > was already too late.
              > >
              > > I have yet to find a way to remove the stains. Someone
              suggested some
              > > rust/bluing remover from a gun shop. I'm going to give that a
              shot.
              > >
              > > Regards,
              > > Ray L.
              > >
              >
            • FocusKnobs
              MDF is notorious for out-gassing formaldehyde, and aqueous formaldehyde is corrosive to carbon steel. Any water-containing coolant will probably activate the
              Message 6 of 17 , Aug 27, 2008
                MDF is notorious for out-gassing formaldehyde, and aqueous formaldehyde
                is corrosive to carbon steel. Any water-containing coolant will probably
                activate the formaldehyde and cause the staining you experienced. The
                problem would probably go away if you can find some sheets of
                "eco-friendly" formaldehyde-free MDF.

                Lou


                -----Original Message-----
                From: mill_drill@yahoogroups.com [mailto:mill_drill@yahoogroups.com] On
                Behalf Of Ray Livingston
                Sent: Wednesday, August 27, 2008 4:14 PM
                To: mill_drill@yahoogroups.com
                Subject: [mill_drill] A Warning For Coolant Users...

                Just in case anyone else is as stupid as I am.... I often use MDF as
                a "spacer" under my work, to protect the table. It's cheap,
                dimensionally stable, and I've got lots of it. Unfortunately, I've
                just learned the hard way it has one major problem - if you use
                coolant, at least the KoolMist mist coolant I use, something appatently
                leaches out of the MDF that will stain your pretty, precision ground
                cast iron table black and splotchy. This just happened to my lovely
                brand new (well, 8 months ago...) knee mill. It happened a couple of
                years ago to my mini-mill, but in that case I assumed it was because I
                had left the wet MDF and fixture plate on the machine for about a
                week. This time, I removed them the instant the job was done, but it
                was already too late.

                I have yet to find a way to remove the stains. Someone suggested some
                rust/bluing remover from a gun shop. I'm going to give that a shot.

                Regards,
                Ray L.
              • j.c.gerber@tbwil.ch
                Interesting this formaldehyde subject. MDF is very porous and I sometimes use it as vacuum holder plate. In Switzerland ALL products containing formaldehydes
                Message 7 of 17 , Aug 27, 2008
                  Interesting this formaldehyde subject. MDF is very porous and I sometimes use it as vacuum holder plate.
                   
                  In Switzerland ALL products containing formaldehydes are legally prohibited.
                   
                  Jean-Claude, Switzerland
                  www.homestead.com/turnandmill
                   
                  ----- Original Message -----
                  Sent: Thursday, August 28, 2008 8:09 AM
                  Subject: RE: [mill_drill] A Warning For Coolant Users...

                  MDF is notorious for out-gassing formaldehyde, and aqueous formaldehyde
                  is corrosive to carbon steel. Any water-containing coolant will probably
                  activate the formaldehyde and cause the staining you experienced. The
                  problem would probably go away if you can find some sheets of
                  "eco-friendly" formaldehyde- free MDF.

                  Lou

                  -----Original Message-----
                  From: mill_drill@yahoogro ups.com [mailto:mill_drill@yahoogro ups.com] On
                  Behalf Of Ray Livingston
                  Sent: Wednesday, August 27, 2008 4:14 PM
                  To: mill_drill@yahoogro ups.com
                  Subject: [mill_drill] A Warning For Coolant Users...

                  Just in case anyone else is as stupid as I am.... I often use MDF as
                  a "spacer" under my work, to protect the table. It's cheap,
                  dimensionally stable, and I've got lots of it. Unfortunately, I've
                  just learned the hard way it has one major problem - if you use
                  coolant, at least the KoolMist mist coolant I use, something appatently
                  leaches out of the MDF that will stain your pretty, precision ground
                  cast iron table black and splotchy. This just happened to my lovely
                  brand new (well, 8 months ago...) knee mill. It happened a couple of
                  years ago to my mini-mill, but in that case I assumed it was because I
                  had left the wet MDF and fixture plate on the machine for about a
                  week. This time, I removed them the instant the job was done, but it
                  was already too late.

                  I have yet to find a way to remove the stains. Someone suggested some
                  rust/bluing remover from a gun shop. I'm going to give that a shot.

                  Regards,
                  Ray L.

                • FocusKnobs
                  There you go, Ray. Ask Jean-Claude to send you some MDF sheets. Lou ________________________________ From: mill_drill@yahoogroups.com
                  Message 8 of 17 , Aug 27, 2008

                    There you go, Ray. Ask Jean-Claude to send you some MDF sheets. <VBG>

                     

                    Lou

                     


                    From: mill_drill@yahoogroups.com [mailto: mill_drill@yahoogroups.com ] On Behalf Of j.c.gerber@...
                    Sent: Wednesday, August 27, 2008 11:36 PM
                    To: mill_drill@yahoogroups.com
                    Subject: Re: [mill_drill] A Warning For Coolant Users...

                     

                    Interesting this formaldehyde subject. MDF is very porous and I sometimes use it as vacuum holder plate.

                     

                    In Switzerland ALL products containing formaldehydes are legally prohibited.

                     

                    Jean-Claude, Switzerland
                    www.homestead.com/turnandmill

                     

                    ----- Original Message -----

                    From: FocusKnobs

                    Sent: Thursday, August 28, 2008 8:09 AM

                    Subject: RE: [mill_drill] A Warning For Coolant Users...

                     

                    MDF is notorious for out-gassing formaldehyde, and aqueous formaldehyde
                    is corrosive to carbon steel. Any water-containing coolant will probably
                    activate the formaldehyde and cause the staining you experienced. The
                    problem would probably go away if you can find some sheets of
                    "eco-friendly" formaldehyde- free MDF.

                    Lou

                    -----Original Message-----
                    From: mill_drill@yahoogro ups.com [mailto:mill_drill@yahoogro ups.com] On
                    Behalf Of Ray Livingston
                    Sent: Wednesday, August 27, 2008 4:14 PM
                    To: mill_drill@yahoogro ups.com
                    Subject: [mill_drill] A Warning For Coolant Users...

                    Just in case anyone else is as stupid as I am.... I often use MDF as
                    a "spacer" under my work, to protect the table. It's cheap,
                    dimensionally stable, and I've got lots of it. Unfortunately, I've
                    just learned the hard way it has one major problem - if you use
                    coolant, at least the KoolMist mist coolant I use, something appatently
                    leaches out of the MDF that will stain your pretty, precision ground
                    cast iron table black and splotchy. This just happened to my lovely
                    brand new (well, 8 months ago...) knee mill. It happened a couple of
                    years ago to my mini-mill, but in that case I assumed it was because I
                    had left the wet MDF and fixture plate on the machine for about a
                    week. This time, I removed them the instant the job was done, but it
                    was already too late.

                    I have yet to find a way to remove the stains. Someone suggested some
                    rust/bluing remover from a gun shop. I'm going to give that a shot.

                    Regards,
                    Ray L.

                  • Doug Rhodes
                    Another idea, just speculation, but ... MDF is made from sawdust, and depending on where the mill gets the sawdust, it could be from various species of wood.
                    Message 9 of 17 , Aug 28, 2008
                      Another idea, just speculation, but ...
                       
                      MDF is made from sawdust, and depending on where the mill gets the sawdust, it could be from various species of wood. Several species, oak prominent among them, are notorious for black staining when they come into contact with iron and moisture. This black staining is very colorfast and durable - so much so that the effect was created on purpose back in the day to color objects by the "fuming" process.
                       
                      It is the tannin in the wood that creates the stain. If your MDF is made of sawdust from any of these woods, that might explain the effect. Certainly if you leave a green (wet) piece of wood on a tablesaw table for any length of time it leaves a dickens of a mark on the metal.
                       
                      If this theory holds up, then even the formaldehyde-free MDF might not avoid the effect, if there is tannin in the wood dust they use to make the panels. 
                       
                      Doug
                       
                      ----- Original Message -----
                      Sent: Wednesday, August 27, 2008 11:09 PM
                      Subject: RE: [mill_drill] A Warning For Coolant Users...

                      MDF is notorious for out-gassing formaldehyde, and aqueous formaldehyde
                      is corrosive to carbon steel. Any water-containing coolant will probably
                      activate the formaldehyde and cause the staining you experienced. The
                      problem would probably go away if you can find some sheets of
                      "eco-friendly" formaldehyde- free MDF.

                      Lou

                      -----Original Message-----
                      From: mill_drill@yahoogro ups.com [mailto:mill_drill@yahoogro ups.com] On
                      Behalf Of Ray Livingston
                      Sent: Wednesday, August 27, 2008 4:14 PM
                      To: mill_drill@yahoogro ups.com
                      Subject: [mill_drill] A Warning For Coolant Users...

                      Just in case anyone else is as stupid as I am.... I often use MDF as
                      a "spacer" under my work, to protect the table. It's cheap,
                      dimensionally stable, and I've got lots of it. Unfortunately, I've
                      just learned the hard way it has one major problem - if you use
                      coolant, at least the KoolMist mist coolant I use, something appatently
                      leaches out of the MDF that will stain your pretty, precision ground
                      cast iron table black and splotchy. This just happened to my lovely
                      brand new (well, 8 months ago...) knee mill. It happened a couple of
                      years ago to my mini-mill, but in that case I assumed it was because I
                      had left the wet MDF and fixture plate on the machine for about a
                      week. This time, I removed them the instant the job was done, but it
                      was already too late.

                      I have yet to find a way to remove the stains. Someone suggested some
                      rust/bluing remover from a gun shop. I'm going to give that a shot.

                      Regards,
                      Ray L.

                    • wildcherrywood
                      I d try vinegar diluted 2:1. Pour it on there and let it soak for 5 minutes then, soak a white/grey scotchbrite pad and scour it off. Regarding MDF, you might
                      Message 10 of 17 , Aug 28, 2008
                        I'd try vinegar diluted 2:1. Pour it on there and let it soak for 5
                        minutes then, soak a white/grey scotchbrite pad and scour it off.

                        Regarding MDF, you might look into Extira as an alternative.

                        www.extira.com

                        Chris


                        >
                        > I have yet to find a way to remove the stains. Someone suggested some
                        > rust/bluing remover from a gun shop. I'm going to give that a shot.
                        >
                        > Regards,
                        > Ray L.
                        >
                      • casy_ch
                        That s a method, but if one is forgetting to oil the surface just after cleaning the vinegared surface then rust is happening very fast (don t ask how I
                        Message 11 of 17 , Aug 28, 2008
                          That's a method, but if one is forgetting to oil the surface just
                          after cleaning the "vinegared" surface then rust is happening very
                          fast (don't ask how I know).

                          Jean-Claude


                          --- In mill_drill@yahoogroups.com, "wildcherrywood" <giordano@...> wrote:
                          >
                          > I'd try vinegar diluted 2:1. Pour it on there and let it soak for 5
                          > minutes then, soak a white/grey scotchbrite pad and scour it off.
                          >
                          > Regarding MDF, you might look into Extira as an alternative.
                          >
                          > www.extira.com
                          >
                          > Chris
                          >
                          >
                          > >
                          > > I have yet to find a way to remove the stains. Someone suggested
                          some
                          > > rust/bluing remover from a gun shop. I'm going to give that a shot.
                          > >
                          > > Regards,
                          > > Ray L.
                          > >
                          >
                        • Dan Mauch
                          Yuk! Dan Mauch economical 3D scanner software and kits low cost stepper and servo motors. cases for Gecko drives kits and assembled 3-4 axis drives
                          Message 12 of 17 , Aug 28, 2008
                            Yuk!
                            Dan Mauch
                            economical 3D scanner software and kits
                            low cost stepper and servo motors.
                            cases for Gecko drives
                            kits and assembled 3-4 axis drives
                            www.camtronics-cnc.com
                            www.seanet.com/~dmauch
                            ----- Original Message -----
                            Sent: Wednesday, August 27, 2008 8:50 PM
                            Subject: [mill_drill] Re: A Warning For Coolant Users...

                            Dan,

                            That won't do it on mine. I even tried Phosphoric acid and a
                            Scotchbrite pad. It did almost nothing.

                            Regards,
                            Ray L.

                            --- In mill_drill@yahoogro ups.com, "Dan Mauch" <dmauch@...> wrote:
                            >
                            > I have a similar problem where I have an aluminum tooling plate
                            that is sometimes bolted to my mill for weeks on end. When I remove
                            it the table is black. I use the 3M scoch pads that are availble at
                            industrial supply stores. A few swipes with that and the table look
                            like new.
                            > Dan Mauch
                            > economical 3D scanner software and kits
                            > low cost stepper and servo motors.
                            > cases for Gecko drives
                            > kits and assembled 3-4 axis drives
                            > www.camtronics- cnc.com
                            > www.seanet.com/ ~dmauch
                            > ----- Original Message -----
                            > From: Ray Livingston
                            > To: mill_drill@yahoogro ups.com
                            > Sent: Wednesday, August 27, 2008 4:13 PM
                            > Subject: [mill_drill] A Warning For Coolant Users...
                            >
                            >
                            > Just in case anyone else is as stupid as I am.... I often use MDF
                            as
                            > a "spacer" under my work, to protect the table. It's cheap,
                            > dimensionally stable, and I've got lots of it. Unfortunately,
                            I've
                            > just learned the hard way it has one major problem - if you use
                            > coolant, at least the KoolMist mist coolant I use, something
                            appatently
                            > leaches out of the MDF that will stain your pretty, precision
                            ground
                            > cast iron table black and splotchy. This just happened to my
                            lovely
                            > brand new (well, 8 months ago...) knee mill. It happened a couple
                            of
                            > years ago to my mini-mill, but in that case I assumed it was
                            because I
                            > had left the wet MDF and fixture plate on the machine for about a
                            > week. This time, I removed them the instant the job was done, but
                            it
                            > was already too late.
                            >
                            > I have yet to find a way to remove the stains. Someone suggested
                            some
                            > rust/bluing remover from a gun shop. I'm going to give that a
                            shot.
                            >
                            > Regards,
                            > Ray L.
                            >

                          • kidharris
                            I m a newbie to this machining business, but I believe I would just let it wear off before I started sanding, scouring, and pouring acids on my table. All of
                            Message 13 of 17 , Sep 1, 2008
                              I'm a newbie to this machining business, but I believe I would just
                              let it wear off before I started sanding, scouring, and pouring acids
                              on my table. All of these processes will remove metal from your table.
                              Seems like the whole idea is to keep the table flat, not pretty. To
                              me, its a tool not a decoration. I would rather have the tolerances
                              rather than the shine. Maybe I'm missing something here.

                              --- In mill_drill@yahoogroups.com, "Ray Livingston" <jagboy@...> wrote:
                              >
                              > Just in case anyone else is as stupid as I am.... I often use MDF as
                              > a "spacer" under my work, to protect the table. It's cheap,
                              > dimensionally stable, and I've got lots of it. Unfortunately, I've
                              > just learned the hard way it has one major problem - if you use
                              > coolant, at least the KoolMist mist coolant I use, something appatently
                              > leaches out of the MDF that will stain your pretty, precision ground
                              > cast iron table black and splotchy. This just happened to my lovely
                              > brand new (well, 8 months ago...) knee mill. It happened a couple of
                              > years ago to my mini-mill, but in that case I assumed it was because I
                              > had left the wet MDF and fixture plate on the machine for about a
                              > week. This time, I removed them the instant the job was done, but it
                              > was already too late.
                              >
                              > I have yet to find a way to remove the stains. Someone suggested some
                              > rust/bluing remover from a gun shop. I'm going to give that a shot.
                              >
                              > Regards,
                              > Ray L.
                              >
                            • kidharris
                              PS. Thanks fot the tip about KoolMist mist coolant staining. ... appatently ... because I ... some
                              Message 14 of 17 , Sep 1, 2008
                                PS. Thanks fot the tip about KoolMist mist coolant staining.


                                --- In mill_drill@yahoogroups.com, "kidharris" <kidharris@...> wrote:
                                >
                                > I'm a newbie to this machining business, but I believe I would just
                                > let it wear off before I started sanding, scouring, and pouring acids
                                > on my table. All of these processes will remove metal from your table.
                                > Seems like the whole idea is to keep the table flat, not pretty. To
                                > me, its a tool not a decoration. I would rather have the tolerances
                                > rather than the shine. Maybe I'm missing something here.
                                >
                                > --- In mill_drill@yahoogroups.com, "Ray Livingston" <jagboy@> wrote:
                                > >
                                > > Just in case anyone else is as stupid as I am.... I often use MDF as
                                > > a "spacer" under my work, to protect the table. It's cheap,
                                > > dimensionally stable, and I've got lots of it. Unfortunately, I've
                                > > just learned the hard way it has one major problem - if you use
                                > > coolant, at least the KoolMist mist coolant I use, something
                                appatently
                                > > leaches out of the MDF that will stain your pretty, precision ground
                                > > cast iron table black and splotchy. This just happened to my lovely
                                > > brand new (well, 8 months ago...) knee mill. It happened a couple of
                                > > years ago to my mini-mill, but in that case I assumed it was
                                because I
                                > > had left the wet MDF and fixture plate on the machine for about a
                                > > week. This time, I removed them the instant the job was done, but it
                                > > was already too late.
                                > >
                                > > I have yet to find a way to remove the stains. Someone suggested
                                some
                                > > rust/bluing remover from a gun shop. I'm going to give that a shot.
                                > >
                                > > Regards,
                                > > Ray L.
                                > >
                                >
                              • Ray Livingston
                                Well, the mild acid I used, and the Scotchbrite are not going to remove any measurable metal, so they really won t do any harm. Even if you were to try to
                                Message 15 of 17 , Sep 2, 2008
                                  Well, the mild acid I used, and the Scotchbrite are not going to
                                  remove any measurable metal, so they really won't do any harm. Even
                                  if you were to try to sand the table, you'd have to do it for an
                                  incredibly long time to remove enough material to be able to even
                                  measure the loss, much less for it to have any effect on the
                                  precision of the machhine or your work.

                                  Regards,
                                  Ray L.



                                  --- In mill_drill@yahoogroups.com, "kidharris" <kidharris@...> wrote:
                                  >
                                  > I'm a newbie to this machining business, but I believe I would just
                                  > let it wear off before I started sanding, scouring, and pouring
                                  acids
                                  > on my table. All of these processes will remove metal from your
                                  table.
                                  > Seems like the whole idea is to keep the table flat, not pretty. To
                                  > me, its a tool not a decoration. I would rather have the tolerances
                                  > rather than the shine. Maybe I'm missing something here.
                                  >
                                  > --- In mill_drill@yahoogroups.com, "Ray Livingston" <jagboy@> wrote:
                                  > >
                                  > > Just in case anyone else is as stupid as I am.... I often use
                                  MDF as
                                  > > a "spacer" under my work, to protect the table. It's cheap,
                                  > > dimensionally stable, and I've got lots of it. Unfortunately,
                                  I've
                                  > > just learned the hard way it has one major problem - if you use
                                  > > coolant, at least the KoolMist mist coolant I use, something
                                  appatently
                                  > > leaches out of the MDF that will stain your pretty, precision
                                  ground
                                  > > cast iron table black and splotchy. This just happened to my
                                  lovely
                                  > > brand new (well, 8 months ago...) knee mill. It happened a
                                  couple of
                                  > > years ago to my mini-mill, but in that case I assumed it was
                                  because I
                                  > > had left the wet MDF and fixture plate on the machine for about a
                                  > > week. This time, I removed them the instant the job was done,
                                  but it
                                  > > was already too late.
                                  > >
                                  > > I have yet to find a way to remove the stains. Someone suggested
                                  some
                                  > > rust/bluing remover from a gun shop. I'm going to give that a
                                  shot.
                                  > >
                                  > > Regards,
                                  > > Ray L.
                                  > >
                                  >
                                • pacer8020
                                  I agree with Ray here -- the Scotchbrite pads are an indispensable item in the shop and using them in this instance--getting spots/stains/minor rust off the
                                  Message 16 of 17 , Sep 2, 2008
                                    I agree with Ray here -- the Scotchbrite pads are an indispensable
                                    item in the shop and using them in this instance--getting
                                    spots/stains/minor rust off the table or lathe ways is a wonderful
                                    means of accomplishing it. The pads and even sometimes a piece of
                                    500-1000grit wet-or-dry with kerosene/light oil is just the only way
                                    to get rid of a problem. And I agree that it would take an awful lot
                                    of scrubbing to do any thing close to damage this way. I use a 'rust
                                    remover' in a squirt bottle that is based on a mild acid, and with a
                                    stubborn rust spot, I'll use it with a piece of wet-dry paper.

                                    I have a table saw that is some 25yrs old and it catches hell with all
                                    the different woods having moisture content and the tannic acids, and
                                    I've been using these methods to clean the surface for all this time
                                    and its still in good condition

                                    When something like this stain mentioned in this thread has gotten on
                                    your tool, its often mildly caustic -- as rust would be -- and if not
                                    removed can do far more damage than "letting it wear off"


                                    --- In mill_drill@yahoogroups.com, "Ray Livingston" <jagboy@...> wrote:
                                    >
                                    > Well, the mild acid I used, and the Scotchbrite are not going to
                                    > remove any measurable metal, so they really won't do any harm. Even
                                    > if you were to try to sand the table, you'd have to do it for an
                                    > incredibly long time to remove enough material to be able to even
                                    > measure the loss, much less for it to have any effect on the
                                    > precision of the machhine or your work.
                                    >
                                    > Regards,
                                    > Ray L.
                                    >
                                    >
                                    >
                                    > --- In mill_drill@yahoogroups.com, "kidharris" <kidharris@> wrote:
                                    > >
                                    > > I'm a newbie to this machining business, but I believe I would just
                                    > > let it wear off before I started sanding, scouring, and pouring
                                    > acids
                                    roblem - if you use
                                  • Robert Hansberger
                                    For what it is worth, I don t get excited over stains and discoloration, but I do cringe at dings and moved metal. Years ago I learned the habit of ALWAYS
                                    Message 17 of 17 , Sep 3, 2008
                                      For what it is worth, I don't get excited over stains and
                                      discoloration, but I do cringe at dings and "moved" metal. Years ago
                                      I learned the habit of ALWAYS using a hard arkansas stone when
                                      changing a mounting on the table of the mill. It does not remove the
                                      metal of the surface, just the raised edges around the ding and areas
                                      where t-nuts were pull way to tight. I my mind it is the best way to
                                      keep the
                                      surface flat and thus greater repeatable accuracy and tight
                                      tolerances.
                                      Cheers to all, Bob









                                      --- In mill_drill@yahoogroups.com, "Ray Livingston" <jagboy@...>
                                      wrote:
                                      >
                                      > Well, the mild acid I used, and the Scotchbrite are not going to
                                      > remove any measurable metal, so they really won't do any harm.
                                      Even
                                      > if you were to try to sand the table, you'd have to do it for an
                                      > incredibly long time to remove enough material to be able to even
                                      > measure the loss, much less for it to have any effect on the
                                      > precision of the machhine or your work.
                                      >
                                      > Regards,
                                      > Ray L.
                                      >
                                      >
                                      >
                                      > --- In mill_drill@yahoogroups.com, "kidharris" <kidharris@> wrote:
                                      > >
                                      > > I'm a newbie to this machining business, but I believe I would
                                      just
                                      > > let it wear off before I started sanding, scouring, and pouring
                                      > acids
                                      > > on my table. All of these processes will remove metal from your
                                      > table.
                                      > > Seems like the whole idea is to keep the table flat, not pretty.
                                      To
                                      > > me, its a tool not a decoration. I would rather have the
                                      tolerances
                                      > > rather than the shine. Maybe I'm missing something here.
                                      > >
                                      > > --- In mill_drill@yahoogroups.com, "Ray Livingston" <jagboy@>
                                      wrote:
                                      > > >
                                      > > > Just in case anyone else is as stupid as I am.... I often use
                                      > MDF as
                                      > > > a "spacer" under my work, to protect the table. It's cheap,
                                      > > > dimensionally stable, and I've got lots of it. Unfortunately,
                                      > I've
                                      > > > just learned the hard way it has one major problem - if you use
                                      > > > coolant, at least the KoolMist mist coolant I use, something
                                      > appatently
                                      > > > leaches out of the MDF that will stain your pretty, precision
                                      > ground
                                      > > > cast iron table black and splotchy. This just happened to my
                                      > lovely
                                      > > > brand new (well, 8 months ago...) knee mill. It happened a
                                      > couple of
                                      > > > years ago to my mini-mill, but in that case I assumed it was
                                      > because I
                                      > > > had left the wet MDF and fixture plate on the machine for about
                                      a
                                      > > > week. This time, I removed them the instant the job was done,
                                      > but it
                                      > > > was already too late.
                                      > > >
                                      > > > I have yet to find a way to remove the stains. Someone
                                      suggested
                                      > some
                                      > > > rust/bluing remover from a gun shop. I'm going to give that a
                                      > shot.
                                      > > >
                                      > > > Regards,
                                      > > > Ray L.
                                      > > >
                                      > >
                                      >
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