Building my first oven

[HammerDownJustin]

Thinking on building the interior 4x4 7 feet tall. Not sure if the 3 elements I ordered would heat it though. Might just go 6 feet tall inside if not. Using 3 3100 watt elements for 9300 total. What is everyone using here?

[HammerDownJustin]

Ohh planning on R-19 on the sides and double R-30 on top.

[Gamelord]

That's very close to the oven I built. I use 6 elements in mine. 3 2500 w, 3 3000 w. When first heating the oven up I use all 6 elements. After it gets to temp I only use one or two depending on outside temps. The issue you will have is that when you open the door, your heat will all go out very quickly and it will take much longer to recover with only 3 elements. If you are quick with the door then it won't be much of a problem. If you are needing to open the door for 30 seconds or longer at a time, you may find that you don't have enough wattage. Technically you can run it with only one element if it is insulated and sealed good enough...but it may take an hour or longer to reach temp when you first start it up and it will take 10 minutes or so to recover if the door is opened for longer periods of time.

If you can squeeze it in, I would go with heavier insulation in the walls. The more you put in now the less it will cost you over the long run in electricity to keep it hot.

[HammerDownJustin]

Damn thats alot of elements..Bet it is a efficient oven for sure. Trying not to haft to run another 60 amp circuit so hopefully I can get away with 3 elements. Did you use real metal or sheet metal studs for your frame?

[Gamelord]

I just used standard metal studs for my frame and screwed them together. Very easy to build.

You can use less elements it will just take longer to heat up and longer for recovery. I ran a 125A 220v circuit to the oven. It goes from cold to 500 in about 7-10 minutes. Recovery after the door is opened is usually less than a minute. When the oven reaches about 60% temp, I shut down 3 of the elements and only fire them up again when it comes time to open and change pieces.

[HammerDownJustin]

Damn that is awesome. My buddy did his same size and he is up north close to the Canadian border. He used 4 2200 watt elements but it takes him about 12 minutes to temp. Not sure what his recovery time is. Read where some people would put item in oven and turn it on. Then when it hit temp they would start the timer. Wondering how good that would work out.

[Garysbiz]

A 60 amp circuit at 240 volts will net 14,400 watts, if you run over 3 hours which is considered continuous duty, then one must derate to 80 % or 11,520 watts. In general ovens, are classified as intermittent duty and subject to load ratings at 100%, hopes this helps size your branch circuit.

[HammerDownJustin]

Thank you sir..

[Garysbiz]

You are welcome Hammerdown hope to see some pic's of your progress, I would like to do this in the future myself.

[_Ogre]

Read where some people would put item in oven and turn it on. Then when it hit temp they would start the timer. Wondering how good that would work out.

i use a house oven for powder coating, i use the thermostat light to start my timer. when the light goes out the oven has reached temp. i used a infrared thermometer the first few times, when opening the door to check temps i noticed the light correlation and drop in heat. now i only use the light

if i had a big oven like you guys, i'd still keep this small oven for small stuff. i run it on a 20 amp circuit.

[HammerDownJustin]

Yes sir Ogre . I was thinking about putting 2 elements lower and one higher up where I could make a slide in divider and turn the lower 2 off if just powdercoating something small. I used to have a kitchen oven when I did it before. Its amazing how easy it is to do. I will post pics as soon as I get the rest of the materials in..

[NDS]

I have a 4x4x8 build with regular steel studs from home depot 4in min wool and 4 3000 watt heat elements takes just short of 20 minutes to get to 400 degrees with the ambient air being about 50 degrees.

[levesquea]

Hello all,
I am currently building a sandblasting cabinet and a small Powder Coating oven.
My oven is planned at 3 x 3,300 Watts requiring about 45Amps on 220V total.
The inside dimensions of the oven are 36" wide, 60" high and 60" deep.
The structure of the oven base is 3"/3" angle iron. The sides and top uses "2 x 4" Metal studs
Insulated with 4" Roxul and finished with 28gauge aluminum with stainless rivets.

I will control each of the elements separatly with SSR (Solid State Relays) via an Arduino microcontroller.
The temperature will be monitored by K-Type Thermocouples on an outside readout and fed to my computer via wireless Xbee communication between the Arduino and my computer. I m using a convection fan as well to evenly distribute the heat.

The bottom of the oven will have tracks to accomodate an internal wall separator to configure the oven in 1/3, 2/3 of full length. That will permit me to heat only what I need from fron to back.

It's an ongoing project but I plan to document the process as I move along.
I will keep you posted on the gotcha's......lol

Andre