Universal Clear

B

Bartman

Member
Does Universal Clear "have" to be wet sanded and buffed? I sprayed a truck about three days ago and I'm just not happy with the finish. I have been painting for 25+ years and have sprayed many brands. The truck looked pretty good on day one but seems to be a little shrinkage or dieback. It was primed with SPI primer, prepped with 600 and sprayed with Diamont base. I let it flash a plenty between coats and before clearing. I let the final flash for about 45 minutes. I applied a wet coat and followed with a second wet coat at between 20-30 minutes. It took me about 15-20 to clear the truck and then I waited about 10-15 and applied in the same order. When I know I want to sand and buff then Universal is the way to go. Not sure anything buffs better. If I'm trying to lay one out like glass and just get it out of here, is universal still the clear I need? Should I try the Euro? Did I misapply?

Thanks, Bart
 
Well, the only time I've seen die-back is when the base hasn't flashed enough. Too fast of reducer or junk reducer in the base will kill the finished gloss even if you give it more flash time. Slow reducer is actually faster in the long run because it will evaporate more completely in a shorter amount of time.
 
Well something under the clear is disrupting the cure and causing the the puckering and die-back. It could be from application speed. It usually stays slick and wet looking. What color? Pics? Did you use a sealer?
 
Off white. 56 ford colonial white to be exact. I'll try to take a pic today. Customer looked at it today and was happy, but I'm not. It's not really up to my standards. I'll have to cut and buff it. No sealer, not really a fan. I find that sealers create a little texture before you apply your top coat and thus hurt the final look before cutting and buffing, and most stay open too long due to being high in tail solvents or to increase adhesion to top coat. JMHO. UV buffs great, but my original question does it "have" to be cut and buffed. Or is it possible to lay it out slick and wet without buffing.
 
it doesnt have to be buffed. uv lays out really well and doesnt shrink much at all. some things to cause would be too fast an activator for the temp outside. slower the better. i've been using diamont for basecoat under uv clear for atleast 10 years now and i can tell you its a great base BUT it does have some super slow tail solvents. while it flashes dry fairly quick it takes 18-24hrs before it hardens up and all the tail solvents come out. if i want everything to lay out as smooth and glossy as i can i always wait that long before i clearcoat. another factor is how you spray the base. if the base lays down with a bit of a texture then the clear will shrink into that. even if the base appears smooth sometimes there is a slight texture and its hard to tell because it dries dull. not saying any of this is your issue, just tossing some ideas.
 
Thanks everyone. I will shoot another soon with UV and see how it goes. Jim do you use the UR series from Diamont in your base or SPI Urethane reducer? 18-24 hours, wow...More like 30-45 minutes. If all I have is restoration work then no problem but we mix in some collision and that will be a problem. Thanks everyone, all input is important to me. I've been at this since I was 14 and now pushing 50, my ego is past the stage of thinking I know everything.
 
Yeah bart obviously for prod work overnight flashes dont work. I am using spi reducer in the diamont. Ur series are even slower. 30-45 min for diamont and it certainly feels dry and it is dry enough to clear over but at that point there is still a ton of solvent both in the base and soaked down into the primer. For resto work and anything you want top notch and overnight flash is where its at. Just for the hell of it next time you are spraying a small item, let the diamont sit overnight then the next day when you spray something else let that flash 45 min and compare the two. You can even feel the difference with your fingernail. The fresh one will be really soft and overnight will be hard and fully adhered. Youll notice a big difference.
 
When you guys are talking about "tail solvents" Are you speaking about the ending dry time on such solvents, or something else? I guess I never heard that phrase before. Thanks guys!
 
moparmusclecars;31210 said:
When you guys are talking about "tail solvents" Are you speaking about the ending dry time on such solvents, or something else? I guess I never heard that phrase before. Thanks guys!
Click to expand...

Reducers are made with three groups of solvent:
Flash solvents-faster
Mid solvents-medium flash solvents like Toluene, MEK, NBA.
Tail solvents- like MAK, PMA, EEP, slow drying solvents.
 
Thanks for the reply Barry! Easy to understand now what you mean. :)
 
I use SPI universal clear and have the same problem now and then, and all i use is RM Diamont paint.
Would hardener help with the problem?
 
I have had a couple die back, but i know myself its that stuff underneath is not dry before i clear. It always buffs right up, no problem. Most of us seem to have a tendency to want to hurry in between coats to get stuff cleared. I am no different, but i am realizing just how important it is to be patient and give stuff proper dry times before proceeding on. As far as how the universal clear lays out for me, never an issue!
 
I know of no way the universal can die back on its own if all things are done right as far as proper speed activator and proper flash, just too high solids.

But here is what can help it to fuzz up:
1.3 tip gun below the Mason/Dixon line in summer.
To low air pressure at the wall regulator must be min of 125 and prefer 140-150.
Baking to high temp.
Leaving the fan running to long after last coat sprayed.
To fast reducer used in base and not enough flash time for the base between coats.
Introduction of a low grade reducer to the clear and with that said the UR is fine as is DT.
 
Universal gives me the best as sprayed gloss I've ever seen. And you won't have any dieback if you're not trapping solvents. And there is definately differences in solvent... I ran out of reducer awhile back and tried using some Matrix 885 to get me through the end of a job-that was a big mistake! I don't know what Matrix uses for solvent in their 885 but man is that stuff harsh!
 
Mek and xylene, way too much but it is cheap, actually acquired a new jobber because of this .
 
Just want to throw this out there. It may have no relation, but when I was very new to both S-W Ultra and SPI Universal, I shot the side of a Honda in a purple pearl color using slow reducer. Came back in an hour with the UC, and boy, you could tell right away something was not right. It died back hard, though in my case I think it was because of the RHF85 basecoat reducer, and not enough flash time. Some basecoats seem like they can absorb some solvent from the clear and release it later, especially if they aren't dry enough.
 
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