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Old 07-12-2008, 02:39 AM
ace4059 ace4059 is offline
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Default Powder coat oven (curing oven)

I am going to be building a powder coating oven AKA a curing oven. This is going to be long winded so bear with me.

I searched and I found lots of threads on the internet about the ovens and I found a few threads here on SFT about PC guns but not really the oven itself. So Ifigured a few of you could help me out.

First off the oven is going to be 8' wide 4' tall and 4' deep. I am going to use Mineral wool insulation that is 2" thick on all walls, top, and floor. It is going to have a roll out rack for hanging smaller items. It is going to have two 4' x 4' doors on the front. It will be made out of 18 ga or 16 ga mild steel (which ever is the thinnest one the local metal supplier has in stock). Looks like I'll need about 350 KW per sq foot on this size of a oven if I go with electric coils(about 36,000 KW total).



Now here are my questions
1. Should I go with electric or use LP (no natural gas).
2. Do I need a vent if I go with electric coils.
3. What type of vent (and how big of vent) for the LP burner
4. How many BTU's would I need to be equal to the 36,000 KW of heating coils.
5. I know I need a circulation fan but what size and what type (just a large squirrel cage blower?).
6. Any easy and SAFE way to hook up the LP that comes in a "everything you need" kit.

here is a site that I found that was of some help

http://www.powdercoatoven.4t.com/Index.html

Thanks in advance for your help.

Ryan
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Old 07-12-2008, 03:08 AM
ace4059 ace4059 is offline
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found this for my parts
http://forum.caswellplating.com/oven-building-forum/
(FIRST STICKY)

Question #4 answer
http://www.heatershop.com/btu_calculator.htm
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  #3  
Old 07-12-2008, 06:38 AM
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ace it sounds like from the dimensions you layed out that you expect to coat alot of larger parts. For the benefit of those looking to coat smaller parts a standard household oven will work just fine. Here at work we send alot of stuff out to the coater but if we need it now we (ie prototype and special work) we coat it ourselves.
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Old 07-12-2008, 06:55 AM
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i once owned a PC oven,a big sucker,8'X8'X16' long.
it was a real simple deal,just a big box,double walled with insulation,NO FLOOR,it sat right on a concrete slab.
it had ""baffles" on each side that were about 2' tall and 8' long that the hot air blew out of,or maybe just had fans inside for "convection''.
it was a propane unit.
now i paid something like $30,000 for that unit,delivered.
it was made out of galvanized sheet metal,and the only thing that looked expensive was the burner unit.
i could have built the oven in a week or two. way quicker than it took to get the one i bought!
the box will be easy,specing the burner i would need help with.
Randy
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  #5  
Old 07-12-2008, 12:52 PM
Synchroman Synchroman is offline
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Default Internet site.

The link below has some good ideas for a powdercoat oven. After seeing the site, I decided to build one that is the same size as the one in the website. His is 36" high, 24" wide and 72" deep. He used four oven heating units of 2,500 watts each. It pulls about 50 amps and needs a 6 ga. line to work properly. It will heat to 450 or more in about ten minutes which is all you need.

The unit in the site used some sort of styrofoam insulation that was unavailable near me. I did some investigatoni and decided, like you, that rock wool was the way to go. The two bails that I bought are good up to 2,700 degrees F. That should be enough. I built a frame ouf of 12 ga. sheet metal "C" sections channel that is 2 X 2 X 2". The sections are mig-welded and then bolted together with 3/8-16" bolts and nut plates that I made myself with square nuts welded to metal plates.

My unit will take a Harley or other motorcycle frame or three Harley cast wheels at a time. The thing I like about having it longer than wider is that you can hang onto your heat and change jobs without cooling down. Wear gloves and long trousers and shorts, of course.......

There is an upper trolley with an aluminum frame for lighter parts. This rolls on two angle iron rails that run the length of the inside of the unit. The bottom trolley is heavier with bolt positions to hold a frame or anything else that will fit inside the oven. It also rides on angle iron rails that are full length.

Take a good look at the electrical controls that the website shows. He really did a nice job laying it out for an electrical unit.

Of course, if you use gas, you will probably only need some lights inside. I have two oven windows on top of the unit and two oven lights in one side for visibility. I use a standard stainless steel oven thermometer inside one of the windows to tell what the actual temperature is.

I had tested the unit when I got ill late last year and I'm just getting back to it. Sorry I will have to take some pictures.

If you go the electrical route, I can't recommend that website highly enough. The man did a wonderful job.

Happy Trails!






http://www.powdercoatoven.4t.com/

Last edited by Synchroman; 07-12-2008 at 07:47 PM.
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  #6  
Old 07-12-2008, 04:09 PM
kbs2244 kbs2244 is offline
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I have seen them made out of old freezers.
Freezers because they are all one compartment.
But one guy did use a refrigerator with a upper freezer.
Small and big oven in one box.
Almost always electric heat elements from junked ovens.
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  #7  
Old 07-13-2008, 02:50 AM
ace4059 ace4059 is offline
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Randy,
thats what I am trying to avoid... the high price tag.


Synchroman,
Thanks for the info. I did read about the build on the mentioned web site.

KBS,
I did read about people making them out of old freezers but it still wouldnt be big enough. If I need a small oven I would have just got a old junker kitchen oven.


Here is what I have found out so far in my research.
Most people do NOT reccomend LP for a heating oven. PC is high flammable (the fumes), so if you use LP you must have a heat exchanger and an enclosed flame for safety. Most of these are the professional ovens that have this and are high dollars. So It looks like I am going to go with electric on this one. Next I have decieded to build a smaller one (around the size of 3'x3'x3' or 4'x4'x4') and after that build a larger one than I expected. I want a small one so It doesnt cost a fortune to heat the large oven for a small item. Plus I can work out the kinks in the little oven.

Now for the windows. Anyone know where I can get some for cheap. Also For the door seal I would like to use some thing like on an oven door. Anyone seen these seals for sale on the WWW.


Thanks,
Ryan
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  #8  
Old 07-13-2008, 03:01 AM
ace4059 ace4059 is offline
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Quote:
Originally Posted by ace4059 View Post
Now here are my questions
1. Should I go with electric or use LP (no natural gas).
2. Do I need a vent if I go with electric coils.
3. What type of vent (and how big of vent) for the LP burner
4. How many BTU's would I need to be equal to the 36,000 KW of heating coils.
5. I know I need a circulation fan but what size and what type (just a large squirrel cage blower?).
6. Any easy and SAFE way to hook up the LP that comes in a "everything you need" kit.
I found the answers to most of these questions so I thought I would go ahead and answer them so future reference (I hate unfinished posts that never have the answers to your question when you are searching).

1. use electric. LP is dangerous if not done correctly. All agree that PC is flammable when applying but there is mix opinions on the flamability of the flumes.(most still do not reccomend LP)

2.No
3.unknown but if need look here http://forum.caswellplating.com/
4. use this site for the equation (see post #2)
5. need high temp circulation fan many on the sticky of the caswellplating in PC section
6. unknown.


Guys I think I have most of my question answered. Ill let everyone know how the build is going.
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Quote:
Originally Posted by Shade Tree Welder View Post
Calling an illegal alien an "undocumented immigrant" is like calling a drug dealer an unlicensed pharmacist.
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  #9  
Old 07-13-2008, 03:23 AM
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GWIZ GWIZ is offline
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Quote:
Originally Posted by ace4059 View Post
Looks like I'll need about 350 KW per sq foot on this size of a oven if I go with electric coils(about 36,000 KW total).

4. How many BTU's would I need to be equal to the 36,000 KW of heating coils.
That would be.
36,000 watts.
Or 36 KW. ( K is thousand), 36 thousand watts.

36,000 ÷ 240 volts = 150 amps.

Your going to need 150 amps at 240 volts to get 36KW.

Last edited by GWIZ; 07-13-2008 at 03:32 AM.
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  #10  
Old 07-13-2008, 06:51 AM
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midmosandblasting midmosandblasting is offline
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Ok anybody built a burn off oven ? roughly 750 degrees.
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