Yellow showing through new white paint

[Packy]

I tried posting this in the paint and body work section but got no responses.

I had my neighbor at work give me a "discount" coat of white paint on the inside of my engine compartment. Welllll, there was a bunch of yellow bleed through. He is the used care salesman type of person and is basically full of ****, so I don't trust a word he says anymore. I suspected the bleed through was from the hardener not being mixed correctly or something like that but he said it was gray paint and green primer not acting right with the paint he used. I'd like to know the real reason why it's coming though. I'm glad I had him do a test in the engine compartment instead of painting the whole car.

Either way, he isn't painting anything else on the car.

Thanks in advance.

-P

[911Freak]

As a former autobody painter, I would say its either the new paint reacting with the old paint and you are seeing the result of this chemical reaction, or, the paint is transperent and your seeing through the top white soat.

I'm pretty sure its the paint reacting together though. Hopefully it hardend and you can sand it all off and repaint it properly.

A good sealer between the base/color coat and the old paint as well as knowing what type of paint your covering will avoid this from happening in the future.

I'm surprised it didn't wrinkle up on him!

I can only offer this having not seen it first hand.

Good luck getting it corrected and properly painted!

Cheers,
Jason

[porwolf]

Old oil residue coming through? Was the area properly cleaned and primed?

[Bob Kontak]

The engine's original coat is Glasurit single stage urethane with hardener. You better have a flame thrower if you want to make it "wrinkle up".

He said green paint? I don't see a green car. The paint in the engine compartment was green?

Did the guy use lacquer? Give us some data. Was it a krylon spray can? Did you buy him the paint at the Glasurit jobber?

[Packy]

I'm not sure what he used. He won't tell me the details and keeps rambling on like an idiot on meth and I can't get any solid info from him. I'm glad I only did the engine compartment.

The green paint was crappy spray on primer. I know the paint was wiped down clean with alcohol or something so it isn't oil. He said he sanded it all down, but when I look closely he didn't even remove some of the rubber gommets/stand-offs that hold the ECU and other electrical boxes off of the body. He didn't use a sealer at all and I think the paint was a two part epoxy. But I didn't know they made epoxy paint. I thought they just made epoxy primer and sealers.

The guy is an ass. I feel like an idiot for giving him a shot.

One question, if it didn't peal or seems solid enough, can I just sand the coat a little, put down a sealer and then paint over it? I don't want to have to sand off the entire new coat.

[911Freak]

You could probably get away with painting over it... Or it could blow up into a big mess with the new sealer/paint biting into that fresh paint and reacting. I've seen it happen with that cheap epoxy crap.


I'd give it a couple of weeks (ymmv) to totally cure, then scuff it up and lay down the 1st 'lite' coat of sealer, wait for full flash (15min+ depending on temp) then follow with another med coat of sealer followed by your base. You don't want to push the paint by hammering it with med to wet 1st coats, that'll bite into the sanding groves in that fresh epoxy and the new paint bites in and it all blows up in a nasty mess...

So, you want to build a bridge between paint to eliminate them from interacting with each other. That's where the lite 1st coat comes in.

Can be done...

Good luck

Btw tweakers, 911s and paint are never a good mix

[Bob Kontak]

Believe you can as long as the issue is not oil like porwolf mentions.

I would use a 3M scuff pad since you should have the pebble surface undercoating. A rattle can sealer from the local auto parts store may work just fine if clean, dry and a warm enough day.

There are some things that the DIY painter can do without a compressor that work real well if you get the right finish paint and a Preval sprayer. If you wish to go that route, advise. This would be for the engine compartment only but could turn out real nice.

[Bob Kontak]

I agree with 911Freak. I am being too casual about what your existing paint may be.

[lonewolf]

If he sanded or scratched through the original engine undercoat then that will react with the white paint and a yellow stain or streak like look will show through.
you could paint over it ten times and it will still bleed through.
Those areas DO need to be sealed.
An easy way would be to use paintable undercoat by wurth and just put it on the areas that reacted and then repaint the whole area.
I've done this before and it works well.

believe it or not any of the pebbly surfaces can be painted by a DIY by just using a brush.
it turns out excellent and no one could ever tell it was done by a brush.

[Bob Kontak]

Originally Posted by lonewolf

An easy way would be to use paintable undercoat by wurth

Pretty sure this is water base and would work real well. Plus you could have control over where the undercoat and paint goes and not have to work real hard to mask everything off.