cutting kiln shelves

[theanimallover]

I'm thinking of making my kiln work for me better by buying a new kiln shelf. I have a hotstart pro which has 7 sides, but a round kiln shelf. I get a bit frustrated as space is wasted. I'm thinking of getting a shelf and cutting it down to size - seven sided with some finger space to lift in and out. Does anyone have tips on cutting? Is it likely to crumble or crack? My boyfriend should be able to do it as he spends his days cutting up paving slabs!

Also, has anyone tried vermacite board as a kiln shelf, this looks like another option.

Thanks,
Karen

[Brad Walker]

Kiln shelves cut with a tile saw. Not difficult, just go slow. It's rough on the blade; I usually cut kiln shelves to sharpen my blade.

Vermiculite board can work as a kiln shelf, but use shelf paper or fiber paper (not kiln wash) and support well to prevent warping. 2" thick board is best for a shelf, but 1" is ok for small kilns.

[Bert Weiss]

Be aware that close to kiln walls, especially brick walls, the temperature changes considerably. During the heatup, it is cooler, during the cool down it is hotter. Annealing can only take place when the entire piece of glass is within 5ºC. Placing glass too close to the kiln walls can make it impossible to anneal.

I can't exactly say how close is too close, but it is something to consider when problem solving. I'll guess that a finger's width is too close.

The tests I use to determine internal stresses are usually drilling, sawing, or glass cutter cutting. If you can drill a hole through the glass without breaking it, you are probably in the clear. I am assuming that a polarizer look will not show stress because of the absence of a clear base.

[theanimallover]

Thanks Brad.
Thanks Bert, bearing that in mind I'll do the template at least 1cm away from the kiln wall and see if it actually gives me much more space inside.

K

[DonMcClennen]

1" not 1cm. away from wall is what has been suggested many times in the past..

[seachange]

Hi,

adding to Brad's post about cutting the kiln shelves (mullite) with a tile saw, have just recently done this for the very first time with the blade that came with the machine, it worked nicely. This was a trial run for the tile saw and for me, so was rather pleased.

This blade has no diamonds, it has a slightly wavy edge all around. Thought it was worthwhile trying it and reserve my nice, and expensivish, diamond saw for glass.

Tried it also on a porcelain tile (the only one I had at home), but it chipped the porcelain a bit.

Good luck with your project, seachange

[theanimallover]

Thanks - I'll cut about an inch away from edge.
We have an angle grinder, is this too heavy handed?
Tile saws are mentioned, would a (cheap) hand held one work? I don't want to pay out for any machinery.

Thanks,
K

[seachange]

Thanks - I'll cut about an inch away from edge.
We have an angle grinder, is this too heavy handed?
Tile saws are mentioned, would a (cheap) hand held one work? I don't want to pay out for any machinery.

Thanks,
K

Angle grinder works also, my husband used it to cut my shelves before we had the tile saw. Ours is a 2300W unit. It should be possible with less powerful grinders as well, probably would need to go slow not to get stuck.

You need a stone cutting wheel, and a steady hand. He cut the shelves outside, makes a mountain of dust.

Best wishes, seachange

[Bert Weiss]

Thanks - I'll cut about an inch away from edge.
We have an angle grinder, is this too heavy handed?
Tile saws are mentioned, would a (cheap) hand held one work? I don't want to pay out for any machinery.

Thanks,
K

You can probably get away with a diamond blade on a skilsaw, with a helper squirting water from a spray bottle.

[rosanna gusler]

any dry cutting can damage the bearings of the saw/grinder with masonry dust. rosanna

[theanimallover]

Thanks everyone. I'll tell you how I get along soon!
K