Thread: Advice: Building a powdercoat oven

frig might not handle the heat, too much plastic in them

Where do you get the powder coating supplies?

Yeah you would need to remove the insulation... basically just use the outer shell and then build an inner one...

Supplies will prob be from: http://www.caswellplating.com/powder/

they have an aus distributor however i havent looked anywhere other then on the net, im sure there prob a supplier locally

I've had a lot to do with powder coating the last 20 years,

Most powder melts about 200 deg C. If they are multi layered then the temp drops with each coat.

eg: If you did silver you would put on the silver first at 200 C

then the clear over the top on the second bake and it would be about 180 C

this stops the original coating being affected ( messing up the pattern)

I bought a large gas fed oven it is 4 metres long x 2 metres high x 2 metres wide. It's basically a large double thickness steel box with a door on the front. The walls are about 120 mm thick and insulated. The door is on the front Having the door on the top would mean you would loose a lot of heat when you opened it up. The floor in our oven is even insulated except for 2 sections each side which contains the tracks for the trolly which rolls in from the floor.

There's a fan in the roof which blasts in the hot air and it is naturally controlled by a thermostat.

As it is so big it takes about 30 minutes to get to the top temp and it looses heat pretty fast when you opened the door. So you heated it up get your bits ready on a trolly, open the door and quickly put them in and close the door. The temp drops to about 170 C in the 20 sec or so it's open and then it takes about 10 -15 minutes to get back to temp.

The powder coating is usually cooked for 10 minutes at 200 C or whatever the recommended temp is to gain the proper standard. If you leave it less it sometimes doesn't flow out properly and if the objects are thick metal (such as an engine block) you have to give it extra time to heat up the article. You get far better results if you heat the articles first then apply the powder and put them back in the oven. This because the electric attraction ofen causes areas close to each other tho repel the powder and it leaves them bare, If you heat the metal the powder will stick even though the magnet field tries to repel it.

As it is such a big oven we put small items in a small electric oven we had in the lunch room. It works just as well and all it is is an element in the bottom and it also has one at the top for a griller. I usually turn both elements on. and set the oven one to 200 C. Works just as well as the big one.

Trouble is with all these things you always have something 1" bigger than the oven you made.

What you haven't said is how you are going to apply the powder? Its usually applied with an electrostatic powder gun. You can also use a diffuser box but it will also require you to construct it. The boxes don't allow you to apply powder to a lot of shapes as you have to dip the article into them.

Powder coat is available from a few sources, Dulux (now PPG) make it. So do a few others. Croda Piants also made it but have been taken over by a firm I can't remember the name of. Its usually sold in 20 kilo buckets though some colours from some companies are sold in 5 kilo ones. It goes a long way so I would only buy small amounts.

You could also probably get some from companies doing powder coating. The few times I have needed odd colours for small jobs they have sold it to me no problems. It is fairly cheap compared to normal paint. Only about $10 for a litre tin but you are going to spend a lot on electricity.

If you make up a booth ( say a fridge with the door removed) and then put a tray in the bottom you can collect the powder that misses and sweep it up and use it again. In Theory you have not waste, all the powder is used ( if you can collect the the unused material)

Classic car restoration on foxtel some time back did some podwer coating (small parts) and they used some application gear that seemed readily available over there and simply used an old oven to bake it all in. I'm pretty sure I have a copy of that episode if your interested in more info I'll dig it out for you.

Thanks for the response guys...

The plan is to use the oven for curing both powder coating and ceramic coating. It all came about as i plan on getting my headers off my boat ceramic coated, unfortunately no one does ceramic coating locally so i got a quote of around $350, add shipping on top im guessing around $500, so i thought about it and figure i could make an oven and DIY for around the same price or a little bit more and atleast i have something at the end of it where i can do side jobs for friends or myself.


So initially it will be used to ceramic coat. I mentioned powder coat as it seems to be more widely used than ceramic... Im not sure why that is but there are a few powder coaters locally but none do ceramic... Maybe someone like Durwood could suggest why that might be?

Im happy to use a standard oven for small parts but it wont fit things like headers, bike frames, rims etc..

Durwood - If you dont mind me asking, what roughly did you pay for the oven you bought? and any contacts? maybe they sell smaller ones?

notenoughtoys - would love to see that episode, let me know the best way to get it to me


If it all goes ahead ill be happy to document and do a write up if anyone is interested.

Cheers,
Flipps

Its been 15 plus years since we bought the oven it was $25000 at the time. It was custom made by a company in Bankstown, don't think they exist now but you can find others in the yellow pages. The price was govened by the cubic metre size of the oven. Most quotes we got varied little. I picked the one we got as the maker was flexible he said we could have any measurements we liked so I picked a long one so we could paint car chassis's in it.

Ceramic coating is done at well over 1000 Deg C you need to have something which will take the heat. Even then it eventually comes off ( check out an older Jaguar thier hedders are always coated. As an exhaust can get red hot its about the only coating which will stand the heat. Its fairly dangerous and there is a lot of safety issues for workers using it, hense the cost.

Powder coating melts at 200 C so its useless even for brake drums Just burns off if you use them heavily.

Beware of the heat from a PC oven, particularly in a woodworking or general use shop. Working in the metal game over a number of years, whenever we moved into a bigger factory, the landlord's insurance broker sent out an inspector a couple of weeks after we moved in searching for a clandestine PC oven. Weren't concerned at all about minor (< 10 litres) of solvent but they were positively dead set against PC ovens.

Apparently structure insurance is very difficult to find if you have a PC oven on the premises, and the brokers prefer to check earlier rather than later.