Is there a way to separate two-part 30-minute epoxy once it's set? I have a 6x6 aluminum Calumet lens board that had an Ilex #4 hole in it. I set out to use a lens mounted in a Copal #1, so I epoxyed a square aluminum piece with a #1 hole in it, over the #4 hole. Well low-and-behold, I'm getting rid of the #1 lens, and now need to mount a #4 shutter.

Is there some type of super-turbo-solvent-from-Hell, or should I take a butane torch to the thing and see if the epoxy will melt? Or, should I just forget it and buy/make another board, and put this one on the shelf?

-- sheldon hambrick (sheldon_hambrick@hotmail.com), January 04, 2000

Answers

You could try soaking the board in dehydrated ethanol for a day or so. This might work if it can penetrate into the epoxy. Keep away from things like butane torches, though!

-- fw (finneganswake@altavista.net), January 04, 2000.

Once set, there is no practical way of dissolving an epoxy. Neither will the epoxy melt. Once set, the epoxy is a 'thermoset' indicating that it will not revert back to a melt by heating as thermoplastics would. Most though not all epoxies can be softened though. With chemicals this can a take a long soaking time in very aggressive solvents. One of the most aggressive is methylene chloride. This is the solvent used in paint removers. You should be careful though, it may dissolve any coating or plastic component even those that you did not intend to. MC is a very thin fluid and it is unlikely that you can buy it over the counter. A high class paint remover based on MC is probably the most convenient way of applying it. Folllow manufactuers instructions when using MC and paint removers. Avoid non MC paint removers, they may be too slow and inefficient. Also avoid alkaline removers, which will cause skin burns but do little if anything to the epoxy. One other thing, epoxies will char, this is true for all epoxies. At temperatures below those at which the epoxy will char, the kind that you have will soften, though this may not occur to the degree you want and may not make it easy to pull things apart. The lesson here is, use epoxies only for permanent attachment.

-- Julio Fernandez (gluemax@ora.auracom.com), January 05, 2000.

Sheldon, Julio seems to be the expert here and have a lot of information, but I seem to remember that heat will weaken the epoxy bond. I imagine it depends on the exact type of epoxy resins you have used, however, I have heated epoxied parts in the oven at 3750-4750F (approx. 200-2500C) and have been able to get them apart after cooling by modest prying. Try and see, I don't think you can hurt the lens board by heating it. Alternatively, you could have the aluminum piece machined off (more expensive). Good luck, ;^D)

-- Doremus Scudder (ScudderLandreth@compuserve.com), January 05, 2000.

Thanks to all those that replied.

Following some advice I got in a private email, I boiled the lens board in regular water for about 45 minutes, and the two pieces pried right apart with a putty knife!! Thanks

-- sheldon hambrick (sheldon_hambrick@hotmail.com), January 05, 2000.