- Joined
- Dec 3, 2013
- Messages
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I have come to a point with a couple of projects that have parts that will need to be heat treated so it is time to build a furnace. This will be my version of the many examples out there on the interweb.
Specifications:
Heat chamber is 7" x 7" x 16"
Dual heating elements wired in series, 240v, 3100w
PID / SSR controller.
k-23 firebrick heat chamber wrapped with three layers of 2300 degree 1 mm ceramic paper.
1" angle iron frame & door skinned with .060 sheet metal
Here is the concept in CAD.
Heat chamber.
With frame and door.
Before I can finalize the frame dimensions I need to get the heat chamber assembled. Today I cut all the bricks in preparation for assembling.
To cut the side and back bricks with the heating element grooves I made a jig out of 3/4" plywood. Time to put the CNC router to work.
Bricks in the Jig ready to cut. The bricks are clamped with screws against plastic shims. I put several coats of shellac on the edges of the plywood to firm up the wood a bit. The jig only needs to last for 10 bricks so this should be fine.
Cutting was done with a hacksaw with a carbide grit blade. It makes short work of the soft bricks. Unfortunately the length of the brick combined with the 3/4" plywood took almost all the blade length leaving a very short stroke. 1/2" or 3/8" ply would have been better.
The jig is also setup to cut the rabbits. Here is the second op on the back bricks.
The way the bricks are laid out there is a 1.5" x 1.5" filler on the corners. I need 16 at 9" long and 8 at 1.5" long. Fortunately I still have the tile saw from my construction business. The bricks cut like butter on the wet saw.
Here are all the bricks cut.
Last thing to do before assembly is drill the holes for the heating element and the thermocouple and make the recess pockets for the bolts that the elements terminate to.
I have to say this is a first. Machining bricks!. I used a damaged 1/2" 4 flute carbide end mill for the pockets. Holes wire drilled with regular drill bits.
Hopefully tomorrow I will get the heat chamber assembled and mortared.
Specifications:
Heat chamber is 7" x 7" x 16"
Dual heating elements wired in series, 240v, 3100w
PID / SSR controller.
k-23 firebrick heat chamber wrapped with three layers of 2300 degree 1 mm ceramic paper.
1" angle iron frame & door skinned with .060 sheet metal
Here is the concept in CAD.
Heat chamber.
With frame and door.
Before I can finalize the frame dimensions I need to get the heat chamber assembled. Today I cut all the bricks in preparation for assembling.
To cut the side and back bricks with the heating element grooves I made a jig out of 3/4" plywood. Time to put the CNC router to work.
Bricks in the Jig ready to cut. The bricks are clamped with screws against plastic shims. I put several coats of shellac on the edges of the plywood to firm up the wood a bit. The jig only needs to last for 10 bricks so this should be fine.
Cutting was done with a hacksaw with a carbide grit blade. It makes short work of the soft bricks. Unfortunately the length of the brick combined with the 3/4" plywood took almost all the blade length leaving a very short stroke. 1/2" or 3/8" ply would have been better.
The jig is also setup to cut the rabbits. Here is the second op on the back bricks.
The way the bricks are laid out there is a 1.5" x 1.5" filler on the corners. I need 16 at 9" long and 8 at 1.5" long. Fortunately I still have the tile saw from my construction business. The bricks cut like butter on the wet saw.
Here are all the bricks cut.
Last thing to do before assembly is drill the holes for the heating element and the thermocouple and make the recess pockets for the bolts that the elements terminate to.
I have to say this is a first. Machining bricks!. I used a damaged 1/2" 4 flute carbide end mill for the pockets. Holes wire drilled with regular drill bits.
Hopefully tomorrow I will get the heat chamber assembled and mortared.