Heating Element Sizing

[BikerBill]

Hello all,

I have purchased a plating kit from Caswell years ago, but never knew they started selling powder untill a recent search turned up their fourm..
alot of great info here. anywho.......

I am in the process of building an oven to coat my motorcycle frame. the oven is
42in wide by 5ft tall and 32inches deep and will have a little over 3 inches of insulation.

It will have a circulating fan as well as an electronic t-stat the I got from and old commercial oven, but the part that I can not figure out is what size heaters to put in it. I would only like to install two (top and bottom) so I can install a shelf so I dont have o heat the whole oven to do smaller parts.

Any recomendations on heater sizes.

I have 220 single phase, if possible would like to keep it under 30 amps (around 6kw). Will this do for this size oven

If this is not enought electric, I have access to 100,000 + BTU propane heaters and controlls, but would need some sort of heat exchanger to keep it safe.
Does anyone have any info on building heat exchagers to run this on propane ?


Thanks
Bill

[getastro]

Okay I just built an oven that’s 4’x 6’ x 4’. I used four elements custom built to my specs. They were 240 volts, 3000 watts, giving me a total of 12kw. This gives me around 60amps for the elements only. The oven heats up quick, but the meter box spins like crazy until it reaches temp. Hope this helps.

[BikerBill]

Thanks for the response,

12 K is a little more than I have. I have 40 amps in the garage but still need to leave a little for the lights, misc controls. and blower motor.

I think what Im going to do a have my heater run on both propane and electric. I will used the propane to heat the oven and preheat the larger parts. Then switch over to electric once I have the parts inside, and hope that I have enough electric to maintain the temp.

If not, is gas fired really that dangerous ???? I can understand the explosion hazard while the parts are being sprayed and a potential for there to be "some" dust floating around from the convection motor. Even an electric heating element could cause an explosion if there were enough dust in a confinded area.

I often use a hand held propane heater to melt the powder on test pieces rather than fire up the oven, If all I want to do it shoot one piece to test a color. The only way I ever got the powder to burn is if I held the torch in one place for a few seconds, and even then it would stop burning as soon as I removed the torch from that area.

Bill

[Livinincolor]

Note the sticky posted in the Oven building forum. It has a url for a calculator for heat needs!
M & J

[Fox]

Originally Posted by BikerBill

Hello all,
Does anyone have any info on building heat exchagers to run this on propane ?


Thanks
Bill

I am wondering this myself.To be on the safe side i would like to run propane to one of those.