Doesn't make any sense to me?
Any oven will have sides, even a round oven though the sides would be round. I was looking at making an oven from an old junk electric dryer, so ya that would be a round oven inside.
I said something about a ball, well even if the oven were round like a ball there has to be a door to open to put parts in and take them out, wherever that door is, the left is left side and right is right side, so there are always sides
If you use only 1 panel as an oven, it must be hollow inside to put the part in it, so yes it still has a left and right side even then.
So no matter what your smallest size oven, make one side a left and one a right, you will always need a right and left side, even if basic shape is round like a dryer drum, and you want to make an oval, you still have 2 sides that are half round.
The Smallest oven would be a simple bread toaster, even that has sides. I do allot of plain flat fancy cut 1/4" plate steel. I should be doing one now instead of typing this since I have to ship it tomorrow, but I have all night to get it done so doesn't matter. If I wait till later I might sell another or 3more etc.., then I can coat and bake 2 at once or more
This part is 1/4" thick and always fits inside a 12" circle, that is the size of part varies and the part is odd shaped, but a 12" tall X 12" long X 1/4" thick box always holds this part for shipping. Building an oven that small or smaller would be pretty silly for most people with normal odd parts done randomly. I do these in different colors as I sell them, so I don't know till sold what color I need. If I sell 4-12 at a time I'll bake them in the normal oven, when I sell just 1 I only need an oven size of the part.
Since I do allot of these type parts and sell them 1 at a time often, I am thinking about building a bread toaster type oven for just these parts.
I need a little extra room for clearance so the part can be inserted and taken out without damaging the raw or hot powder. 12"x12"x1" inside will fit all these parts I sell like this, 1 at a time. I plan to use NI-chrome wire for the heating elements on the 12"x12" sides, just like a bread toaster. I'll either sit the part in from the top with a frame or slide in it from one end on a frame. The part can sit on the bolt holes so I only need a smooth sliding frame and a couple pins for the part to hang on from the bolts holes.
Why would anyone ever need an oven this small or smaller? Unless doing special parts often like mine? If doing parts like these on a regular basis it would be silly to worry about making the toaster Modular since it would be needed often, AND it's so small you could just hang it on any wall anywhere when not in use until it's needed!
Making a modular oven this small would be worthless, other than 1" of space thickness it still takes the same space to store it basically!
I thought we were at first taking about modular ovens as in normal sized oven for normal parts, valve covers, wheels, bike frames maybe, etc... and the reason to be modular was when larger parts needed done at times like engines or frames, etc... and since the large parts don't need done often then no reason to waste the space permanently for an oven that large. This would make sense. I need an oven 20'x 4'x7' or so if I want to do a truck or van frame, but that will be rare I do those, probably just my own so maybe 2 or 3 will ever be done? So a modular would work well when I need it maybe once a year. Also as I plan it out, I could assemble 2 or 3 different size ovens at once from the panels for several different parts. Like do small parts in oven one, engine block in oven 2, bike frame in oven 3, all would need various bake times perhaps and I would have extra ovens as needed. Also if powders need different cure temps, say I want High temp coatings for headers in an oven, may not need same oven temps and time as for valve covers, so just set up an extra oven and run 2 at once. Many reasons modular might work well this way if built well and easy to assemble and run as needed.
Trying to build a 2"X2"x1" modular oven though would be pretty nutty! There would seldom be any reason for the smallest possible oven. Are you going to bake 1 nut for a 1/4" bolt at a time often? First wasting the powder to coat one nut at a time will cost more than the power to run an oven to bake it anyway, also if that small and using it often enough to worry about it you don't need to take it apart to store it. That would be the smallest oven I could ever think of needing unless your doing 1/4" square sheet metal parts LOL
Heck, my 12"x12"x1" inside oven may be nutty even, but if it works after built I will use it often, maybe 2-3 times a week when I only need to do 1 part like today! Why heat up the big electric stove oven on 220V when a 110V toaster type would work and use much less power.
Parts cost the same either way, so less power I use the more profit for me!