DIY Powder Coating.

Has anyone been doing thier own powder painting at home? I just bought a $70 powder coating gun from HF and some paint and tried some test parts and the results look much better than anything I could get from a spray can. I cured the small test parts with a heat gun after being advised not to use my kitchen oven(said it would make the food taste funny).

I have a friend that is going to let me borrow a kiln or I might even rig up an oven from some old BBQ parts. A lot of guys use old ovens from Craigslist etc but I rather have something a little easier to move around and store.

Just wonder if anyone else has played with it. Most of the things I've read are really positive and you don't have to spend much money. Eastwood has a gun and powder also but the cost was a little higher. The HF gun seems to work well but I did order some higher quality powder from Powder By The Pound.

 

There are some nicer guns with adjustable high voltage for around $300 that are good home use but so far this one seems to work. The higher voltages are better for putting on thicker coats or re-coating parts like putting on a clear coat.

 

Seems like it would be hard to control but it seems a lot of the people are doing it that way. I was thinking an old metal parts cabinet with a heat source inside would make a nice oven. One site showed guys using metal wall studs, sheetmetal and rockwool insulation to make thier own ovens. You only need about 400f

 

When they talk about curing time of 10 minutes are they talking about waiting till the paint flows and keeping it at temp for 10 minutes or do you just heat it till the paint looks the way you want it to and let it cool?

My test part I just heated with a heat gun untill the powder melted to a smooth finish.

 

I would think a good spirited run or track day and the brake calipers would get about 400F. For powder coating aluminum parts they recommend putting them in the oven 50 degrees hotter to outgass anything inside of the aluminum that would otherwise outgass while curing the powder. This keeps it from outgassing while curing and bubbling the paint.

Certainly something to think about

 

I did a little searching on some of the engineering sites and most say 375f for an hour should not be a problem for most aluminum parts and in most cases my actually be of slight benefit. It looks like 400f is too low to anneal most aluminum but can do something called "artificial aging" which in most cases gives some stress relief. They did say to be carefull on some high tensil strength heat treated parts and to keep the time to a minimum.

Certainly I need to do some more research on this before doing structural parts. Master cylinders and calipers shouldn't be a problem and most wheels are powder coated and baked from the factory but some racing wheels and suspension pieces probably need to be done with much care and as little heat as possible.

 

I am not doubting the heat treating data but I have boiled 600 degree brake fluid on a fairly regular basis on the track. I'm pretty sure most calipers see over 400f degrees on a sportscar fairly often if it's driven hard. I'm not sure what alloys they use for calipers but my guess would be that if they were heavily heat treated they would be brittle and would warp when they got hot the first time.

AP Racing makes temperature indicating paint that changes colors for brake calipers so you can see how hot they have gotten during runs. I just looked at AP racings website and the lowest temp indicator paint they sell for brake calipers is 300f degrees going up to 500f. I am not disputing the facts of heat treatment but just making a case that you should be able to powder coat brake calipers without worry since they are designed to work in higher temps durning normal operation than you would see in a powder coating oven. Typically your powder coating is going to be around 350f for about 10 to 50 minutes depending on the thickness of the metal

 

I'm not disputing heating aluminum changes it's properties even at low temps but title on the graph you posted makes me think it's showing the properties of the t6 at a given temp/time and not the affects on heat treatment or temper once the alloy has cooled? I'm just looking at the title of the graph?

 

I'm thinking you are asking is it ok to use aluminum oxide in as a bead blasting media prior to powder coating? I would think it would not affect the powder coating in any negative way? The powder seems to adhere to just about anything. They recommend media blasting the parts to rough up the surface before coating to enhance adheasion.

You would obviously want to make sure you cleaned out any media from any moving parts like the bore of a brake caliper.

 

I did find it extremely interesting from his graph that time was a factor as well as temp. I would have never expected the properties of aluminum to change at a steady temp over a period of time. I learned something, makes for a good day