Planning to construct a good composite curing oven...request some feedback/input

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pictsidhe

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I used 2 inch flameproof polystyrene that I covered in aluminium foil from the building supply shop.
I'd be dubious about using polystyrene, it melts too close to the target temp. One controller issue and you have a horrible mess at a minimum, or worse, fire. Polyiso takes way more heat, but more dollars.
 

Hot Wings

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The European aerated concrete blocks are made by mixing aluminium powder with cement.
I did not know that - but this path is overkill for the oven the OP is considering. Isocynate foam and a bunch of aluminum tape should do the job.

I have used the aluminum/cement in the lab but was never on location when it was actually mixed and pumped in the field. I imagine that in large quantities it could get exciting if the process wasn't well controlled.
 

Pops

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Neighbor makes animal xray tables . Power coat oven. 4'x4' x8' long from 11 ga steel , fiberglass insulation on the outside covered with plywood. 4'x4' door on end with an overhead sliding rail and hoist. Heats with electric oven elements with a thermostat for temp control. Works very good. Way overkill for your needs.
Had rudder pedals, stick parts, flap handle, etc, power coated for the JMR.
 

Derswede

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My old neighbor did military work, silkscreening on military gear. He had a huge oven to bake on the paint. Would hit several hundred degrees with no problem...we baked a few pizzas a couple of times, more as a joke. It used oven heat elements. They had them against the ceiling, a steel caged fan to circulate air, and 220V power and a temp controller was all it consisted of. Sheet steel outside, high temp insulation inside. I modified it so that he could start up with half the elements and increase the temp by switching in the rest when needed. Should work to get the heat you need. An industrial controller, temp controller, relays and power. The oven elements proved to be cheap to replace as well.

Derswede
 

Pilot-34

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My paint oven was made from Steel studs and plain (unpainted ) steel roofing.
I eventually insulated it with unfaced fiberglass insulation.
Easy and cheap
 
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pictsidhe

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I did not know that - but this path is overkill for the oven the OP is considering. Isocynate foam and a bunch of aluminum tape should do the job.

I have used the aluminum/cement in the lab but was never on location when it was actually mixed and pumped in the field. I imagine that in large quantities it could get exciting if the process wasn't well controlled.
Yes, foiled isofoam is a good choice for the OP's walls and top. But a bit fragile for the floor. Those aerated blocks are much softer than concrete, but would still be way better than any cheap foam sheets for the floor.
 

pictsidhe

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My paint oven was made from Steel studs and plain (unpainted ) steel roofing.
I eventually insulated it with unfazed fiberglass insulation.
Easy and cheap
Hmmm, I've been pondering a big oven. Needs steel lining for the heat. Hadn't thought of roof sheets.
 

Lendo

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For smaller heaters to heat Foam for bending I used Fibrous cement sheeting (won't burn) and cooking foil stuck on with silicone.
Any variation of that for bigger ovens would do, you don't need thick steel lining, just something for reflecting the heat and something that won't burn for the Backing, silicone has heat resistance, which helps. for a Fuselage, or Wing heat treatment, the Fibrous Cement sheeting might be too heavy, maybe just Polystyrene with Al foil would do, or a product similar with a few strips of wood for stiffening.
George
 

pictsidhe

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I'm thinking thin galvanised HVAC sheet for lining roof and walls. Maybe I'll go cement board though. But it's heavy and my oven will be built in a 5' high crawlspace adjoining my basement.
 

Bill-Higdon

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I did not know that - but this path is overkill for the oven the OP is considering. Isocynate foam and a bunch of aluminum tape should do the job.

I have used the aluminum/cement in the lab but was never on location when it was actually mixed and pumped in the field. I imagine that in large quantities it could get exciting if the process wasn't well controlled.
Aluminum & CaOH from the cement gives AlOH & H2
 

Hot Wings

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For those that haven't done this, besides being flammable the H2 from fine aluminum powder makes the cement expand quite rapidly. Think yeast/H2O2 YouTube videos.
 

User27

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I've built one of these ovens for post curing whole wings & fuselages. I used 100mm (4") foiled foam boards, called Celotex here. Many people have burnt down their workshops using unattended electric heaters for post curing, so our oven is plumbed into the radiators. Perhaps not that easy in the US. I have used heat guns at the bottom with a temp sensor at the top controlling a relay board switching the heat guns. A blower is required to ensure a consistent temperature around the oven. If using radiators shuttering is required to get a circulation within the oven. To make sure we know the required temperature has been achieved for required time these things Temperature Logger are used - great little devices that last for days. If you do use electric heaters consider having it turned on only when someone is present - it does extend the time taken for the full cure due to heat up time (max of around 40F per hour) - it may prevent your whole workshop going up in smoke.
 

User27

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...He thought that it worked best if you have completed all of the bonding of the assembly before doing this - it made for a structure that did not creep and change shape as much when heated.
We have also seen this happening, I would call it shrinkage more than warping, but post cure before final finishing is a good plan.
 

pictsidhe

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I would prefer a non-flammable oven...

A simple over temperature protection would be a fusible link controlling a master cutout. 60/40 electronics solder melts at around 360. Ideal safety temp for me. There are many other grades of solder with different melting points.
 

User27

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But the stuff inside the oven is also flammable. The shop next to ours burnt down a while ago, they lost all their moulds and had to pretty much start again. We unplug all the non-consumer electronics each evening.
 
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