Tuesday, May 18, 2010

Powder Coating painting your bike - DIY tips from AtomicZombie.com builders forum

Thee Powder Coating Thread
By Odd Man Out, AZ Krew Guru 

My goal is to start a "master" thread on all things powder coating. A place where people can come and get their questions answered.

First my qualifications. I am self-taught and have powder coated four trikes with a cheap Harbor Freight powder coating gun. I have experimented with multiple coating techniques and am almost done building a 3.5 x 4 x 6.5 foot interior dimension powder coating oven and once done will build another for my own use (much smaller).

I am not saying I know much on the subject, but I am eager to tell you what I do know. So, here we go.

Powder coating is a technique of painting that is very durable, easy to apply and can create stunning results. The cons is that you need specialized equipment to apply it and an oven to put it into to bond it to what you want painted.

The reason why it is called powder coating is that the "paint" is actually powdered paint that you apply to a part through an electrostatic process. The paint is put in a container that is screwed into a gun looking thing (technical I know...). The gun is hooked up to an air compressor at 10 to 15 psi. This is really not much and the paint comes out of the gun like a small cloud and not like a spray gun. There is a clip that comes from the powder coating machine (the gun) that applies a static charge to things. You attach the clip on the part that you are hanging the part you want painted on. The static charge flows through the clip, down the hanger and into the part you want painted, making it statically charged and thus attracts the paint.

This is a neat process to watch. The paint goes on and you can easily see where you need more. You need a clean and non drafty area to work. You can literally blow the paint off the piece if you are not careful. is is only being held on by the electrostatic charge and when you unclip the piece to move it into the oven, you want to be Very careful to not whip it around or bump it.

There are a range of powder coating equipment to choose from ranging from $99 and up. Cheap powder coating guns come with a fixed voltage. This is okay for simple jobs but if you want to do multiple layer coatings or if you need to get into tight places, then a higher priced gun with the option of multiple voltages is a much better option.

Back to the paint. It goes on dull, very dull. The first time I sprayed gloss red and it went on dull I thought I had done something wrong. Not to worry. When you put it in the oven, when it gets to the recommended temp it will "flow out". You will see the part change from dull to glossy - another neat process to watch.

All powder coat paints should come with instructions on how long and at what temp to cook them. It is really important the follow the directions. A timer will become your friend. For instance, a paint may say, "bake at 375 degrees for 18 minutes after flow out. Another may say, bake at 425 degrees for 23 minutes after flowout. I forgot a piece in the oven and can attest that if you do not follow directions that you will not like the results. My gloss red turned really dark and not so glossy.

As I said PC paint is tough! bout the only way to get it back off if you make a mistake is to sand blast it.

There are some myths about PC, like you can't mess up, that up can't put too much paint on a piece -- Wrong! Put too much on and you will get either what looks like the surface of an orange or you will get subtle runs; slightly raised lines. I agree that PC seems easier than rattle can or spraying but it still is an art to be mastered.

You can get a wide range of PC colors from the net, just need to search under "powder coating paint". About anything that your mind can conjure up is available -- mattes, satins, semi gloss, high gloss, translucents, mirrors and holographic colors to name a few. The problem that most will have is finding someone to apply the colors for you. My experience has been that most powder coating shops will not want to do anything that they are not comfortable with, that is why I am building my own oven.

I need to ask for forgiveness at this point since I seem to be disjointed since I am typing this off the top of my head.

There are specialized things that you can use with PC: tapes and silicon plugs that can be used to safely cover and plug areas that you do not want PC'ed. Since 475 degrees is about the highest temp that your piece will reach, any delicate welds or brazings are safe.

Clean up is a breeze. Since the PC paint is a powder, after you are done all you have to do is turn up the pressure on your air compressor and blow out your gun and then sweep up the PC paint that did not attach itself to the piece off the floor. If you build a great paint booth you can reuse the powder that you re-collect. The powder is never sticky, only when it comes under heat.

PC paint can be bought in quantities as small as 1 ounce and as large as 50 gallon drums. Pricing (as of May 2010) is not bad. You can easily PC a recumbent frame with a single color for $15.

You can multi-coat with PC for various effects. For instance, you would apply a base coat of high gloss silver and put in in the oven. When the silver flowed out you would bring it out of the oven and spray it with a coat of translucent candy apple red and put it back in. The silver base will make the candy apple POP. When the candy apple flows out, bring it out on the oven and apply a clear gloss topcoat for protection and extra POP!!! The really neat thing is that as soon as the piece has cooled down (20-30 minutes), you can put everything on and it is good to go. You can literally ride what you PC'ed an hour after you finish.

Another example would be to apply a base coat of gloss black, then apply a coat of multi color glitter flecks, then a coat of silver translucent and finish it off with a clear gloss topcoat. You want to talk about a stunning paint job!!! With PC'ing your only limitation is your imagination.

The things you need to PC are the following:
1. PC Spray gun
2. PC paint
3. Something to hang your piece from
4. A air compressor that will produce 10-15 psi
5. A still area to powder coat your piece
6. An oven to put the piece in

Now the oven is the biggy, but not insurmountable, especially for the likes of we Zombies!
I have nearly finished one and am looking forward to another. My next installment will tell you what to consider, what materials you need and how to build one.

Hope this helps!
~ Odd Man Out
Follow OMO's powder coat painting thread on the Atomic Zombie builders forum: http://forum.atomiczombie.com/showthread.php?t=4105