Need some basic help

[mafrye1]

Just found this forum today. It is awesome. I'm looking to build a large oven. 6'w x 6'h x 10'long, lined with 25 gauge stainless steel. I was thinking of using bake or broil elements from a common household range oven. Bake element 2400w, broil element 3400w. I figured on placing several on floor of unit and several on the two long side walls. I only need to reach about 180 degrees and maintain that temp for about an hour. 15-20 minutes to reach temp is fine also. I need help calculating how many elements I would need. Appreciate any advise.

[ed_denu]

There are 2 calculators in the sticky at the top of the page. Either would be a reasonable starting point for temperature estimations.

[mafrye1]

Ed,
Appreciate your response. The calculators are helpful. My main problem is that I need the elements not to glow hot at start up. Do you know if the top burner control knobs from a range would be able to be wired in to control the voltage to the range elements. In theory this would limit the voltage and not let them heat up to full power at start up. I only need to reach about 180 degrees and even 30 minutes to reach that would be OK.
Thanks, Mike

[Zigeuner]

Hello,

I'm new here myself and I'm building a powder coat oven. I was wondering what you are coating that only requires 180 deg. F.

I'm thinking that the proper thermostat setting in an oven would cause your power to cycle and limit temperature to 180 deg. F. Of course that will be on the low end of what an oven is capable of doing. Possibly you could use infrared lamps to get that amount of heat for only a half hour.

Maybe someone else can comment...............

[ed_denu]

Ed,
Appreciate your response. The calculators are helpful. My main problem is that I need the elements not to glow hot at start up. Do you know if the top burner control knobs from a range would be able to be wired in to control the voltage to the range elements. In theory this would limit the voltage and not let them heat up to full power at start up. I only need to reach about 180 degrees and even 30 minutes to reach that would be OK.
Thanks, Mike

I'm not very familiar with oven controls and if they are capable of controlling voltage to the elements. If so, that would certainly work.

If the concern is radiant heat from the elements, you could build a shield of sorts around them.

But your concern is legitimate in that with a pid, the elements would be on full power until the set temperature is reached. A better pid with ramp/soak capability might help some.

[philipd]

Never mind.

[FigureLLC]

Ed,
My main problem is that I need the elements not to glow hot at start up. Thanks, Mike

get a watlow sd-32 pid. it lets you control the ramp up. so you could put your parts in with the oven cold, program the dwell temp to 180, set your dwell time to 60min, set the ramp to 5deg/min, and hit the start button. it will ramp up to 180 deg at 5deg/min, then when it hits 180, it'll start the timed countdown, and when the time expires it'll turn the elements off. the pid is more expensive at around $200-250, but probably a drop in the bucket for such a big project.