Powder Coating for Underbody

[Army]

Originally Posted by Burdekin

Surface profile and cleanliness play a large part in primer longevity as well.

Don't forget sod's law - if you don't want it to stick there - it probably will!

[Army]

Originally Posted by Bob Meadows

I've used hot zinc spraying for chassis & suspension parts:~

A little specialized I suppose but I used a metal spraying firm in Liverpool-now closed- and more recently a boat restorer (barges) in Wigan.
They media blast and then spray the zinc on via a sort of flame spray gun, you can then follow through with a paint process of you choice- I use a zinc rich primer then a top coat.
Had the Riley chassis & most of suspension/some engine parts done back in the 80s it has never shown any rust since- probably not suitable for body panels but certainly worth considering for other parts.
I'm not keen on the powder coating process as a lot of parts seem to deteriorate quickly (flaking) the exception being original coatings on Volvo wheels-240
Hope it helps
Bob.

Wow - a flame throwing zinc spraying gun.

Sounds like a WW2 weapon that would now be banned!

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Have you (ever) noticed any shifting in the top coats you've applied over the zinc treatment?

[Bob Meadows]

One link:~
https://www.nspcoatings.co.uk/hot-zinc-spray

Quote
"Have you (ever) noticed any shifting in the top coats you've applied over the zinc treatment?"

Nothing- just used the zinc rich primer (two part or single) and for the Riley a Polyurethane based top coat- as with all the rust protecting systems the preparation is the most vital part- top coat can be a chassis black or similar.
Bob.

[Laird Scooby]

Originally Posted by Bob Meadows

I'm not keen on the powder coating process as a lot of parts seem to deteriorate quickly (flaking) the exception being original coatings on Volvo wheels-240
Hope it helps
Bob.

I think you may find the 240 wheels were actually painted. When i refurbished the first of my 760 "Omega" alloys, i discovered a multi-layer paint system had been used, first a primer then a high-build primer (several layers!) then a barrier coat followed by two or three layers of the silver colour coat and 2-3 coats of clear lacquer to seal it all.

I doubt Volvo would have used powder coating on earlier models as it tended to be a costly, specialised system before the 90s and even now still isn't as cheap as normal paint.

Another thing to consider is Volvo bought the wheels "rough-cast" so there were many casting imperfections in the surface which had to be sanded and filled then sanded again - hence the multiple coats of high-build primer.

[Bob Meadows]

I restored a full set of Virgo wheels for my 240- exposed surfaces and hidden areas:~
Nitromors paint striper wouldn't do anything so had to revert to a specialist product but it still took an age to get the wheels back to aluminum- certainly seemed stronger than a paint process.
Bob.

[Bracpan]

That's very interesting regarding POR 15 ( and appreciate peoples advice) what I am looking for is a tough paint I can apply easily myself to a Space Frame/Roll cage on a competition car.
I have been told the Eastwood stuff is good and was going to try that next. Is it easy to apply by Brush like the POR 15 ?
I wont go for powder coat route because it easily chips and lifts from the surface.
And cant really spray any epoxy paints as my Garage is part of my house and would get drawn in....nasty stuff.
Any advice would be appreciated as I hope to paint it in the summer ASAP after I have finished the Welding. Its nice new clean tubes no rust.
Its a good link as im also learning about good under body protection as well for my Volvo

[Laird Scooby]

Originally Posted by Bob Meadows

I restored a full set of Virgo wheels for my 240- exposed surfaces and hidden areas:~
Nitromors paint striper wouldn't do anything so had to revert to a specialist product but it still took an age to get the wheels back to aluminum- certainly seemed stronger than a paint process.
Bob.

I'd definitely agree with you on that, the paint seemed to be some heavy duty stuff! I suspect it may have been an early resin based paint that had well and truly hardened over the years. My original intention had been to return the wheels to the metal and mirror polish them. However because they were rough cast, that just wasn't possible.



That was about as good as i could get them but obviously that's only the main face that is that shiny, you can also see the inclusions in the finish detracting from the shine. For that reason i decided to paint them instead but went for a different colour. I should really get on with the other 4 now!

[Army]

Originally Posted by Bracpan

That's very interesting regarding POR 15 ( and appreciate peoples advice) what I am looking for is a tough paint I can apply easily myself to a Space Frame/Roll cage on a competition car.
I have been told the Eastwood stuff is good and was going to try that next. Is it easy to apply by Brush like the POR 15 ?
I wont go for powder coat route because it easily chips and lifts from the surface.
And cant really spray any epoxy paints as my Garage is part of my house and would get drawn in....nasty stuff.
Any advice would be appreciated as I hope to paint it in the summer ASAP after I have finished the Welding. Its nice new clean tubes no rust.
Its a good link as im also learning about good under body protection as well for my Volvo

If you want something that is hard wearing my vote would be to go down the epoxy route (present day advice) if you want a conventional finish.

Just because it is a "two component" solution it doesn't mean that it necessarily carries the same dangers as old fashioned automotive paint. Don't get me wrong - don't breathe it in - it isn't that safe.

If you have a normal household fan you could leave that running to put air from the house into the garage.

You DO need decent spraying masks and top grade filters (which during the pandemic have somewhat gone up in price) - don't skimp on your health.

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If you really don't want to spray - and you don't mind a "rough as a badger's arse" finish then Zinga would be fine and quite practical as it is easy to repair if it does get scratched,

If you want I can take a picture of cured zinga on my shed's steel structure to show you exactly how "fire escape" it really looks. It is not an ideal finish for inside a car in my opinion unless you're going for a full on rat rod look of course...

...some people in the Land Rover world rave on about (pick up) bedliner stuff. May be that would suit?

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I've only ever used the Eastwood (rust treatment) products from spray cans but I understand from others it behaves like the POR-15 during brush application.

For a nice underside black finish I don't think you can beat the extreme chassis black for colour - but - as a hard wearing paint I don't think it is quite as tough as the 2 component epoxy / poly marine paints.

[Burdekin]

Originally Posted by Bob Meadows

I've used hot zinc spraying for chassis & suspension parts:~

A little specialized I suppose but I used a metal spraying firm in Liverpool-now closed- and more recently a boat restorer (barges) in Wigan.
They media blast and then spray the zinc on via a sort of flame spray gun, you can then follow through with a paint process of you choice- I use a zinc rich primer then a top coat.
Had the Riley chassis & most of suspension/some engine parts done back in the 80s it has never shown any rust since- probably not suitable for body panels but certainly worth considering for other parts.
I'm not keen on the powder coating process as a lot of parts seem to deteriorate quickly (flaking) the exception being original coatings on Volvo wheels-240
Hope it helps
Bob.

Thermal sprayed aluminium is also very good. We had some pipes at a gas terminal which was coated with it, we had to inspect for internal corrosion and couldn't inspect through it so tried to media blast it off. It was just so tough to get off we gave up and replaced the pipes instead.

[Army]

Originally Posted by Bob Meadows

I restored a full set of Virgo wheels for my 240- exposed surfaces and hidden areas:~
Nitromors paint striper wouldn't do anything so had to revert to a specialist product but it still took an age to get the wheels back to aluminum- certainly seemed stronger than a paint process.
Bob.

Might not be relevant info - but:-

Nitromors of new ain't the same as nitromors of old. Around 2010-ish there was a European wide restriction for the chemicals used in domestic paint and paint strippers. The interweb was awash with complaints about how ineffective domestically available paint strippers had become and that they really did not do what they said on the tin...

...perversely I believe Hammerite - now made by Axo Nobel here in Europe - with a different recipe seems to out perform the old version (even though the colours are slightly different - for example I can't find that nice blue grey hammered finish that was all over the place in the 1960s).