redknight1

I've been trying to paint a few of these parts off the roof on my truck. I've prepped them with wax n grease remover, scuffed them with a scotch bright pad. Used adhesion promotor, and for the love of god they keep getting the fish eye effect as soon as I put black paint down. I'm using black krylon plastic paint. Any advice? Here are two of the parts I'm painting to give you an example.

Summers22

iTrader: (2)

What are the air conditions ? Cold, Warm? Humidity? Shaking the cans for a full 2 minutes and doing a test spray on a piece of scrap? I always, even if its warm out, soak my spray cans in warm water for 10 minutes for a more even spray.

Wanna Ride

Someone has covered them with Armor-All or similar protectant. Wash them a couple dozen times with warm, soapy water. Well... not a dozen, but it will feel like it. It's hard to get that kind of stuff off of plastic parts.

Scrub them down really good with a tooth brush and Simple Green. Scrub hard, and cover every square centimeter. Get two or three buckets of warm, soapy water and have the hose close by for fast rinsing. The soapy water should almost be too hot to leave your hand in for more than a few seconds. Do one part at a time. Drop the first part in, let it soak for about two minutes, then rinse the bejeezus out of it with the hose, and immediately throw it in the second bucket of soapy water, for about three minutes, and then rinse it like crazy again. Then throw it in the last bucket for about five minutes... and you guessed it again... rinse like mad.

Now dump all the water, and rinse the buckets really good with some Simple Green and water. You have to be sure not to leave any of the contaminated water or film in the buckets. Wipe the entire part down with rubbing alcohol, and let it air dry.

During this process, warm the cans in a separate bucket of warm (not hot) water. And don't spray in temps below about 60 degrees.

Then try to paint. If it fish-eyes again, start the whole process over and do it again. Some times, it's just tough to get rid of all of that Armor-All.

redknight1

what if I just run them through the dishwasher?
The conditions are inside, probably 68 degrees. Low humidity.

Summers22

iTrader: (2)

^^^Great advice on the rubbing alcohol. It really makes the paint stick bettter when you clean with it right before paint.

redknight1

alright I'll try alchohol. Should I be using primer between the adhesion promotor and paint?

powerranger262

I always wipe everything down with a very high quality adhesive remover that body shops use. Then, make sure you have gloves on whenever you touch the parts you are painting. The oils from your fingers will ruin a paint project everytime.

kobayashi maru

If you get fed up you can try plastidip or a vinyl wrap on those pieces.

Wanna Ride

I wouldn't. Could be too hot, maybe, maybe not. But more importantly, I'd be concerned with grease/oil residue in the dishwasher. The problem you're fighting already, is from oil or similar substances. There's a very distinct reason why most body shops have a practice of no penetrating lubes, oils, or interior protectants (WD-40, Armor All, tire foams, etc) even being stored in the same building as the paint booth. Literally, one drop of Armor All can, and will wreak havoc with paint adhesion, specially if it vaporizes in the air around the painting area. Absolute number one enemy of adhesion, is oil.

I've never been a fan of painting interior plastic parts because they never look just right in my opinion, but I don't believe you would need a primer if you have a good promoter. But there's been a lot of developments in that particular corner of the industry in recent years.

Did you happen to get any pics of the parts when they were painted, with the fish-eye?

jshillin

iTrader: (1)

Armor All is the devil to a painter... Scrub them with hot water with lots of Dawn dish detergent with a scrub brush. Then acetone and/or lacquer thinner and finish with wax & grease remover. Use a good adhesion promoter, then primer before painting. It's a tedious job, but that's the only way you'll get good results.