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charlie coghill
02-17-2004, 11:24 PM
Hi All;
I am working on building a powder coating oven to do some small parts for my self.

The question is, can aluminum be powder coated being that aluminum is non-ferrous?

Thanks for any answers.
Charlie

Evan
02-17-2004, 11:29 PM
Absolutely no problem.

canonicalman
02-17-2004, 11:33 PM
Sure, aluminum can be powder coated. Many things can.

Powder coating is basically the process of coating an item with powered thermoplastic ingredients, and then heating the powder so it melts, flows together, and reacts to form a solid permanent thermoplastic coating.

Pretty much anything that that the powder will adhere to, that won't react with the powder, and can be heated to the melt/cure temperature can be coated.

The cure temp is usually about 180C. But, there are some low temp powder coatings to coat plastics. Also, there is a little trick that can be used for low temps of about 120C with regular powder coating. Just cook it much longer, up to an hour or more, until all the ingredients melt and react.

I actually use the regular powder coating material to coat polyurethane plastic by carefully controlling the temperature and time.

CCWKen
02-17-2004, 11:38 PM
Any material that can take "the heat" can be powder coated including some plastics and rubber compounds. It's not the porosity that matters but the ability of the material to withstand the temperatures of the process.

gunsmith
02-18-2004, 07:51 PM
Charlie, is this oven from drawings of your own? I want to build one myself but I have not found any details for the construction of the oven. I was going to use a kitchen oven but it is not the right size or shape. How are you construction yours?

MikeHenry
02-18-2004, 11:58 PM
Can quartz or chrome plating be powder coated?

Mike

charlie coghill
02-19-2004, 12:16 AM
Thanks guys for the comeback. I thought that aluminum could be coated but than I got to thinking,bad thing for me to do,about aluminum being a nonmagnetic material.

Gunsmith; I am building the oven with what ever I can find. I started with a bun warmer oven from a resteraunt,that was no good. The foam insulation would not take the tempture and would burn.

I found a steel box that is 24"X24"X6.5ft. 2 inch angle iron was welded around the out side of the box providing a space for fiber glass insulation. The insulation is covered over with sheet steel which is fasteded to the opposite leg of the angle iron.

The sheeting was salvaged from a job that was done 7 or 8 years ago and is pretty rusted but was just begging to be used for some project. So the oven looks like H-- but the price was right. Talk about a scronger,me.

A 60 amp contactor and a 8KW heating element was salvaged from a plasitc sign forming machine. I jury-rigged (I am good at rigging jurys) http://bbs.homeshopmachinist.net//biggrin.gif the heating element to heat the 26cu. ft. box for a test to see if there was going to be any problems. It took almost 30 minutes to bring the temp. up to 450*

To complete the oven I need a thermostat that will controll at the 450* and a 60 minute timer. A pizza oven thermostat will reach 900* giving a midrange controll of 450*.

A couple of brackets were bolted in side of the box that holds a piece of pipe from which things can be hung.

If you are interested I can post a pic. tomarrow.
Charlie

dvideo
02-19-2004, 12:37 AM
I believe IBEW.. mentioned a fan in such a box some time ago... evens the heating...

I found a used Blue-M POM-7 to do part some time ago. The manual costs more than the oven, which was quite large...

Could you post progress from time to time?

--jerry

ibewgypsie
02-19-2004, 06:49 AM
Charlie.. I been kinda busy..

Sometimes powdercoating something for beauty is not a good ideal. Paint is better.

S&S engine cases are tempered to withstand the vibrations of a harley motor. Warranty is null and void if they have been powdercoated.

If you need help I can direct some to you about the selection of insulation, elements, etc.

The frame pretty cool I made with metal house building studs, notching them with a pair of snips and bending corners. Covering it with lateral aluminum sheet made it stiff. I riveted it all together, once the 5 walls were made I tack welded the corners with my mig. It'd be rough to move now. That oven has treated fiberglass board insulation in it. It was kinda expensive at $450 for materiels. I have the reciepts here denoting materiel type. Probably, the cerwool is much better, with a sheet steel inside, you could melt aluminum, making it the largest smelter in your area.

Lots of ovens don't have floors in them now, by the way, designed to go onto concrete.

ibewgypsie
02-19-2004, 06:51 AM
Ohh yeah, time to go...

Anything bare clean metal can be powdercoated, you must heat it, wipe it with thinner, heat it, wipe it with a clean cloth, then powdercoat it.

David (gone to the hydro plant) zoom....

PorscheNut
02-19-2004, 02:38 PM
If you are only doing a few parts, no need to get so involved with the oven. I did many of my engine parts and other doo-dads using a propane IR aimed into a foam box like this guy did...

http://forums.pelicanparts.com/showthread.php?s=4e9eedbb28960e5b51c232a0d625ce10&threadid=142071&highlight=powder

Stick a grill thermometer through the foam to watch your temp...shoot your parts right in the oven...

canonicalman
02-19-2004, 03:15 PM
If you're just going to do a few parts, and they are small enough, use the oven in your kitchen. Cooking ovens will easily reach the temperatures that you need to cure the powder.

The real problem is how do you coat the part with powder before you bake? A simple way that has worked for me is to put the part in a plastic bag containing an excess of paint powder. Then shake, toss, and tap like you were making "shake and bake" chicken. The part usually comes out with an even coat of powder. Then into the oven, bake, and ummmm good!

Szatniasz
02-19-2004, 04:06 PM
<font face="Verdana, Arial" size="2">Originally posted by canonicalman:
If you're just going to do a few parts, and they are small enough, use the oven in your kitchen. Cooking ovens will easily reach the temperatures that you need to cure the powder.</font>

Do not use the oven in your kitchen!!! If you do you will not be able to use it again for food!

Well, you will, its not like you're oven will all of a sudden break or something. But, your food will taste like powder. There are plenty of chemicals in powder that I would never like to eat, so stay away from your kitchen oven.

The best thing to do is to find or get a second oven to do your powder coating. This is what I have. If you're lucky you're neighbour will be throwing one out next garbage day. Remember as soon as its on the curb its a free for all! Or you can pick one up for under $100 at a thrift store like the Salvation Army.

Szatniasz

Neil
02-19-2004, 04:48 PM
The original question was, can you powder coat aluminum? As others have answered, yes. There are some consideration you'll need to address. Primary coat adhesion on untreated aluminum is half that of pretreated AL. The impact resistance is only fair. Remember, the powder sticks tenaciously to the substrate. In this case, it would be an aluminum oxide surface.

Powder coating porous surfaces can be done with some reserve. For instance, a casting will retain oils, release agents or other contaminants deep in the grain structure. It would need to be preheated to a temperature greater than the cure temperature to outgas those contaminants before coating. Otherwise, the outgassing will occur in the powder coat with resultant pinholes.

Quartz probably could be coated but not with electrostatically applied powder. Perhaps a conductive precoat could be applied, but that's questionable. Fiberglas panels are done so. However, the quartz could be coated if it were heated to a temperature above the powder melt point. Electrostatics would not be an issue as you would then be thermally applying the powder. Chrome plate could be coated electrostatically.

In both of these cases, there will be virtually no tooth for the powder molecules to attach. Primary coat adhesion will be extremely poor.

For small parts, I've seen fellows using old toaster ovens with fair results. They also use the ovens for stress relieving... dual purpose item.

All thermoset powders need a specific time at or above a cure temp threshold to obtain all of the physical capabilities of the coating. If you just melt the powder, you'll have a very glossy surface with almost no adhesion or chemical properties. The coating needs to coalesce to obtain all of the characteristics of the base resin.

Once again, painting with a broad brush!

gunsmith
02-19-2004, 08:14 PM
Ya Charlie, send some photos when your done.
I'm going to build mine to a similar size as yours but on the outside of the steel wall studs I'm going to finish it with fire rated dry wall. Inside like you I'm going to use a steel liner of some type . I still haven't figured out what my heating plan will be yet. Thanks

charlie coghill
02-19-2004, 09:10 PM
Thanks for the replays, I am learning a lot from you guys.

David did say to use a fan in the oven, and I forgot to mention that I did in the above post. In one of the pictures it does show the fan that was used. I used David's advice where I could.
I used material that was already on hand. Instead of the cerwool that was suggested, fiberglass house insulation with the paper taken off was used.

If the oven would get used more than I believe that it will I would have spent the money and made it as David suggested.

I posted a couple of pictures on photobucket.
Charlie
Pourchnut; If that fellow that your link lead to is using the hardboard foam insulation, he could have a fire on his hands. That is why I gave up on using the bun-warmer. You touch an open flame to the foam and it was on fire.

http://www.photobucket.com/albums/0903/kcprecision/


[This message has been edited by charlie coghill (edited 02-19-2004).]

ibewgypsie
02-19-2004, 10:08 PM
Charlie..

How much heat can the untreated strand fiberglass take?

I used to be partners with a insulator. He is a full blown NUT thou. "Doc" He recently told some kids he was immune to electricity. Holding a hot wire in his dry callused hands. Handed it off to a kid, got him shocked good, then I suggested he lick his fingers which he did. I thought I would have to pry him off.

Snow.. we haven't got a lick here yet.

One more thing, seal the inside from the outside with 600 degree caulk. THE fuzz from the insulation gets into the powdercoat.

AND remember the fumes will make your throat sore. We all had sore throats at Docs house.

A fan must be remoted, usually long shaft and bearings, belt drive. Turn it really slow. You just want even heat inside.

We have powdercoated aluminum fork legs normally, headlight bells, frames, engine parts, I am too scared to do a set of engine cases thou.
ONE fingerprint, will show. one dirty spot the powder won't melt in. Cleanliness is next to godliness. Wipe clean, heat, wipe, clean spray bake.. is the method I use.

David

charlie coghill
02-19-2004, 10:22 PM
I don't know what the temp. limition is on the fiberglass. For the stack on the boiler in the boat I used bouble wall pipe. The inter pipe was wrapped with fiberglass. I have a thermometer in the stack and the stack temp. gets up to over 800* at times. The glass has not been hurt yet. Fiberglass does not like a plasma arc, guess how I know.
Charlie

WJHartson
02-20-2004, 03:02 AM
Is the powder coating on the house thick enough? Will it fit in the oven?

Oven looks nice.

Joe

ibewgypsie
02-21-2004, 11:06 AM
Ohh..

Docs garage is connected to his house. Powdercoating in the garage gave everyone in the house a sore throat.

Painting with epoxy/urethanes "ONE TIME" without proper resprirator can kill you, sometimes. Seems like the stupid people never get hurt thou. The paint coats your lungs with the lil air sacs never to work again. Never.

Powdercoat paint gives off a burning plastic smell as it heats up. Slightly poisonous and toxic. It irritates your throat.

See what I mean, I learned that the hard way. I already have respriatory problems from chemical pneumonia (chlorine)

David