Craters, help

[DakotaVTX]

I just did my test panel and after the flames were done I put two coats of HOK UC 35 clear. It didn't seem to flow well and has craters in it. I was painting the test panel on black anodized aluminum to simulate the black currently on the bike. I'm glad this is just a test panel but what caused the craters? I wasn't real accurate on the mix of reducer catalyst and clear, may have been off a bit. The ratio I used was 2 parts clear, 1 part reducer and 1 part catalyst. Any suggestions?

DakotaVTX

 

[BonesFX]

Looks like you mixed the clear right. 2:1:1 Craters or fish-eyes are caused by contamination. It could be from unmasking your panel with bare hands and some of the oil from your skin got on there. Could be from the lubricating oil in your gun, airlines or just a bit of water that your trap didn't catch. To eleminate it fron your panel you can wipe it down with some PPG 330 wax and grease remover, wipe gently though, too much rubbing will take the "art" off. I'm terrible at never washing my hands and touching my face and transfering skin oils to every piece I'm painting. One trick I do when I'm ready for final clear is to shoot 2 very light (dry) coats of clear 5 minutes apart and then start my wet coats. This seems to not only help with craters and fish-eyes, but also makes sure that the art doesn't "melt" and get ruined from having too much wet clear on it --
Stay tuned for our next topic " Pin-Holes and Solvent pops"!!! - Peace - Bones!~

 

[Burton]

I went through the same thing. I checked for mixing problems, dust, contaminates .... So finally I went out and got some of those last chance air filters for the end of the gun ($3 - $5 a shot). I change them out evey couple of paint jobs and I haven't had the problem since.

Let me know if this helped.

 

[DakotaVTX]

I think you guys hit on the problem. I am painting in a factory that probably has water in the line. It has a reservoir ahead of the gun that probably hasn't been cleaned in 10 years. I'll start there and if that doesn't work try your other suggestions. Bones, doesn't spraying the first two passes dry cause a rough finish? Does the wet coats smooth it out enough? Thanks for all your help.

dakotaVTX

 

[BonesFX]

The first 2 coats are very light - like a mist. I'm sure HOK doesn't like you to do this, but it has seemed to work great for me. I always use RU 310 - Fast reducer no matter what the temp - just have to becareful with solvent pops. I never count the 2 tack coats - and my usual paint job has 3 -5 coats of clear on them - and I really pound it on - never had a problem with it not being smooth -- Bones!~

 

[BonesFX]

The over-reducing will will always help with the flow out. I really don't worry about the finish coat being "flowed out" as I'm going to colorsand and buff anyway. I only use the medium reducer in the middle of the summer when the temp in my garage is around 85 -90 --- Helps out with the solvent pops.

The guy I get my supplies from told me the opposite of what you'res did as far as Build coats are concerned. He said to get thicker coats use less reducer - thus making the clear thicker. I've talk with HOK's support when I was having a problem with solvent pops and he told me to mix up the clear with out reducer and a little more catalyst to help thin it - - the stuff was like sraying liquid plastic - and it actually flowed out pretty good.

I've found that here in Virginia with the different extemes of the seasons that it doesn't hurt to try anything different with clear - That way you have a couple options in your back pocket just in case one doesn't work --- I'd kill for an AC / Heated spray booth!!! LOL!!! -- Bones!~

 

[Burton]

BonesFX is right. If you need a reel heavy build you should minimize the amount of reducer and add extra catalyst. This works real well when you have a thick graphic edge. When you add more reducer and go a little slower on the grade of reducer you will loose mils (thickness) but you will gain a smoother final coat. You might have to put a few more coats on if you over reduce to gain some thickness back. The “flow” is not a big deal like Bones said it just cuts some time off the color sanding because there is a lot less orange peel. For me the less sanding the better, I hate worrying about sanding through the clear. Also I forgot to mention if you do choose the use a slower reducer don’t go over board. It can help to lay the paint down but it can also cause the clear not to cure correctly. What I mean is don’t use slow reducer if it’s only 55F in the shop. Only go up one step. Good luck.

 

[Burton]

I do the same thing as BonesFX except I only do one round of the tack coat. I have had some major problems with flow for the Hok (build) clear. The first thing that my supplier suggested was to use a slower reducer meduim to slow even though the shop was only 50 - 60F degrees and if you use build clear over reducer by 10 %. I've been using the medium reducer with a little extra reducer in the mix and have had wonderful flow results. Also really pay attention to the wait time in between and do the tack test that the Hok manual suggests if your not sure when to start the next coat.