Register now to get rid of these ads!

Make Your Fenders Into Mirrors! - Color Sanding Tech

Discussion in 'The Hokey Ass Message Board' started by SlowandLow63, Jun 1, 2009.

  1. SlowandLow63
    Joined: Sep 18, 2004
    Posts: 5,958

    SlowandLow63
    Member
    from Central NJ

    Seeing as we already have a great Buffing and Polishing tech by GaryC and no real techs on color sanding, I decided while doing NirtoFC's Dodge that I should try and write one. The Dodge is a solid black car shot in my "booth", so what better patient to make an example of. As most of you will find/have found, even in a real booth, color sanding is usually necessary for a slick finish. Whether it be dust, runs, or orange peel, color sanding will help to alleviate these concerns.

    I will try to wait at least a week if not more before I will start the color sanding process. This way the paint is hard and you'll get a good sanding out of it, but not too hard that you kill yourself. Certain paints will be different, but for me its a week plus. Check your tech sheets though, you can color sand as soon as the day after if you're in a rush.

    All you need to get the job done right is a few sanding blocks (I will usually use a harder block on the initial cut just to make sure everything is straight and then switch to a softer block the higher I go in grit), waterproof sandpaper (I use 3M Imperial 800-2500, worth the extra cash), water, and a squeegee. I'll get into more detail of when and how each tool is needed later.

    *DISCLAIMER: You will need to buff the finish when you are done color sanding to get the shine back. Refer to this tech, http://www.jalopyjournal.com/forum/showthread.php?t=184233.

    **DISCLAIMER: If you only put on the bare minimum of paint, you will surely cut it. Check the tech sheets for the product you are using and see what they recommend. For this job I used PPG Concept Acrylic Urethane (DCC). Its dry film build per coat is 1.1-1.3 mils. I used 3 coats here and had no real problems cutting through.

    This is how the front fender looked after I shot it. Here you can see the orange peel and small specs of dust. This fender was the worst of it and is really no challenge once you break out the sandpaper.

    [​IMG]

    I will usually start off with 800. On flatter panels I use a hard block to keep the panel straight as I go. The 800 will get most of the crap off and even out the orange peel quick. At this point you aren't looking to hit every inch of the panel, just get out the worst of it. Keep the paper wet and flush the panel often. This helps to rid the panel of debris and material that will cause more scratches. Use the squeegee to check your progress. Remember to leave yourself something to sand off in the next grit, I try not to "oversand" in one grit. You can always go back. Better to take off less material than to cut to quickly and end up in the base. If the water turns the color of the car, you're in the base. No good. (In this case I used single stage so the water is already black, but the same rules apply.)

    [​IMG]

    After a quick 800 cut, the panel is already looking better. You can see exactly what needs work. At this point I might do some more with the 800 or move up to 1000 depending on how impatient I am. You can add waves in the panel if you aren't careful which will ruin all the great bodywork you did before you painted it so be careful to sand as evenly as possible.

    [​IMG]

    I still keep the 1000 on a hard block. On panels with less peel or less dust you can start with 1000. I wouldn't start any higher though. The 1000 will also remove material quickly. Remember to keep everything wet and keep checking your progress. You can see less dust in this pic and the peel is just about gone. Notice that the sand scratches are alot less coarse. Ignore the smudge, that was a drop of water I wiped off with my thumb. I moved up to 1200 here.

    [​IMG]

    After the 1200, a few dust particles remain, but overall we're almost there. You might be tempted to skip some steps at this point, but its best to move up gradually and take your time in each grit. By moving up the grits slowly, you get rid of all the sand scratches from the previous grits. Skipping grits will leave those scratches which will show up in the finish. Here I would go with 1500 on a softer block to get out the last few particles and to remove the 1200 scratches. After the 1500 the panel should be pretty much clean. I don't have a picture for that, but imagine the above, minus the the last couple particles.

    Now some painters might go right on to buffing here, and that is an option. It will just require a little extra elbow grease in the compounding stage. Being a solid black car, I opted to go on to 2000, and then 2500 on soft blocks or by hand.

    [​IMG]

    Runs happen people. I was told when starting out, "If you don't run it you're not doing it right!" It was a joke, but it actually makes sense and is decent advice for a beginner. *This applies to your gloss coats only!* :D To be honest, I can't think of a full paintjob I've ever done without a run. To quote my good friend Overspray, "Professional painters do not get runs, they are called flow checks."

    Treat a run like a really big piece of dust. They sell run files or run blockers for this but another trick is to use a razor blade. Drag the blade of a 45* angle trailing the direction of the run. Anotherwords, don't shovel the paint off the car. In this case I would be pulling the razor blade towards the bottom right corner of the pic with the blade to the top left and my fingers towards the bottom right. I hope that makes sense.

    You'll notice the run has a big drip on the end. Try to get the drip shaved down closer to the panel but of course, not completely out. You want to remove only the run here, not the surrounding material. It should look like this when its close to even.

    [​IMG]

    Now get out the paper and work up just like we did before. Start with 800, 1000, 1200, 1500...

    [​IMG]

    What run?

    Now that the run, peel, and dust is gone, break out your buffer and go to town via GaryC's tech, http://www.jalopyjournal.com/forum/showthread.php?t=184233.

    Here we are after the compounding and a swirl mark remover.

    [​IMG]

    And after a final glaze.

    [​IMG]

    You can almost comb your hair in it...

    This was my first ever tech, so please if I missed anything or confused you, please ask. I'm sure myself as well as the other painters will do our best to help.

    Good luck!
     
    Last edited: Jun 2, 2009
  2. chaddilac
    Joined: Mar 21, 2006
    Posts: 14,021

    chaddilac
    Member

  3. motoandy
    Joined: Sep 19, 2007
    Posts: 3,334

    motoandy
    Member
    from MB, SC

    Great work and a great post. thanks
     
  4. SteadyT
    Joined: Sep 11, 2007
    Posts: 482

    SteadyT
    Member

    Thanks man, that's awesome.
     

  5. Good info... How long after painting do you wait to color sand/buff?
     
  6. SlowandLow63
    Joined: Sep 18, 2004
    Posts: 5,958

    SlowandLow63
    Member
    from Central NJ

    Thats what I forgot to add! I knew it was something. Hold on....

    I wait at least a week if not more. This way the paint is hard, but not too hard and impossible to sand.
     
  7. ArtofHotRod
    Joined: Feb 26, 2008
    Posts: 467

    ArtofHotRod
    Member

    Any more pics ???
    <input id="gwProxy" type="hidden"><!--Session data--><input onclick="jsCall();" id="jsProxy" type="hidden">
     
  8. SlowandLow63
    Joined: Sep 18, 2004
    Posts: 5,958

    SlowandLow63
    Member
    from Central NJ

    I have a million. Click on Moonlite Kustoms in my sig to see some more.
     
  9. 38jon
    Joined: Oct 28, 2007
    Posts: 82

    38jon
    Member
    from York,PA

    Hey thanks, I tried skipping grits before and you're right it will show up later. Did you ever try a orbital sander or do you always hand sand? I used PPG Velocity clear and I thought my arm was going to fall off, I sanded my ass off and didn't seem to be getting anywhere on the really flat surfaces. Anyways good tech. Thanks
     
  10. mpls|cafe|racer
    Joined: Jun 18, 2006
    Posts: 1,323

    mpls|cafe|racer
    BANNED

    Wow!!!!!

    AWESOME tech post man.

    I'm going to pick up my new compressor tomorrow, and have access to all sorts of painting gear to try this stuff out. I'm learning so much on the HAMB lately for body work stuff that it's ridiculous.
     
  11. SlowandLow63
    Joined: Sep 18, 2004
    Posts: 5,958

    SlowandLow63
    Member
    from Central NJ

    I didn't mention a powered sander in the tech because for a first-timer, chances are it will ruin a paint job, but yes I do use one. A Hutchins Waterbug with a soft backup pad. It takes ALOT of getting used to and I wouldn't advise someone doing one paint job to get one. It cuts extremely fast and leaves alot of sand scratches. I use it only in the 1200 and 1500 stages right now. I will probably add 2000 to that list soon.
     
  12. slddnmatt
    Joined: Mar 30, 2006
    Posts: 3,685

    slddnmatt
    Member

    great tech! i hate color sanding. it has to be the worst time consuming stuff to do....
     
  13. Black Primer
    Joined: Oct 1, 2007
    Posts: 965

    Black Primer
    Member

    Dude,...Thats beautiful ! Makes my garage paint job look like it was done by a monkey.
     
  14. Von Rigg Fink
    Joined: Jun 11, 2007
    Posts: 13,418

    Von Rigg Fink
    Member
    from Garage

    Do you use a ridged block or a contour block to sand like the curved surfaces of fenders and aprons and such?

    Awsome finish job..looks great
     
  15. SlowandLow63
    Joined: Sep 18, 2004
    Posts: 5,958

    SlowandLow63
    Member
    from Central NJ

    I use a hard block only for the 800 and 1000. If its really contoured and I feel I'm doing more harm than good with it, I'll use a softer block like the Durablocks. Most often times I end up using my hand very softly.
     
  16. Von Rigg Fink
    Joined: Jun 11, 2007
    Posts: 13,418

    Von Rigg Fink
    Member
    from Garage

    Gotcha, thanks

    Really looks nice:cool:
     
  17. Fogger
    Joined: Aug 18, 2007
    Posts: 1,804

    Fogger
    Member

    What was the paint used in your post? I've sprayed lacquer, acrylic lacquer, acrylic enamel, Centari with hardener, urethane single stage with hardener throughout the past 50 years. Recently redid a panel on my '32 roadster and could only get single stage urethane. Color sanded and buffed within 24 hours. Instructions stated not to wait more than that amount of time or the catylist would have completed its kick and the finish would be too hard. Panel turned out great. You did a great job describing the color sanding process, good work. The FOGGER
     
  18. SlowandLow63
    Joined: Sep 18, 2004
    Posts: 5,958

    SlowandLow63
    Member
    from Central NJ

    This was PPG Concept Single Stage Urethane (DCC). I started color sanding about 2 weeks after I shot it, and it was fairly hard but not impossible. You get a better polish out of it when its hard IMO.
     
  19. one37tudor
    Joined: Mar 3, 2001
    Posts: 146

    one37tudor
    Member

    One question I have never seen addressed is, is it ok to "color sand" a rough base coat prior to adding the clear coat? If so I would assume that you would not go to a really fine grit paper?

    Scott...
     
  20. SlowandLow63
    Joined: Sep 18, 2004
    Posts: 5,958

    SlowandLow63
    Member
    from Central NJ

    How rough are we talkin? There are some loopholes, but the short answer is no. If it needs to be sanded at all I would do it wet with 600 tops and absolutely recoat it before clear.
     
  21. one37tudor
    Joined: Mar 3, 2001
    Posts: 146

    one37tudor
    Member

    Thanks, I don't really have an example to show but I ask out of general curiosity more than anything. I have seen some really orange peel areas on cars that would appear to need several coats of clear to smooth out and was just wondering if you could minimize the clear some by sanding the rough areas down some.

    Again, thanks for the reply.

    Scott...
     
  22. SlowandLow63
    Joined: Sep 18, 2004
    Posts: 5,958

    SlowandLow63
    Member
    from Central NJ

    When you color sand the clear, it takes out the orange peel. Unless it is dimpled like a golf ball, it shouldn't really ever need more clear, although it isn't a bad idea to color sand and reclear. Most often the clear will take up any roughness in the base to an extent.
     
  23. bondolero
    Joined: Dec 10, 2008
    Posts: 562

    bondolero
    Member

    Terrific article how to. thanks for sharing your expertise.

    dillo
     
  24. 57JoeFoMoPar
    Joined: Sep 14, 2004
    Posts: 6,138

    57JoeFoMoPar
    Member

    Great tech Billy! Very confidence inspiring. T minus 1 week 'till I start on the '57...get ready
     
  25. Anderson
    Joined: Jan 27, 2003
    Posts: 7,155

    Anderson
    Member

    You shoulda let Stacey take the pictures, hahaha. Nice tech!!
     
  26. overspray
    Joined: Jan 14, 2003
    Posts: 1,417

    overspray
    ALLIANCE MEMBER

    OUTSTANDING!! Very well explained and great shots of the process. I picked up some very useful tips.

    Thanks Bill. (Elvis says thanks, too.)
     
  27. chopolds
    Joined: Oct 22, 2001
    Posts: 6,208

    chopolds
    Member
    from howell, nj
    1. Kustom Painters

    You're really getting good, there, Bill! That finish looks great!
    To add to this post, if you don't mind, Bill, the longer you wait to sand and buff, the harder the paint gets. Bodyshops do it the easiest way, usually the next day, when the paint is softer. Bill's waiting a week is a good comprimise, the paint is pretty hard by then, but still workable.
    I usually wait a month, if I can, but the paint is pretty hard and you have to really work on it to get the finish nice.
    So why wait so long? Well, even though the paint is hard, it is still going through a curing process, even shrinking some. The sooner you do the sand and buff, the more the paint will shrink, later on. The paint also will dull, or "die back" as it's called in the business. Sometimes just rerunning the buffer over it will cure any problems, but if you'e after a NICE finish, usually you'll have to resand, and then buff again. You don't have to go through the whole process, sometimes just a quick 1500 cut and then buff is good. Other times you might have to step back to 1000 again.
    I like to revisit the paint finish 3-6 months after painting to inspect it, and correct any dieback or shrinking. Just to keep the quality of the job up.
    I've found on Kustom paint jobs, like a real Kandy job, the shrinkage is more. The extra amount of paint on the car shrinks more than on a regular base/clear job. More paint = more shrinkage. I've even gone back and resanded and buffed a Kandy job a year or two after painting it, to keep the finish top notch.
     
  28. bbc 1957 gasser
    Joined: Aug 3, 2007
    Posts: 683

    bbc 1957 gasser
    Member

    first off ..how much clear do you have on there ?and what kind ?
    if some joe blow trys to do all theses steps on his 2 coat max clear coat he will be buffing primer ...
     
  29. haroldd1963
    Joined: Oct 15, 2007
    Posts: 1,154

    haroldd1963
    Member
    from Peru, IL

    How many coats did you spray? You did say this was single stage, didn't you? When spraying base and clear coats, how may coats of base color, and how many coats of clear do you spray?
     
  30. teddyp
    Joined: May 28, 2006
    Posts: 3,197

    teddyp
    Member

    Great job bill
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.