Mold Furnace Ideas?

[H.Callahan]

I am looking for ideas for a mold furnace using a hot plate for a heat source. Up to this point, I have just preheated on the hotplate, but I would like to figure out a way to more evenly heat the mold. I have seen "tin" cans being used, but is there a more elegant solution?

[Whiterabbit]

I'd use sheet metal.

If I had a permanent casting location setup, I'd consider using firebrick. Would end up looking very similar to a miniaturized cobb oven. Not very portable though. A sheet metal box covered in insulation would fit the bill nicely and be much lighter.

[CGT80]

I made a mold oven out of some 3/8" thick rectangular steel tubing. I welded a back on it and put a base in it so that I can slide in my MP mold if I want to cast flat point boolits (the pins needed a place to go). The problem is that the hot plate won't keep the heavy mold oven hot enough. I put the molds directly on the coils of the hot plate but the molds get too hot and the temperature control is crude. Ohhhhhhh Noooooooooooo..........................Maybe I need a PID for my mold oven:twisted:

That same hot plate struggles to bring a small metal coffee can of water up to boiling temp as well. I have read of others saying that there is a safety switch in the hot plates that will limit them. Others reported not even being able to boil water when using them for cooking. I have not tried using sheet metal yet.

[Frozone]

I took a 3/8" plate and welded 1/4" wall rectangular tubing to it. It holds 6 molds.
I added a plate in the rear to keep air flow to a minimum, and insulated the outside with Kaowool.

I use a 1100 watt hot plate and while I CAN use a PID to control the heat, I don't, I have found it is over kill.

The large mass of the oven evens out the plate so that the simple infinite control works well, once you know where to set it.

Since different molds like different temps there is no reason to control to the degree.
I keep the oven at about 400º and adjust the molds when I change to them. It's only a pour or 2 to get them to proper temp that way.

I found instrumenting the molds Far more effective than instrumenting the oven.

[H.Callahan]

Sorry it took so long to respond. The wife has been in the hospital all weekend.

At any rate, I have no fabrication capability. No welder, no way to braze, etc. I'm probably going to need something already made and repourpsed, like the a can or something.

Thanks...

[montana_charlie]

Sorry it took so long to respond. The wife has been in the hospital all weekend.

At any rate, I have no fabrication capability. No welder, no way to braze, etc. I'm probably going to need something already made and repourpsed, like the a can or something.

Thanks...
Sorry I took so long to respond. I was banned from the site, so I could only 'lurk', not 'help'.

This isn't mine, but it is a picture I have had for a long time.
It's based on a standard electrical enclosure and cover ... from the hardware store.
I think it can be built with minimal mechanical capability.

http://castboolits.gunloads.com/attachment.php?attachmentid=50219&d=1238431668

CM

[Whiterabbit]

that's fantastic. It's close to what I posted in post #2, but using a junction box instead of surrounding the hotpad with firebrick.

I like that alot. I'd have widened the hole so the top doesnt need a hinge. Just slip in and out from the side.

[Taylor]

Good deal,I like it,that goes on the to do list.

[H.Callahan]

THAT, I could probably do. Is it big enough for a 6-banger, though?

[Whiterabbit]

nope. But find some bar stock, have the shop cut it to length and wrap the other end in tin foil. You have the same thing and it fits a 6 cavity mold.

[zxcvbob]

Get one of those hotplates with a solid cast iron top instead of an exposed coil.