Thread: Paint help

Hi,

Sounds like something contaminated the surface - or the paint has not flashed or cured properly or through the full film.

99% paints and our coatings like no more than 85% humidity and the dew point to be 3 degrees above the metal temp. This can leave water & vapour on the surface or bound in the film as its flashes and cures - generally ruining it. This sounds like it didn't flash properly or cure.

Also painting with the surface (not air) temp over 35 will generally ruin it too.

Maybe something was on the surface - sanded paint? - clean off with a tack cloth any dust which can wreck the finish. Really - really - make sure its dry - towel's s bit sus. to me -

I'd day you'll have to do it again - 360 grit is pretty (too) fine for a key Id go down to 240 or even 180 as well. 360 is more for between coats.

Some of those paint tins lay out a very fine film (40 microns or less) - just build it it lightly in layers - too thick and you may prevent flashing through the full coat then you rub down to the unflashed coating

Clive

thanks clive,

humidity wasnt at 85%....probably around 65-70%. Temp was fine, I was working in my garage not in the sun. They were definitley dry as I did all the washing day/days before, the only thing I did was to whipe down with turps prior to painting.

The colour is "Storm front pearl"...it has a fleck/pearl to it. I do wonder if that has something to do with it. The can says light coats are best (all cans/brands say that) allowing 4-5mins between coats, up to 4 coats. I actually think I may have gone a little light on the coat. Where it was built up more at spoke to rim junction it is smoother and fuller body look. Feels like that area may be good?????

The 360 was a "between coat" rub down...from the old to new, not the bare metal. I started with 240, but that seemed to leave to "heavy" a scratch in the surface. I figured it would show through.

I can't really says what has happened specifically, but in general I don't know the product just have experience with industrial coatings on buildings, etc

The 4-5 mins between coats seems too short you really want the paint to cure not just flash off between quotes
Maybe it reacted with the turps . Usually you use metho. For metal



Sometimes you never really know why a coating failed, just that you have to redo it.

Is there a primer this is normally what you do, I,d prime it if it where mine even just to build up film thickness to take up the feather

Clive

prime over the exsiting powder coat?

Not really just over the patches were the powder coat has been flappered back to bare metal. You did say yo had local rust spots rust on it.

Originally Posted by clive22

Not really just over the patches were the powder coat has been flappered back to bare metal. You did say yo had local rust spots rust on it.

yes, but these account for only 2-3% of total surface area. Its ALL the new spray that is failing. Much more of it over good clean original powder coat that has been washed well.

Turps is a paint retarder, so it slows drying down. It may not be the cause of the problem but it may have left a residue. You would be better off wiping it down with something lighter, metho, thinners, brake cleaner or petrol for examples.

Yes I know you haven't flappered the whole wheel. But you normally build up the film and 'stripe' the patches before applying the film - stops paint settling in dip and/or pulling away from edges.

Really you have a problem, but you defend how 'clean' it is - the fact that the paint film has failed tells me it ain't clean and something has gone wrong and you must do it again with different parameters. After all its the chemical reaction of the paint and its bond on the surface that matters not whether you think its clean or not.

Try cleaning with proper thinners or method as both me and others have said. Use a tack cloth get all - like all the dust off the surface.


Clive