Wet Sanding UV clear by hand on lower grits

B

bowtiebubba

Guys,

I'm looking for advice on wet sanding UV clear (3-4 coats) by hand. I'm so tired of the pig tails created by the DA especially below 1500 grit. Seems like I always have some sand scratches or pig tails show up LATER in the buffing process. Alot of them will not buff out completley or easily. So, I want to give the sanding process a try by hand at least up to 3000 grit trizact.

I've read somewhere where Jeremy recommends: 800, 1000, 1200, 1500, 2000, then 3000 trizact on a DA. I'm gonna give this a try on my next paint job. Sure you might be able to skip some grits or steps. But I'm going to follow this plan and see how it works.

Also, I know some use hard block, plexiglas, durablock,etc.. Regardless of the block used, how are you sanding the clear? Are you sanding in one direction with say 800 grit, and then the opposite direction with the next grit up. Or is the preferred technique just like block sanding with an X pattern. The reason I ask is that I want to make absolutely sure my previous grit sanding scratches are being removed, and I don't want to be guessing about it, only to find them later when buffing. It's has become so frustrating! Am I alone?

I'm with Shine, I would rather sand than buff anyday. I know JimC does most all his sanding with a DA and gets great results. I sure wish I could, but those damn pigtails are the devil. I think he dry sands most steps as well.

How are you hand sanding the clear with a block? Straigh line, X pattern, circular motion?

Thanks.
 
i do dry 1000, 1500 then goto 3000 wet and now 5000 wet. first 2 grits are eagle yellow finishing film discs. the 3000 is eagle bufflex green and the 5000 is 3m's trizact discs. pigtails are from dirt getting trapped between the sanding disc and the clear NOT the disc clogging and loading up. it wont matter if you hand sand or if you use a da. the dirt will scratch either way. just one is straight and other is corkscrew shaped. its very important to be clean. i will blow off and tack rag the panel before sanding each grit and i have a dedicated sander for wet and another for dry colorsanding to eliminate any dirt from them. dirt can come from anything. clean panel before and the end of each grit and blow off during. air hoses give off alot of dirt as well. they hold all kinds of stuff and drop it on the paint.
 
JimC,

Thanks for your advice. I understand about the dirt. I think some of my dirt could be nibs or trash that are sanded off early and then trapped in/under the pad. I was sanding dry first and then wet from 1500 up. I will try to add the tack rag. Between sanding grits, I usually blow off and/or rinse with water and wipe dry with a water blade and microfiber cloth between grits.

Another reason I wanted to wet sand by hand is to block down alot of the urethane wave that I get when I spray four coats of UV. I know that urethane wave is best controlled by spray technique. But I'm a hobbyist and I dont spray every week, or even every month. I find that four coats is best compromise between added film build for buffing, durability/longevity and a single clear spraying session.


Thanks again.
 
You can do it all by hand, knowing when to switch grits is always a guessing game but you'll develop a feel for it. Take a mental note of how long you spend in one area with each grit and take that first panel from start to buffed to check your proceedure. A lot of things can affect the amount of time spent sanding-hardness of the clear, quality of paper... When done right all the way to 3000 the amount of time buffing is very minimal.
 
One place to check for the fines that can cause a pigtail is your sander.

Keep it clean, there always seems to be a buildup around the spindle and again at the air valve (throttle).
Have a dedicated place to set it when you are using it .
I have a small folding step stool with a shelf on it that I lay a micro fiber towel on , then lay the sander on the towel when I need to set it down.
Keep your hose wiped down and keep the floor as clean as possible too. Many places for that little pos to come from.

Just a few tips to think about
 
Thanks for all of the help and advice. I have a new dynabrade that I may break out for just wet sanding. I have been using a dedicated sander for "color sanding" but this included the dry and wet methods. I haven't used my DA that I use for body work. I will try to improve my work environment and techniques. It would be nice to see the pigtails and go correct while still sanding. I just seem to always miss some.

I'm thinking that I will still need to do some wet sanding by hand with a block to knock down some urethane wave that I get. On my next job or panel, I'm still going to try all sanding by hand up to 3000 just to see how that works for me.

This is not related to my dirt and pigtail problem, but just curious. The 6" dynabrade sanders that I use have a 3/32 throw compared to the more agreesive 3/16. What are you guys using for color sanding? I've read on one forum that to properly use the 3M 3000 and 5000 trizact correctly that you NEED a 3/16 sander, like it is required or something. My dynabrade 3/32 throw sanders have a done a good job for me. Just curious to see what you everyone thinks. Maybe I have to sand a little bit longer to get the same correction? If that is the case, so what? lol
 
JimC,

I've done some more reading on this forum. And believe I am experiencing similiar problems as other forum members. Also, I was generalizing all unrefined scratches at half buffed out pigtails or pigtails, where alot of them may have been just sanding grit scratches.

I have been using the 3M sanding and perfect it system. That is the purple 3M P1500 Trizact Clearcoat Sanding Disc (02088) which 3M recommends as part of their system. Jim, I've read other posts were you strongly recommend NOT using this sanding disc and it causes big problems! Am I correct? Maybe others have used this with no problems.

I believe that could be where the majority of my problems are coming from. After reading, I'm experiencing similiar issues as esahlin problems:

http://www.spiuserforum.com/showthread.php?995-egale-abrasives/page4

Sounds like I need to swap out the P1500 Trizact Clearcoat sanding disc with the 3M P1500 Finishing Film Disc (00950) or the Eagle stuff you are using. That means this step needs to be DRY as well as all the other steps I was doing previously. Will the P3000 Trizact Foam Disc (02085) remove the 3M P1500 Finishing Film Disc scratches? Or do I need another step? I know is designed to remove the P1500 Trizact Clearcoat sanding scratches.

Obviously, I'm still learning on this buffing thing. Damn, on my next project, I'm still tempted to wet sand by hand up to the 3000 Trizact step just to see how it goes. Good thing I'm a hobbyist, or I would starve to death!

Again, thanks for all the help and advice!
 
omg yeah man get rid of those purple discs. those things are a nightmare. 1500 dry finishing film either 3m or eagle. both work fine i just prefer eagle because it lasts 4:1 longer than 3m and its 1/3 the price. after 1500 move to the 3m trizact 3000 or the green eagle bufflex. again both work but the eagle last waaay longer and is far cheaper. also problem with the foam 3000 discs is you cant tell when they stop cutting because they just keep making a foamy surface. i have always been left with areas of unrefined 1500 scratches. the green bufflex doesnt do that. like any sandpaper you can tell when it stops cutting. i just did a 67 nova except hood and trunk. whole car i did with 3 bufflex discs and the third was still cuttin strong. once you get that step done goto the 5000 trizact foam disc. 3m improved this one. its newer tech, cuts forever and works fantastic. i am told they are revamping the 3000 to the same quality as the 5000 but not sure when.
 
JimC,

While were talking about sanding and buffing, what is your buffing system and steps?

I've been using the 3M 3 step system as well. White foam pad, black foam pad, blue foam pad. I have tried to avoid a wool pad since I've sanded up to 3000, but that wouldn't probably help with that mess the 3M P1500 Trizact Clearcoad Sanding Disc made.

Also, I would like to add a finer compound, and polish steps but I think I would have to buy some Lake Country pads and go with a different system or polishes.
 
yes i use the same 3m system. i use the black and blue pad for polish but i dont use their pads for compounding. i use a yellow foam lake country pad which is more aggressive. if you goto the 5000 you should be able to buff so fast its not funny. i compounded that whole nova in about an hour then run over it real quick with the polish steps and its done. whole car, sand, buff polish i had like 7 hrs. no hood or trunk. 1000,1500, 3000, 5000
 
Which style of Lake country Yellow foam pad? the hybrid, CCS, flat, hydro-tech, kompressor? You get the question? lol

Here is a link:

http://www.autogeek.net/lakecountry.html

I'm a little worried about heat build up with a foam pad, but so far, I dont think that has been my problem. If I can solve my 1500ish type scratche probelm, and finish with the new 5000 trizact, I bet I might actually enjoy the buffing process again.

I bet there waffle pads are meant as a direct replacement for the 3M system of pads.
 
hmmm, i dont even think they make the pads i have anymore. i bought a case maybe 8 years ago. looks like the closest thing is the advanced curved edge ccs pads. you do have to watch your a$$ with the yellow foam. only on edges but if you got 5000 the buffing should be a breeze and you'll barely need to work the paint at all
 
You must log in or register to reply here.
Back
Top