I'm bonding one piece of plastic to another with west systems epoxy. The epoxy is spread on one piece, the second piece is laid on top, and the two pieces are squeezed together with stainless steel screws. The problem is that epoxy gets into the screw holes and it becomes impossible to back the screws out, which I need to be able to do. The screws are held so tight that I've torqued the head off of them trying to back them out. I'm wondering if there's a way to apply something to the screws that will prevent the epoxy from gripping them. Maybe dipping the screws in vaseline before hand IDK. Suggestions?
Preventing epoxy from gripping steel screws
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I suppose it is not possible to eliminate the screws and use another way to sandwich your laminate?
Wax should do the trick. I use wax paper to keep west system from bonding to my clamps and tables. I use Vaseline to keep polyester resin from sticking to stuff. Maybe even wrap the screws in plumbers tape.....I am just guessing......
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Honey wax or PVA mold release.
Cheers ,Don
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No I can't use a clamp or something else, the surfaces are not even and the secondary purpose of the epoxy is to fill the gaps.
Then I suppose this will work too? MEGUIARS Wax at West Marine
Do globs of this stuff have to stay on the screw or just a micro film?
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I believe that is MO-8, I apply a coat with a sponge, than let is set 10 min and apply a second. You do not need to glob it on, just make sure in covers all surfaces. Threads that are well machined will release better than a pitted or coarse surface. Try a test piece.
Cheers, Don
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MO-8?
Will dipping or screwing the screws into the wax be sufficient? Or should I pack it into the screw holes?
Test the dip method, I work it into the surface, how about heating it to liquid and dip with a needle nose pliers.
Cheers, Don
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If the mold release is still sticky or not working as well as you would like you can try heating the pieces up. The plastic and steel will have a different expansion rate and heating and cooling the pieces will help free them.
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i would also suggest looking for really shitty screws, super crap, made of zinc...then rust or drill them out after the plastic is set
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Teflon plumbing tape on the threads? Maybe it works,
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Dan, I use engine oil for a release agent when bedding rifle actions, I just dip the hold down screws in oil then wipe off the excess. Of course if there are any notches or anything in the screws and the epoxy gets in, you may end up with it locked in. Maybe you could use the smallest screws possible then just drill then out with a larger bit?? (if that suits)
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Epoxy doesn't stick to saran wrap either. But I need a sure thing.
A good friend suggested this cure all. :laughing:
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