Building oven question?

[Deecoat]

Hello all, My search is over! This board is excellent,very knowledgeable people on this board. I'm new to PC and have been reading alot about it for the past year. I'm going to build my own oven(fathers a sheet metal master) and was wanting to know about how many elements to use? The oven size will be 6' tall 5'wide 8'deep all inside diminsions. Any help would be great! Keep up the good advice!

[trsick]

If it were me... I would put 6 - 3100w elements (3 on eash side wall ) down low to the floor. 2 thremostats. Run 3 elements thru each thermostat. That way you can set one thremostat to cut out 3 elements at 350F & the other stat set to 400F to keep it at temp. A fan inside to move air is also a great help. I just finished a 8'x8' oven and it has 8 - 3100w elements. It comes to 400F in about 15 minutes.
Good Luck
Bob

[Deecoat]

Thanks for your reply trsick. Do you think putting them in the floor would be ok? Or putting them on the side walls make better sense? I should use 6 elements ? How many amps would that pull?Let's see if I can remember. Amps x Volts =Watts,so watts divided by volts =amps. I think thats right? So 3100watts x6=18300w,so 18300 divided by 240v=76.25amps. Thats alot of amps to pull in a garage. Does that sound right to you?Any suggestions? Thanks for your help.

[tavo1765]

Put them on the side walls and have motorized fans that can carry a go cfm rating, this will help dead spots and provide a horizontal flow which is great for getting the powder to flow out like water.

[trsick]

Hey Dee:
All I can tell you is, I placed the elements on the side walls as that was my preference, as I wanted to be able to "walk" into the oven with out worrying about stepping on the elements.
Like the last poster stated "put them on the side & get a good cfm rated fan to move the air". I did that & all I can tell you is the oven works flawlessly!!! As for current & amps. Although the "math" will tell you that a 3100W element will draw 12.9 amps. I have been monitering my elements for a long time with a meter. I have NEVER seen one element draw over 10 amps. So 3 elements powdered by a 40 amp breaker will do. Times 2 if you want to use 6 elements. I would break it done to 2 thermostats running 3 elements. So you should have 2 - 40 amp breakers. Is that allot?? I guess I have a 100 amp service just installed for use of my oven. Another 200 amp panel services the rest of the shop space.
Good Luck
Bob

[Deecoat]

Thanks trsick: Yes that does sound better.I'm just finishing my garage and my plan is to use a 200A panel. What do you think about expanded metal on the floor to cover the elements? I'm going to use a rack to roll my parts in. Or I can use it on the sides I guess to cover the elements. What HP fan do you recommend? And where would you put the sending units for the t-stat?Any problems w/cold spots?I know I ask alot of questions and I thank you for thoughts. But I only want to build this once. Thanks again for you help! Dee

[trsick]

Hey Dee:
Glad to help. I got most of my ideas & supplies from Vipers aka Jim's website & previous post on this forum. Go to http://www.stivermotorsports.com/id44.htm . Jim did an awesome job detailing his oven construction. Although, the one he built was smaller his ideas & places to buy the items was extremely helpful to me (thanks Jim!)
I bought the heating elements & fan blade & motor via links on his web page. I did add a ceiling fan dimmer switch to control the air movement of the fan.
I placed the thermostat sensors on the back wall middle of the panel (both up & down & side to side). It seems to work fine & having the heating elements on each side wall, the thermostat sensors are far enough away from the heating elements, so they don't get direct heat from them!
Good Luck!
Bob
PS: If you want, call me at my shop, you can get the phone # & hours from my web site below. I would be happy to help you out.

[viper56]

Bob,

Thanks for the good word. Just wanted to tell you that your new oven looks great. Glad to see it working well for you.

Jim

[gourdhedd]

Hey, Deecoat, I've had good luck with using about 330 watts per cubic foot of volume. My oven heats up in less than 10 minutes. I went the sheetmetal panel route for the sides and top. You can check it out below.

www.powdercoatoven.4t.com

Gary

[Deecoat]

Thanks guys! I'm in the process of buying my material,and your help has really helped me greatly and I thank you. I have decided to go w/a 6x6x8 oven heated by 4 elements recessed in the side walls,and 2 elements in the floor covered by expanded metal,so I can roll my rack on. Maybe everything will work out ok? Trial and error I guess. Thank you again for all your help! Look foward to reading tips from this forum, I'm sure I will need it. Wish me luck. Dee