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MG Midget and Sprite Technical - One for the painters, clear coat crazing

I have been trying to use U-Pol powercan clear coat (an acrylic clear) to give me a deep shine on some panels. But after a few days of drying the clear coat starts to craze. If you sand it down, it seems confined to the clear coat (but the crazing is too deep to just sand and polish out). The colour and primer coats seem unaffected.

Any ideas on what I might be wrong?

I have asked U-Pol for advice, but no response as yet.

Cheers,
Malcolm

Malcolm Le Chevalier

I'm not a painter but it looks like a chemical mismatch. Is the clear coat you're using compatible with your base & color coats?
SK Kowznofski

U-Pol were quick to reply and suggest it might be due to too thick a film. I wondered if this was the case as it seems worse on bits that I know I have coated more heavily.

However, even when super careful, I can't seem to spray it consistently thin enough to stop this happening, so maybe it is a compatibility issue too.

Malcolm.
Malcolm Le Chevalier

Malcolm
UPol speak words of wisdom
It's common to try and get that shiney gloss finish with your clear coat and get it on too thick-then it does what you have there
Secret is- nice warm environment and just dust on a thin coat-Then give it plenty of time to dry off (drying time will be on the can)before you put the next thin coat on -Don't rush it- two or three well dried thin coats is the go then leave it for a day or two before you give it the cut and buff job
willy
William Revit

Giving it another crack. Chuff me it doesn't half knacker you having to sand an bonnet by hand (for the fourth time)!

I had about six square inches that worked really well. So just have to replicate that all over.

I worry with such thin coats there won't be much meat to then cut and buff.

Malc.
Malcolm Le Chevalier

Is it two pack clear or 1k, I.E. straight into the gun and ready to spray ?
I used a 1k product recently and found that to be thicker than I would normally be happy with, but I didn't get any crazing, this was onto fibre glass where I had used a solvent base coat.
I talked myself into potentially thinning the clear coat a little if it didn't cut back to a good shine but it did so I was OK.
Hope that is off some use.
P Bentley

I think it was just putting it on too thick too fast.

I have since sanded it back and done five fresh super light sprinkly coats, like a chef sprinkling salt onto a dish from great height!

Looks naff as painted and is taking ages to flat and polish up (and I am being super careful, as I am not sure how thick the resultant coat is). But no crazing so the end result looks a lot better.

Cheers,
Malcolm
Malcolm Le Chevalier

This thread was discussed between 04/07/2016 and 15/07/2016

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