I’ve just had a call from the bodyshop that has been working on my car. They sprayed it this morning (normal 2-pack paint I assume), and apparently the paint has reacted with silicone under the bonnet (it uses silicone brake fluid and there is a fair bit of it around the bulkhead and engine frames) and the paint is ruined.
They’re not actually painting the under bonnet area, but they say the fumes must have blown the silicone out.
I’m on my way over there now to see what’s going on, but I’ve never heard of this happening.
Yes, I’m afraid I have, more than once. And it’s the second reason why I will not use silicone brake fluid. The first being a sudden and very scary loss of brakes on two occasions in different cars equipped with the stuff.
The bad news is that the bonnet, scuttle and roof are ruined. They have to let it harden off over the weekend then rub it all down again and start over.
Hello Tim,
Silicone can be the bane of a paint shop and the reason why few, if any, will have any product containing silicone in the building.
It causes a paint condition called Fish Eye; the name is very descriptive of the appearance in the paint. Ironically, Silicone drops could be added to the paint, but it is a work around, not a panacea.
Its mostly seen when paint work is carried out over existing paint that has been subject to car polish that contains silicone. Usually Wax and Grease Remover, or Prepsol used in the preparation for painting is sufficient to remove traces of it, but on cars where the owners have lovingly applied it frequently for years, it may be hard to remove.
Even using silicone based polish on a vehicle 50M and more away from a panel being prepared for paint can cause problems with dried silicone particles floating through the air and landing on the panel.
Don’t shops use a wax and silicone remover anymore? I don’t know if they are 100% effective but it’s worth asking your shop how they prep the surface prior to painting.
The whole of the outside of the body has been stripped, straightened, etch-primed, etc, and so there was not a trace of anything on the bit that was going to be painted. But the issue seems to have been that the film of silicone brake fluid that’s smeared round everything in the engine compartment and the underside of the bonnet got dissolved and spread over the top of the car (possibly blown out through the louvres).
This despite the under-bonnet area being well masked off.
It’s heart-breaking for me, but more so for the guy who did the painting, and has to do it all again. He seems to think he can clean it and mask it better next time, I just hope he’s right.
Odd that this wasn’t an issue when they did the primer. Maybe it’s a different solvent.
I also wonder if it hasn’t contaminated his entire spray-booth.
Hmmmmm… I’ve always been highly suspicious of such claims… I painted a lot of cars when I was younger, and using fish-eye remover in the paint always dealt with it effectively. My own cars, for as long as I can remember, I periodically clean the engine bay, then empty a full can of silicone spray lubricant on everything, to keep dirt and grime from sticking. The engine bay of my '01 325i looks just like new, after 18 years/225K miles. When it had an “incident” with an air-borne deer about 7 years ago, it was repaired, and the whole front end re-painted. Came out perfect.
Personally, I think this is something the painter did wrong. Perhaps he forgot to add the fish-eye remover, or just didn’t think it worth the cost. Silicone waxes, and other products have been in common use for many decades, and painters NEED to be able to deal with it, because it is completely unavoidable. I don’t think there’s any magic to it, and no reason for you to feel bad.
Tim, there many causes of fisheye. Water or oil coming out through the air hose. Air tank and water trap not drained. In the end it doesnt matter what the cause as long as they can fix it. hope they get all the contaminants off before they sand it down. Good luck with it.
Cheers Jim
I’ve had many problems with silicone contamination, especially back in the day with acrylic lacquer. There was a whole literature based on the problem. Sanding before thorough cleaning with prepsol was one cause. It was generally agreed that it was best practice to avoid the trick of simply adding more silicone to the paint (fisheye remover) if at all possible.
Hello Tim,
The “fish-eye remover” being referred to as a paint additive is pretty much pure silicone, referred to in my first Post. Its not general practice to use it preemptively, but more in a reactive manner.
In the vast majority of cases, thorough preparation using Wax and Grease remover, or Prepsol is sufficient.
Having read your further Posts above, if the area that was originally contaminated with silicone was not disturbed after masking, then a more likely scenario is that the painter contaminated the the outside of the car with material that has been in contact with silicone. Oil in the delivered air is a cause, but it generally presents over the whole of the car, not just in an isolated area.
