Powder coating v spraying

[Andrew1967]

It won't be long before I have to think about getting the subframes and running gear sandblasted and refinished for my pick up project.

My previous pick-ups running gear was sprayed with chassis black and I achieved a good finish. I am thinking of possibly going along the powder coating route and am wondering if there are any drawbacks to counter the benefit of a harder wearing finish. I've never had any dealings with powder coating.

What would be a ball park figure cost for coating the subframes and suspension components ?

Any help and hints/tips would be greatly appreciated.

[STG95F]

Andrew , Its the first time i have had my frame powder coated and its saved me a lot of time and the finish was good who did mine

Mine cost £50 a frame

Ian

[Andrew1967]

They look great Ian, are the suspension parts coated as well ?

I did wonder if there would be issues with the powder coating making fitting tolerances too tight and would end up having to scrape some off when fitting bushes etc.

Andrew

[STG95F]

Thanks .

Yes i had to fit nuts and bolts to all the threads to save the coating blocking them up , so you have to be careful of that

I only had the frames coated . The rest of the suspension i 2K black them

[swifty]

That looks great . ... Ken

[STG95F]

thank you

[rich@minispares.com]

They look great Ian, are the suspension parts coated as well ?

I did wonder if there would be issues with the powder coating making fitting tolerances too tight and would end up having to scrape some off when fitting bushes etc.

Andrew

if its done right its no worse than a good paint job, so the threads etc wont be that bad (I always clean them out with a tap)

I have seen frames in the past that look as if they have been dipped in toffee apple coating the power coat was that thick - that wasn't a good look!

[STG95F]

[davidnutland]

I've had frames coated that were too thinly coated and started to rust like pin pricks all over, had to have them blasted again and then went down the paint route!

[mk1]

I PC subframes & paint everything else.

As Rich says nothing looks worse than too thick a coating of Powder coat.

M

[dklawson]

I've had frames coated that were too thinly coated and started to rust like pin pricks all over, had to have them blasted again and then went down the paint route!

My experience with powder coat is industrial, not automotive. When we would see pin holes in the coating it was typically from poor surface preparation. It doesn't take much in the way of oil, wax, or other volatile contaminants under powder coat to ruin it.

Powder coat is tough but it is also brittle. Keep that in mind when working with the fasteners and don't be upset if stone chips eventually require a little bit of chassis black touch up for protection.

[mowog]

I work for a firm that does powder coating for the contract office furniture industry so I will put my 2 pence worth in for what it is worth.
Powder coating is like any other paint process in that surface prep is key to getting a good long lasting finish.
I have powder coated all sorts of bits for my minis over the years with good success.
Ideally parts should be sand or media blasted to remove all previous coating and/or rust.
For heavier steel parts, we put them in a burn-off oven to bake off the old finish reducing it to ash prior to sand blasting.
The baking also eliminates all remaining grease or oils
Any decent powder coater will have a multi-stage wash system. Typically that will be a spray system with an alkaline cleaner followed by a clean water rinse and then an iron phosphate bath. That will be followed by another rinse or two. A final rinse of DI or RO water is ideal.
The washed parts then see a dry-off oven to bake all the residual moisture out.
The parts should now be ready to coat.
Your coater should have a supply of silicone masks to keep threads and critical bores free of powder.
On things like sub-frames, I like to do a zinc rich powder primer prior to a chassis black top coat.
If parts are too hot when coated, the film thickness may end up too thick.
Pin holes can be from poor surface prep or from the applicator getting his powder gun too close to the part ( static burn / back ionization)
Powder coating that chips easily or seems brittle is probably not fully cured.
Powder coating comes in many formulations and like liquid paint they are not all created equally.
For automotive use, one should ask for a UV stable powder coating (polyester or urethane formula)

Paul

[mk1]

Thanks Paul,

Most informative.

So a quick blast with 20 year old grit & a squirt of powder in a 1/2 derelict mill that looks like something out of Dante's inferno isn't the way to go then

M

[rich@minispares.com]

when I was a kid, my old man used to get loads of stuff stove enamelled at a place that looked like hell on earth, it was a real dump

the owners wife used to do all the sand blasting - its fair to say that her skin was 'well ingrained' with sand

her protective gear was a black beret hat, a filthy gabardine mac and a roll up cigarette in the corner of her mouth.

she never wore a mask or goggles and spent all day blasting stuff - including lorry chassis etc

they did beautiful work, but I bet she died years ago from lung issues

[MiniBob]

Have a look at the article by Keith Calver on powder coating.
He had some motor cycle parts done.

[ianh1968]

Have a look at the article by Keith Calver on powder coating.
He had some motor cycle parts done.

Got a link? The URL button in the post editor allows you to insert a hyperlink!

I had some bits powder coated a while back and they looked fantastic
until the leaking brake fluid stripped a lot of it off...

Ian

[Highnumbers]

One bit of advice I can give is don't cut corners on powder coat by going with the cheapest bid (or doing it yourself) especially on something as big as subframes.

If powdercoat doesn't adhere properly to the base metal, it can allow moisture in and rust from underneath the powdercoat, doing far worse damage than paint would (paint would crack easier, letting water moisture out).

But if done properly, powder coat is a great option for subframes, wheels and other parts prone to road chips. I've had motorcycle frames and other parts powdercoated for years with no problems. Plus these days it's available in a wide range of colors.

[Spider]

If powdercoat doesn't adhere properly to the base metal, it can allow moisture in and rust from underneath the powdercoat, doing far worse damage than paint would (paint would crack easier, letting water moisture out).

That's something I've noticed with it. A small and easily unnoticed crack in the coating, 999 times out of 1000 on an edge where it's thinnest (as would be most paints), the water gets in, after short time, a big pocket has formed and often it's only found after the metal under it has rusted that an issue is realised.

I guess if it's done right and properly, it can be good. I've been reliably informed that it's the bee's knee's on alloy parts, much better than nearly all paints, but on steel it's no better than paint, though with paint, it won't form a 'plasic sheet' that holds water under it.

Given how 'fussy' it is (after reading mowog's post ^), I think most paint systems are a bit easier to use. I've been using POR15 now for subframes and suspension parts for a number of years and very happy with it, but like anything, including powder coating, preparation is everything.

[surfblue63]

Have a look at the article by Keith Calver on powder coating.
He had some motor cycle parts done.

Got a link? The URL button in the post editor allows you to insert a hyperlink!

I had some bits powder coated a while back and they looked fantastic
until the leaking brake fluid stripped a lot of it off...

Ian

http://www.calverst.com/articlefm.htm

Click on "Powder coating, caliper grease"

[snoopy64]

mowog's post has the magic words... zinc primer....it makes a massive difference!