All you need is a hand held circular saw and a masonry blade. The blades don't last a super long time....in this case only about 3 separate cuts. but that's ok..they're pretty cheap. Just a few bucks at the hardware store. Buy a few extra.
Here's a few tips to make your life a little easier while you do this:
- it's not possible to cut silicon carbide shelves in this way. i've never tried to..but i've been told not to do it, so i just don't do it. but if you think about it, silicon carbide shelves are going to be so much harder then this type of blade..so... yah, it won't work. only use these on the softer, clay type of kiln shelves.
- wear eye protection. this one is a must. bits of sharp, very hot pieces of shelf and parts of the cutting blade will be flying around so keep your eyes protected.
- wear a respirator. this is seriously dusty. you don't want to breathe in any of this stuff. and if your going to do multiple cuts be prepared to get dirty. wearing a hat or something to cover your head is a good idea too.
- use ear plugs. this is loud.
- adjust the cutting depth accordingly to the thickness of the shelf. have the blade cut just enough..maybe a quarter of an inch deeper.
- support each side of the shelf while cutting. if you slice off a part of the shelf without proper support once you get far enough the weight will cause the shelf to snap off, creating a jagged, broken edge or snap off, ruining both pieces.
- go slow. pushing really hard will ruin the blade quickly and your cut probably won't be straight. also there's the possibility of causing the blade to seize up, which could be dangerous.
- be aware of obstacles around your cutting area.
- use a dry wall t-square to draw your cutting line. 9 out of 10 times the side of kiln shelves will be pretty straight..so when you use one of these you'll have a super straight line to follow.
- don't forget to adjust your measurements for the blade thickness. if you're a stickler for details and you cut straight down the line that you've drawn at 12", your finished shelf dimension will be 1/8" shorter..or longer..or whatever. so watch out!
- when you're finished cutting, if you have access to an air compressor, use it to blow all the dust off the shelves. then use the air on yourself, you'll need it!
- Once your newly cut shelves have been dusted off, inspect them closely for cracks. all the jarring and cutting will sometimes reveal a problem spot before you have a problem later in the kiln.