paint pin holing desperate help needed
Discussion
I was a professional car painter for 15 yrs.. 35 yrs later still ocassionally painting one or 2 bits . I am now having trouble never experienced before. I was told by an ebay seller that 2pk paint is a sealer and celluose can be put on top.
A modded hood with bulge, I used good body filler and applied two coats of primer sealer. All ok so i sanded and then 2 weeks later repimed.
20 days later celluose 4 coats . all dried fine. a few weeks later pin holes appeared . I wet and dried and repainted celly again. days later pin holes now ruff as 40 grade sand paper appear showing gloss coat underneath of previous paint job.
I did a very real deep wet and dry job taking hrs, 80gt, then 240, 600 then 800 paper. Repainted and later polished to a high gloss red metallic.
DAM, pin holes back in a week. Only way is to body fill them holes then is ok. But pin holes appear eslewhere then. . I have inspected with a magnifier, those pins holes must be gass excaping as look like a miniture volcano showing no adhesion in the centre of the hole to previous gloss paint.
I have tried partly painting one side with 2pk and the other in celly. some how underneath will not accept any top coat. The hood has been out side sanded for weeks and still will not heal or accpt paint. I do not want to go back to body filler as the bonnet was gas welded and leaded, beautiful shape which i am proud of.. cutting back now to the body filler will in volve so much work. must be away to seal these bad bits, otherwise it will be a tar brush and bitumen job. One final point guys, is i am a firm beleiever in time between coating, I really allow to cure for days if not weeks and wet and dry a lot between coats. cleanliness is a must for me as well. I was conservative when applying paint. but years ago have glossed on top of heavy gloss, some times double wett glossing every caot. never had a B like this in heat or windter snow cold. I HAVE PAINTEED IN SIDE , OUTSIDE AND IN EXTREME COLD. NEVER A FAILURE LIKE THIS ONE.
A modded hood with bulge, I used good body filler and applied two coats of primer sealer. All ok so i sanded and then 2 weeks later repimed.
20 days later celluose 4 coats . all dried fine. a few weeks later pin holes appeared . I wet and dried and repainted celly again. days later pin holes now ruff as 40 grade sand paper appear showing gloss coat underneath of previous paint job.
I did a very real deep wet and dry job taking hrs, 80gt, then 240, 600 then 800 paper. Repainted and later polished to a high gloss red metallic.
DAM, pin holes back in a week. Only way is to body fill them holes then is ok. But pin holes appear eslewhere then. . I have inspected with a magnifier, those pins holes must be gass excaping as look like a miniture volcano showing no adhesion in the centre of the hole to previous gloss paint.
I have tried partly painting one side with 2pk and the other in celly. some how underneath will not accept any top coat. The hood has been out side sanded for weeks and still will not heal or accpt paint. I do not want to go back to body filler as the bonnet was gas welded and leaded, beautiful shape which i am proud of.. cutting back now to the body filler will in volve so much work. must be away to seal these bad bits, otherwise it will be a tar brush and bitumen job. One final point guys, is i am a firm beleiever in time between coating, I really allow to cure for days if not weeks and wet and dry a lot between coats. cleanliness is a must for me as well. I was conservative when applying paint. but years ago have glossed on top of heavy gloss, some times double wett glossing every caot. never had a B like this in heat or windter snow cold. I HAVE PAINTEED IN SIDE , OUTSIDE AND IN EXTREME COLD. NEVER A FAILURE LIKE THIS ONE.
You are correct in the using 2k undercoat then celly over the top, not that we liked using celly much but some of the old boys and their cars insisted, so a good 2k undercoat is fine. You don't need much more drying time that a few days at normal temps with 2k as it is a chemical reaction, so it will dry, the only issue you could get is a bit of sinkage if there is a lot of filler below and you reduce the primer down too much.
You don't say where the celly came from or the reducer ( thinner ) cheap paint and or reducer will cause issues, more overly cheap thinner ( I will call it that as most are used to that term ), buying from fleabay is a no no and some cut price outlets as well will be flogging recycled thinner/gun wash and or decoloured gun wash, so it looks like thinner. These could be one of your issues. It could be disparity between the paint and the thinner or the aggressive thinner causing solvent pop and not evaporating fast enough. The other issue is that the celly could have been subjected to extreme heat or cold, either in its mixed form at some time and or 1 or many of the binders etc from the same, this could cause it to skin over too quickly and not allow evaporation of the solvents and correct flow out.
I have seen fine airborne dust particles cause this issue you mention as well, was someone using an aerosol, WD 40 etc near by just before or at the time, this will cause surface issues ?
Others have mentioned Barcoat, not a bad product but is air drying so can be upset by very wet coats and heavy thinned paint. One of the best would be use an Epoxy sealer, Lechler 29107 is a superb product, re-coatable after 20 min or so, or light scuff up to a few days and top coat. Word or warning, leave it any more than a week and you will have to cut it with at least a 320 dry or 600 wet to get an adhesion as it it super tough.
You don't say where the celly came from or the reducer ( thinner ) cheap paint and or reducer will cause issues, more overly cheap thinner ( I will call it that as most are used to that term ), buying from fleabay is a no no and some cut price outlets as well will be flogging recycled thinner/gun wash and or decoloured gun wash, so it looks like thinner. These could be one of your issues. It could be disparity between the paint and the thinner or the aggressive thinner causing solvent pop and not evaporating fast enough. The other issue is that the celly could have been subjected to extreme heat or cold, either in its mixed form at some time and or 1 or many of the binders etc from the same, this could cause it to skin over too quickly and not allow evaporation of the solvents and correct flow out.
I have seen fine airborne dust particles cause this issue you mention as well, was someone using an aerosol, WD 40 etc near by just before or at the time, this will cause surface issues ?
Others have mentioned Barcoat, not a bad product but is air drying so can be upset by very wet coats and heavy thinned paint. One of the best would be use an Epoxy sealer, Lechler 29107 is a superb product, re-coatable after 20 min or so, or light scuff up to a few days and top coat. Word or warning, leave it any more than a week and you will have to cut it with at least a 320 dry or 600 wet to get an adhesion as it it super tough.
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