What can i use to dissolve an epoxy bond? I have a broken former I want to replace - can i soak the epoxy with something (acetone?) to remove it and drop in a new former and then re-glue it again with epoxy?

Mrcosmo,
As far as I know, cured epoxy is immune to chemical attack.
A heat gun might soften it enough to be wiggled out, then scraped clean?
Cheers,
PeteM

What Pete says

I've not tried it but it has been said that a polyester resin finish over an epoxy joint will disolve/soften the epoxy. I have used polyester resin to soak expensive art brushes that have dried hard with acrylic artists paints(children/grandchildren!!) and brought them back to usefulness.

I use un-catylized resin, straight from th can poured over the dried Acyrilic, and it works near instantly. I then clean the brush in acetone or laquer thinner, as per normal.

I would experiment before trying it on/in your model! However, I would think the thick resin would be easy to place/control, as needed, with a pointed artist's brush. Again clean with acetone or thinner.

If you try this, PLEASE let us know if it works.

If you have a soldering gun, clamp or bolt an Xacto blade to the tip. The hot blade will cut through the cured epoxy (with a lot of smoke and stink).

Like Rodney says - here's my soldering iron "hot knife". It's an Exacto blade silver soldered to a brass screw that threads into the soldering iron. It has many many uses.
http://www.rcgroups.com/forums/showp...6&postcount=21

Thanks for the idea, I have a purpose made hot knife, I will try that next - but first a quick update of a test done over the last two nights.
I glued some scrap 1/8 ply with 5min epoxy and left it overnight. One joint i added some CA 'un-cure' and it instantly made the joint go 'crystally' and the upright piece fell over by itself. The second joint I brushed on some polyester resin as suggested and it took much longer but it softened the joint to the point where I gave it a gently 'poke' and the upright piece fell over. However it's just a gooey mess now.
I guess a solvent isn't a good idea because it would also penetrate the ply and weaken the glued layers of ply?
I will set up another test and try my hot knife.

mrcosmo,

Some things in life ARE messy! But so glad you shared your findings! Thanks.

I recently had to remove some formers that I glued into place outside of proper sequence. One was CA'd and the other was set with aliphatic. I found best way to remove CA'd joint was to simply run a thin Knife blade in the joint. The other took repeated applications of water with a pointed brush and some gentle prying. Both came away pretty clean and were re-installed at the proper time in the build.

Originally Posted by mrcosmo

Thanks for the idea, I have a purpose made hot knife, I will try that next - but first a quick update of a test done over the last two nights.
I glued some scrap 1/8 ply with 5min epoxy and left it overnight. One joint i added some CA 'un-cure' and it instantly made the joint go 'crystally' and the upright piece fell over by itself. The second joint I brushed on some polyester resin as suggested and it took much longer but it softened the joint to the point where I gave it a gently 'poke' and the upright piece fell over. However it's just a gooey mess now..

Very interesting and surprising results you got.

I'm wondering about that 5 min epoxy. Is it really curing?
If you repeat the test and then physically break the joint, how much pressure did it take? Did the wood break or did the glue joint fail?

Fully cured epoxy is pretty solvent resistant. Here's some info on the subject.
It may just be that the 5min stuff is pretty poor epoxy strength wise.
http://www.epotek.com/SSCDocs/techti...ed%20Epoxy.pdf

Originally Posted by mrcosmo

Thanks for the idea, I have a purpose made hot knife, I will try that next - but first a quick update of a test done over the last two nights.
I glued some scrap 1/8 ply with 5min epoxy and left it overnight. One joint i added some CA 'un-cure' and it instantly made the joint go 'crystally' and the upright piece fell over by itself. The second joint I brushed on some polyester resin as suggested and it took much longer but it softened the joint to the point where I gave it a gently 'poke' and the upright piece fell over. However it's just a gooey mess now..

Very interesting and surprising results you got.

I'm wondering about that 5 min epoxy. Is it really curing?
If you repeat the test and then physically break the joint, how much pressure did it take? Did the wood break or did the glue joint fail?

Fully cured epoxy is pretty solvent resistant. Here's some info on the subject.
It may just be that the 5min stuff is pretty poor epoxy strength wise.
http://www.epotek.com/SSCDocs/techti...ed%20Epoxy.pdf

The mess left by the polyester resin will make the area pretty much impossible to glue. So while the test was a success the results left behind make it unworkable.

Still, that is a trick well worth remembering. I'd never heard of this use for the polyester resin. Nor using it to clean dried brushes.