Base wrinkled over denibbed epoxy sealer

[fireboat]

I did a search but I didn't see an answer to this. I'm painting a new plastic fascia but I had a problem with some small areas of the base wrinkling over where I denibbed the epoxy sealer. I am trying to figure out why this happened so I don't do this again.

I had sanded the fascia, applied adhesion promoter and SPI epoxy followed by SPI 2k primer several hours later. The next day I sanded it with 600and shot a layer of reduced epoxy as a sealer. I had several gnats commit suicide and several dust particles land in the wet sealer. I waited about 30min and very lightly sanded these spots, not going through the sealer. I waited 15-30min and shot the activated base. While applying the universal clear, I noticed the base was starting to wrinkle in the spots I sanded. I continued to spray the clear that I had in the gun. Temps were about 80-degrees. I let everything set for several days and I lightly sanded the clear, shot some more base and clear again and it came out fine.

But I was wondering what happened? Should have I shot another coat of sealer after denibbing? Or should I have waited another hour or two before applying the activated base? Thanks.

 

[jcclark]

Was it pr-primed?
A lot of the new primed plastics that are primed from the factory
are having this problem. Especially aftermarket bumpers.
Some dealers are stripping them completely and repriming them.

 

[Barry]

True what Jim said but also, could be the adhesion promoter, especially if you did 2 coats and waited too long, it will get into the epoxy and break out where you nib-ed it and get into the base.

 

[fireboat]

The plastic was raw and not very good quality so I sanded it, did the adhesion promoter, epoxy and 2k primer and then blocked it. Everything seemed good even after I sprayed the epoxy sealer. It wasn't until I shot the base that it started to wrinkle in the spots where I had sanded the sealer. Perhaps the freshly sanded sealer allowed the solvents in the base to penetrate underneath it?
I have the feeling that perhaps I should have waited another day after the denibbing, and then shot another coat of sealer and then the base and clear? This would have given me a cured layer of epoxy to work on.

 

[Barry]

From my experience, if the problem was cause by the plastic or the adhesion promoter, it would have done it the same day or a month later and it is always the base or most of the time that will do the wrinkling.
It has nothing to do with you, as this is a major problem with a lot of shops and our only line of defense that I can figure out, is with the adhesion promoter do the following to a tee.
Spray one medium wet coat. (ONLY)
Wait EXACTLY 15 minutes and then spray the sealer or epoxy or base and that will pretty well solve the problem.
The only thing that won't solve the problem on is the ones that come with a defective primer.

 

[fireboat]

Thanks Barry, I'll do that the next time. I think you hit it on the head. I remember now about a year ago I had a more severe wrinkling issue and it was when I had used adhesion promoter also. Thanks for your help.

 

[crashtech]

Out of curiosity, would you mind telling us what basecoat brand and basecoat reducer were used on this job?

 

[fireboat]

This time I was using S/W Ultra 7000 basecoat and Matrix medium reducer.

 

[Bob Hollinshead]

What fascia? What type of plastic? The denibbed areas were showing some bare plastic then you resealed and applied base?

 

[streamlinecollision]

I have had a simular problem with aftermarket bumpers. Not wrinkling but I used SPI sealer over the scuffed primer that comes on the aftermarket bumper and it mudcracked! Have never has this issue in the past with the sealer or the epoxy. Supplier took back bumper & replaced it with new one. Any ideas on why this might happen? As I said never an issue in the past just this one time. On the inside of the bumpers there is usually a sticker saying it is coated with waterbourne primer & to sand with 600 grit or finer. Lately the stickers have changed to stating solvent primer. In my mind it should not make any differance as long as it is cured sanded primer.

Rob

 

[Barry]

I have had a simular problem with aftermarket bumpers. Not wrinkling but I used SPI sealer over the scuffed primer that comes on the aftermarket bumper and it mudcracked! Have never has this issue in the past with the sealer or the epoxy. Supplier took back bumper & replaced it with new one. Any ideas on why this might happen? As I said never an issue in the past just this one time. On the inside of the bumpers there is usually a sticker saying it is coated with waterbourne primer & to sand with 600 grit or finer. Lately the stickers have changed to stating solvent primer. In my mind it should not make any differance as long as it is cured sanded primer.

Rob

This has been a MAJOR issue for last 2 years on and off, who knows why, some of these the primer is great, others, I swear was scrap stuff left over.
I'm sure they said you are the only one that had this problem but let me assure you they took it back because they KNEW!
Some of the bigger shops are even getting some labor credit, when they get one of these bumpers.

 

[fireboat]

What fascia? What type of plastic? The denibbed areas were showing some bare plastic then you resealed and applied base?

It was a rigid white plastic grill and headlight support for a Mercury Marquis. It is for my son's freind. He had ordered a CAPA certified aftermarket part but Fedex must have run over it with a truck as it was smashed when it got here. The company he ordered it from refunded his money but refused to ship another one saying they were having too many damage claims for this part and are going to re-evaluate their shipping process.
So he ended up ordering some cheap chinese part from somewhere else that was crudely made.
When I denibbed it, I just lightly sanded the epoxy sealer without breaking through I thought. I was wondering if by sanding the sealer it allowed the solvents in the base to leak through to react with the adhesion promoter underneath.

 

[Bob Hollinshead]

ABS plastic I bet, you shouldn't use promoter on ABS.

 

[Tinman]

I have had a simular problem with aftermarket bumpers. Not wrinkling but I used SPI sealer over the scuffed primer that comes on the aftermarket bumper and it mudcracked! Have never has this issue in the past with the sealer or the epoxy. Supplier took back bumper & replaced it with new one. Any ideas on why this might happen? As I said never an issue in the past just this one time. On the inside of the bumpers there is usually a sticker saying it is coated with waterbourne primer & to sand with 600 grit or finer. Lately the stickers have changed to stating solvent primer. In my mind it should not make any differance as long as it is cured sanded primer.

Rob

Had some here too,a couple plastic fenders and a bunch covers. For some of these suspect solvent primers on these aftermarket parts,I stopped using a sealer or expoxy sealer before base and went directly to base.Not ideal I know,but hav'nt had any issues doing that way for awhile.I know I sure don't want to waste time trying to strip bare,almost more cost effective to by an oem part in that case.Never had too many issues with the waterborn aftermarket stuff(other than the orange peel texture),seems to only be with this newer crappy solvent primer they started using.