New panel paint remove or not?

[mowogg]

I have received conflicting advice on the paint which covers repair panels for Minors (e.g. floor pans etc). Is it best to remove the paint before coating, or can you just roughen up to provide a key as suggested by the supplier.

If you need to remove all the paint, is there an easy way?

Thanks

[MGs]

No experience with Minor panels, but plenty with Mini ones. My recommendation would be to remove it. I have tried flatting the black coating before painting (required to get the paint to stick). It always seems OK to start with, but I have had problems
with the paint de-laminating from the black coating after a month or two. Maybe I have just been unlucky, but I have never had this problem with bare metal panels.

[kennatt]

I once left the black coating on a mini wing ,just flatted to give a good key,and three months later used a jet wash(OK so maybe over the top ) and it cleared the top coat and primer back to the black coating. Always cleared it off since and used etch and primer on the bare metal not going to be caught out again

[ASL642]

Strip it back to bare metal. It seems to be just a paint cover to protect the panels before sale. Nothing keys to it.

[chickenjohn]

There are two types of black coating used on panels:-

1) cheap black transport primer
2) anodic primer coating (a type of e-coat)

You can test which you have on the panel by wiping with a cellulose thinners soaked rag, if lots of paint comes off, then you have 1) and the cheap primer needs to be removed, if none or a trace comes off then you have the decent anodised coating and you can just key the surface and start painting!

This is why people sometimes "get away with it and sometimes don't".

[MGs]

You learn something new every day

[Fingolfin]

This is why we love chickenjohn.

One always strips paint away from areas to be welded, because (as I was told by my Sage of Welding) contaminants in the area can weaken the weld. So, for instance, when I replaced my floor pan, I stripped the black shipping paint off the edges of the new panels, but left the inside; eventually, I changed my mind on keeping it all, and took some sandpaper to the shipping paint and took most of it away, re-covering with Rustoleum. May strip it down and cover it with something better sometime.

You know what they ought to do? Have giant sealed rooms, so we can get the whole undersides of our cars powder-coated.

[Neil MG]

Powder coating is not a good solution against corrosion. Looks lovely when new, but it very prone to failing to cover sharp edges. The worst thing is that when moisture does penetrate it will corrode unseen under the coating, in a similar way to old hardened underseal!

Here is an example from a TVR[frame][/frame][frame][/frame][frame][/frame]

[Neil MG]

Oh yes, before you say well that's TVR, Here is a powder coated bracket from a Porsche 996[frame][/frame]

[Fingolfin]

Huh! Well, never mind then. I guess there isn't a really good way of protecting the underside of a car. I'm still gonna go with undercoating, after removing all the rust...

[Neil MG]

Regular cleaning and waxoyl/dinitrol will keep it rust free for decades!

[Fingolfin]

*grumbles about not being able to procure Waxoyl in America* But I DO have a can of Dinitrol. I feel I've hijacked the thread, let's move on.

[chickenjohn]

Regular cleaning and waxoyl/dinitrol will keep it rust free for decades!

Agree!

For bare metal protection, etch prime or zinc prime, then paint, finally use underbody wax. If in a high impact area, apply anti stone-chip coating before the top coat, and seam seal any seams.

*grumbles about not being able to procure Waxoyl in America* But I DO have a can of Dinitrol. I feel I've hijacked the thread, let's move on.

Dinitrol is a better product! Dynax is supposed to be good as well.