Lots of good advise here, but how bad is it? If its real bad, no amount of sanding will be able to knock it down with out going through the clear. Pictures? It may be tough to capture the surface on film. Also, how many coats were put on? What product was used? Maybe try a small, out of the way spot to see what happens, you're all ready not happy with it so you cant really ruin it. Remember, the goal here is a flat surface because any thing else will show through in the end. Another thing to watch out for is if you get it flat, spraying clear over fine sanded clear has a different feel to it on the first coat. You have to move faster to avoid runs. Just trying to help. Let us know how it turns out. Good luck
The clear is called U-TECH. That is the company anyway. I applied 1 thin and 3 very wet coats. The pictures do not do it justice. Can hardly see it with my ****ty camera. You can tell it is a bit rough, but not really see just how bad. Plus, I got a good amount of dirt in the clear by the deck lid. One real good gust of wind got under teh door on what I remember being the last coat, and it has setteled real deep in. I figured that coupled with the rough coat, might as well reclear it. No sense in patching things that can just be fixed.
Not that long. Clear can take up to 60 days to completely cure depending on brand and how it was shot. Those are real important in the equation. Not sure exactly how long on a reclear. But I know that sanding it rereleases the chemicals. ( see earlier post )
I was a bodyman for 6 years, the last 4 spent painting cars. I stayed between 600-800 for a re-clear. Make sure your water and paper stays real clean so dirt doesn't cause a deep scratch that might show up later. If your existing clear is really rough, you could start with 400 to get it knocked down before moving up in grit. If you're not real experienced with a DA, I'd avoid it, you might burn through the clear on the panel edges or body lines, that's a common mistake. Hell, you have to be careful of that even with hand-sanding....
You could wait 20 years if you wanted. Think of it like re-painting a car... Once the clear is cured, you're relying on mechanical adhesion for the new clear, that's why sanding is important. That's also why some people (and paint brands) say that 1,000 grit is too fine and delamination can occur...I agree with them....
Utech is not a very good clear..I used to use it then switched...it's Sikkens version of Shopline..=junk...as far as comparing HoK to any of this...it's kind of a stretch since they use different base materials...if I remember correctly, HoK uses a polyester base.? which if you use that brand you need to stick with it from first prime to final clear or things don't adhere and you end up with delam or other things they can't explain other than "why did you use this or that?".... As far as timeframe on a re-clear..I think you meant after it's sanded how long can you wait...well, urethane (which U-tech is) tends to heal itself. in other words, your sandscratch will lose it's edge and the clear will actually start to become shiny again. I, in my shop, would not let a sanded clear stand for more than 2 days. Give it a good 24 hours to "air out" in a well ventilated shop after it's sanded, then get back on it with clear. (you could even use a floor or box fan to rotate fresh air into the mix which will help get the solvents out) Easy on the first coat cuz your applying over a "hard" substrate now...it will lay out super slick, but be patient, don't put the first coat down how you want it to look and monitor your flash times or you'll run the **** out of it. I also used to use 1000grit in a collision shop and had no probs with it, but 800 cuts quicker and will get it flatter, too. just my .02 good luck!
HAHAHAHA..... Sorry, it is a good product, but hearing company reps talk about it always makes me skeptical. Its definitely faster than doing it by hand but if you're looking for the slickest paint job possible, block it with a paint stick. I have all those nifty sanding blocks made out of all kinds of nifty material, but i find myself using a paint stick more than anything. It just works better.
Trencher's advice is right on, he knows. I would start with something co****r(600-800) to knock it down first, you want the paper to cut not glide over the top of what you have. Use something firm to block with, not just your hands or fingers and you'll be fine.
I never do that. I have seen results of people doing that in school. Talkabout trenches and strange sanding scratches.
When I paint a car I make it a practice of shooting 2 or 3 coats of clear, let it sit overnight, and then wet sand with 800 to follow with 2 more coats of clear. This produces a very deep looking finish once it is sanded and buffed if that is what you are looking for.
I have a small P+B shop, and ran into an interesting product, with a crazy name. I do wholesale work for a dealership, so I have to get in and out quickly, and produce a good job at an attrative price. Super ***ilex See, I told you it has a crazy name! I use the Lemon {800 grit} and go back over it with Orange {1500 grit} before compound and polish. They claim it is a dry system, but I still use it wet. This stuff is amazingly efficient without being over aggressive. The time savings is quite noticeable. It takes a special block/hand pad. I can knock the nibs down on a panel and have it completely dull and ready for compound in just a few minutes! And the stuff lasts and lasts! It isnt cheap, but it is worth the cost to someone in the biz. For the DIYer, maybe they could share the costs by splitting it up with other hobby painters they know? http://www.eagleabrasives.com/***ilex.html
sounds to me you might have enough clear on there to sand and buff it without reclearing. i would try sanding a section with 800, then 1200 and finish with 2000. buff it and see what it looks like. maybe just pull the decklid off the car or reclear just the backhalf of the car and reclear that? definitly would give it a try. if the dirt is as bad as you say it is or visable, re clearing may just bury it deeper, so you might end up dusting color on it anyway. and u-tech is not a **** clear, i've been using sikkens products for over 20 years, and while u-tech may not be in the higher end of their clears, i have NEVER had a problem with it what so ever. remember, paint is just like any other tool in the box, it's only as good as the person using it. but, seriously, you have almost 4 coats of clear on that car, plenty enough to to sand and buff, unless of course, the dirt is visable, and you have to repaint anyway. you have nothing to lose trying it.
800 for sure. 400 or 600 will cut the clear too fast and you will more than likely cut through to your base coat. It is always nice to use what you have left over but it will be far less expensive and far less trouble to buy the 800 and cut it with that prior to recoat.
The Jalopy Journal
