Paint adhesion
 

For the first time in years, had a shell flake a plain fluorescent yellow around the front wheelarches and bumper. Customer not entirely chuffed, but I think tbf, it was simply too fresh and he did smash it into just about everything on its first run.... Did warn him... usually leave shells somewhere warm for several days before handover...



Has anyone ever used any sort of adhesion promoter?


Until now, washing liquid, cold water and a soft household paintbrush has been more than adequate to ensure a clean and grease free surface...


cheers


J

Used an adhesion promoter before, for plastics specifically and not a universal one but didn’t have much joy the paint still flaked in places. Perhaps I should have given it more than one coat however using it in other applications on a day to day basis I didn’t feel the need to. You could alternatively apply it by hand with a cloth then you know for sure you’re getting into all the tight spots.

There’s a lot of reasons it could flake, how heavy, time between coats, products have a shelf life.

If it wasn’t lexan specific paint some paints/plastics need additives added to the paint as obviously the plastic flexes a lot.

Could be so many reasons, or, ultimately like you said it was too fresh.

I’d go with your gut and if it works 99% of the time stick to doing it that way. It’s not your problem if advice wasn’t followed.

I have heard numerous stories that fluor paints tend to suffer from flaking more easily; of several Tamiya paints I know this from my own experience, too (for example adhesion of fluor orange is terrible). Which brand of fluor yellow did you use?

To get better adhesion I usually sand my bodyshells. It's not a perfect solution (particularly in creases and detailed areas), but it does help.

Also, just thinking out loud here, maybe the adhesion of the fluor paint to another paint is better? If so, it could help to spray a clear coat on the inside as a compatibilizer?

Have had flaking in the past with tamiya flourescent, lots of thin coats helps. with all paints i now go over the areas of the shell to be painted with a very fine wire wool lightly before washing

It was a fresh bottle of Auto Air/Createx Fluorescent Yellow. Touched up the damage and stuck it in an airing cupboard for a week. Seems to have solved it. A coat of Shoe Goo sealed the deal... cheers chaps

I don’t sand shells, but I do clean them with fairy liquid and a green scouring pad before I paint and that seems to just “key” the lexan slightly.
Not had any flake that I am aware of
Tend to do a few thin coats then back with white then final coat of clear lacquer

I do exactly the same but I dry the bodyshell with a high quality kitchen towel the ones that don’t leave any white bits, then a final wipe out with a fresh piece of kitchen towel dampened with methylated spirit to completely degrease the bodyshell, I’ve never had any paint flake off doing this process

Hi Julian

I have been painting for 5 years now, hundreds and hundreds of shells, Never had this problem.................Until last month and it was with a bottle Autoair Florescent Yellow! I have heard a few people now mention this same problem with flo yellow. :thumbdown: