The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support ExtremePSI
Please Support STM Tuned

What causes paint to do this while painting?

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

ziggo0

10+ Year Contributor
774
7
Oct 13, 2009
La Porte, Indiana
You must be logged in to view this image or video.


You must be logged in to view this image or video.


Prep includes sanding the plastic, brake clean to get oils off, clean with dish soap/clean water, primer, wet sand, clean with dish soap/clean water - then what you see happened in a few spots. Paint was applied lightly and this still happened...
 
That happened to my brother in law all the time, he now uses a pre spray paint or something???I can call him tomorrow and find out the name. It does not happen too him anymore when he spray paints stuff using that stuff before he paints.
 
My guess, oils from the soap or water. This happened to me once on a plastic when i didn't apply any primer. You primed it though but then washed it with soap and water and finally applied the paint, right? I would have just applied the paint with out wash.
 
Oh, I forgot to add in there right before primer I use adhesion promoter, is that what your talking about?

My guess, oils from the soap or water. This happened to me once on a plastic when i didn't apply any primer. You primed it though but then washed it with soap and water and finally applied the paint, right? I would have just applied the paint with out wash.

Primer needs to be wet sanded so there is no getting around a rinse...perhaps it is the soap, i'll try that on the next few pieces (converting the whole interior to black..>!)
 
The problem is most likely contamination, something like armor all will fisheye/distort long after the last time you put it on. It may have contaminated the plastic, and the brake clean didn't get it all diluted or clean.
Did the brake clean discolor the plastic?

Do any research on dying the plastic for interior pieces?
 
May want to use some paint thinner to clean the part before applying the final coat. I've personally never seen anything like that, it almost looks as though the peice was flexed before the paint cured.
 
Looks like silicone residue, it can be difficult to remove, I would use a paint prep designed for silicone. Brake wash does well in removing oil, but doesn't terrible job with silicone.
 
I agree with the above. Brake cleaner and paints don't go together very good. Depending on the paint supplier your using. You should use something like power clean which will get all the oils off and not contaminate. To paint plastic, I would clean with power clean or another degreaser, dry and then wipe down with a wax and grease remover like dx330 from PPG and then spray a adhesion promoter and then paint. Hope this helps.
 
There a few things you did wrong. 1st you should have used a degreaser for paints, no dish soap it will leave a residue. Before paint you use something like Final Wipe to get rid of any residue left from sanding, oil on hands etc. Anything you leave on the surface can ruin the paint job. When wet sanding you only need 1-2 drops of soap to help lube the paper, no more and make sure you use a prep wipe after to get all residue off.
 
Where all the spots that failed in the sharp inside corners and rigdes?
Which means there was something still in there oil/water/etc.

As said above try and stay away from using soap at all if you can, and on some of the harder interior plastics (i.e. ABS) I like to some denatured alcohol for a final clean before anything goes down, which also helps with the static issues.
 
that comes from mixing paints... for example oils and acrylacs.. not a speller so bare with me...
the best way to avoid it is to wash it in rubbing alchol and then use a automotive grade pimer... and dupli-color rattle can spray paint with a couple coats of clear
 
the problem i had when painting plastics is that the first coat when on great, but when i let it set up and resprayed 15 minutes later, the new coat made the first coat start to wrinkle just like that.
did it wrinkle on your first coat or after that?
 
the problem i had when painting plastics is that the first coat when on great, but when i let it set up and resprayed 15 minutes later, the new coat made the first coat start to wrinkle just like that.
did it wrinkle on your first coat or after that?

Different paints cured at a different rate?
 
Incompatible substrates. Either your paint doesn't like your primer, your primer doesn't like your paint, or both don't like the adhesion promoter or the plastic's polymers.

If you look at how the lifting has occurred, it's happening around the groove where the paints / primers may collect and not dry fully. I'm guessing that something wasn't fully dried with the topcoats were applied and it caused the topcoat to lift.


I've never used actual sandable primer when painting plastic. PPG sells a plastic primer (otherwise known as adhesion promoter) in a spray can which is nothing more than a thin, reducer-like product which literally softens the uppermost layer of plastic in preparation for a topcoat. You must be quick- the topcoat must be applied within 20 minutes after the plastic primer has been applied.

It works great- seven years ago I sprayed an all-plastic shelf in my girlfriend's bedroom to match her wall color, and the shelf is still in her room; no paint cracking or flaking despite tons of items being placed on the shelf over the years. It was an experiment, and it's withstood the test of time.
 
Guess I'm gonna have to go get some actual prep wipes after all. I wet sanded with water the areas that were screwed up. Rinsed it off, wiped it down with a clean cloth rag, no soap. Second i started spraying it INSTANTLY did the same thing.
 
Incompatible substrates. Either your paint doesn't like your primer, your primer doesn't like your paint, or both don't like the adhesion promoter or the plastic's polymers.

If you look at how the lifting has occurred, it's happening around the groove where the paints / primers may collect and not dry fully. I'm guessing that something wasn't fully dried with the topcoats were applied and it caused the topcoat to lift.


I've never used actual sandable primer when painting plastic. PPG sells a plastic primer (otherwise known as adhesion promoter) in a spray can which is nothing more than a thin, reducer-like product which literally softens the uppermost layer of plastic in preparation for a topcoat. You must be quick- the topcoat must be applied within 20 minutes after the plastic primer has been applied.

It works great- seven years ago I sprayed an all-plastic shelf in my girlfriend's bedroom to match her wall color, and the shelf is still in her room; no paint cracking or flaking despite tons of items being placed on the shelf over the years. It was an experiment, and it's withstood the test of time.


He's right.Try using the same brand of paints,primers clears so that you know they're compatible.Also try to spray lighter coats.Too much solvent will cause that.
 
Next time you want to spray paint plastic, try Krylon Fusions. You don't need to prime it. Prep just consists of cleaning the piece before hand. Any degreaser and/or soap and water will work, followed by a quick blast of brake parts cleaner. Paint with Krylon Fusions directly onto the plastic. It's bulletproof after that.
 
fusion FTW on plastics.. i always wipe down with a degreaser like simple green, and hit with a primer (even tho u dont need to when using fusion) then i hit it with 3 coats,..11st a light coat, let dry 30 min, then 2 good coats bout an hr apart and a clear.
 
oil doesn't cause cook up or also refered to as lifting as shown in the picture.
Oil's or silicones cause a fisheye problem, which is where the paint will seperate causing a slight circle that resembles a fisheye.

this is most likely from using a laqure product, also reffered to as raddlecan.

if your parts have been painted raddle canned before then you may have used anothe laquqre product that re activated the previous product causing it to cook up like this.


another scenario, is that you put to much paint on at once, instead of putting really light coats waiting 3-5 min in between each coat on a 80 degree day.


another scenario is that you just didn't wait long enough between coats.


a good flexible adhesion promoter is a great way to open the pores of plastic so that you have a perminant bond but it will still cook up if not applied correctly.

One thing i do before i paint interior plastic, is to get a good red 3m scuff pad and comet and wet scuff these with the comet, so that it cleans and degreeses them while giving it some scratches for the paint to adhere..

then clean them dry . tack them off, spray your adhesion premoter, wait a couple of minutes and begin to spray your paint.

i know the pics aren't the best but this is a small demonstration on how i painted mine on my cb7

You must be logged in to view this image or video.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

You must be logged in to view this image or video.


the same goes for other plastics like shown in the pic,,, i had decided to use cobalt candy blue over the dry carbon fiber mirrors, as well.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

You must be logged in to view this image or video.



You must be logged in to view this image or video.
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top