Casting in black epoxy?

[gerti]

Hi All,

I have a project in mind where I would cast items into black epoxy and turn the result. There would be quite large gaps (approximately 50% would be epoxy), and I'd like the epoxy to be black.

I have not much experience with epoxy beyond 5 minute epoxy for glueing.

What type of epoxy can you recommend that is not too expensive, and can be cut and polished to a high gloss? How can the epoxy be colored to be deep black? Or should I look at other materials, and if so what would those be?

Thanks

Gerd

[chopnhack]

i have no turning experience but I have perused this website before for casting ideas http://www.smooth-on.com/Urethane-Pl.../c5/index.html
hth

[BigguyZ]

Penturners.org has a LOT on casting.

But in general, I've used testors to color epoxy with good results. Just don't go overboard with the testors- a little dab will do you.

I think Woodcraft also carries a product specifically for that as well.

[LCHIEN]

your biggest problems in casting epoxy are:
1. mixing the epoxy and then getting the bubbles out. Turning it will show tiny bubble voids so you need to evacuate it after casting to boil off the bubbles. Like a bell jar and a vacuum pump. A low viscosity mix helps avoiding entraining bubbles.
2. having the epoxy flow all around the item and leaving no voids - requires an item that can be poiured with no concave surfaces facing down that will trap bubbles
3. selecting the right epoxy - slow set up you'll have to wait a long time, fast setup you will get heat damage, shrinkage and capture of bubbles before letting them get out.

I've not cast items in black for machining/turning but I've cast items in clear that required through visibility after curing.

[leehljp]

Michaels and Hobby Lobby both have casting resins and tints for them. In general, these work better than epoxys with colors added.

Also, there are different kinds of resins so a little research will help. Some resins set in 5 minutes; some set in hours.

[gerti]

Thanks everybody for the tips! I found this stuff which looks promising:

http://www.smooth-on.com/Urethane-Pl...325/index.html

It'll be a while before I get to this, but when I do I'll let you know what I ended up using and how it went.

Gerd