Prep aluminum for powder coat?

[gofastnut]

Hey guys,
I've got a cheap, cast aluminum air cleaner lid. I soda blasted most of the painty off (then rinsed it), then used some paint remover to get the remainder of paint off.
I only used metal wash to clean it and didn't heat it to out gas(I know that now). It came out TERRIBLE!!
I've heard of soaking/boiling in a simple green/water mix solution, using some obscure prepping juice, and just sand/water rinse and go.
So, what are the PROPER procedures to prep a (cheap) piece of cast aluminum for powder coating?
Also, how do I fill scratches in the metal?
I can post pics if needed.

[BigDan3131]

Most of the time they either blast it or bake it clean the powder coat it.

[Tx Firefighter]

If its a known low quality cast aluminum I use outgas primer then the desired topcoat.

A lot of materials simply can't be outgassed enough to remove all problems and have to be covered with the RO primer. I do a bunch of motorcycle brake plates on old Hondas. I've even outgassed them for a full 24 hours before but they still outgassed when I top coated them. The RO primer is the only safe bet to assure you're not getting into an endless cycle of stripping and redoing.

As far as prep otherwise, I don't use any potions or secret cleaners. The B17 will get it clean and grease free. Then media blast and coat.

I've been doing it this way for several years and haven't had any hassles once I figure out the technique.

[gofastnut]

[QUOTE=Tx Firefighter;6318920]
I've even outgassed them for a full 24 hours before but they still outgassed when I top coated them. QUOTE]


HOLY SCHNIKES!!


I've only done a few things with my little eastwood coating kit, so;
what is the B17 cleaner and RO primer you're talking about, and where to get it?
Thanks again for the help so far!

[Tx Firefighter]

RO primer is red oxide primer. You can get it at Powder365.

http://powder365.com/store/index.php...roducts_id=212

Its unlike other powders in that you get the part to full 400 degrees and shoot the primer on hot. The cure time is about 1 minute after that. Then you shoot your normal topcoat over it.

B17 is powdercoat stripper. I'm not exaggerating when I say this stuff is lethal. You can take a powdercoated part, dip it in the B17 and 3 minutes later its bare metal again. No scrubbing, no sanding, no blasting. It will strip paint off as fast as you can submerge the part and pull it out again. I'm not kidding. Paint something then tie a wire to it. Dip it in the B17, count to five and pull it out. No more paint.

Its expensive but an absolute requirement to me. When doing customer work, I screw up all the time like anyone. I have to have the quick option of stripping the part and redoing. Blasting powder off is horrible. It destroys the detail of the part and it just takes too long. Imagine blasting a 20 inch aluminum wheel that you powdercoated and screwed up. You'd be there for hours and by the time you got it all off, you'd have killed any fine detail in the aluminum wheel by focusing the abrasive on it so long. B17 turns that into a 30 minute mistake not a "buy the customer a new wheel" mistake. I buy it 55 gallons at a time, but you can buy it in 5 gallon increments. You store it in a sealed drum and its infinitely reuseable. I only have to order new stuff every couple of years and that's only due to evaporation when I have the lid open.

Notice the price reflects the to-your-door shipped price.

http://bencosales.com/store/product_...products_id=12

Its the industry standard and all powdercoat shops have it on hand to solve their mistakes with.

[gofastnut]

Wow, that's a lot of great info, Thanks Tx!
I have used some high quality paint stripper to remove the powder coat, but it takes a lot of scrubbing, and I definitely agree with any type of blast media.
Thanks again!

[Tx Firefighter]

Originally Posted by gofastnut

Wow, that's a lot of great info, Thanks Tx!
I have used some high quality paint stripper to remove the powder coat, but it takes a lot of scrubbing, and I definitely agree with any type of blast media.
Thanks again!

All B17 is is methylene chloride. I suspect you'll find the active ingredient in your stripper was also methylene chloride. Same thing, but B17 is pure while commercial paint stripper has other "filler" materials in it with a lower overall concentration of methylene chloride.

Depending on how serious you want to be with powdercoating, an investment in 5 gallons of B17 pays dividends. Keep it in an airtight tub and you can use it forever. I use a big giant rubber horse watering bucket. But, 5 gallons is enough for most smaller operations. Even if you can only dip part of the item in at one time, you can remove it, turn it a different way and eventually get it all stripped. When I started out with just 5 gallons, I kept it in a ten gallon tub. I couldn't submerge a valve cover or an intake completely, but I could lift it out, flip it over and do it half at a time. Not ideal, but worlds better than any other option.

[gofastnut]

Again, Thanks tx!
Yep, the B17 is a bit too expensive to do right now. But, as I plan to grow my hobby, I can see needing that in the future.
I'll be ordering the RO from powder365 this weekend, maybe a couple other colors too.
I'll keep you posted on how it comes out.
I haven't posted pics because I didn't want anyone to puke!

[gofastnut]

Well, after 2 more tries, the finish getting progressively better, I cleaned/stripped the air cleaner, put some good etching primer, followed by several coats of satin black spray paint. Owner couldn't be happier, and he knows it's spray paint!
This was an expensive learning experience...