Good Powdercoating - what to look for?

[TrevS]

Hi all

I am taking a couple of test panels from my 40 to be powder coated today at a local company. As I've no previous knowledge of the company and powder coating generally can anyone tell me what process they should be carrying out if they are good.

The guy on the phone said I could have it powder coated or powder coated with a zinc primer (or something like that). Also should the panels be blasted (sand blasted I am guessing) before they are powder coated. They are only thin sheet polished aluminium so is it possible to blast them first and will this give better results?

Thanks

Trevor

 

[Simon]

YES!
Panels that are blasted (you need a fine, gentle media) then powder coated immideatly afterwards stand a very good chance of staying powdercoated.
99.9% of all bad experienced with powdercoat come from the base material not being properly prepared. In some cases they are just wiped over with solvent!
My RAM Cobra chassis was blasted then powdercoated straight away. Fantastic and a REAL pain to get off (as it should be) it was almost bonded to the metal. Even hammer blows wouldn't shift it.
If you decide not to blast it first, why not just use paint? powdercoat WITHOUT blasting is like throwing money down the toilet.
There is a company in Basildon Essex called Vulcan shotblasting V V good, everything done in-house and they've done work on original cars so must be up to scratch.

Simon

ps, no connection other than a satisfied customer

 

[Randy V]

YES!
If you decide not to blast it first, why not just use paint? powdercoat WITHOUT blasting is like throwing money down the toilet.

X-2... I've got a friend that owns a Powder Coating business and he's the first to tell you that the preparation of the part for PC is every bit as important as the rest of the process.

 

[Andy Green]

Get them to chemically de-grease and then etch prime them before paowder coating. This is how the company that did my panels prepared them
R
egards
Andy

 

[TrevS]

Hi all

I took my panels down to the company today. I explained I was concerned about the powder staying on the panels etc and explained I wanted a good job doing regardless of cost.

They said they would key the panels by sanding them over to roughen the panels (as they are polished at the moment). The panels would then be de-greased. Once de-greased they will have a zinc primer applyed to them and then a top coat of 'automotive' matt black powder. The guy said that the automotive stuff is slightly tougher than regular.

The customer service was top notch, very helpful guy and showed me examples of their stuff which seemed good, at least to the untrained eye.

What do you think, does the above sound about right? Oh an price is £24 per square metre (£12 without primer but I was insistant on having the panels primed).

They are due to start on the panels tomorrow so if anyone has any concerns about what they are going to do please raise them now.

Thanks

Trev

 

[Bill Cooke]

Trevor,
I would ask them if a light sand blast wouldn't give better bite. You do have to be careful about to much blast pressure as it can warp the panels but it gives a better overall finish. This is what the shop that did my powder coating does.
Bill

 

[Seymour Snerd]

...price is £24 per square metre (£12 without primer but I was insistant on having the panels primed).

I just had a bell housing powder coated by a highly regarded shop for US$65. Based on rough arithmetic your pricing looks consistent if not lower.

 

[TrevS]

Trevor,
I would ask them if a light sand blast wouldn't give better bite. You do have to be careful about to much blast pressure as it can warp the panels but it gives a better overall finish. This is what the shop that did my powder coating does.
Bill

Thanks Bill, I'll give them a call first thing this morning and raise my concern over not blasting the panels.

Trev

 

[David Morton]

Trevor,
I hope this is not too late but under no circumstances have your carefully made panels shot or bead blast. They will definitely warp and you will be making them all over again.
Dave

 

[TrevS]

Right, just spoke to the powder coaters. I said that I am happy to give them some more money so they can dedicate some additional time to prepping the panels. From your comments above it seems blasting the panels could (might not) cause issues so instead the panels are going to be sanded and rubbed down by hand to key the surfaces. Then they will be coated.

Fingers and toes crossed everyone

Trev

 

[Bill Cooke]

Dave, had mine blasted with no problem,pressure was kept low.
Bill

 

[40 Bud]

The speed of oxidation on clean fresh ali is amazing and oxidation is yuor enemy when it comes to powder coating. Ask your powder coater if he has a chromate dip or something of that nature to apply immediately on completion of sanding a panel _ to stop the oxides from forming before coating.

 

[David Morton]

Bill,
It is another method for applying bends and curves to anything aluminium that is subsequently going to be immediately treated with a chromate.
Have a go and see what I mean. ie - cut a section approx 5mm by 250mm and bead blast it only one side completely. You can almost form it into a semi circle the longer you blast it.
Castings and forgings fare a lot better than sheet aluminium but a very short
bead blasting is all that can be done.
Talk to any reputable fabricator and they will tell you all about it.

 

[Powdercoater]

People need to be very very careful with their powder coater selection. It seems over here in America, there's a powdercoater on every corner. Everyone's a powder coater! Buy a cheap gun, a cheap oven and you're in business!

Not so.

Most powder coating applicators, if they have a sandblaster, they likely have large size media (boulders as we call it) that will do nothing but warp and bend sheet metal if the technician isnt trained. The larger the media, the less it breaks down, and the less the powder coater has to spend to replenish his material. Yep, those "cheap" shortcuts get passed along to you. For price hunters, maybe that's the coater for you.

If you're looking for VALUE, however, look for a coater that blasts stuff with ALUMINUM OXIDE 80 grit. It's very fine, angular, and expensive. That's the stuff we use here.
We also run all of our air through a double refrigerated air dryer and 4 filters before it ever gets to the blasting room or machines, or to our powder coating booth.
We do not have rust issues because of this equipment. The cheap powder coater cant even compete with that.

Just as a "for instance", since we are on a GT40 forum, we had the honor of restoring Dean Jeffries 1965 GT40 Roadster, the one used as a test at LeMans, to be presented at Pebble Beach in 2003 to introduce the new Ford GT.
As you all know, this car (the only one in the world by the way) is a monocoque frame with super thin aluminum panels... Screwing up wasnt an option.
We blasted it and coated it to it's original OE color of dark metallic blue.
The vehicle can be seen here: ----- ANDREWS POWDER COATING ----- powder coating, rims, spokes, hubs, Harley, candy, bobber, hardtail, softtail, Davidson, BMW, Suzuki, Aprilla, Ducati, Yamaha, Honda, Kawasaki, chopper, motorcycle, dirt bike, custom, auto, classic, car, ATV, sport

Make sure the coating facility is CLEAN. If they dont care about their shop, they dont care about your parts!

Take care and post photos!

Sandee Andrews
Andrews Powder Coating, Inc.
Chatsworth, CA, USA

 

[David Morton]

Brilliant posting. Thank you.

 

[Randy V]

Welcome to the GT40s forum Sandee...

Great post with a lot of good information!

Please do us a favor and check out our FAQ;
GT40s.com - FAQ

In particular - item number 2. If you could make the appropriate adjustment to your user name, we'd be most appreciative..

On to the blasting of materials..

Yes, depending upon the material you are powder coating, the Aluminum Oxide is one of the best - however, not the only one. At my pal's shop, he will sometimes use Soda, sometimes media (plastic) and sometimes walnut shells as well.. In any event, the parts are then washed thoroughly with a 3 step process to remove any residue.
And cleanliness! You are spot on. I'd put his shop up against most any. The shop is run 24 hours a day sometimes, but even then there are shut-down periods where the booths are cleaned (and vacuumed) and the ovens are inspected.
When color changes are made, the booth and equipment are all fresh so as to minimize the potential for contamination.

When I visited another PowderCoater in my area a few years ago, I had to remove my shoes and put them in my trunk before I could get in my car. I had been walking in about an inch or so of powder from the various spills and mishaps.. I don't think they're in business anymore. I wonder why?

 

[TrevS]

Well my panels came back from the powder coaters today and I am VERY impressed with the results. Every panel is perfect and no patches or rough spots, swirls etc. The colour is classed as automotive black and has a matte/satin type finish and matches the colour of the chassis exactly.

Trevor

 

[Randy V]

Looks really good Trev! :thumbsup: