Sand Blasting Media?

[MMB]

So Ive been cleaning up my studio a bit and trying to get more productive these days since I left my job at the end of august. Being I dabble in some metal work with lost foam casting etc Ive come to realize I have a good amount of sand blasting sand that Ive used for investing my foam work. Its Black Diamond brand and a 30-60 mesh if Im not mistaken. I was curious if I could use it as a grog? From what I found out about the brand is that its a "low silica" media and comes from coal slag. I fire electric so would this possibly be bad for my elements if I were to add it to a clay body? I used the search function and it doesnt seem like a topic thats been covered before. Just thought Id throw it out there. Google only brings up pages about industry uses for coal slag. Am I wrong to think that the firing to ^6 the slag might emit too much carbon for my kiln?

[Marcia Selsor]

I don't know if you would get any liquid type of slag but I agree with your intuitive sense that the burning coal could damage the kiln elements. Most US coal has sulphur in it. That would be damaging. You could mix a little in a test bar and see what happens. Is your kiln vented?

 

Marcia

[MMB]

Yeah I dont know if it undergoes any process before its crushed into different mesh sizes. Ill probably do a test bar on my next firing which is a bit further down the road. The only ventilation my kiln has is the peep holes. Its an old knob operated paragon. Ive never attempted to fire with the lid cracked. There is a metal hinge that will prop the lid about an inch but Ive only utilized it during lower temps to dry pieces.

[perkolator]

interested in seeing the test results.  if it doesn't work out, you could always use your sand blaster to remove glaze on fired pieces.  i've always wanted to fire on layer after layer of commercial glazes and sand blast through them for an Everlasting Gobstopper-like surface.

[oldlady]

MMB, firing with the lid open until all water vapor leaves the kiln is easy.  just put a small broken piece of firebrick about half an inch thick just at the outer edge of the wall (right under the handle) to support the lid. a half inch post will work too but it is a harder material.

 

when you are sure all water vapor is gone, put plugs in the peep holes and lower the lid.

 

a heavy hooked piece of metal will help lift the handle and hot lid when it is time to remove the prop.  naturally, you will have gloves on to protect your hands and use a small metal rod to flick the prop out of the way as you GENTLY lower the lid.  this assumes the VERY HOT prop will land somewhere safe once it is flicked away.  and you lower the lid gently enough not to drop anything onto your work.  working with both hands to do this takes a bit of practice.

[Chilly]

I'm amazed you can fire a kiln with the lid open. All the kiln's (UK) I've ever fired have an interlock device of one kind or another that prevent switching on unless the lid/door is properly shut.

[CarlCravens]

a heavy hooked piece of metal will help lift the handle and hot lid when it is time to remove the prop.  naturally, you will have gloves on to protect your hands and use a small metal rod to flick the prop out of the way as you GENTLY lower the lid.

I use a 1" triangular post on its side... when it's time to close the lid, I just hook the hole in the post with a piece of wire to extract it.

[oldlady]

but carl, you are somehow supporting the lid while doing this.  my "hooked metal" is half of a plumbers pliers with a long handle.  i use only half an inch so the vapor can escape but the kiln retains more heat than leaving it open a whole inch.

[High Bridge Pottery]

I'm amazed you can fire a kiln with the lid open. All the kiln's (UK) I've ever fired have an interlock device of one kind or another that prevent switching on unless the lid/door is properly shut.

 

I was sad when I bought a new kiln and couldn't turn it on and look inside