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concrete curing time

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  • shondabarda
    Is there a general estimate for the time the concrete has to cure before parts can be embedded with accuracy? I ve heard 4 weeks, but the Yoeman s design only
    Message 1 of 8 , Sep 2, 2011
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      Is there a general estimate for the time the concrete has to cure before parts can be embedded with accuracy? I've heard 4 weeks, but the Yoeman's design only took 28 days to get a working model, so it has to be less. (I do have a book on concrete counter top laying, its just two states away right now)

      Shonda
    • Nick Andrews
      You mean like drilling into the concrete to embed? Embeds are normally attached to forms to hold them in place in wet concrete. It depends on mixture,
      Message 2 of 8 , Sep 2, 2011
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        You mean like drilling into the concrete to embed?  Embeds are normally attached to forms to hold them in place in wet concrete.  It depends on mixture, strength, any additives, etc, but after 12 hours or so it will generally be for all normal intents hard.  There is a calcium additive you can use to accelerate hardening.  Technically, concrete never stops curing; it hardens more and more until the end of time.  But practically, it has over 98% of ultimate strength by 28 days.

        On Fri, Sep 2, 2011 at 11:30 AM, shondabarda <jershond@...> wrote:
         

        Is there a general estimate for the time the concrete has to cure before parts can be embedded with accuracy? I've heard 4 weeks, but the Yoeman's design only took 28 days to get a working model, so it has to be less. (I do have a book on concrete counter top laying, its just two states away right now)

        Shonda




        --
        Nick A

        "You know what I wish?  I wish that all the scum of the world had but a single throat, and I had my hands about it..."  Rorschach, 1975

        "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety."- Benjamin Franklin, Historical Review of Pennsylvania, 1759

        "Suburbia is where the developer bulldozes out the trees, then names the streets after them." Bill Vaughan

        "The price of apathy towards public affairs is to be ruled by evil men." Plato
      • BRIAN GLACKIN
        24 hrs strength ~1000 PSI (can remove forms) 7 Days ~ 85% full strength 28 days ~98 full strength as noted previously During the curing stage and after
        Message 3 of 8 , Sep 2, 2011
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          24 hrs strength ~1000 PSI (can remove forms)
          7 Days ~ 85% full strength
          28 days ~98 full strength as noted previously
           
          During the curing stage and after removing forms, keep it moist by draping it with wet muslim or burlap then covering with plastic. 
           
          You could use other cements (not a 3rd world options though) that are alumina silicate based and cures are 24 hrs for ~90% of full strength.
           


           
          On Fri, Sep 2, 2011 at 1:42 PM, Nick Andrews <nickjandrews@...> wrote:
           

          You mean like drilling into the concrete to embed?  Embeds are normally attached to forms to hold them in place in wet concrete.  It depends on mixture, strength, any additives, etc, but after 12 hours or so it will generally be for all normal intents hard.  There is a calcium additive you can use to accelerate hardening.  Technically, concrete never stops curing; it hardens more and more until the end of time.  But practically, it has over 98% of ultimate strength by 28 days.



          On Fri, Sep 2, 2011 at 11:30 AM, shondabarda <jershond@...> wrote:
           

          Is there a general estimate for the time the concrete has to cure before parts can be embedded with accuracy? I've heard 4 weeks, but the Yoeman's design only took 28 days to get a working model, so it has to be less. (I do have a book on concrete counter top laying, its just two states away right now)

          Shonda




          --
          Nick A

          "You know what I wish?  I wish that all the scum of the world had but a single throat, and I had my hands about it..."  Rorschach, 1975

          "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety."- Benjamin Franklin, Historical Review of Pennsylvania, 1759

          "Suburbia is where the developer bulldozes out the trees, then names the streets after them." Bill Vaughan

          "The price of apathy towards public affairs is to be ruled by evil men." Plato


        • shondabarda
          What about for shrinkage and warping? Can I cast a hole in the concrete and then 24 hours later grout a pipe in place without the concrete shrinking more
          Message 4 of 8 , Sep 2, 2011
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            What about for shrinkage and warping? Can I cast a hole in the concrete and then 24 hours later grout a pipe in place without the concrete shrinking more (tolerance of thousandths, everything, two pipes and spindle, needs to be axially aligned)?

            Thanks

            --- In multimachine@yahoogroups.com, BRIAN GLACKIN <glackin.brian@...> wrote:
            >
            > 24 hrs strength ~1000 PSI (can remove forms)
            > 7 Days ~ 85% full strength
            > 28 days ~98 full strength as noted previously
            >
            > During the curing stage and after removing forms, keep it moist by draping
            > it with wet muslim or burlap then covering with plastic.
            >
            > You could use other cements (not a 3rd world options though) that are
            > alumina silicate based and cures are 24 hrs for ~90% of full strength.
            >
            >
            >
            >
            > On Fri, Sep 2, 2011 at 1:42 PM, Nick Andrews <nickjandrews@...> wrote:
            >
            > > **
            > >
            > >
            > > You mean like drilling into the concrete to embed? Embeds are normally
            > > attached to forms to hold them in place in wet concrete. It depends on
            > > mixture, strength, any additives, etc, but after 12 hours or so it will
            > > generally be for all normal intents hard. There is a calcium additive you
            > > can use to accelerate hardening. Technically, concrete never stops curing;
            > > it hardens more and more until the end of time. But practically, it has
            > > over 98% of ultimate strength by 28 days.
            > >
            > >
            > > On Fri, Sep 2, 2011 at 11:30 AM, shondabarda <jershond@...> wrote:
            > >
            > >> **
            > >>
            > >>
            > >> Is there a general estimate for the time the concrete has to cure before
            > >> parts can be embedded with accuracy? I've heard 4 weeks, but the Yoeman's
            > >> design only took 28 days to get a working model, so it has to be less. (I do
            > >> have a book on concrete counter top laying, its just two states away right
            > >> now)
            > >>
            > >> Shonda
            > >>
            > >>
            > >
            > >
            > > --
            > > Nick A
            > >
            > > "You know what I wish? I wish that all the scum of the world had but a
            > > single throat, and I had my hands about it..." Rorschach, 1975
            > >
            > > "They that can give up essential liberty to obtain a little temporary
            > > safety deserve neither liberty nor safety."- Benjamin Franklin, Historical
            > > Review of Pennsylvania, 1759
            > >
            > > "Suburbia is where the developer bulldozes out the trees, then names the
            > > streets after them." Bill Vaughan
            > >
            > > "The price of apathy towards public affairs is to be ruled by evil men."
            > > Plato
            > >
            > >
            > >
            >
          • Pat Delany
            Thanks guys for this thread. How much shrinkage in a 5 x 8 x 6 cube? If it is excessive (remember that the shoes are firmly clamped first) then the shoes
            Message 5 of 8 , Sep 3, 2011
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              Thanks guys for this thread.

              How much shrinkage in a 5" x 8" x 6" cube?
              If it is excessive (remember that the shoes are firmly clamped first) then the shoes can be attached the same way the ways and spindle are mounted (grouted after the concrete sets up).

              About bevel gears driving the carriage, this could easily be more difficult to make than the entire rest of the lathe. My main interest is making the machine cheaper and easier to build and align.

              My latest idea is to do away with the thrust adjusters and just use a steel washer between the chuck backplate and the front bushing shoulder. End play would be taken up with a simple clamping collar on the spindle.

              The machine could be made easier to build by eliminating the 2 hump design for the headstock. The Yeomans design uses the inner space for a big gear. I thought we could continue this in order to get the 4 stock size spindle bushings as was shown in his patent. If you want a more simple 1 hump design, you could start with a long outer cartridge pipe that is bored to stock size and as deeply as possible. When the stock bushing would wear it could be be replaced with a longer, self made bushing.

              Pat


              From: shondabarda <jershond@...>
              To: multimachine@yahoogroups.com
              Sent: Friday, September 2, 2011 4:04 PM
              Subject: [multimachine] Re: concrete curing time

               
              What about for shrinkage and warping? Can I cast a hole in the concrete and then 24 hours later grout a pipe in place without the concrete shrinking more (tolerance of thousandths, everything, two pipes and spindle, needs to be axially aligned)?

              Thanks

              --- In multimachine@yahoogroups.com, BRIAN GLACKIN <glackin.brian@...> wrote:
              >
              > 24 hrs strength ~1000 PSI (can remove forms)
              > 7 Days ~ 85% full strength
              > 28 days ~98 full strength as noted previously
              >
              > During the curing stage and after removing forms, keep it moist by draping
              > it with wet muslim or burlap then covering with plastic.
              >
              > You could use other cements (not a 3rd world options though) that are
              > alumina silicate based and cures are 24 hrs for ~90% of full strength.
              >
              >
              >
              >
              > On Fri, Sep 2, 2011 at 1:42 PM, Nick Andrews <nickjandrews@...> wrote:
              >
              > > **
              > >
              > >
              > > You mean like drilling into the concrete to embed? Embeds are normally
              > > attached to forms to hold them in place in wet concrete. It depends on
              > > mixture, strength, any additives, etc, but after 12 hours or so it will
              > > generally be for all normal intents hard. There is a calcium additive you
              > > can use to accelerate hardening. Technically, concrete never stops curing;
              > > it hardens more and more until the end of time. But practically, it has
              > > over 98% of ultimate strength by 28 days.
              > >
              > >
              > > On Fri, Sep 2, 2011 at 11:30 AM, shondabarda <jershond@...> wrote:
              > >
              > >> **
              > >>
              > >>
              > >> Is there a general estimate for the time the concrete has to cure before
              > >> parts can be embedded with accuracy? I've heard 4 weeks, but the Yoeman's
              > >> design only took 28 days to get a working model, so it has to be less. (I do
              > >> have a book on concrete counter top laying, its just two states away right
              > >> now)
              > >>
              > >> Shonda
              > >>
              > >>
              > >
              > >
              > > --
              > > Nick A
              > >
              > > "You know what I wish? I wish that all the scum of the world had but a
              > > single throat, and I had my hands about it..." Rorschach, 1975
              > >
              > > "They that can give up essential liberty to obtain a little temporary
              > > safety deserve neither liberty nor safety."- Benjamin Franklin, Historical
              > > Review of Pennsylvania, 1759
              > >
              > > "Suburbia is where the developer bulldozes out the trees, then names the
              > > streets after them." Bill Vaughan
              > >
              > > "The price of apathy towards public affairs is to be ruled by evil men."
              > > Plato
              > >
              > >
              > >
              >



            • BRIAN GLACKIN
              I would recommending waiting to get the 7 day cure. Especially early on you should keep the concrete covered and moist. Not the best time to be putting metal
              Message 6 of 8 , Sep 3, 2011
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                I would recommending waiting to get the 7 day cure.  Especially early on you should keep the concrete covered and moist.  Not the best time to be putting metal into the form.
                As to shrinkage, it should be minimal assuming you follow the directions for the mix you plan on.  I would personally go for a slightly drier mix and pack the mold as if I was packing a mold for a foundary.  Thats basically how the make highways and dams with roller compacted concrete - drier mix and pack the heck out of it.

                On Sat, Sep 3, 2011 at 2:21 PM, Pat Delany <rigmatch@...> wrote:
                 

                Thanks guys for this thread.

                How much shrinkage in a 5" x 8" x 6" cube?
                If it is excessive (remember that the shoes are firmly clamped first) then the shoes can be attached the same way the ways and spindle are mounted (grouted after the concrete sets up).

                About bevel gears driving the carriage, this could easily be more difficult to make than the entire rest of the lathe. My main interest is making the machine cheaper and easier to build and align.

                My latest idea is to do away with the thrust adjusters and just use a steel washer between the chuck backplate and the front bushing shoulder. End play would be taken up with a simple clamping collar on the spindle.

                The machine could be made easier to build by eliminating the 2 hump design for the headstock. The Yeomans design uses the inner space for a big gear. I thought we could continue this in order to get the 4 stock size spindle bushings as was shown in his patent. If you want a more simple 1 hump design, you could start with a long outer cartridge pipe that is bored to stock size and as deeply as possible. When the stock bushing would wear it could be be replaced with a longer, self made bushing.

                Pat


                From: shondabarda <jershond@...>
                To: multimachine@yahoogroups.com
                Sent: Friday, September 2, 2011 4:04 PM
                Subject: [multimachine] Re: concrete curing time

                 
                What about for shrinkage and warping? Can I cast a hole in the concrete and then 24 hours later grout a pipe in place without the concrete shrinking more (tolerance of thousandths, everything, two pipes and spindle, needs to be axially aligned)?

                Thanks

                --- In multimachine@yahoogroups.com, BRIAN GLACKIN <glackin.brian@...> wrote:
                >
                > 24 hrs strength ~1000 PSI (can remove forms)
                > 7 Days ~ 85% full strength
                > 28 days ~98 full strength as noted previously
                >
                > During the curing stage and after removing forms, keep it moist by draping
                > it with wet muslim or burlap then covering with plastic.
                >
                > You could use other cements (not a 3rd world options though) that are
                > alumina silicate based and cures are 24 hrs for ~90% of full strength.
                >
                >
                >
                >
                > On Fri, Sep 2, 2011 at 1:42 PM, Nick Andrews <nickjandrews@...> wrote:
                >
                > > **
                > >
                > >
                > > You mean like drilling into the concrete to embed? Embeds are normally
                > > attached to forms to hold them in place in wet concrete. It depends on
                > > mixture, strength, any additives, etc, but after 12 hours or so it will
                > > generally be for all normal intents hard. There is a calcium additive you
                > > can use to accelerate hardening. Technically, concrete never stops curing;
                > > it hardens more and more until the end of time. But practically, it has
                > > over 98% of ultimate strength by 28 days.
                > >
                > >
                > > On Fri, Sep 2, 2011 at 11:30 AM, shondabarda <jershond@...> wrote:
                > >
                > >> **
                > >>
                > >>
                > >> Is there a general estimate for the time the concrete has to cure before
                > >> parts can be embedded with accuracy? I've heard 4 weeks, but the Yoeman's
                > >> design only took 28 days to get a working model, so it has to be less. (I do
                > >> have a book on concrete counter top laying, its just two states away right
                > >> now)
                > >>
                > >> Shonda
                > >>
                > >>
                > >
                > >
                > > --
                > > Nick A
                > >
                > > "You know what I wish? I wish that all the scum of the world had but a
                > > single throat, and I had my hands about it..." Rorschach, 1975
                > >
                > > "They that can give up essential liberty to obtain a little temporary
                > > safety deserve neither liberty nor safety."- Benjamin Franklin, Historical
                > > Review of Pennsylvania, 1759
                > >
                > > "Suburbia is where the developer bulldozes out the trees, then names the
                > > streets after them." Bill Vaughan
                > >
                > > "The price of apathy towards public affairs is to be ruled by evil men."
                > > Plato
                > >
                > >
                > >
                >




              • Pat Delany
                Thanks Brian Good stuff to know. Pat ________________________________ From: BRIAN GLACKIN To: multimachine@yahoogroups.com Sent:
                Message 7 of 8 , Sep 3, 2011
                • 0 Attachment
                  Thanks Brian
                  Good stuff to know.

                  Pat


                  From: BRIAN GLACKIN <glackin.brian@...>
                  To: multimachine@yahoogroups.com
                  Sent: Saturday, September 3, 2011 9:51 PM
                  Subject: Re: [multimachine] Re: concrete curing time

                   
                  I would recommending waiting to get the 7 day cure.  Especially early on you should keep the concrete covered and moist.  Not the best time to be putting metal into the form.
                  As to shrinkage, it should be minimal assuming you follow the directions for the mix you plan on.  I would personally go for a slightly drier mix and pack the mold as if I was packing a mold for a foundary.  Thats basically how the make highways and dams with roller compacted concrete - drier mix and pack the heck out of it.

                  On Sat, Sep 3, 2011 at 2:21 PM, Pat Delany <rigmatch@...> wrote:
                   
                  Thanks guys for this thread.

                  How much shrinkage in a 5" x 8" x 6" cube?
                  If it is excessive (remember that the shoes are firmly clamped first) then the shoes can be attached the same way the ways and spindle are mounted (grouted after the concrete sets up).

                  About bevel gears driving the carriage, this could easily be more difficult to make than the entire rest of the lathe. My main interest is making the machine cheaper and easier to build and align.

                  My latest idea is to do away with the thrust adjusters and just use a steel washer between the chuck backplate and the front bushing shoulder. End play would be taken up with a simple clamping collar on the spindle.

                  The machine could be made easier to build by eliminating the 2 hump design for the headstock. The Yeomans design uses the inner space for a big gear. I thought we could continue this in order to get the 4 stock size spindle bushings as was shown in his patent. If you want a more simple 1 hump design, you could start with a long outer cartridge pipe that is bored to stock size and as deeply as possible. When the stock bushing would wear it could be be replaced with a longer, self made bushing.

                  Pat


                  From: shondabarda <jershond@...>
                  To: multimachine@yahoogroups.com
                  Sent: Friday, September 2, 2011 4:04 PM
                  Subject: [multimachine] Re: concrete curing time

                   
                  What about for shrinkage and warping? Can I cast a hole in the concrete and then 24 hours later grout a pipe in place without the concrete shrinking more (tolerance of thousandths, everything, two pipes and spindle, needs to be axially aligned)?

                  Thanks

                  --- In multimachine@yahoogroups.com, BRIAN GLACKIN <glackin.brian@...> wrote:
                  >
                  > 24 hrs strength ~1000 PSI (can remove forms)
                  > 7 Days ~ 85% full strength
                  > 28 days ~98 full strength as noted previously
                  >
                  > During the curing stage and after removing forms, keep it moist by draping
                  > it with wet muslim or burlap then covering with plastic.
                  >
                  > You could use other cements (not a 3rd world options though) that are
                  > alumina silicate based and cures are 24 hrs for ~90% of full strength.
                  >
                  >
                  >
                  >
                  > On Fri, Sep 2, 2011 at 1:42 PM, Nick Andrews <nickjandrews@...> wrote:
                  >
                  > > **
                  > >
                  > >
                  > > You mean like drilling into the concrete to embed? Embeds are normally
                  > > attached to forms to hold them in place in wet concrete. It depends on
                  > > mixture, strength, any additives, etc, but after 12 hours or so it will
                  > > generally be for all normal intents hard. There is a calcium additive you
                  > > can use to accelerate hardening. Technically, concrete never stops curing;
                  > > it hardens more and more until the end of time. But practically, it has
                  > > over 98% of ultimate strength by 28 days.
                  > >
                  > >
                  > > On Fri, Sep 2, 2011 at 11:30 AM, shondabarda <jershond@...> wrote:
                  > >
                  > >> **
                  > >>
                  > >>
                  > >> Is there a general estimate for the time the concrete has to cure before
                  > >> parts can be embedded with accuracy? I've heard 4 weeks, but the Yoeman's
                  > >> design only took 28 days to get a working model, so it has to be less. (I do
                  > >> have a book on concrete counter top laying, its just two states away right
                  > >> now)
                  > >>
                  > >> Shonda
                  > >>
                  > >>
                  > >
                  > >
                  > > --
                  > > Nick A
                  > >
                  > > "You know what I wish? I wish that all the scum of the world had but a
                  > > single throat, and I had my hands about it..." Rorschach, 1975
                  > >
                  > > "They that can give up essential liberty to obtain a little temporary
                  > > safety deserve neither liberty nor safety."- Benjamin Franklin, Historical
                  > > Review of Pennsylvania, 1759
                  > >
                  > > "Suburbia is where the developer bulldozes out the trees, then names the
                  > > streets after them." Bill Vaughan
                  > >
                  > > "The price of apathy towards public affairs is to be ruled by evil men."
                  > > Plato
                  > >
                  > >
                  > >
                  >






                • Jack Coats
                  To get it to cure the best, I agree about packing it, and keep it moist. Once you remove the mold, it won t hurt if you put it in a tub of water and keep it
                  Message 8 of 8 , Sep 4, 2011
                  • 0 Attachment
                    To get it to cure the best, I agree about packing it, and keep it moist.  Once you remove the mold, it won't hurt if you put it in a tub of water and keep it there till the 7 days or however long you can keep away from moving on with your project.  The longer the better.

                    This makes sure there is enough water to hydrate all the cement it can get to.  Dry cement mix is the best, but once you get it so it will keep it's shape, it is OK to keep it submerged.  When you do pull it out of the water, you might want to dry the surface of the concrete well before you start installing the metal.

                    I went to a large local concrete plant, they even have an engineer on staff and the equipment, all certified to crush cylinders.  Anyway, when they receive the cylinders, they strip off the plastic form, use a magic marker to mark the sample number/information on it, and place it in a tank of water totally submerged.  They keep it that way till right before they are going to crush it.  They said it made sure as much of the cement in the concrete got hydrated to increase it's crush strength.  Evidently it is a normal and suggested part of the process to test concrete.  Anyway, that is why I suggest keeping your lathe concrete parts well hydrated till you are getting ready to assemble.

                    BTW, they normally do breaks as early as 24 or 48 hours, but most are 7 day or 28 day breaks.  The concrete keeps getting stronger as it grows older. ... a friend in the concrete business said his company recently removed a bridge that was 78 years old.  The cement in that concrete was only about 90% hydrated after being in use for that long.  I was pretty amazed.

                    Anyway, concrete keeps hydrating and getting stronger throughout its useful life.  I guess that was the point the war stories were trying to make.

                    Take care
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