Professional Paint Job Flaking!

[Squiggle]

Hi folks,

Two wings replaced in January 05 by a garage.

Paint now flaking off both wings around inner lip of arch. I realised one lip looked slightly mottled after the work was done but after a lot of problems with this garage I hoped it would be ok.

Q1 Does the coating already on the new metal on arrival provide sufficient ongoing protection?

Q2 What is the correct procedure when spraying new metal?

Q3 What would cause the paint to flake off now revealing rust-coloured metal?

Q4 What is now needed to prevent this happening again?

Many thanks for any advice.

Squiggle

[Pyoor_Kate]

Qs 1 and 2: Was it a matt black coating on the wings when they arrived? If so, it (almost certainly) should have been removed prior to spraying, it's simply a coating to prevent it rusting before painting and iirc washes off. If they didn't remove it before painting it'd explain the paint's rapid disintegration...

Otherwise, I guess incorrect prep, mixing the paint with something incorrectly, something like that could make the paint prone to allowing water in and it to then rust.

Q3: The correct procedure is to prepare the surface (i.e. remove that black crud), smooth it if necessary (which probably shouldn't really be necessary on a nice new wing), spray it with primer of some description and then n-coats of paint (where n is the number required .

Well, if they didn't take that matt-black anti-rust coating off then probably stripping back to bare metal and respraying. Either way, I'd be inclined to complain and demand the money back.

[normal caveats apply, this is all from memory and I know precicely >< much about paint; I'm sure someone who knows more will be along to tell you the correct answer in a bit ]

[Alec]

Hello Squiggle,
Q1, it varies, some panels come with a base primer, others the coating should first be removed.
Q2, ideally, on clean metal (latter option Q1) etch primer, primer and then top coat.
Q3, poor prepartion giving insufficient adhesion to the steel.
Q4, strip back all defective paintwork to clean steel surface, i.e. all rust removed, then as Q2 reply. On steel, the etch primer may be ommitted but it is essential on aluminium panels. Etch primer on steel, should give a better job however.

Were the replacement wings new?

Alec

[Cam]

but after a lot of problems with this garage

I think this might be the source of the problems. If they have been slapdash with other things, then I can't see them being ultra careful with painting.......

In answer to the questions, it sounds very much like the steel was not etch-primed and they just sprayed over the black 'from supplier' covering. If the metal is not etch primed then it will start to flake around the edges which is what yours is doing.

To remedy this, I would suggest stripping it back to bare metal and doing it PROPERLY again and not try to cut corners just to make a bit more profit

For the correct painting procedure there are a lot of folks on here (brixtonmorris for one) that are experts on prep and painting so I'l leave it up to them to provide a technical explanation......

But if the wings were painted in January this year (less than 4 months ago) and they have started flaking then clearly something is VERY wrong. It needs doing again, so you'll have to take it back and tell them to do it properly. But make sure that they do it correctly. No point in them spraying it again to have the same happen in another 4 months....... Oh and make sure that they don't just do the wing edges either! Insist on the whole job being done properly.

[Squiggle]

Many thanks 4 all the responses.

Yes, Alec, the wings were NEW, cut specifically for the higher arch of the Series MM I'm told.

Thanks again. I'll let you know how it goes...
Fed up with having to go back for corrective work yet again!



Squiggle

[guydenning]

in agreement with cam - sounds like a deficiency of the olde etche primer stuff...
and spraying ordinary primer on top of the protective black stuff will lift quite quickly - i know, found out the hard way years ago...

[chickenjohn]

In the past I've painted over the black protective stuff on replacement wings and it didn't flake after several years.

The key is to get a good key and then etch prime. Or maybe I was just lucky. ;)

Flaking paint could be due to some sewaty mechanic handling the panel with bare hands before priming it.

Grease, salts and sweat don't do much for paint adhesion............