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Re: Preventing damage when Transporting Mirrors

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  • dulhas2001
    HI I use a simple thermocol box A thick sheet square of thermocol somewhat larger than the mirror is the base upon which a second sheet in which a circular
    Message 1 of 26 , Oct 1, 2010
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      HI
      I use a simple thermocol box
      A thick sheet square of thermocol somewhat larger than the mirror is the base upon which a second sheet in which a circular hole of diameter just a bit larger than the mirror has been cut. After placing the mirror face up in the hole the mirror is covered with soft cloth and the package topped off with another thermocol sheet. The whole package is sealed with tape and finally wrapped with cloth and stitched .
      Voila a sturdy package which can take quite a bit of rough handling and is is lightweight
      Cheers
      Ulhas
      --- In atm_free@yahoogroups.com, "art.bianconi" <artbianconi@...> wrote:
      >
      >
      > Hi Dave.
      >
      > It occured to me after I posted the question that my mirrors are glued
      > to the cell with daubs of acquarium silicone. That means I must
      > incorporate the complete cell or some portion of the cell (mirror and
      > backplate) in whatever transport enclosure I make.
      >
      > Gene's idea would still work, with some mods. Yours would too if the
      > mirror backplate is part of the conversation.
      >
      > None of my telescopes are Dobsonians (not yet) so the complexities of a
      > large mirror box are not something I must deal with.
      >
      > This subject took on an element of urgency when I realized I must soon
      > take three mirrors to Jeff Decker at Majestic-Coatings. I'll use a wood
      > box built up with half inch plywood sides and quarter in tempered
      > masonite for the bottom and hinged top.
      >
      > Home Depot and Loews sell tall sheets of closed cell pink insulation in
      > variour thickness up to two inches. I'll size the wood box so it will
      > have a floor of solid foam on the inside bottom followed by a center
      > sheet with a hole for the mirror and a third plain sheet for the top.I'm
      > not certain that's how I'll protect each in the future but it will
      > suffice for the trip to the coaters in my Van.
      >
      > Thanks all for helping me think through this.
      >
      > Art
      >
      >
      > --- In atm_free@yahoogroups.com, "brock.family" <brock.family@>
      > wrote:
      > >
      > > Hi Art,
      > > as far as transporting a mirror goes I use a close fitting plywood box
      > with wedges glued to the bottom
      > > in the corners positioned so that when the mirror is placed in, face
      > down, the mirror rests on the wedges.
      > > The wedges have their thin end pointing to the box centre and the
      > mirror rests on their mid point. The lid is then
      > > screwed on. The box is sized so that the mirror can move only a tiny
      > amount in any direction (1/2mm). This
      > > way it's impossible for anything to touch the mirror face.
      > >
      > > > > I have this idea that if the mirror is for a Newt, one could make
      > a soft
      > > > > pad, using a low durometer rubber and size it so its smaller in
      > diameter
      > > > > than the secondary. If the pad is taller than the saggita is deep,
      > the
      > > > > compression by installing the lid will compress the pad and keep
      > the
      > > > > mirror from moving.
      > >
      > > I would advise against this as it would likely mar the coating and
      > even if it's in the secondary shadow it
      > > could possibly allow for an early coating breakdown.
      > >
      > > Now as for your original question, I just transport my 20" in a van
      > sitting on carpet and drive carefully. I don't
      > > know that you can guard against a major accident. For example I don't
      > think it'll matter much how careful you
      > > pack the scope if you find yourself stuck on a railroad crossing.
      > >
      > > Dave
      > >
      >
    • Vladimir Galogaza
      Hi Ulhas, ... Thermocol is probably a trade name of something. It may be known differently at other places or even unavailable. Instead of using only such
      Message 2 of 26 , Oct 1, 2010
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        Hi Ulhas,
         
        >A thick sheet square of thermocol .......
         
        Thermocol is probably a trade name of something.
        It may be known differently at other places or even unavailable.
        Instead of using only such names it will be better to describe in addition
        what it actualy is .
         
        Regards
        Vladimir.
      • waldo kitty
        ... agreed... to a point... a quick google shows that thermocol is simply polystyrene... http://encyclopedia2.thefreedictionary.com/Thermocol
        Message 3 of 26 , Oct 1, 2010
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          On 10/1/2010 05:49, Vladimir Galogaza wrote:
          >
          >
          > Hi Ulhas,
          > >A thick sheet square of thermocol .......
          > Thermocol is probably a trade name of something.
          > It may be known differently at other places or even unavailable.
          > Instead of using only such names it will be better to describe in addition
          > what it actualy is .

          agreed... to a point...

          a quick google shows that thermocol is simply polystyrene...

          http://encyclopedia2.thefreedictionary.com/Thermocol
        • Vladimir Galogaza
          Waldo, ... You were googling? So it seems that you also id not know what it is. instead of letting many to google to find out what this is, it would be kind
          Message 4 of 26 , Oct 1, 2010
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            Waldo,
            >a quick google shows that thermocol is simply polystyrene...
             
            You were googling? So it seems that you also id not know what it is.

            instead of letting many to google to find out what this is,  
            it would be kind from authors to use  generic names like expanded polystyrene or styrofoam  or solid foam. That was the point.
             
            Regards
            Vladimir.
          • waldo kitty
            ... it didn t matter if i knew what it was or not... my goal was to answer your question and provide at least one link to that answer... i simply typed
            Message 5 of 26 , Oct 1, 2010
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              On 10/1/2010 13:16, Vladimir Galogaza wrote:
              >
              > Waldo,
              > >a quick google shows that thermocol is simply polystyrene...
              > You were googling? So it seems that you also id not know what it is.

              it didn't matter if i knew what it was or not... my goal was to answer your
              question and provide at least one link to that answer... i simply typed
              "thermocol" in to the google search box and hit enter... the first entry was a
              link to a dictionary so i provided the simple and direct answer as well as the
              link in my response...

              > instead of letting many to google to find out what this is,
              > it would be kind from authors to use generic names like expanded polystyrene or
              > styrofoam or solid foam. That was the point.

              i understand that... i also provided you with the answer and a link so you could
              verify it yourself ;) :P
            • Vladimir Galogaza
              Waldo, ... It does matter. I was not interested in what is Thermocol, so much should be obvious, I hoped. I wrote appeal to all to use words understandable to
              Message 6 of 26 , Oct 1, 2010
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                Waldo,
                 
                >it didn't matter if i knew what it was or not.
                 
                It does matter. I was not interested in what is Thermocol, so much should
                be obvious, I hoped. I wrote appeal to all to use words understandable
                to others due to international nature of the list. Thermocol was just example. 
                A commercial name which can be different in different places and
                therefore requiring further correspondence or search.
                Of course I could find it by myself, and thank you for taking care of it,
                but I have obviously failed to be clear in my intention, sorry.
                 
                I hope no hard feelings.
                Regards
                Vladimir.
              • waldo kitty
                ... it didn t matter to me because i was only interested in answering what i saw as a round about question (asking a question without really asking one) if i
                Message 7 of 26 , Oct 1, 2010
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                  On 10/1/2010 13:57, Vladimir Galogaza wrote:
                  > 
                  >
                  > Waldo,
                  > >it didn't matter if i knew what it was or not.
                  > It does matter.

                  it didn't matter to me because i was only interested in answering what i saw as
                  a "round about" question (asking a question without really asking one) if i
                  could... in that process i might also learn something that i didn't already know
                  or may have forgotten... so it was a help you and help me type of thing ;)

                  > I was not interested in what is Thermocol, so much should
                  > be obvious, I hoped.

                  i took it as a serious question but that's ok... it is not like it is a big deal
                  or anything :D

                  > I wrote appeal to all to use words understandable
                  > to others due to international nature of the list. Thermocol was just example.
                  > A commercial name which can be different in different places and
                  > therefore requiring further correspondence or search.

                  yup, that's understandable and i have no problem with that... you are correct,
                  too ;)

                  > Of course I could find it by myself, and thank you for taking care of it,

                  you'd be surprised at the numbers of people who can't find things for
                  themselves... i do tech support, live and online, and i'm simply amazed that
                  someone can be lead right to an answer (ie: book->page->paragraph-sentence) and
                  still not see it...

                  > but I have obviously failed to be clear in my intention, sorry.
                  > I hope no hard feelings.

                  no hard/hurt feelings over here... i guess i still had my support hat on :) :lol:
                • art.bianconi
                  Vladimir, it s quite easy to simply Google Thermocol and get the answer if you you really want to. As I suspected, it s a low density, closed cellular foam,
                  Message 8 of 26 , Oct 1, 2010
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                    Vladimir, it's quite easy to simply Google "Thermocol" and get the answer if you you really want to.

                    As I suspected, it's a low density, closed cellular foam, that is popular for packaging where shock protection is needed.

                    See? Easy!

                     

                    - In atm_free@yahoogroups.com, "Vladimir Galogaza" <vladimir.galogaza1@...> wrote:

                    >
                    > Hi Ulhas,
                    >
                    > >A thick sheet square of thermocol .......
                    >
                    > Thermocol is probably a trade name of something.
                    > It may be known differently at other places or even unavailable.
                    > Instead of using only such names it will be better to describe in addition
                    > what it actualy is .
                    >
                    > Regards
                    > Vladimir.
                    >

                  • art.bianconi
                    Since the mirror is already restrained in the cell somewhat, that suggests that a simple pillbox cover will suffice. If your mirror is an 8 diameter or
                    Message 9 of 26 , Oct 4, 2010
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                      Since the mirror is already restrained in the cell somewhat, that
                      suggests that a simple "pillbox" cover will suffice. If your mirror is
                      an 8" diameter or smaller you can easily pickup a galvanized tin stove
                      pipe cap from a home center or plumbing supply. Pop rivet some flanges
                      to it and your done. That will protect the mirror from flying objects
                      but won't be of much help by itself if the mirror breaks free in
                      tranport.

                      The mirror is held to the cell's back-plate with only a few daubs of
                      silicone. That appears to be SOP for most everyone, unless you are a fan
                      of Adler and Flexing. In that case your mirror is firmly captured and is
                      not likely to come free.

                      I'm not comfortable traveling with a mirror that could come free so I've
                      come up with a clear Lexan cover for mine that has a rubber ring around
                      the inside corner. I chose the Lexan primarily to satisfy the security
                      staff at airports who get suspicious of anything that they can't see.

                      Art
                    • art.bianconi
                      Francis (aka Gene?) wrote: Yes, Art. I have to say I like Dave s suggestion better. It is simpler. Your modesty nothwithstanding, by the time I used the
                      Message 10 of 26 , Oct 4, 2010
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                        Francis (aka Gene?) wrote: "Yes, Art. I have to say I like Dave's suggestion better. It is simpler."

                        Your modesty nothwithstanding, by the time I used the existing cell geometry to drive a cover design, the end result was virtually identical to what you suggested at the onset! I didn't intend to do that. It just naturally evolved.

                        It was simple really.

                        I merely copied the geometry of the mirror backplate to another file name; changed the properties to clear Lexan and deleted the cooling holes from the original donor file.

                        I placed a ring of rubber 0.060"thick and 0.500" wide to the Lexan cover to protect the edge of the mirror. I placed it on top of the primary mirror and then screwed it in place with 8x32 Wing Nuts.

                        Done!

                        I chose Lexan for it's strength and transparancy so that Security staff at airports could see underneath that there is just a chunk of glass there.

                        Thanks!~

                        Art

                        I've posted some renderings in the 6" open truss album in Photos

                         



                        --- In atm_free@yahoogroups.com, Francis Smith <smithhill1@...> wrote:
                        >
                        > Yes, Art. I have to say I like Dave's suggestion better. It is simpler.
                        > Do not worry about the name. I guess I am the victim of overly helpful
                        > software when i registered. I am Francis Eugene, but go by Gene. You are
                        > right, the firm rings over the pegs could cause a flake damage on the
                        > mirror. Perhaps those useless plastic hose washers, Yes the plastic yellow
                        > or black ones, would be better. Concering the splitting of the pegs, the
                        > top portion would be contained in 3/8 inch hole to limit effect. OK for
                        > now. Gene
                        >
                        >
                        >
                        >
                        > On Thu, Sep 30, 2010 at 8:26 PM, art.bianconi artbianconi@... wrote:
                        >
                        > >
                        > >
                        > >
                        > > Hi Dave.
                        > >
                        > > It occured to me after I posted the question that my mirrors are glued
                        > > to the cell with daubs of acquarium silicone. That means I must
                        > > incorporate the complete cell or some portion of the cell (mirror and
                        > > backplate) in whatever transport enclosure I make.
                        > >
                        > > Gene's idea would still work, with some mods. Yours would too if the
                        > > mirror backplate is part of the conversation.
                        > >
                        > > None of my telescopes are Dobsonians (not yet) so the complexities of a
                        > > large mirror box are not something I must deal with.
                        > >
                        > > This subject took on an element of urgency when I realized I must soon
                        > > take three mirrors to Jeff Decker at Majestic-Coatings. I'll use a wood
                        > > box built up with half inch plywood sides and quarter in tempered
                        > > masonite for the bottom and hinged top.
                        > >
                        > > Home Depot and Loews sell tall sheets of closed cell pink insulation in
                        > > variour thickness up to two inches. I'll size the wood box so it will
                        > > have a floor of solid foam on the inside bottom followed by a center
                        > > sheet with a hole for the mirror and a third plain sheet for the top.I'm
                        > > not certain that's how I'll protect each in the future but it will
                        > > suffice for the trip to the coaters in my Van.
                        > >
                        > > Thanks all for helping me think through this.
                        > >
                        > > Art
                        > >
                        > > --- In atm_free@yahoogroups.com <atm_free%40yahoogroups.com>,
                        > > "brock.family" brock.family@
                        > > wrote:
                        > >
                        > > >
                        > > > Hi Art,
                        > > > as far as transporting a mirror goes I use a close fitting plywood box
                        > > with wedges glued to the bottom
                        > > > in the corners positioned so that when the mirror is placed in, face
                        > > down, the mirror rests on the wedges.
                        > > > The wedges have their thin end pointing to the box centre and the
                        > > mirror rests on their mid point. The lid is then
                        > > > screwed on. The box is sized so that the mirror can move only a tiny
                        > > amount in any direction (1/2mm). This
                        > > > way it's impossible for anything to touch the mirror face.
                        > > >
                        > > > > > I have this idea that if the mirror is for a Newt, one could make
                        > > a soft
                        > > > > > pad, using a low durometer rubber and size it so its smaller in
                        > > diameter
                        > > > > > than the secondary. If the pad is taller than the saggita is deep,
                        > > the
                        > > > > > compression by installing the lid will compress the pad and keep
                        > > the
                        > > > > > mirror from moving.
                        > > >
                        > > > I would advise against this as it would likely mar the coating and
                        > > even if it's in the secondary shadow it
                        > > > could possibly allow for an early coating breakdown.
                        > > >
                        > > > Now as for your original question, I just transport my 20" in a van
                        > > sitting on carpet and drive carefully. I don't
                        > > > know that you can guard against a major accident. For example I don't
                        > > think it'll matter much how careful you
                        > > > pack the scope if you find yourself stuck on a railroad crossing.
                        > > >
                        > > > Dave
                        > > >
                        > >
                        > >
                        > >
                        >

                      • dulhas2001
                        Hi Vladimir Sorry Thamocol is the commercial name used in India for Expanded Polystyrene packing material. It is light and absorbs shocks nicely. It is
                        Message 11 of 26 , Oct 4, 2010
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                          Hi Vladimir
                          Sorry
                          Thamocol is the commercial name used in India for Expanded Polystyrene packing material.
                          It is light and absorbs shocks nicely. It is available in sheets of various thickness and easily cut by a sharp knife.
                          Hope this helps
                          Ulhas
                          --- In atm_free@yahoogroups.com, "Vladimir Galogaza" <vladimir.galogaza1@...> wrote:
                          >
                          > Hi Ulhas,
                          >
                          > >A thick sheet square of thermocol .......
                          >
                          > Thermocol is probably a trade name of something.
                          > It may be known differently at other places or even unavailable.
                          > Instead of using only such names it will be better to describe in addition
                          > what it actualy is .
                          >
                          > Regards
                          > Vladimir.
                          >
                        • Vladimir Galogaza
                          Hi Ulhas, ... Shock is the force on the mirror because of acceleration it was subjected to. In transport bad case is dropping the box. Expanded polystyrene is
                          Message 12 of 26 , Oct 4, 2010
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                            Hi Ulhas,
                             
                            >Thamocol is the commercial name used in India for Expanded Polystyrene >packing material. It is light and absorbs shocks nicely.
                             
                            Shock is the force on the mirror because of acceleration it was subjected to. In transport bad case is dropping the box. Expanded polystyrene
                            is rigid, not spongy (springy) material, and therefore less shock absorbing.
                            To increase protection from shock it is advisable to use in addition
                            some material which will lessen the acceleration like bubble wrap
                            around the expanded polystyrene. When dropped, the mirror weight will
                            compress the air in bubbles and some energy will be absorbed in the process. Compression will last some time and will result  in lengthening the velocity change time and thus decreasing acceleration and resulting destructive forces on the mirror coming from its own weight.
                            If the Mirror box is at rest but overrun by truck, the bubble wrap protection
                            principle does not apply.  What applies is insurance  (perhaps).
                             
                            Regards
                            Vladimir.
                          • dulhas2001
                            Thanks Vladimir I will keep it in mind next time I transport the mirror. Ulhas
                            Message 13 of 26 , Oct 5, 2010
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                              Thanks Vladimir
                              I will keep it in mind next time I transport the mirror.
                              Ulhas

                              --- In atm_free@yahoogroups.com, "Vladimir Galogaza" <vladimir.galogaza1@...> wrote:
                              >
                              > Hi Ulhas,
                              >
                              > >Thamocol is the commercial name used in India for Expanded Polystyrene >packing material. It is light and absorbs shocks nicely.
                              >
                              > Shock is the force on the mirror because of acceleration it was subjected to. In transport bad case is dropping the box. Expanded polystyrene
                              > is rigid, not spongy (springy) material, and therefore less shock absorbing.
                              > To increase protection from shock it is advisable to use in addition
                              > some material which will lessen the acceleration like bubble wrap
                              > around the expanded polystyrene. When dropped, the mirror weight will
                              > compress the air in bubbles and some energy will be absorbed in the process. Compression will last some time and will result in lengthening the velocity change time and thus decreasing acceleration and resulting destructive forces on the mirror coming from its own weight.
                              > If the Mirror box is at rest but overrun by truck, the bubble wrap protection
                              > principle does not apply. What applies is insurance (perhaps).
                              >
                              > Regards
                              > Vladimir.
                              >
                            • Bill
                              Vladimir- I m curious. Does the packing react with the coating do you think? I once put a rubber band in one of my mother s silver candy dishes... she wasn t
                              Message 14 of 26 , Oct 6, 2010
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                                Vladimir-
                                I'm curious. Does the packing react with the coating do you think? I once put a rubber band in one of my mother's silver candy dishes... she wasn't too pleased two years later when she found it.

                                -Bill

                                --- In atm_free@yahoogroups.com, "Vladimir Galogaza" <vladimir.galogaza1@...> wrote:
                                >
                                > Hi Ulhas,
                                >
                                > >Thamocol is the commercial name used in India for Expanded Polystyrene >packing material. It is light and absorbs shocks nicely.
                                >
                                > Shock is the force on the mirror because of acceleration it was subjected to. In transport bad case is dropping the box. Expanded polystyrene
                                > is rigid, not spongy (springy) material, and therefore less shock absorbing.
                                > To increase protection from shock it is advisable to use in addition
                                > some material which will lessen the acceleration like bubble wrap
                                > around the expanded polystyrene. When dropped, the mirror weight will
                                > compress the air in bubbles and some energy will be absorbed in the process. Compression will last some time and will result in lengthening the velocity change time and thus decreasing acceleration and resulting destructive forces on the mirror coming from its own weight.
                                > If the Mirror box is at rest but overrun by truck, the bubble wrap protection
                                > principle does not apply. What applies is insurance (perhaps).
                                >
                                > Regards
                                > Vladimir.
                                >
                              • Vladimir Galogaza
                                Bill, ... Polystyrene foam or polyethylene foil not. The coating is Al with very thin but hard oxide layer which is chemically quite inert. The contact with
                                Message 15 of 26 , Oct 7, 2010
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                                  Bill,
                                   
                                  >Does the packing react with the coating do you think?
                                   
                                  Polystyrene foam or polyethylene foil not. The coating is Al with
                                  very thin but hard oxide layer which is chemically quite inert.
                                  The  contact with coating must be prevented
                                  for other reasons like  mechanical damage.
                                   
                                  Regards
                                  Vladimir.
                                   
                                • Bill
                                  Ah! of course, I forgot about the coating. One of the last things I will do when I make my telescope is to make a box to transport it. I like woodworking, so
                                  Message 16 of 26 , Oct 8, 2010
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                                    Ah! of course, I forgot about the coating.

                                    One of the last things I will do when I make my telescope is to make a box to transport it. I like woodworking, so it won't be plain ;)

                                    But I was worried about how the coating might be affected by the out-gassing of the finishes I will use on the wood inside the closed environment of the box over long periods. Can I assume this will not be a problem then?

                                    One thing I considered was to build a little "potpourri" container in one of the corners of the box that would contain packets of silica salt like you find in new electronics appliances. While this might seem like over kill, is there any extra advantage to doing that? Any potential harm do you think?



                                    --- In atm_free@yahoogroups.com, "Vladimir Galogaza" <vladimir.galogaza1@...> wrote:
                                    >
                                    > Bill,
                                    >
                                    > >Does the packing react with the coating do you think?
                                    >
                                    > Polystyrene foam or polyethylene foil not. The coating is Al with
                                    > very thin but hard oxide layer which is chemically quite inert.
                                    > The contact with coating must be prevented
                                    > for other reasons like mechanical damage.
                                    >
                                    > Regards
                                    > Vladimir.
                                    >
                                  • Francis Smith
                                    The subject of packaging impact protection deserves some discussion. Google has a lot to say, but it is mostly concerning commercial interests. Here are some
                                    Message 17 of 26 , Oct 8, 2010
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                                      The subject of packaging impact protection deserves some discussion.  Google has a lot to say, but it is mostly concerning commercial interests.  Here are some general comments that occur to me:

                                      Urethane plastic is some what unique in that it absorbs energy and rebounds slowly after deformation.   Of course it is highly temperature sensitive as far as stiffness.

                                      The ideal energy absorber consumes energy as it is deformed and does not store it for a nasty rebound, which can be more destructive.   A thin aluminum honeycomb can be very efficient in that it will collapse at a nearly constant force with no rebound.  The collapsed structure is not there for a second impact, however.   An air pillow or air bubbles compress at an increasing force and the energy is 100% stored for a nasty rebound, but remains intact for later protection. 

                                      Modern styrofoam extruded sheet is quite rigid and perhaps of not much use for impact protection.   If one were to carve away material an leave flat topped pyramids it would be better.  The older foam sheets fabricated from steam heated styrofoam beads is softer, more compressible, not likely to cause excessive rebound.  It is widely used in unique supporting forms molded to fit edges of appliances for shipping.  For commercial applications the supporting foam structure can be fabricated to give a designed compression strength.   

                                       Thick corrugated or honey combed cardboard is also a useful energy absorbing material.   The random nature of foam plastic peanuts is also an efficient packaging.  They need to be prevented from moving out of position, however.  Packing tightly will help, or they could be contained in small perforated plastic bags, perhaps glued in place.    

                                      These packaging ideas have validity, but soon lose their imagined significance when extended.  Some actual testing seems to be worth while.  For an example, a inexpensive electronic impact accelerometer could be fabricated with a small weight and a piezoelectric crystal.                Gene

                                       

                                    • Vladimir Galogaza
                                      Bill, ... No you can not assume it. It depends strongly on used finishes. Their properties should be well known to you. ... Silica gel is there to absorb
                                      Message 18 of 26 , Oct 9, 2010
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                                        Bill,
                                         
                                        >But I was worried about how the coating might be affected by the
                                        out-gassing >of the finishes I will use on the wood inside the closed environment of the box >over long periods. Can I assume this will not be a problem then?
                                         
                                        No you can not assume it. It depends strongly on used finishes. Their
                                        properties should be well known to you.
                                         
                                        >in one of the corners of the box that would contain packets of silica salt
                                        >like you find in new electronics appliances.
                                         
                                        Silica gel is there to absorb moisture. I think that mirrors are not in danger
                                        from the presence of the moisture. But moisture can support growth of
                                        fungi or similar on the wood. Silica will not harm the mirror.
                                         
                                        Regards
                                        Vladimir.

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