Chassis painting

[jeff jackson]

Hi All,
I have a second hand chassis that has been powder coated. The back end of the chassis is still pretty good, but the front is a different story. The powder coat has chipped allowing rust trails all over the front, especially on the vacuum resevoir.
I have wire brushed all of the powder coat from the offending areas.
I have some POR-15, that I intend to use on the chassis, the question is, do I just use it on the front affected area or all over the chassis? How well does POR-15 stick to powder coat?
Has anyone done this already?
Any help gratefully received.
Jeff

[englishmaninwales]

I used the POR15 system when I refurbished my Caterham space frame. I stripped all the powder coat off (original Nitromors and scraper / wire brush and through wash off - or one could shot blast) as there was a lot of tracking corrosion under powder coat.
Then POR marine clean to degrease, through wash off, then POR phosphate etch and wash off, then POR 15 brushed on. This gives a smooth surface when cured, but any remaining original powder coat can react with this system.
Malcolm

[Matt Elan]

I think you are asking for trouble if you try painting over the powder coating. In my experience once the outer layer of the powder coating is breached you will likely have corrosion running under the coating, and it is really difficult (if not impossible) to reseal the coating. This is I believe what killed so many TVR chassis in the 80s.
Unfortunately it is very hard to take the coating off so you are trapped between a rock and hard place. I would get the chassis blasted then use POR15 which is a really good system.

[pharriso]

I think you are asking for trouble if you try painting over the powder coating.....

I would get the chassis blasted then use POR15 which is a really good system.

Agreed

[Donels]

In my experience powder coating is a really poor coating for chassis. Once chipped the corrosion occurs underneath but it all looks fine on the surface. POR 15 by contrast is excellent. I did get it all over my hands and it took about 2 weeks to wear off. I was embarrassed to meet anyone that I had to shake hands with. Strip it all off.

[LaikaTheDog]

Loath powder coating, once it is damaged... just a tiny scrape while fitting bushes will do it.. 10 years later you have a part held together by plastic paint... the metal underneath is worse than if left open to the elements !!

Por15 has a good rep and can be patched if damaged by MOT station poor jacking techniques..
I personally use a rubberised paint that can be patched and has a rust inhibitor built in. It can be overpainted with laquer or a color of your choice.

Advantage of paint is that you can take it off at the next restoration with a wire brush or stripper without having to chem dip.

[mikealdren]

Hi,
what's the rubberised paint you use?
thanks
Mike

[benymazz]

I did get it all over my hands and it took about 2 weeks to wear off. I was embarrassed to meet anyone that I had to shake hands with. Strip it all off.

Same here... just had my front suspension completely apart so I put por-15 on it (vertical link, caliper bracket, and steering arm). About 1 week since I did and about half the stuff has yet to come off my hands.

Not like spray paint where a rag soaked in brake cleaner takes it right off

-Ben

[h20hamelan]

I enjoy the rust converter (now Rust Treatment) built by permitex.

The only trick, like POR is the pre-treatment. Though the permitex seems to stick fine no matter.

I coated one of my Lorry frames when changing wrecker body 15 years ago. And its still fine, used in the winter. Calcium chloride and salt mix on the roads here. She gets ridden hard, and put away wet (no daily heated storage) The permitex is still on there for the most part. Now they have rattle can/spray bomb which I use to touch up. But, the tips of the cans just plugs up, so be ready to use the entire can.

[Frogelan]

Jeff

If you are 100% sure the chassis has been powder coated, then it is possible to blast the damaged area and have it re-coated.

The existing PC will not be damaged by doing this, if indeed it is PC.

By doing this, it might give a more reliable answer.

Ask a PC specialist.

Andrew

[jeff jackson]

Hi all,
Thanks for the replies chaps. I appreciate you all taking the time to respond.
The chassis is definitely powder coated.
I think what I will do is try my soda blaster on the chassis and see if I can get the powder coat off.
POR-15 is horribly expensive, but from the small things I have seen coated in it, appears to be sturdy stuff.
I have around 1/2 litre of the stuff, I think I will need a shedload more for a complete chassis!
Before I do all that though, I may blast my lower front suspension arms, these were from Spyder, new and powder coated around seven years ago. They are not in great shape, so l could try the soda balster on those to start with.
If the soda blaster makes no impression, then it's pointless trying it on the chassis.
Kind regards
Jeff

[benymazz]

POR-15 is horribly expensive

Yes, but inexpensive when compared to the cost of a replacement chassis

-Ben

[jeff jackson]

TRUE that Ben!!

[Davidb]

I had my chassis sand blasted and I painted it with POR15 the same day-very impressed with the finish and no chips or marks after three/four years of hard use.

[vstibbard]

I'd get the chassis and arms blasted and then use POR15, the fact that your arms are already in poor condition shows how poor powder coating if for areas which can be chipped. I always sue a har industrial or chassis paint only cars, generally have the chassis and arms etc blasted and painted immediately.

Its lot cheaper than replacing a chassis, let alone all the work to do it.

On some I use electrolysis nickel for suspension trim etc, but the last set I had done is showing signs of not having been applied properly.

Cheers

V