The rear panel on my car is a fiberglass one from ST, iv'e never been happy with the ripply finish of it, so decided to spray it. Struggled all day trying to fill all the depressions in it, but finally thought it looked ok, gave it a final coat of primer and flatted it down eventually to 1200grit.
sprayed it with 3 coats of cellulose black, the final coat with lots of thinners, it looked ok till i pushed the car out into the daylight and then, Oh dear! looks worse than when i started, from some angles you can see loads of marks and dips in it.

Iv'e filled and painted stuff before, mainly bike tanks and been very happy with the results, but this has been a complete disaster, i think the problem is partly because the panel is flat (or should be).
Can anyone offer any advice?

TIA

Wadders

Try some primer filler. You'll need a good compressor and a nozzle size like 1.8 or 2.0 and use a block when you flat it off. You can put it on like pebbledashing and then rub it down to the thickness you want if you have the patience. It rubs down o.k with 360 to 400 wet and dry to start with.

yours, Pete.

quote:

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Originally posted by Wadders
snip
sprayed it with 3 coats of cellulose black, the final coat with lots of thinners, it looked ok till i pushed the car out into the daylight and then, Oh dear! looks worse than when i started, from some angles you can see loads of marks and dips in it.

Wadders

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Probably cos i'm a Tw#t Terry!!!

iv'e just been searching tinternet for clues
and one site suggests that when spraying GRP, lots of thinners is a very bad idea as it draws repairs up through the finish layers, i think this is what has happened to me, the final finish is fine, lovely and shiny, unfortunately from certain angles you can see filled areas and scratches etc below the surface.

Why did you put load s of thinners in the final coat?
If the previous coats were going on ok why change?
Did you let the other coats flash off before recoating or were they still wet?
If they were still wet you will probably have what is called orange peel. The paint finish looks like the surface of an orange under a magnifying glass!
If this is the case then just flat it back until it is all smooth and polish.

Terry

I have used primer filler Pete, but am handicapped by a small compressor and a low cfm gun (1.4 nozzle) i can barely coat the panel before waiting for the compressor to refill. Also the panel was really uneven to start with, one area in particular about 6"-8" round was approx 3/8" deep, and for a supposedly flat panel, it looked like the north sea.
i think the filling is where i'm struggling, cos its such a big area i have had to keep adding bits of filler.
Sould i rub it all back to GRP and start from scratch? or can i just key the finish and try more filling/priming?

Ta

Al.


]Originally posted by Peteff
Try some primer filler. You'll need a good compressor and a nozzle size like 1.8 or 2.0 and use a block when you flat it off. You can put it on like pebbledashing and then rub it down to the thickness you want if you have the patience. It rubs down o.k with 360 to 400 wet and dry to start with.

yours, Pete.

Rub down the bits that look worst with some roughish abrasive paper then try some stopper on it, proper name is cellulose putty, it fills in scratches and surface hollows, then try your 400 again. Don't put stopper on too thick or it takes ages to go off, just scrape it across the surface with your applicator(bit of plastic) to fill the ruts. Worth a try.

yours, Pete.

Cheers Pete i'll try that, although last time i tried to use cellulose putty, it kept blistering up when i tried to prime over it, maybe i was too impatient and didnt leave it to dry long enough.


i]Originally posted by Peteff
Rub down the bits that look worst with some roughish abrasive paper then try some stopper on it, proper name is cellulose putty, it fills in scratches and surface hollows, then try your 400 again. Don't put stopper on too thick or it takes ages to go off, just scrape it across the surface with your applicator(bit of plastic) to fill the ruts. Worth a try.

yours, Pete.

Obviously it is difficult to give advise on something I cant see, but I would suggest that before you flat it down and start again, let it harden for a couple of weeks, and then flat it down with 1200 grit wet and dry (using a sanding block and frequently dipping the paper in water with a little washing-up liquid), and then polish using cutting compound, or T-cut. You will be surprised at what will disappear.....
Of course, if you have big ripples/repair marks, you will have to start again, but the secret is to use a block for flatting down any repairs on flat panels, especially with black paint as this colour shows every last mark (as you now know....)

[Edited on 7/7/03 by Stu16v]