Jim Moore Glass Tools
Frequently Asked Questions
The cork I sell can be used on any metal surface. For example, the inside of a pipe can be corked and used as a mold. The old cast iron molds that are available on eBay should be corked. A corked mold will produce a product that is free of chill marks and surface defects. The cork is only used on molds where the piece is turned. Sharp angles inside of the mold will burn out quickly.
It is the moisture that turns to steam that protects the cork. Make sure that all vent holes are open after corking, so that the steam can escape and allow the glass to fill the mold completely. There are different sizes of cork powder. Coarse powder seems to work well in wonder blocks, while the finer cork should be used on closed molds.
Try to keep the cork moist. This will make the cork last longer.
Mr. Wizard's Corking Instructions
- Brush on even coat of linseed oil.
- Dust on cork, shake off excess.
- Bake at 500 to 550 deg. F. for 45 to 60 minutes, until dark brown.
- Let cool.
- Brush on linseed oil.
- Bake at 500 to 550 F. for 15 to 45 minutes or until dark chocolate brown. (do not burn black).
- When used, burn off the old cork at 700 to 750 degrees F. for three hours and wipe clean. Then start over with step number 1.