painting a 911, need help! technical issues and process
 

Hi

To all of you who are expert painters...I bought my 911 without history, with fantasticly clean body, but with the paint peeling off big time, exposing areas of bare meta.

As the car is glavnaizd, I suspected that the reason is unsitable paint base (dont know the exact term, i am from Israel...but its that gray material under the paint...) . i spoke to painters who wantd sand down the old paint, use a sealer and paint again, and one painters instracture who thought it was better to use paint remover up to the point of bare metal.

As i saw that there are areas were i see bare metal, i thought the paint instracture was right. my conclusin was that for some reason the new paint base and the original paint didnt go on too well...and there is a reaction between them so that if i dont remove everything, my new paint will buble again, as the reaction underneath still goes on.

So..i tried using a small amount of paint remover to see what will happen. the later paint and base go off without any trouble. then there is the original paint, the factory base, the black paint of the metal, and finaly the glavanized body.

I see that the factory base is amazingly strong, and as most of the metal underneath is still original, i feel that it may be wrong to expose it. the other way to go about is to sand off the paint and base, spray a seeler on the original paint and pray there is no reaction going on...

Some of you may have encountered the same problem...what do you prupose?

Thanks
Eitan

This may be a dumb question but if you sand bare metal do you risk removing the layer of galvanization? I'd think in the areas with bare metal you'd just want to lightly prep it and then make sure it's utterly clean then prime it....
Surely someone here has a more useful answer than mine.

galvanising isn't that easy to get off. a sanding with 180 grit or so would prep for primer without really affecting the galvanising. the galv. on the outer body doesn't really matter much anyway. ie; cars don't rust in the middle of the roof. the galvanising is more for areas you don't ever see but get damp and stay that way. immediately after sanding, one or two panels at a time, put on epoxy primer then high build primer/surfacer immediately after as per manufacturer directions.

be sure to use a fine bristle brush...

Hi Eitan,

It sounds like the last paint job applied primer (gray coat (?)) onto the previous paint with incorrect prepping, therefore poor adhesion. I would suggest that you have removed any layer that is peeling since there's nothing you can do to stop the peeling. Plus you wouldn't want to place new paint on a poor base. If you do need to go down to the galvanized metal, just clean and smooth the surface. You don't need to grind past the galvanize plate.

Uhm didn't Wayne promise us a body/paint forum ??

Eitan, Gary is right. Incorrect prep/process/product is usually reason.

There are a few good threads around on preping for paint.

Without knowing exactly what you have there,
and assuming you do have an original finish under a crappy respray...I might:

-Sand down to the original paint
-Lightly sand the bare metal, staying on top of the galvanizing
-Clean the entire job twice with wax and grease remover
-Etch and prepare the bare metal areas with metal cleaner
-Treat the bare metal areas with metal conditioner
-Clean everything again twice with wax and grease remover
-Tack rag the surfaces
-Shoot on a good epoxy primer (non sandable primer) to seal everything

If the epoxy primer sits for any length of time, scuff pad the surface
and clean twice with wax and grease remover and use your tack rags
before doing bodywork with filler or primer/surfacer (sandable primer),
or before topcoating.

Use professional tools and product.

Oh yeah...did I forget to mention using wax and grease remover between steps?

Any pics of your car?

-Ernie

Thanks guys
 

I Thank all of you who took the time to answer me.

I think i didnt make myself clear enough...the rubbish paint and primer (and yes, it is gray...) are on top of an almost perfeft body. this means that underneath it, most of the car still has factory preperation and paint, and therefore - perfectly glavanized too.

I discovered yestardy, that the areas were paint is peeling are in places were the metal was sanded (all sorts of small chip fixing that was done in the past before paint) and therefore, it is were this gray stuff was sprayed directly ontoo the metal without proper preperation.

In Israel cars rot - big time! therefore i was so afraid of exposing a perfect body to humidity were its is so original underneath.

I would hapily send pictures (though the car is realy ugly now - better to wait for a month...) as soon as i discover how to actualy do it...i hate computers...)

Thanks again
eitan

These cars don't get ugly. They acquire "patina".