Oven using metal studs and aluminum

[Popeye]

That's great, I'm glad it worked out for you!
LOTS of water in LP, Natural and kerosene... I used to know the gallon to btuh formula, I'll see if I can find it, but it's ALOT

[jrow]

Just a question from a non-powder coater, soon to be a powder coater!

If you are building a big oven, with dual elements, to cure bigger parts would it not be advantageous to put a removable baffle/wall in the middle so you could use half the oven for smaller jobs?

John

[sdold]

It would. Actually that's a pretty good idea, John. I didn't think of that. I already have a smaller oven, so I might not do it to this oven, but I might change my mind or add it later.

I'm glad you brought this up because it'll change the way I was planning to orient the elements.

It would be pretty easy to make a slide-in wall down the center.

I think I'll do it! Thanks John.

Steve

[jrow]

Steve, ETAL,

I guess I'll be one of the fortunate ones. I have a stove that has an upper and a lower oven. The upper oven sits above the burners. Now I didn't say this oven is old but it is!

John

[sdold]

Hey guys: here's a progress report on the aluminum oven.

Even though I have not built the top lid yet, and one wall is not insulated pending installation of the electrical stuff, I decided to fire it up tonight. It took about 30 minutes to get to 380 degrees. I am pretty optimistic that it will work OK though, because I was operating with the following deficiencies:

1. Where I'm building this thing, I only have one 15A circuit, and I'm 500 feet from the breaker panel. For the test, I wired both 1500 watt elements to this one circuit (I plan to use two circuits later, much closer to the panel). It's funny, it didn't trip the breaker until the instant I pulled the plug after the test This load brought the voltage down to only 100V.

2. Since I don't have the top lid ready, I just layed a sheet of aluminum over the top. I think a lot of heat was lost in the uninsulated side and top.

I am happy to report that the aluminum expansion did not cause problems, the "floating" inner panels seem to be working. The outside remained cold, so the insulating action seems good too. I'm using plain fiberglass insulation with the paper backing removed. I think using the 1/8" fiberglass tape between the inner panels and the frame studs is doing a lot of good too, because when I felt the inner skin on the uninsulated side, it was way too hot to touch (obviously!) but the stud surface next to the inner panel was only warm, not hot.

With a step drill, it's EXTREMELY fast and easy to install these inner panels with a larger hole in the panel than the stud underneath (for expansion). Having the 1/8" thick fiberglass tape between them makes it easier to tell when you have drilled the larger hole in the top skin, so you don't go too far.

Stay tuned...

[sdold]

A couple of pics:

[Popeye]

That sounds great Steve!!
Looks good too... Once you get things buttoned down I'm sure it will work fine....Good Job!

[bluegiller]

How hot are you wanting to get your oven?

I have a electric tempeture guage similar to the one you using at mine goes blank at 411 degrees. (tops out)....

They have a sweet one at Foam Creepo that is wireless with the timer so you could actually sit on the couch during curing time. I just dont know where it tops out either. (20-30$ I forget exactly)

[sdold]

Thanks Popeye! Bluegiller, I will probably only use it at 375-400. It would be great if it heats up a little faster, but I can't be too picky at only 120V. Hopefully there are no issues with slow ramp-up time and curing. I guess I'll find out. Thanks for the tip on the thermometer, I'll check it out tomorrow.

[sdold]

The oven is basically done. The lid's on, temp controller and thermometer are working. It heats up to just over 400 degrees in 1/2 hour with both elements running (both on one 15A circuit, which is not a good way to do it, only used for this test). It'll probably heat slightly faster when I move the oven closer to the panel and use two circuits. It's not great performance, but pretty good for 110V.

If I only run one element (1500W) it heats up to about 335 degrees in one hour and stabilizes there. So that answers THAT question

I guess this means it's possible to a) build an oven out of aluminum and steel studs/tracks, and b) you can run it on 110V, using two elements on two 15A circuits. I think both are compromises, if I had more electrical power available, I think I'd forget all the tricky insulating and just brute-force it, using steel and more/bigger heating elements.

Aluminum doesn't seem to be a great material to use because of the expansion. It worked here, but it was a pain to build because of having to insulate all the inner panels and drilling the oversize holes.

But with the power limitations I have, that's probably the only way it could have been done. It is pretty darned efficient, the outside doesn't get very warm at all.

All that's left is to put a couple of latches on the lid to seal it better while it's running, install a couple of rails to hang parts from, put a chain on the lid to keep it from opening too far, and if necessary, install a fan. And maybe a small vent. And maybe a small window with a lid, like Jim did.

I'm sure glad this is done, it wasn't a very fun project at all! I'm not sure why.