Mold oven atop a hotplate

[Jlamont2020]

So, I've been struggling a little bit keeping my mold up to temp after a few dozen castings. (it's a 9mm Lyman devastator mold for those of you who know how finicky they are) and decided it was a good opportunity for me to go ahead a build a mold oven. With a little oven atop my hot plate, I can swap between my tried and true (but finicky) Lyman mould, and my new MiHec 4 cavity. Simply for safety, I was going to build a small base that fits securely around the element on my hotplate that I'll mount the oven atop of. just a simple circular base to prevent the oven from sliding off after swapping molds several times. As such I'm lookin' at aluminum junction boxes with flanges that can mount to the "Base" easily. This is what I've been looking at:

http://www.amazon.com/BUD-Industries-CN-6704-Aluminum-Enclosure/dp/B005T78R22/ref=sr_1_270?rps=1&ie=UTF8&qid=1428274168&sr=8-270&keywords=bud+industries+natural+finish

It's just a simple aluminum enclosure from Bud Industries on Amazon. My question is what would be the best size to make the oven? I can find junction boxes that fit to it very snugly, but with little air around the mold, I don't know how well that would work. Would a oven that is ~3x the volume of the mould work well? or should the oven be much larger/smaller than that? I'd do a 10" cube oven if it's what is recommended, but I figured I should ask before I buy anythin'.

Thanks.

[pretzelxx]

I put a boolit on my hotplate to measure temp. If it melts I cool it just a touch and keep my molds on top, if they're aluminum I set a muffin of lead on top of the mold to keep it flat. Then I run a few pours super fast to heat the cavities and it churns out great boolits.

[RobS]

A very cheap way is to use a bit of aluminum foil that is around 6 inches wide and simply shape it loosely around the mold with the extra flattened out on the hotplate. Very easy to do and keeps the heat in on the mold. Reshape/reuse for other molds etc.

[Jlamont2020]

pretzelxx - Unfortunately, that doesn't really help. The first few dozen castings aren't a problem as I preheat. The devastator mold takes a bit of time to manipulate the HP pin and to drop the boolit. It starts to cool down after about 50 or so boolits. After 100 it needs to go on the hot plate again. The hotplate does a good job heating up the mold, but is terribly inefficient. Too much of the heat is distributed into the air and not directed to the mold. This makes the time on the hotplate longer than it should be; this time is what I'm trying to adjust with a mold oven. I'm trying to make use of the heat lost to the air.

[Jlamont2020]

Ah, great idea RobS. I want somethin' a bit more durable and a bit more permanent, but this I'm goin' to try tonight.

[dragon813gt]

I use a metal coffee can cut in half. It fits a four cavity Cramer mold w/out a problem. There isn't much extra space so the mold takes up most of it. I'm all for buying things but this is one case where I used what I had on hand. I even have an extra backup since I have the other half of the can ;)

[Yodogsandman]

I use a #10 peach can, cut in half with a cut out on the side for the mold handles. A piece of scrap wood screwed to the top for a handle keeps me from being burned moving it off the mold. No bottom needed because I have a solid top hot plate.

You need to cast fast and hot for a HP mold to keep the pins hot. No time to fool around looking at them while you cast.

[mongoose33]

Here's what I use:

136108136109

The thermometer clip is held in place by a cotter pin.

[Bullwolf]

I use an metal coffee can and a skill saw blade with my electric hotplate.

Inexpensive, and easily made.

http://castboolits.gunloads.com/attachment.php?attachmentid=114714&d=1409027142

Works great when a mild breeze or wind is blowing while you're casting.

Acknowledgements go out to Gearnasher for the original idea, and to JohnB_in_Glencoe for the super convenient top handle idea which I shamelessly borrowed.


- Bullwolf