If it's width, then just make a second pass slightly off-set from the first? I assume you're using a fence or guide of some sort? EDIT: Just remebered the shape, guess you doing it free-hand?
I was thinking a guide for the straight bits with a second pass if needed but maybe a pivot point for the curved bit. Or just very careful free hand. I'll see how it cuts and handles tomorrow and send if I can do it free hand. I wonder if the diamond burr is going to work or get clogged. I'm thinking I'll need a blade to make it work but we will see. Maybe I'll just have to hand file the overhangs?
I thought you did the math on total length of your sized wire? This is something that can be calculated easily. The guys that do these on a regular basis pull this wire through a meter like the ft counter at the hardware store when ya buy wire by the foot. Then ya just coil X amount of feet tightly on a rod and stretch to fit. On a big kiln, ya would need to spin 20ft long of rod using your spacing method. Obviously ya don't have one of those, just unroll the stuff in the driveway and cut to the resistance you need then twist it on the rod. The only reason I have experience with this, I make my own coils for my vape. I run 4 different sizes of wire. Some wire I have is fat with a tiny wire wrapped around it. Cool stuff you can do with wire and smoke with it. https://vapingdaily.com/what-is-vaping/vape-coils-wires/
As long as you have a guide the brittle brick will do fine. Free hand you'll probably break it. Cutting brick on the table saw I would up with offcuts as small as 1/8" tapered to a feather edge, as long as the brick, come off the saw in one piece.
I've only used an old hacksaw, but they really do cut nice and easy. You should not have any real trouble. Jeff
Looks like you're making progress Zap. You may want to twist an additional piece of wire onto the 4" leads that exit the kiln to your electrical connection. Halving the resistance will make the wire cooler and more manageable for conventional conductors. Save your money on the multimeter. It'll probably have more resistance in the probes than your 10 ohm coil. You can bank on the resistance value provided with the wire if you bought it from a reputable source. IFB wicking water away from mortar is typical. Instead of soaking the brick, don't fight it. Try diluting the mortar, thin brush coating the brick, and just let it dry. The next layer will bond to itself tenaciously and the first layer will provide barrier. Best, Kelly
I forgot about doubling the last 2inches of wire. My kiln has that too. Keeps you from melting your kiln wires. DOH!
I went looking for a bit I could use to make the undercut for the wire to sit in and I ended up spending about 260 bucks on cool tools I found at horrible freight. I got two benders which I got for 60-70 bucks each, a table vice, drill press vice and a couple of other random things. The multimeter isn't registering correctly on the wire for some reason. I probably need to review the manual again and set it up differently to get a proper reading. I followed the calculations above so the wires are probably correct. Do you mean just wind kanthal wire around the straight bits in a very tight circle around the single 16g strand? That reduces the temperature?
Yup.. just twist a second piece around the last 2 inches and connect that to your wires in the kiln. Should be come kind of screw connector like this. http://www.kilnparts.com/1000113.html
It reduces the temperature in that section of wire because the amperage is determined by the total length of conductor and when you double the circular mils in that section it's not enough amperage to really heat. The same as making the wire twice the size at the ends. Then the copper connected to that section doesn't get too hot.
Not to be nitpicky, but in a series circuit, the amperage is the same regardless of whether the wire gets bigger or smaller through certain sections. What does change is the resistance of the doubled section, which would be roughly 1/2 the resistance of the rest of the circuit. The heat generated in a conductor is I squared R, so if the resistance of that section is 1/2, then the heat generated along that section will be 1/2 as much. I think I have that right. .
I did say the amperage is determined by the total length of conductor. Doubling the ends does increase amperage minimally because voltage drop through that section is less, but basically the amperage is fixed by the long conductor coil. Not to be nit picky. I think we agree. Not only is 1/2 the heat generated, but the temperature rise is less than 1/2 because most of the doubled wire is in an uninsulated, cooler area.
I'm still having trouble finding a tool to make the undercut. I'm starting to think I need to make my own custom cutter somehow.
You have a router? Make an angled sledge for the shoe plate out of a bit of scrap timber to tilt the body or use a dovetail bit, more undercut than you need but does that matter?
You also could hand file it, or use a short burr in a router or drill press. A rasp cuts soft fire brick very quickly.
Take a look at a "Keyhole" Router bit. https://www.amazon.com/s/?ie=UTF8&k...hvtargid=kwd-899986759&ref=pd_sl_8zf85oce9i_e Instead of using it as designed ( round entry to a Tee slot. run it along the bottom of the straight cut. This should make a nice quick square relief in the bottom for you. You're going to want a dust mask for this... Might want to cover the air intake on the router also. CBB
.....and do it outside so you don't coat your entire shop with the dust. Then change and wash your cloths afterward. Best, Kelly
