Refractory blocks

[Kopperwood]

I've done the search and found a lot of good info on using plaster, paper clay and other materials for kiln carving molds, but I don't really want to take the time to go thru the trial and error process of learning how to do that.

I want to use my CNC router to do some very detail carving for a kiln carving mold. Is there a source for pre-made high quality refractory blocks that can be carved and then cured. The mold will be used for many, firings and needs to be able to hold fine detail. I will be making ornament sized pieces.

Thanks
Perry

[Brad Walker]

I want to use my CNC router to do some very detail carving for a kiln carving mold. Is there a source for pre-made high quality refractory blocks that can be carved and then cured. The mold will be used for many, firings and needs to be able to hold fine detail. I will be making ornament sized pieces.

We're doing this using vermiculite board and Ceramaguard (and have worked with plaster/silica as well). In fact, I'm teaching a class on the technique in a couple of weeks: http://www.kilnforming.com/workshops/14 ... al-july-13

[rosanna gusler]

Kaiser lee board. Stan Harmon uses that. Get up with him. Comming to the obx any time? R.

[Bert Weiss]

Try Unifrax Duraboard. Treat afterward with colloidal alumina. I usually lean toward HD boards, but I know of companies that use LD board and CNC routing. The primary reason they use LD is that it is the only style available in oversized boards.

[Kopperwood]

Thanks, for getting me started.

Brad, sounds like a good class.

Perry

[Bert Weiss]

If you work with vermiculite boards, I have learned how to make an additive paste that can be sanded down. Take coarse sandpaper and make dust. Mix it in with colloidal silica to a putty, apply, dry, sand, and fire. You could use this to repair any anomalies from the CNC routing. I see no reason you couldn't do this with any type of board fibers.

[Brad Walker]

If you work with vermiculite boards, I have learned how to make an additive paste that can be sanded down. Take coarse sandpaper and make dust. Mix it in with colloidal silica to a putty, apply, dry, sand, and fire. You could use this to repair any anomalies from the CNC routing. I see no reason you couldn't do this with any type of board fibers.

Thanks for the tip on the paste. I'll give it a try.

FWIW, we haven't seen any issues with CNC and vermiculite boards. But sometimes vermiculite board chips if mishandled, the paste could come in handy there.

[Bert Weiss]

If you work with vermiculite boards, I have learned how to make an additive paste that can be sanded down. Take coarse sandpaper and make dust. Mix it in with colloidal silica to a putty, apply, dry, sand, and fire. You could use this to repair any anomalies from the CNC routing. I see no reason you couldn't do this with any type of board fibers.

Thanks for the tip on the paste. I'll give it a try.

FWIW, we haven't seen any issues with CNC and vermiculite boards. But sometimes vermiculite board chips if mishandled, the paste could come in handy there.

I was in a shop helping out one day, and my project was to resurface a Best Mix mold. I rubbed the paste in, dried it, sanded it, and fired the mold. It worked beautifully to make a smooth surface. I was surprised considering the 2 materials must have different expansion characteristics. I am told the fix was durable. It does need kiln wash though.