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Hot Rods paint shine question for the pros

Discussion in 'The Hokey Ass Message Board' started by in the weeds, Dec 6, 2019.

  1. in the weeds
    Joined: Mar 7, 2009
    Posts: 100

    in the weeds
    Member
    from Kansas

    So i do restorations and paint. I was doing some reading and this article was talking about shine. Im not talking about wich is better single stage or base coat im talking top surface shine. Anyway when colorsanding i usually stop at 2000 it buffs out nice you cant see any imperfections in it. The article was stating that when you stop at 1500 or 2000 you still have scratches you just dont see them with the naked eye, if you were to continue to 2500,up through 4 or 5000 you actually create a much higher top surface shine because the light is not as easly fragmented at the suface and can get better refraction of the pigment of the color, creating a higher reflection or shine.( most of you by now are going who gives a crap) but to the guys that do this for a living and take it serious like any proffesion you start looking at every detail to see if you can create a better end result, Some guys say that going to a higher grit paper only makes the buffing process easier some say that they think it does help create that liquid wet look. Im on the fence because if you have ever colorsanded and buffed a car you know that each sanding step takes considerable time. Is it really worth the extra hours to go through 3 or 4 more sanding steps. So other proffesionals and builders that are just anal about paint detail give your opinions, does it really help!! or are we just buying more paper and spending even more time sanding.
     
    arkiehotrods likes this.
  2. I can’t imagine buffing without 3000 or higher grits.
     
  3. john worden
    Joined: Nov 14, 2007
    Posts: 1,827

    john worden
    Member
    from iowa

    The theory is sound. Finer paper equals finer scratches equals more "shine"
    The DOI (distinctness of reflected image) is also a result of finer scratches.
    The theory that more time/money equals better "shine" and DOI is also good.
     
    loudbang likes this.
  4. The variable here may the buffer and polish.

    When you start talking abrasives on the micron level, the polish is basically doing the job of the higher grit color sanding paper. You work through polish the same way you do papers, coarse to fine, so... it kinda seems like the guy writing the article is wanting to sell sandpaper. :D
     

  5. Whatever the science is the amount of time I spend buffing after 3000 is much less than stopping at 2000
     
    pitman, lothiandon1940 and HSF like this.
  6. HSF
    Joined: Oct 25, 2014
    Posts: 225

    HSF
    Member
    from Lodi CA

    I stop at 2000, sometimes 2500. I have tried 3000 on a DA wet and I will say, it buffs like butter. I can't say it looks any more shiny though. Maybe paint a hood, finish half in 2000 and the other half in 3000. Buff and polish and see what it looks like.
     
    loudbang likes this.
  7. lippy
    Joined: Sep 27, 2006
    Posts: 6,825

    lippy
    Member
    from Ks

    You and Mr. Myrick have the same tag line. :D Sorry just thought it was odd.
     
  8. Squablow
    Joined: Apr 26, 2005
    Posts: 17,390

    Squablow
    Member

    I didn't even know 3000-up grit sandpaper existed until a couple years ago when I was trying to buff out the ancient, rock hard paint on my dad's 57, someone here told me about it, and the difference was amazing. Had to special order it at my local jobber. I'll never not use it again.

    Not only did it produce a beautiful shine, better than what I had been getting, it's also easier to control than a heavy compound. You won't burn an edge off with sandpaper since you're going slow but it's really easy to do with aggressive compound and a big buff pad on difficult/sharp areas.
     
  9. oldiron 440
    Joined: Dec 12, 2018
    Posts: 3,301

    oldiron 440
    Member

    I'm a 3000 grit final sand here also, I use the da on the big flat panels.
    I've read that a buffed finish is equal to a 7000 grit paper so sand it smooth.
     
    anthony myrick and loudbang like this.
  10. The real benefit of the finer grades is the ability for the surface to polish up much faster with less chance for swirl marks. Swirl marks are caused by the heat generated from a wool pad spinning at 1800 rpm and the abrasive mineral in the compound.
    Notice you all said “when I go to 3000 my buffing goes way faster” your correct in that statement..and the decreased buff time leads to a better finish due to less heat...

    I’ve been in the Collision Repair business for 20 years....3000 and 5000 grade abrasives were a God send for the world of paint finishing
     
  11. The average person can’t tell, but shiny is shiny is shiny. Now how far can you clearly read a tape measure in the reflection? Try that on a 2000 grit buff or a 3000 and 5000 grit buff job.
     
  12. Rocky72
    Joined: Nov 22, 2008
    Posts: 207

    Rocky72
    Member
    from Pa.

    I paint my own cars but I'm no pro and have a question for you pros . To be sanding the car up to 5000 grit just how many coats of clear have you laid down to color sand that much and still be safe ? I've sanded mine up to 3000 then buff and I was always thinking that I'm going to go through the clear .
     
  13. I like puttin 3 on, then sanding with 800, then 2 more and work up to 3000 from 1200 and buff. Takes the Urethane wave out.
     
    Rocky72 likes this.
  14. jbon64
    Joined: Jul 26, 2006
    Posts: 511

    jbon64
    ALLIANCE MEMBER

    i'm no pro , just a cheap ass that doesnt want to pay someone else to do it. had excellent results on my last garage paint job using 2k wet ,then 3k trizact pad then a 5k trizact . buffed using a chemical guys orbital and their buff & polish compounds. time consuming yes , but then again i didnt have a dead line .
     
  15. cheezwiz
    Joined: Oct 11, 2008
    Posts: 170

    cheezwiz
    Member

    That was always my concern...If the grit in the compound is coarser than the sandpaper then wouldn't you be going backwards? Been painting my whole life , ALWAYS interested in learning from others ! I suppose if you sanded with super fine paper you could just polish it with glaze?
     
  16. 1500,2000,2500 by hand(wet), then 3000 and 5000 trizak on a finish sander (wet) then three stage 3m polish system. All done at home-single stage urethane
    [​IMG]
     
  17. squirrel
    Joined: Sep 23, 2004
    Posts: 55,942

    squirrel
    Member

    interesting, lots of talk about the specific grit sandpaper used on the final sanding, but no mention at all of the specific compounds used.

    I'd think that it would make a whole lot of difference to know exactly what "grit" compound you are starting with after you are done sanding with 2000, 3000, etc.

    As for wearing down the paint by sanding with finer and finer paper--remember, the finer you go, the less material it can take off per stroke. I think the idea is to always be sanding off the "top" of the finish, so you work your way down to the bottom of the deepest scratches left by the coarsest paper you started with. Kind of like starting with mountains, and eating away at them with finer and finer, paper, but never scratching the valleys until the very last buffing is done.
     
    john worden likes this.
  18. Rocky72
    Joined: Nov 22, 2008
    Posts: 207

    Rocky72
    Member
    from Pa.

    Then on single stage paint you can sand and buff if it's not metallic correct ?
     
    john worden likes this.
  19. Yep
     
    john worden likes this.
  20. Tri-power37
    Joined: Feb 10, 2019
    Posts: 510

    Tri-power37
    Member

    I use the same system above as Asphalt Angel and anything roughly above 2500 wet sand paper has no real cutting power . But the 3000 and 5000 tritrizact paper do a excellent job of of taking out the sand scratches of the lower number grit papers.

    In the first class of trade school for auto body the teacher made us cut a block of steel with a hacksaw and shape it with a file into a heel dolly. Then only by hand working up through all the grits of sandpaper and polishing it by hand to a mirror finish would it be considered finished.

    When the teacher could hold the dolly at arms length and see his teeth in the dolly then you could work on cars in the shop! It was supposed to teach you patience and how you couldn’t cut corners in a process or you had to go back and do it again.
     
  21. HSF
    Joined: Oct 25, 2014
    Posts: 225

    HSF
    Member
    from Lodi CA

    Shoot 3 coats of clear, knock it flat with 600-800 then shoot 3 more. Color sand and buff. Looks like glass before you even sand and polish it, just watch out for runs on those last 3 coats.
     
    427 sleeper and da34guy like this.
  22. Exactly!
    That phrasing should be a sticky!!

    Lately I’ve been doing a flow coat.
    After the last coat cures it’s blocked down with 500 grit dry. Use hard blocks and trying to get it even straighter. Some is gone over with finish DA at 500. Then another nice wet coat. That last coat lays out damn near perfect.
     
  23. Forgive me for asking,,,,,but what about the base prep,,,,primer finish ?

    Many years ago,,,,I was looking at my friends car one night in the street lights reflection.
    It was smooth as glass by day,,,,,but at night in the lights,,,,you could see the sander scratches from the primer showing through,,,freaked us all out.
    This was only visible up close,,,,really close,,,and in the street lights.
    Sounds crazy,,,I know,,,but I think enamel shows a lot more,,,,,where as the old lacquer was sanded so much it looked like glass.
    Am I wrong ?

    Tommy
     
  24. Depends on color for me on finish sanding and paint type.
    Solid color single stage I finish with 400 wet. 500 for solvent based 2 stage.
    600 for solvent based metallic 2 stage. ( this guy doesn’t mess will single stage metallic)
    800 on water based colors.
    Your final sanding recommendations are on the paint tech sheets.

    I do recommend a light DA sanding to remove straight line scratches.
    Also how you finish body work is important. I don’t expect a primer to fill a 40 grit scratch. I always finish body work at the highest grit the tech sheet says a primer can fill. Removing straight line scratches in body work also helps.
    A sand scratch can’t show up if it doesn’t exist.
     
    Last edited: Dec 7, 2019
    Tri-power37 and Desoto291Hemi like this.
  25. I would think that 3000 grit paper, that fine. You could just rub it down with news paper. LOL.
     
  26. Tri-power37
    Joined: Feb 10, 2019
    Posts: 510

    Tri-power37
    Member

    At work recently we painted a off topic truck and after it came out we just denibbed about 10 to 12 spots and then the owner took it to a place that does high end ceramic coatings. There was no cut and buff done just the ceramic coating (1500.00$). It looks amazing. I can post a picture of it but I think it might get taken down?

    I have yet to see how ceramic coating is done bit it sure is shiny!
     
  27. Slopok
    Joined: Jan 30, 2012
    Posts: 2,919

    Slopok
    Member

    Paint should be allowed to cure before being sealed with anything!
     
    anthony myrick likes this.
  28. Tri-power37
    Joined: Feb 10, 2019
    Posts: 510

    Tri-power37
    Member

    I think a month or so went by before it was ceramic coated.
     
  29. He needed just one more light round of primer laid out nice and then blocked down with 600, no break thru and then Sealer.

    Or don’t take it out at night :p:D
     
  30. Tri-power37
    Joined: Feb 10, 2019
    Posts: 510

    Tri-power37
    Member

    In Canada we have been using water base basecoat since 2010 and it doesn’t have the strong solvent bite that solvent basecoat has. It doesn’t swell/shrink sand scratches or the edges of primer like solvent base does. Most people who switch to water base basecoat find it easier and wouldn’t want to switch back for that reason and many others.
     
    Last edited: Dec 7, 2019

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