Painting new panels

[Nick Jackson (2)]

I'm wondering what to do by way of painting preparation with the black paint that comes on new panels.   I thought the black stuff was cheap primer to be rubbed off, but mine is obviously quite a hard surface.

Should I rub off to bare metal?

Should I key with 400 grit or similar and apply primer on top?

Polite suggestions welcome.  Thanks.

[Spitfire2500]

The usual advice is to test with cellulose thinners and/or try rubbing it with a coin. If the primer comes off in either case then it's recommended to strip the panel back to bare metal. Otherwise key and prime as normal.

The hard black primer used on OE panels is good stuff and normal advice is that it can be left on.

However I recently had a couple of the OE panels that came in the hard black primer media blasted as part of a job lot and I'm glad I did cause there was corrosion starting under the primer in a few places. Maybe not that unexpected bearing in mind the age of OE panels and the conditions they may or may not have been stored in.

For peace of mind I'll be doing this with all the new panels for the Saloon.

[sparky_spit]

^^^^^ What he said.....

A quick way to remove the black paint is to use paint stripper, such as Nitromors.  Then wash it off and you are left with a bare metal panel with no marks.  A good going over with 400 or 600 to provide a key, and then a coat of etch primer.  Either use the type that needs an activator, or you can now get a single pack version which has much less wastage for the DIYer. I used this last time, it was fine with celly, and I had no problem with it.

[Nick Jackson (2)]

Thanks guys.  I haven't had the chance to get in the garage since because the arrival of our first grandchild has taken precedence!   I'll do some testing and see what happens.

[Tim Bancroft]

Nitromors is'nt as good as it used to be, try Wickes Paint and varnish stripper, £12.95 for 2.5L.

Evidently paint stripper cannot have methylene chloride in it anymore?

This comes from the recent edition of Classics Monthly.

[GT64fun]

Nick

If the panels are new (eg Heritage) I think it would be normal practice to leave the black primer on and sand into it as it will provide a good first layer and work as a guide coat to show up any panel imperfections.

If you use paint stripper, there is always a chance that some of it will remain in crevices and cause problems with the bonding of any susbequent paint layers, unless you wash it off really well, but then you risk flash rusting.  

Photo attached of my GT6 just prior to final paint.

R ;)egards

Ian F

[Mark Hammond]

I would use an 80 grit disc on a DA sander, etch prime and paint as normal.

Mark

[Nick Jackson (2)]

Well cellulose thinners or a coin didn't touch the black primer, so I'll be sanding a sample panel initially.  

[thescrapman]

If thinners and a coin don't touch it then it is an electro-coat of some type, so just probably just needs keying, but do not go through it.

Cheers

Colin

[Nick Jackson (2)]

Too late!   While keying I went through in a number of places such as the edges. swage lines.  Problem being I had some over spray in some places that was tricky to get off and various splodges, drips of unknown things that the car collected in the garage.  

I suppose I've now got to get some etch primer on those spots without building up the paint thickness in adjoining areas  :-/

A bit of a learning curve to climb here  ;)