Releasing Agent For Casting Glass In Cast Iron Mold??

[man7sell]

I'm doing a mosaic on the pizza oven I built. Using mainly glass and much in 3D. The theme is an underwater with many sea creatures. I came across a cast fish and found out it was cast in a cast iron cornbread pan.
My question is what would you use as a releasing agent? I was thinking of a coating of carbon from oxy acetylene touch with no oxygen on. Thoughts?

[menty666]

Might work, but I'd just get good old fashioned kiln wash and use that; it's not terribly expensive if you order it dry and mix it up yourself. Just keep in mind that the iron will shrink at a different rate than the glass, so you may see some loss.

[somewhere]

As long as the mold stays cool you can drop hot glass in the mold wait a sec and flip it out. Quench the mold rinse repeat.

[highwater]

For kiln casting use kiln wash. You can dip it, but will lose much detail that way. I think it works best with a paint sprayer. Just rinse out the gun with water afterward, and you'll be good (might need two coats). Also, not sure about how iron holds up in the kiln, but you'll definitely want to run just the iron mold through the kiln cycle to get rid of any oils etc. that may result in off gassing. If you have a sand blaster, give the mold a once over so the kiln wash sticks well. You will hate it if a piece gets stuck.

If you are gonna hot cast into the mold, just heat it ahead of time a little and melt some beeswax into the surface. Again, not too sure about cast iron in the kiln. Finally, if you want the shape of that fishy but the cast iron won't work, you can take a positive of the fish with wax, and make a plaster-silica mold off of that. That stuff will definitely hold up in the kiln, but I don't like it for hot casting.

Best of luck.


BTW, if you don't wanna mix up your own mold mix, the stuff I've had the best results with is called Castalot. It's pretty cheap, too.

[AdamCotter]

beeswax or aquadag. Pam? Water maybe. shouldnt stick if the iron isnt hot i dont think, but it it warm you will get better detail. i used molds, had better results with wax than aquadag. use a a lot.

[AdamCotter]

aquadag is basically spray on carbon. like the acetylene idea, gonna try it.