1st attempt: powdercoating aluminum wheels

[barebonesgarage]

Hello guys,

I've been reading and re-reading the forum Q&A this winter before I do my first coating job (Near Chrome and Clear Coat on aluminum wheels). Lots of advice here, but I'm a bit unsure on a few details such as heating, cooling, preheating, time between procedures, etc.

Below is what I've put together for the process. Please review my procedure and tell me what you think needs to be adjusted, changed, or added. (bold font is questions I still have):

1.sandblast with aluminum oxide
2.wash with isopropyl alcohol or Brakleen (rinse with water?)
3.bake @ 20-30* hotter than cure temp for 30 min. to outgas & dry; let cool
4.submerse in iron phosphate per instructions; air dry
5.pre-heat wheel again to 250*
6.while still warm, apply Near Chrome powdercoat
7.bake according to instructions on can (bringing slowly up to final cure temp)
8.turn oven down to 150*, crack open door, let cool for 30 min. Turn oven off and leave door open
9.let wheel cool, then wipe down again with alcohol
(OR: skip steps 7-9; bake wheel until powder turns 'glossy', then shoot clearcoat and cure them together?)
10.apply clear coat powder, bake per instructions on can, bringing slowly up to cure temp
11.turn oven down to 150*, crack open door, let cool for 30 min. Turn oven off and leave door open to cool before baking the next wheel.

Any comments about my intended procedure are welcome! I want to do this right the first time.

Reid

[FSTFBDY]

What finish are the rims now? painted? Chrome? polished?

This is how I do a bare rim assuming its raw aluminum.

1. 120grit Aluminum Oxide
2. Dip in water to clean em or blow em off really good.
3. Wipe down with Denatured Alky.
4. Out gas at 400-450* ( always above cure temps)
5. Let cool down a little (150*-175 range)
6. Shoot the Chrome
7. Bake for 15min or 5min longer after it flows out.
8. Let cool back to the 150ish range
9.Shoot clear
10. Final Full Cure.

The only thing I wouldnt do in your steps above is Turn oven down and crack the door. Just seems like alot of wasted heat and energy to me.

I dont use caswell chrome so maybe Im wrong here and thats the best way to do it with their chromes.

[callmej75]

I did some aluminum alloy wheels last weekend. This is my process...
1 Wire wheeled rim to rough it up a little
2 Blow rim off
3 Warm up Aluminum Chromate and spray it on
4 Let set for about 3 minutes
5 Hit again with Chromate and let sit for another 2-3 minutes.
6 Rinse off with distilled water
7 Put in oven for 20 minutes to outgas and dry
8 Pull out of oven and wait til it cools to about 90* and coat
9 Baked powder at required temp

Heres the rims...I had to strip the insides of the slots and middle too. Satin black.

[barebonesgarage]

My wheels are bare aluminum...I've already blasted them with alumnum oxide.

The reason for turning down the oven and opening the door is that I have read that I should let them cool down slowly.

So.... at what point should I do the iron phosphate dip? Before or after outgassing?
Thanks.

Reid

[mtnbiker]

Why are you dipping in iron phosphate?

[barebonesgarage]

Also learned that from here. Adhesion.

[FSTFBDY]

For aluminum you want a chromate conversion. Iron Phs is for steel.

[barebonesgarage]

Caswell advertises iron phosphate as being effective on aluminum....

...is this incorrect? I should use aluminum chromate instead?

Thanks again.