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  • Bakelite Repair

    I am thinking about repairing a missing edge of a Bakelite cover: it has been cracked off. I have two questions, so far, anyway.

    First if I use common silicone caulk to make a form using the opposite edge, what would be an effective release agent so the silicone caulk will peal off the Bakelite easily? Just plain grease? Silicone grease? Or what?

    And second is there a black epoxy that would adhere to the Bakelite properly? My first thought is J-B Weld but do they make a black? Or could I add a color to it?
    Paul A.
    SE Texas

    Make it fit.
    You can't win and there IS a penalty for trying!

  • #2
    Paul,
    Here is a search link to the Antique Radio Forum (antiqueradios.com) where there is a lot of discussion about Bakelite Repair.
    https://www.google.com/search?q=bake...iqueradios.com
    Be_Zero_Be
    ------------------------------------------------------------
    You Never Used To Be Older

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    • #3
      That article was a bit of help. I still would like to know what can be used as a release agent. The opposite corner is the same shape and can be used to form a mold.
      Paul A.
      SE Texas

      Make it fit.
      You can't win and there IS a penalty for trying!

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      • #4
        I have used carnuba wax as a release agent for epoxy vacuum bagging. Might be worth looking at.
        Sole proprietor of Acme Buggy Whips Ltd.
        Specialty products for beating dead horses.

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        • #5
          Mig welder spray has worked for me. There is also cooking anti stick spray that also works.
          Helder Ferreira
          Setubal, Portugal

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          • #6
            Could you make a cast of the good corner using candle wax? Once set, put it in the fridge / freezer, it should turn the wax hard and it should just come off the bakelite. A wipe with silicone grease before casting will certainly help though.

            Colourig the epoxy - any colour you like: https://www.amazon.com/dp/B088D3CGKB...NsaWNrPXRydWU=

            Ian
            All of the gear, no idea...

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            • #7
              Originally posted by Ian B View Post
              Could you make a cast of the good corner using candle wax? Once set, put it in the fridge / freezer, it should turn the wax hard and it should just come off the bakelite. A wipe with silicone grease before casting will certainly help though.

              Colourig the epoxy - any colour you like: https://www.amazon.com/dp/B088D3CGKB...NsaWNrPXRydWU=

              Ian
              I've done this before only I used body filler. A light coat of wax or any oil film will ensure a smooth release, it might take a little effort to get it to pop loose.
              Body filler sets up quickly and is easy to work with and it's thick and pasty and doesn't usually run.

              I think silicone will be too soft to hold any shape or form.

              If needed you can always make a reverse of that mold.

              JL..................

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              • #8
                As for a release agent, ...depending on the shape(s) involved, simply covering with a layer of plastic wrap (e.g. Saran wrap) could work.
                Another possibility: I just recently learned of glass masking coatings to facilitate window painting. Paint it on the glass, from which it peels right off, taking any stray paint that would otherwise be stuck to the glass. This too could serve as a release agent, but maybe a little pricey unless you already have some on hand.
                Lynn (Huntsville, AL)

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                • #9
                  Silicone mold rubber should not stick to the Bakelite, so no release is necessary unless the good portion of the Bakelite cover
                  is very porous ( unlikely ) then you might get a mechanical lock.
                  Silicone caulks would require some mold release, since they're designed to adhere, wax or petroleum jelly ( Vaseline ) works well.
                  Note there will be some shrinkage with caulks.

                  Bakelite is phenolic resin, so epoxy might work if it's ornamental, if it's a cooking utensil lid I wouldn't use epoxy of any kind.

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                  • #10
                    Bone Black works really well to make epoxy black. You'll probably still have to paint it to get an even color.

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                    • #11
                      I have used the two part silicone mold compounds before but I was hoping to do this on the cheap and dirty and I already have some of the silicone caulk so I thought I would try that. It dries to much the same consistency as the actual silicone mold compound so it should be OK on that count.

                      This is a repair on the battery cover of one of the Simpson 260s that I recently obtained. The corner has it's edge chipped off. There is a lip a short distance in from the edge which can be used to hold the mold in place and, along with the rubber nature of the silicone, help with any shrinkage.

                      As for those suggesting coloring agents, I already have that covered the Henry Ford way: any color you want as long as it is black. I found that J-B Weld has a black epoxy that if intended for plastics. It seems to be the only J-B Weld product that dries black. I picked up two packages of it this afternoon and will be mixing up a trial batch in a few minutes. I have high hopes that it will be a good match for the black Bakelite. And I will also see how it binds to the Bakelite inside the cover.

                      I can also test some release agents on the inside of the cover where a mistake will not show.



                      Originally posted by jcfx View Post
                      Silicone mold rubber should not stick to the Bakelite, so no release is necessary unless the good portion of the Bakelite cover
                      is very porous ( unlikely ) then you might get a mechanical lock.
                      Silicone caulks would require some mold release, since they're designed to adhere, wax or petroleum jelly ( Vaseline ) works well.
                      Note there will be some shrinkage with caulks.

                      Bakelite is phenolic resin, so epoxy might work if it's ornamental, if it's a cooking utensil lid I wouldn't use epoxy of any kind.
                      Paul A.
                      SE Texas

                      Make it fit.
                      You can't win and there IS a penalty for trying!

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                      • #12
                        In my experience silicone caulk WILL stick to bakelite. It is not a good permanent bond, but it is a "just good enough" bond that you may damage the silicone as you remove it. A release agent would be a good idea.

                        The other problem with the caulk type silicone is that it does NOT stick to the release agent, and it is pretty thick stuff. That makes it difficult to get a good mold, it does not want to stick to the "model", but it sticks fine to the tool you are using to get it pressed into the details of the "model". You can see the difficulty that creates.
                        1601

                        Keep eye on ball.
                        Hashim Khan

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                        • #13
                          J, I do see your point. The details are not that complex, just flats and smooth curves. If an air bubble in the silicone would allow a bit too much epoxy when I use the mold, then a bit of filing or sanding would take care of it. I am not going to spend too much time or money on this, it just isn't worth it.

                          I am testing things now. It takes a while for the silicone caulk to set. If the tests come out OK, I am going to smear on the best of the release agents that I tested and go for it. We shall see how it comes out. I will take and post some pictures.

                          Thanks to all for the suggestions.



                          Originally posted by J Tiers View Post
                          In my experience silicone caulk WILL stick to bakelite. It is not a good permanent bond, but it is a "just good enough" bond that you may damage the silicone as you remove it. A release agent would be a good idea.

                          The other problem with the caulk type silicone is that it does NOT stick to the release agent, and it is pretty thick stuff. That makes it difficult to get a good mold, it does not want to stick to the "model", but it sticks fine to the tool you are using to get it pressed into the details of the "model". You can see the difficulty that creates.
                          Paul A.
                          SE Texas

                          Make it fit.
                          You can't win and there IS a penalty for trying!

                          Comment


                          • #14
                            I like JoeLee and Lynnls ideas combined.

                            The bondo is nice depending on which type you get it can become firm for a 2-4 minutes before it sets up giving you time to really push it into the details. When it harden you will have a really hard mold to work with. And the saran wrap for a release.

                            No mess, no fuss. JR
                            My old yahoo group. Bridgeport Mill Group

                            https://groups.yahoo.com/neo/groups/...port_mill/info

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                            • #15
                              Keep the silicone caulk damp, it'll cure faster.
                              Southwest Utah

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