Designing a smoker and other cooking devices for catering

I love to cook, love to cook outside and love to cook with family.
My sister is chef with private clients, a teaching position and and a good reputation.
We have made a nice profit grilling/ smoking leg quarters for a client event, but our technique and tools need refining.
So I'm noodling about how to build a reliable smoker.
For food safety, tastiness and efficiency I plan on basting the meats to 165 F after smoking them and before finishing them on a grill.

I'm interested in making a smoker built around standard food service sized pans.
1/2 sized sheet pans is 13"x 18" and we already have a lot of them.
I'm not sure if I should just drill holes or cut slots the ones I have (for smoke to get to the meat)  or buy cooling racks that are sized to these pans.
Either way, I need a rack size to start off with and these are not bad.


I want to avoid dealing with toxic paint and such, other wise I would build a  fridge or file cabinet style smoker.
Instead I think of building a box with interior dimensions of  60"x 20" x 13.5".
The lining would be aluminum flashing, the shelf supports aluminum angle, the fasteners self tappers, the frame would be steel studs, the insulation would be rockwool, and the exterior would be pallet wood.
Outside dimensions should work out to about  68"x 28"x 21.5"
I think this design would give me space for at least 8 pans , and that is a lot.
The door design isn't clear in my mind, so I could really use help with that.


Smoke will be provided by woodpellets and  gas or electric burner.
A TLUD burning pellets in order provide the heat to make is another option , but I worry about the space it needs.

The idea is to build one and test it, then see if it can be used to hold food at temp with a heat source and fan.
If it can, It would build a second one for holding the meat at temp.
If not, we will need a way to drop the temperature  of the food rapidly and fridge for holding it.
That might be a better plan anyway.
I still want to attempt to add  even and controlled  low temperature to this device so it could be used for dehydrating or even sous-vide, but those would be bonus activities.
A  big food safe insulated box is my goal.

The other thing on my mind is a pig roaster.
Same basic build, but bigger and horizontal, with the heat coming from charcoal burning on the lid.
I would also build this around sheet pans, full sized ones, so a foot print of 26" by 54" , three pans long by one wide.


I'm just getting started on this, and will no doubt get distracted, but its aimed to be a September birthday present, and  any suggestions would be most welcome.

I started researching smokers and I scored a commercial freezer to refurbish.
I figured the steel interior lining would eliminate the concerns about plastic toxins.
I then learned that the existing insulation in refrigeration devices makes them only suitable for cold smoking.
Removal and replacement of the insulation is very resource intensive
I've placed my cart before my horse, yet again!

So after a lot of rethinking, I'm changing plans again.
The freezer will be a cold smoker, proofer and hopefully, a dehydrator.
It is sized for sheet pans, and has racks for them, so there is that.

I still need a way to hot smoke.
After more thinking and research I conclude that most smokers are just low heat ovens with smoke added.
Some people use propane ovens outdoors for their canning and summer cooking.
I could use that as well.
So I'm gonna seek out a gas range I can convert to propane and add an exterior smoke box.
If it works out, I'll put another couple on a trailer so I can move them around  to my sisters house, church, my yarden, etc.
Its fun to make stuff, but I would rather not reinvent the wheel when its pretty good wheel to begin with.
I could see adding mass or improving the insulation, but either of these could be done incrementally.
The worse case scenario is not finding used gas ranges in my price range, in which case, I might convert an electric oven and find a gas cook to to go with it.