OI just painted my battery tray with Por 15. This is the second tray I have done. Both were sand blasted, marine cleaned (por 15 product), metal preped with the POR 15 metal etcher, then painted with POR 15. After painting I noticed lots of the tiny dots in the finish as if it is dirt. Any body else have this issue? Yes, I blew off the battery trays with air before I started all of this, to hopefully eliminate any remaining sand. I notice when I apply the metal etcher lots of tiny bubbles form, so I wipe down the battery tray with a rag to smooth it out. Could that be the issue?

Can POR 15 be painted at this point to get rid of the shiny finish?

Don't know what the "dots" are, unless it's lint or the like from your rag when you wipe it down. As for painting on the POR 15, yes you can. But you need to rough it up a little first.

I a not sure, but I think you are not supposed to "just wipe off" the POR Metal Ready.

From the POR 15 Web Site......
Must I wash off the Metal-Ready after using it?

Yes. Otherwise, a powdery residue will be left after the metal dries. This can be removed with a wet rag or by
hosing it off. After washing off the treated Metal-Ready surface, dry it with warm air (hair dryer) or with towels,
etc. Flash rust could appear if the surface isn't dried quickly, but your first coat of POR-15 will remove it and adhesion
will actually be enhanced because of the flash rust. Remember, POR-15 can be painted right over rust.Unless a part was really greasy and I could get it blasted really good (no grease stains), I never do anything to freshly sand blasted parts, except blow off the sand grit, rinse with water (I know, sounds wierd, but any flash rust won't hurt it), and paint.

POR really bites into sand blasted metal, but it's hard on brushes. I use the 1" hair brushes on sand blasted parts because it chews the foam one up. But if it's not sand blasted, maybe just wire-wheeled, then I use foam.

The dots could be little tiny CO2 bubbles, they form if the humidity is too high (or the surface isn't bone-dry. POR gives off CO2 gas as it cures, and since POR cures in the presence of moisture, what happens is the POR cures before the CO2 bubbles dissipate and "flow out" again.

Sanding POR sucks but can be done. An easier method is the Tie-Coat primer they sell, you paint right over clean but unsanded POR, then you can paint straight over the primer with anything you want, no further sanding.

I had this issue too, and yes it was in cold-moisty wheather. I was kinda in a rush before the raining season out here started. All I did was pop the bubbles and sand it a little and reapplied another coat. Also, I remember reading in the searches somebody had good luck w/ spraying a primer on the POR surface then your top coat. I did this and sanded the POR before the primer, comes out alright. Good Luck w/ that.

Where did you get the quote for washing the powder off? I rinse the heck out of it and still always get that, but it is my understanding that is what the por sticks to best. There is no mention of it in any of their tech sheets or FAQs.
:confused:

It says on the metal ready bottle to wait at least 20 or 30 min. then wash off w/ water, then you let that dry, then you apply the POR. I don't think you should have that white powdere after you wash it off, only when the metal ready dries.

The quote I put on the post came from the POR web site.

DG

Somewhere I read to never shake POR-15, always stir. Air Bubbles in the paint?

Lots of good input here, I will re-evaluate my processes. Foam brushes could be a problem to, I guess.

I doubt the foam brushes would introduce air, if that's what you are thinking. Most bubbles flow out, anyways.

Yes, always stir, never shake.. That creates way too many bubbles to flow out.

Also, you can leave the battery tray in the sun for a week and the high gloss will disappear. If you don't like the effect you can still paint over it whatever color you want, but this method is a lot less work! The sun won't harm the coating in any other way other than the gloss.

Bubbles in battery tray paint is easily solved - put your battery on it and you'll never notice. Unless its the highlight of your ride and you like to yank your battery out at shows and let everyone gawk at your tray. :D


I kid.

One thing that confuses a lot of people and in my opinion, causes a lot of grief with Por 15. If you sandblast the part, there's no need for the Metal Ready etching solution. Metal Ready is used on slick shiny sheetmetal surfaces that you may not want sandblasted or don't need sandblasting. It shouldn't be used on sandblasted surfaces or cast iron because you can't get it all off before painting.

The other advice about stirring and not shaking is sound advice. Also, it doesn't hurt to mix in a couple of drops of fish eye eliminator.

Could be when you blew it dry, water or oil blew through your line onto the surface. The bottom line is that you contaminated the surface with something.

Part of the problem may the fact that you blew dry the tray before painting.I'm assuming that you blew dry the parts in the same garage that you painted it in and not a spray booth. When you blew the parts dry, you may have launched dust particles into the air. Then the dust landed into the paint while it dried. Recommend prepping the parts the night before(so the dust settles),then wiping the parts before painting.

You must rinse the Metal Ready off thoroughly after about 15-20 minutes.... let part dry completely, then brush on POR-15.

Were you sweating when you painted it? I have seen bubbles appear in parts painted with POR 15 that have come into contact with H20.