Huge powder coat oven?

[MatBirch]

Hey gang,
once again I'm tasked with another project for work. This time, it's a powdercoat oven. A BIG one. Probably looking at 8-10' wide, 25-30' long!
We are a structural steel fabricator, and many clients are requesting powdercoat for things like railings, trellis' and pergolas. An upcoming job is spec'd to have the steel facia/soffit system all done. This job alone will buy our system. We currently farm it out, but we struggle with getting good results, prompt service, and transporting parts 90 miles to get it done. We need to take control of our own destiny!

So- Anybody built larger than the typical Eastwood level oven?
We have plenty of juice- 1000amps/460V. From what I'm reading though, at the size we want, gas would be better. It's also below zero much of the winter around here, so the build will need to account for that.

I know we could just call several companies and have a system built, but we're a resourceful group of fabricators, scroungers, and scrappers. I'm sure we can assemble what we need to fit our needs.

Thanks!

 

[ljhhontx]

Maybe save some time and labor and start with a cargo container??

 

[jake28]

Take this with a fist full of salt, since I’ve never built anything like this. In your shoes, I’d be checking the specs of industrial wood kilns. Perhaps lower heat, but similar capacity.

Jake

 

[txvwnut]

I believe there are commercial made units the size you need. I use place local to me that has a booth that’s 50 feet in length and I think 15 to 20 feet wide. They did a crane boom for me many years ago which was thirty feet long and said they could do my airplane fuselage no problem.

 

[dogdog]

You might needed to contact an industrial oven builder... not something DIY in that scale, pretty sure there are insurance and safety osha involved in that size of things.

 

[Gotcha640]

I've watched some big jobs at the heat treat shop near us. They keep some kilns set up for regular jobs, but they also have an insulated shipping container with the bottom cut out so they can drop it over the parts.

They have a bed of limestone, then support the parts with firebrick and rockwool, rockwool to make a seal around the base of the container, arrange a few dozen thermocouples and place the burners. Sometimes if doesn't work correctly, and parts get distorted with too much heat.

In Houston, we're more likely to be delayed by rain than snow. The arrangement I've watched couldn't be covered by a relatively cheap steel shed, since you have to lift the container on with the crane. No idea if this could be done in a warehouse with an overhead crane, the heat and the CO and the Co2 might require an impossible amount of airflow to work indoors. If you're doing massive parts, maybe it's only available when it's not snowing. Maybe the shipping container goes on rails and you push it over the parts with a dozer.

Whatever the container looks like, I think you're just talking about a few (yards of) flame tubes and a bunch of thermocouples. You're only going for under 400f. Add some uv lights and it's even lower.

 

[bradpac]

I know a guy that built his own about that size 20x8x8 that is propane fired. It is steel frame with 16ga sheet metal inner skin Insulated with rock wool. We're in Texas so not dealing with any real cold outside temperatures, but he can keep it at a consistent temperature really well.

 

[930dreamer]

Sounds like an interesting project, keep us updated on your progress.

 

[Firebrick43]

Natural Gas + Enclosure = what possibly could go wrong.

Buy one.

If you had an industrial electrician that was intelligent and was doing an electric oven I would say have at it.

But were I used to work we had large heat treat ovens that injected methonol and natural gas for the carbon and you could not believe the complexity of the safety systems. Its not a DIY thing. Even then they scare the %$(# out of me.

 

[nadogail]

If I were a member of the team at your shop, I would scale up an electric baking oven probably starting with a core of a shipping container.

 

[PugetDude]

If I were a member of the team at your shop, I would scale up an electric baking oven probably starting with a core of a shipping container.

^^This. ^^

 

[u3b3rg33k]

Hey gang,
once again I'm tasked with another project for work. This time, it's a powdercoat oven. A BIG one. Probably looking at 8-10' wide, 25-30' long!
We are a structural steel fabricator, and many clients are requesting powdercoat for things like railings, trellis' and pergolas. An upcoming job is spec'd to have the steel facia/soffit system all done. This job alone will buy our system. We currently farm it out, but we struggle with getting good results, prompt service, and transporting parts 90 miles to get it done. We need to take control of our own destiny!

So- Anybody built larger than the typical Eastwood level oven?
We have plenty of juice- 1000amps/460V. From what I'm reading though, at the size we want, gas would be better. It's also below zero much of the winter around here, so the build will need to account for that.

I know we could just call several companies and have a system built, but we're a resourceful group of fabricators, scroungers, and scrappers. I'm sure we can assemble what we need to fit our needs.

Thanks!

I don't think you need an 800kW oven to do this. I work with heat and plastics. I've looked into using gas to run a thermal fluid systems and they're far harder to spec than electric heat and PID controllers.

a well insulated oven is where I'd look first. find a way to keep the heat in.

I'd start by evaluating the eastwood oven if you modified it (in theory) to be the length you want.
their 4x4x6' oven is well, 4' deep. 30'/4'=8 ovens. 8*8.5kW = that's 70kW. at my commercial rates that'll cost $1200 to turn on and $5 in electricity to heat it up after 9am.

heating it up at 8:45 would cost me $205. not sure what the demand would be to keep it hot (my guess about 25kW/$440 + $14/8hr day), but managing demand is a process and controls issue. someone leaves the door open it'll cost a lot more to operate.

since it's got 3 elements it could easily be wired for 3 phase operation.

this seems very doable.

 

[danski0224]

I'd recommend discussing a DIY oven with the business insurance underwriter first...

No UL labeling on a fabricated oven will likely be a dealbreaker.

 

[harley jim]

My neighbor has five ovens in his shop, three of them are big enough to drive my F250 superduty into. He built them from sheet steel, there are pre made oven panels available that can be ordered to height and screwed together. The shipping container is a viable option you will need to deal with the wood floor and the door seals. He heats them with heating elements from ovens. I can get some specs on the electrical if you want them. Myself I would use a trolly rail to suspend the parts from. The longer beams can be lifted into place with a fork truck, rolled in and out of the oven on the trolly, the neighbor uses rolling frames for all of his smaller parts and he made some pyramids about one ft. tall to set large heavy objects on. If you need pics or any info let me know and I'll help with what I can.

Sent from my SM-A102U using The Garage Journal mobile app

 

[el monte slim]

Two websites that might be worthwhile to check out:

https://www.laxengineeredsolutions.com/Paint-Cure-Oven-s/276.htm

https://a1walls.com/

 

[RogueFab]

Can you retain your use permit (or whatever documentation your locality assigns to give you permission to run a business in your area) with a home made furnace? That would be my second concern. After Safety. Respectfully.

 

[MatBirch]

Thanks for all the input guys! I hadn't really given the regulation issue much thought. We are in the middle of nowhere with no local "authority". However, the company was evidently popped pretty bad by osha a few years back. Disgruntled employee... There is now an expectation of them dropping by someday. If it's a stand-alone building, I think we could still build it ourselves. Electrical is no problem if we go that route. Plenty of access to commercial electricians that we work with/ alongside daily. We'd do everything "by the book" and not make some sketchy deathtrap, but it still wouldn't have the almighty UL listing...
time for more discussions with the boss. and maybe his banker...

 

[dzahm]

I built mine out of steel framing studs, and light gauge sheetmetal- It is 3 x 3 x 6 and powered by 4 3600w electric burners. PID controlled- with fan to eliminate hot/cold spots- (gentle fan with baffles in front so not to blow off powder.) Insulated with normal insulation (paper removed) and the oven converts to 6 x 6 x 6- (also has an insulated divider to reduce it to 3 x 3 x 3) It was simple to build and use (also used it to heat the old shop- leave the door open for a few mins) That being said- commerically and the size you want- thats gonna be a monster- I would think an overhead trolley would be the best way to go so you will have to figure that out too. There is a company locally that makes ovens for commerical powder coating- I have no financial ties to disclose/no relation to whoever owns it- FWIW_

www.pneu-mech.com- they have been around for a while and make a ton of stuff-

 

[Honch]

I have to agree with what a lot of others have posted, building a 400-450° oven that size for a commercial business is just asking for trouble. Even if you and your team are capable the liability would be huge.

I bought this heat treat oven for work just over a year ago.



It has a 400° aeging oven on top, the center is a 1200° solution oven and a roll out quench tank underneath. The solution oven will run at 250° from purely air friction with just the blower motor running. Large commercial ovens are all about airflow, its not as simple as just putting heat in a large container.

Delta-H the manufacturer was incredible to work with, I got weekly updates on the build process along with pictures. Once it was installed the company owner/designer came onsite for a week to test, setup and train five of my people on using the oven. We have his personal cell for questions or issues, which he has addressed in less than 24 hours. You wont see any powder coat ovens on their site but I'm fairly sure the owner told me they have built them. They are very similar to composite curing ovens.

This company is at the upper end of the spectrum, both in cost and performance. For example their ovens have to meet uniformity requirements that call for ±2° at any location to be certified as ASM Class 1 ovens.

We also have a 8'x8' Wisconsin walk in curing oven. It also has an air system which has baffles and vents that are individually adjustable to allow it a ±10° deviation at any location.



Wisconsin states:

Most powder coatings require a tolerance of ±10°F from setpoint to obtain ideal curing conditions.

Safety / legality concerns aside that would be a fairly tall order in a homemade oven the size you are looking to build.

 

[pstnbly]

A guy I know runs a powder coat business. He has a 24' conex box with a big torpedo type salamander heater poked through a hole in the side. Stupid simple, very effective. he does a lot of powder coating.

 

[harley jim]

That is all you need is a box and a heat source, my neighbor uses surpluses heating elements for ovens.

Sent from my SM-A102U using The Garage Journal mobile app

 

[hawkeye2]

Search for insulated oven panels. This site list 4” x 26” x 8’ panels for $200.

https://www.laxengineeredsolutions.com/Colmet-4PNLMF26-p/4pnlmf26.htm

 

[david3921]

Nobody has mentioned anything about prep. After fabrication, the surfaces that are to be coated needed to be cleaned of oil, dirt, grease, ect. so that the coating will adhere. How will this be accomplished?

 

[Bodj Built]

Nobody has mentioned anything about prep. After fabrication, the surfaces that are to be coated needed to be cleaned of oil, dirt, grease, ect. so that the coating will adhere. How will this be accomplished?

Probably because that wasn’t the OPs question lol

 

[david3921]

The reason I mention it is that often there are companies that make complete systems. We had one where I retired from. It was called "Paint Shop in a Box". It has an overhead conveyor running through a washer, dry/cure oven, and a four station powder booth. The powder coat room is climate controlled for temperature and humidity.

 

[Ipassgas]

Any reason you couldn't use a used commercial refrigerator (walk in) as the box, and heat with gas or electric? They're already insulated metal boxes, and they're modular.
Just spitballing here.

 

[u3b3rg33k]

my first guess: seals and insulation weren't intended for 400F+ temps.

 

[JJohns3WG]

I'd keep an eye on the industrial auctions. Might find a deal on one or one that could be enlarged to fit your needs, at least that way you could have a UL listed heat source.

 

[engineer2]

I used to design furnaces and ovens in my younger days.
400°F isn't too bad to design for. As mentioned, insulation is your friend.
A steel I-beam down the middle to suspend parts should work. An alternate is steel carts on angle iron tracks. Or both.
I like the idea of electric because it is easier to control and a bit safer than numerous gas burners. Flip a switch to turn it on or off.
A convection fan can produce more even temperatures, but then cleanliness becomes important to prevent **** in your coating.
UL doesn't come into play for site-built custom equipment, but...
Your electrical should follow the NEC and your control components should be UL, if available.
A local panel shop should be able to set you up with a control panel. A good panel shop will follow UL and NEC guidelines. This will keep your insurance company happy.
There needs to be an emergency shutoff cable along the INSIDE of the oven and a way to open the door(s) from the inside. Google "employee cooked inside industrial oven" on how to avoid being on the evening news.

 

[kwb]

A guy I know runs a powder coat business. He has a 24' conex box with a big torpedo type salamander heater poked through a hole in the side. Stupid simple, very effective. he does a lot of powder coating.

I am pretty sure that his customer base isn't writing real specs for performance of the coatings that he is doing.

Material applied is probably the simplest part of the whole process. Even temp distribution, temp control, cleanliness, and a whole lot more goes into getting a good adhesion between coating and substrate.