Over the weekend, I painted a spare bootlid for practice and it worked out quite well I thought. Followed Lord JAM's method (etch x 1, primer filler x 4, acrylic (metallic in my case) x 4, and clear 1K over the top x 5).

The gloss on the final finish was really quite good I thought, but there is orange peel over the whole panel. Not too dramatic, but enough to make me want to work out what I did wrong before I paint the 850.

The Haynes Bodywork manual says it is either too much pressure or not enough. How helpful... anyway, I was using an HVLP gun, with 35psi into the gun and adjusted the pressure at the gun to give what I thought was roughly the right 'psssst' out of the gun. Is it likely to be too low? Or too much paint in one coat?

I tried to sand it out, but ran out of patience and 600 grit paper. Plus I tried to use the buffer on it, and it dug in twice causing little 'wounds' in the finish so I put it back on the shelf...

I'll put a photo up tonight, but it's your common or garden orange peel...

How'd it go with the metallic.....

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[Maverick] 1971 Mini K

did u sand back the colour coats before applying a clear coat? Best to get rid of oragnge peel in that coat before tacling the clear coat i would have thjought

Cheers

Aaron

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Here's orange peel finish (close up):

and here's the overall panel, which looks okay to my non-car friends but I'd like to do better on the actual car.


It's a BL colour, probably from a late model Rover called Metallic Red but is more like a reddish bronze.

Not sure about sanding the orange peel out before the clear coat - I might take the panel in and get some advice from the body supply shop.

At a guess, i'd say yes your pressure was too low. I typically use 40-50 for a conventional gun and up to 80 for the HVLP(depending on what type of paint is being sprayed).

But it all really depends on your setup. The compresser, the gun (type: either gravity or suction as well as needle size), the i.d of the air lines, the i.d of the fittings, etc as to what pressure the regulator should be set at. Did the gun come with any recommendations for the regulator pressure or the pressure at the air cap?


If its a metallic and you sand it smooth before the clear coat, you can loose all of the pretty little metallicly flakes.

That's what I thought. And the advice about pressure being too low is probably right. 80psi for HVLP? I'll give it a crack. It's a fairly good quality gun (NZ$150), gravity fed.

The feed line is one of those curly wurly ones so there's probably pressure loss over that, but it did seem to spray okay. It's a 3hp belt drive compressor with a big tank.

WIth the metallic, what i did was to spray it on to get the colour to cover, sand that back smooth and then put on a final light-ish coat to get the metallic flakes back. You can also then thin it down about another 50% to make it really thin and put some more on again to help make it really flat ( I havent tried this myself yet). But be careful with runs!!

The HVLP I use is a conventional feed type(~ $800) so that puts the pressure up. Plus it was also up to 80psi, which is normally what ive used for the thicker crap like epoxy high builds, polyurethane topcoats etc. From memory i used about 60-70psi when i sprayed acrylic.

The line is most likely a bit small, especially for a HVLP as you need the volume of air. I think the curly ones are 3/8"? where as its recommended ,for my gun at least, to have 1/2" i.d lines.

What's the CFM rating of the compressor?

The paint doesn't look all that bad, if it was me and if it was thick enough, i'd get out the sander with some 320-400 on it, go at it until it was smooth-ish and then go the hard yards with with wet rub and the finer grades.

What kind of preparation did you do after you applied the Primer/filler???

judging from the number plate area it looks like it hasnt been rubbed at all or it could just be the way the pic came out. For Acrylic i'd start with 320 and work my way up to 800 wet and be finishing off with 1000 -1200. You'll need to make sure you have adequate primer on here to do so, may even need to primer it twice.

If your spraying a metallic base coat i wouldnt be rubbing that down between coats at all like mentioned you'll only disturb it and ruin the effect. I'd apply 2-3 clear then rub the clear with 1500 wet then another 4 coats of clear and then 1500-2000 wet rub it before buffing.

Its all very hard to determine exactly what caused the peel, whether its surface prep, air pressure, technique etc. without seeing the panel right in front of you.

I'd keep trying with different methods on your spare panels until you reach a method your happy with that produces the desired results ( everyone has different ways of painting acrylics)

Thanks for the advice. I stripped it to bare metal, and gave it one coat of etch, then four coats of primer filler which I then sanded back with 400 grit.

The orange peel probably occurred in the metallic, but it really noticeable in the clear. I'll keep practicing and see if a higher volume of air helps. I'll also try running progressively more thinners in the clear coats - might help.

Once I do the 850, I've got my Commer van to do, and then my Clubman, and then (four decades down the track at the current pace) my Clubman van.