I was wondering what would be the best bare metal prep to stop any pin rust spots from coming up thru the paint in a couple months? I have painted my hood twice now and i get a little pin head bubble that comes up in a month.
Picklex is a metal conditioner which will neutralize any rust. It's applied on all bare metal surfaces before primering.....It's HIGHLY regarded by the posters on the autobodystore.com message board. Check out the message board here: http://www.autobodystore.com/cgi-bin/config.pl?index
What kind of primers have you used? If you do use Picklex do not use an etch primer, use an epoxy over the picklex.
???!!! What would happen if you did? I've used a phosphoric acid and then etch primer. Never saw anything that said not to. What might happen?
I use a metal conditioner (acid wash) directly to bare metal. Once that has been applied and dried i continue with the etch primer. You can then apply your 2k primer over that. I have also listed i few other thing that might be happening to you only because i can't see what you are looking at. Hope these help. Probable cause: #1 You know you might have what they call "solvent popping" This happens when you don't use the proper reducers/thinners for your climate(temprature) along with the fact that you might not be waiting long enough between coats. (recomended 15 min.) If your spraying to quickly it traps the solvents trying to escape thus giving it the look of little pin marks. It creates a kind of bubble effect. Almost like boiling bubbles as i put it. #2 You could also have contaminated air hoses, which in some cases may have tiny particals or droplets of water in your hoses. These will also be trapped under the surface only to come up later. Sparying with this problem would result in the same effect.... or something close. I change my air hoses every 6 months to prevent this problem. I also have a top of the line Air Filtration System to keep an water or oily substance out of my hoses.I realize you might not have the air filtration system but you can always go and buy those filters you put right on the end of your gun. Use the Big Black Round ones sold by Devilbiss or maybe something equivalent usually orange in color. Once again i hope this helps. GOOD LUCK. Jarrod :TU:
The acid in the etch primer (we are talking REAL etch primer that contains acid) can attack the acid that may still be on the surface left from the metal conditioner and it doesn't adhere to the metal as designed. Some etch primers have this recommendation in the tech sheets. S-W for instance does, I just looked at a few other tech sheets. DuPont doesn't say NOT to but in the "surface preparation" of bare metal it doesn't tell you to use a metal conditioner either. It does say just clean with a "wax and grease remover". Sikkins "Washprimer" again, sand the bare metal. PPG's DX1791 specifically says "If applying DX1791 to clean, bare metal substrates metal treatmens are NOT REQUIRED OR ADVISABLE". The bold large type you see is not my idea, that is just as printed in the tech sheet. You see, it is redundant if nothing else.The acid etch primer is ETCHING so you don't need the other. I personally have seen the failure it causes. I had a large manufacture of a piece of equipment that I serviced as a paint rep. This piece of equipment had one large piece of aluminum on it. I was called out there to find they had a complaint that the etch was easily scratched off these alunimum pieces (along with the paint of course). Well, after a little detective work, sure enough, they were washing the aluminum in a phosphoric acid solution prior to priming. I had them stop the practice and the problem was gone.
