Oven dimensions and element placement

[IanS]

Which scenario would be best for a larger type of electric oven? Interior dimensions would be 30"x30"x72". I am thinking that I will need a dual element setup, and have a source for cheap parts. Which setup would be best for even heating? Please forgive my bad MS Paint skills...

Black line signifies wall and sold black box signifies heating element.

TIA

-IanS

A&B

[IanS]

more ideas

C&D

[pickleboy]

most ovens have the element at the bottom due to the fact that heat naturally rises. that said i would decide if you want the oven to be tall or wide. then place them on the bottom and place a fan near the top to circulate the heat around the whole area.

[tavo1765]

place the elements to the left of the ovens wall, with the fans blowing the heat accross the rack.

[sswee]

I'm with Pickle on the elements in the bottom. My choice of your drawings would be "C". Some factors will be the kind of parts your intending on doing, how you decide to rack or hang the parts, and space available for the oven. Let us know how it goes. SS

[tavo1765]

If your going to place them on the bottom, you can route the airflow.

High air flow in an oven heats metal faster resulting in shorter cure cycles.
High air flow causes powder to flow out better to produce the very best finish possible.
If you only learn one thing from my comments its that HIGH AIR FLOW MATTERS! so that should be your focus.

[IanS]

So would it be best then to place a small breather hole in the bottom of the oven and a larger one at the top so that air can easily flow up through the oven (heating chamber)? Would this cause a contamination issue? Most likely the oven will be placed in my garage so it is safe to say that the environment will not be as clean as it should be (though it seems that no environment is).

Tavo1765, when you say that high air flow means shorter cure times, would this possibly mean that I COULD make it tall (taking up less floor space) and as long as the air flow is high enough to not hinder the temperature I could possibly use only 1 heating element (pic B). I plan on doing some long objects such as strut tower bars, headers, etc. as well as some wide objects such as wheels. I will go with pic C if the majority of the people think that it would give me the most even heat. Personally, I would think C would be the best but I figured I would ask people with much higher experience than me. Thanks for all the help and for any future help that you may bring.

-IanS

[sswee]

The smaller hole on top or adjustable. You don't want the heat to get out faster than it can be produced. The home oven I use and most others have a 1" to 1-1/4" vent tube in the top right rear corner. Your pic "B"would be my other choice. It should be good with proper insulation and air flow but may take a little longer to get full even heat than the lower profile oven. SS

[tavo1765]

I would only have one hole for an exhaust out the top of the oven for expansion. Airflow inside the oven would be all up to the size and powder of your fans, also where you place them. My oven is set up with the elements on the right side facing if you were facing front of the oven with the fans blowing the heat accross the parts, with 2x 18.5 K.W elements. I run 220 with 76.0 amps being drawn, 450f in 30mins. The size is 8x4x6

[IanS]

Would it be worth it to aim the fans at an angle so they circulate around the part in the oven? Perhaps if I make a cylindrical oven this would be best. I guess shape isnt that important. What I am really trying to do here is figure out the best plan for this figured out and drawn up so I can execute said plan with a solid understanding of how everything goes together and why. I hate getting half way into a project and having to tear down because of a "better idea". I would prefer to do this once and have it be as close to "right" as I can and still maintain some cost effectiveness (not sure if thats the word I want, maybe economical is better).

Again, I really appreciate the help so far.

-IanS