casting epoxy

[Vince Williams]

what is the best casting epoxy for turning??

[richard shelby]

I use generic "Bar Top" for everything. It's cheap by the gallon, 1:1 mix and cures overnite at 70F.

[Peter Blair]

Richard, how thick can I make a pour. I'm trying to make a pinecone sphere and have had problems with resin cracking?

[richard shelby]

Richard, how thick can I make a pour. I'm trying to make a pinecone sphere and have had problems with resin cracking?

That's a tough question. I rarely have epoxy in a void space thicker than 1/2". The problem with thicker pours is heat buildup, I think. Polymerization is an exothermic reaction, so if you could keep a thick pour cool, you might evade the issue. I assume you will put the pine cone in something like a paper cup? Perhaps some of our more experienced polymer chemists might share their wisdom.

[Marvin Hasenak]

I would use Alumilite. Find a plastic container to use as a mold. Spray the inside with cooking spray Pam. Allow the Pam to dry before casting. The Pam step is not necessary, you can turn the container off on the lathe. If you will be adding dye, make sure it is compatible with Alumilite. Guessing you do not have a pressure tank, so you might have air bubbles. To keep the bubbles at a minimum do NOT STIR aggressively when mixing. You can also use an upside down vibrating sander to shake the bubbles out. Clamp the sander in a vise and mix the dye in before adding the hardener, vibrate the dye mix, then add the 2 parts and gently mix, vibrate a minute or so and then pour. Again pour gently so as not to add air. The slow set Alumilite would be my choice, cost more but available at Hobby Lobby and on Amazon so it is too convenient.

The red plastic cups will melt when used as a mold for some resins. I found a bunch of Tupperware glasses that I used as molds. I spray with Pam let them dry about an hour and then pour, the castings pop out. Goodwill and Salvation Army resale store are a good place to look for used Tupperware.

[Peter Blair]

Thanks Richard and Marvin. Alumilite sounds like the ticket. Does anyone know if that is what is used when I see burls and clear plastic turned for boxes etc? I'm hoping the Plastics shop sells it!

[Marvin Hasenak]

Spend an afteroon reading the casting threads on the International Asociation of Penturners forum. In my opinion, the penturners are the ones that have "perfected" the casting of turning blanks. Take notes, there is more info there than one can absorb by reading, you will later want to know what and where your source of info came from.

[Peter Blair]

Thanks Marvin!