Any ideas what’s going on with this clear coat?

[shannon1305]

Hi Everyone,

long time lurker and tinkerer here trying to figure out why my clear coat is picking up moisture or fisheyeing.

I’m setup with a 50l compressor, water trap on the gun and fairly old water trap at the compressor, short air hose and the compressor is drained of water regularly. The gun is an Iwata Air gunsa HTE2. Not Hvlp but it’s a nice gun. My compressor can just keep up with it and it’s ok for small panels, can normally get a nice atomisation at 30psi.

I’ve been hitting some real issues trying to lay down some max meyer 0200 clear coat on a wing. Started out with really bad fisheyes all over. Panel was well prepped, panel wiped and tack clothed. As soon as the clear hit the panel it was fisheyeing.

I’ve moved to test panels now to figure out what’s going on. So far I’ve replaced compressor hose, tested another gun and tested different environments (inside and outside). Tomorrow I’ll change the main water trap as I don’t think the humidity is helping matters.

The only other things I can think of trying are:
- slower hardener, although even on a tiny test panel I’m getting fisheyes
- different clear coat mix
- different thinners, current using a 2K universal
- oil getting through the compressor? Not sure

My experience is mostly trial and error. Anyone have any ideas if there’s anything else I could try?

Here’s some photos of the test panel and a fisheye and maybe a solvent bubble? The white dots aren’t dust, there some form of contamination that seems to be coming from the gun.

 

[vw1]

Hi are you using a filter strainer before pouring clear into gun ? Not saying this is the problem but you have not mentioned it ?

It looks like silicone but I'm not an expert.

 

[steveo3002]

one pic looks like a spec of dirt, other a fish eye

sand them flat with a small block and 1200/1500....the fish eye you could dab in with a drip of mixed clear then sand smooth if its just the odd one , then polish up to a shine

 

[8ob]

All of our air lines are contaminated, the lad that does our spraying uses an additive if he sprays anything for us in the yard and he won't bring his good gun. Something like this https://www.u-pol.com/uk/en-uk/prod...liminator-anti-silicone-additive#.Xvbxt6bTXcs

Bob

 

[shannon1305]

Hi are you using a filter strainer before pouring clear into gun ? Not saying this is the problem but you have not mentioned it ?

It looks like silicone but I'm not an expert.

yeah, using a 250 micron strainer.

one pic looks like a spec of dirt, other a fish eye

sand them flat with a small block and 1200/1500....the fish eye you could dab in with a drip of mixed clear then sand smooth if its just the odd one , then polish up to a shine

Thanks for the advice, I’ve done this on the wing that I painted and ended up with the fisheye spots looking a little flat compared to the rest of the paint. I’d be happy enough doing that if there were just a couple.

All of our air lines are contaminated, the lad that does our spraying uses an additive if he sprays anything for us in the yard and he won't bring his good gun. Something like this https://www.u-pol.com/uk/en-uk/prod...liminator-anti-silicone-additive#.Xvbxt6bTXcs

Bob

I had really hoped to avoid doing this, I bought a new hose and gun water filter to test of it were the actual line and still getting the same result. I don’t think the actual compressor would produce the silicone unless oil is making it that far?

thanks for the advice so far! I’m still a bit stumped. I’ve sprayed other bits and bobs with this setup on previous years without issue. The main changes this time are the clear coat I’m using, older water trap and the thinners

 

[vw1]

Have you got a water and oil separator trap ? Maybe ditch wall or compressor trap and get an upgrade ?

 

[shannon1305]

Have you got a water and oil separator trap ? Maybe ditch wall or compressor trap and get an upgrade ?

just stuck on a new wall mounted water trap today, it’s a cheapie one but should be ok.

Also picked up a different clear coat to test, local motor factors version, not sure who the original manufacturer is but this one is from Fyffes. It might be medium solids because I’m getting a much better finish, still some dust and crap but no fisheyes.



I did notice some crap coming back through the gun when tipping the max Meyer out to swap for the Fyffes clearcoat. Might be flaking off the paint gun cup, it’s the only bit of the gun I haven’t managed to fully clean through


if I can get a consistent finish with the Fyffes clear coat I’ll use it, still not sure why I’m not getting as good a finish with the max meyer, I’m running 2:1 tried no thinner and up to 10% and getting much the same issues

 

[steveo3002]

not a heavy user of hair products /smellys are you?....heard of it causing fish eyes

sometimes it just happens though , when i was painting cars you would get one now n then that was trouble , assume the owner used bumper sprays etc

 

[shannon1305]

not a heavy user of hair products /smellys are you?....heard of it causing fish eyes

sometimes it just happens though , when i was painting cars you would get one now n then that was trouble , assume the owner used bumper sprays etc

Not really, not enough to cause issue I’d guess.

It’s my own car so it’s had tonnes of products used on it, silicon based stuff included which isn’t helping I’d say.

I’ve been blasting away at test panels all day and I think I’ve got the defects to a level I’m happy enough with from the gun. Not many fish eyes, little bit of dust but at a level where I reckon I can get oem orange peel after flatting back the issues I get.

I’ve settled on using no thinners, a well cleaned gun and well cleaned between coats. First coat wet, flash off then a dusting from a distance before applying the second wet coat. Saw the gunman doing this to get some lacquer dust to land in any of the defects and help stick the second wet coat.

getting similar results with both the Mac Meyer and the Fyffes clearcoat. Going beyond 2 wet coats without thinners is leaving far too much orange peel. I could probably go to 5% thinned for a third coat if needed but only if I’m not happy with the first 2.

ill flat the wing back with 800 tomorrow to get the clearcoat back down and clean it well with hot water/fairy then panel wipe then tack just before paint.

I’m guessing I’ll need to flat back with sandpaper to get the low spots from the old fisheyes out instead of going over it with a grey scotchbrite

long monologue of a post but it’s a plan.