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    Results 1 to 13 of 13
    1. #1
      Join Date
      Aug 2004
      Location
      San Bernardino, CA
      Posts
      852

      Finishing grit for poly primer before urethane high build

      What is a good grit to finish my poly primer to before I move on to urethane high build? I am using Eastwood Contour Poly and its FRIGGIN AMAZING! spraying it on with a cheap ebay 2.5 tip gun at 37psi with 4% reduction (twice activator volume) acetone and it lays down pretty smooth. Still a slight orange peel but I spray a heavy guide coat and hit it with 80 grit and its easily reduced to a fine powder that doesn't load up my sand paper.

      Here was my plan:

      1. spray 3 wet coats of poly
      2. guide coat
      3. block with 80
      4. guide coat
      5. block with 180...
      6. ???????


      that's were I stopped. I scuffed up a small section of 180 with some 240 and man is it smooth! still have material to sand.

      do I stop at 180? go to 240, then 320, then urethane, 320, 400 wet.

      OR

      do I stop at 180, red scotch brite it then move to urethane, 320, 400 wet.


      Fresh Poly


      Blocking with 80


      blocking out 80 scratches with 180 and lightly sanding with 240 by hand with an interface pad


      Fresh poly on the body of my dads 67 Fastback

    2. #2
      Join Date
      Nov 2006
      Location
      Mountain Springs, Texas
      Posts
      3,801
      Country Flag: United States
      Any quality 2k urethane should fill 180 scratches. I use SPI Turbo primer. Not sure I would trust the job to Eastwood/Kirker 2k.

      Also would not apply that poly on bare metal. Quality epoxy only on bare metal.



      Don
      1969 Camaro - LSA 6L90E AME sub/IRS
      1957 Buick Estate Wagon
      1959 El Camino - Ironworks frame
      1956 Cameo - full C5 suspension/drivetrain


    3. #3
      Join Date
      Feb 2019
      Location
      Kankakee IL
      Posts
      285
      I'm sure the material spec sheets would have exactly what the manufacturer recommends for proper adhesion. Paint's a big dollar investment. I wouldn't guess on it.
      Tracey

    4. #4
      Join Date
      Nov 2006
      Location
      Mountain Springs, Texas
      Posts
      3,801
      Country Flag: United States
      Quote Originally Posted by Tsaints1115 View Post
      I'm sure the material spec sheets would have exactly what the manufacturer recommends for proper adhesion. Paint's a big dollar investment. I wouldn't guess on it.
      Keep in mind tech sheets are directed toward collision repair, not restoration work. Huge difference in goals etc….

      Don
      1969 Camaro - LSA 6L90E AME sub/IRS
      1957 Buick Estate Wagon
      1959 El Camino - Ironworks frame
      1956 Cameo - full C5 suspension/drivetrain

    5. #5
      Join Date
      Feb 2019
      Location
      Kankakee IL
      Posts
      285
      Quote Originally Posted by dhutton View Post
      Keep in mind tech sheets are directed toward collision repair, not restoration work. Huge difference in goals etc….

      Don
      Proper paint adhesion is proper paint adhesion. And collision repair is a huge chunk of the market compared to anything else so the last thing they'd want is warranty claims on any paintwork.
      Tracey

    6. #6
      Join Date
      Nov 2006
      Location
      Mountain Springs, Texas
      Posts
      3,801
      Country Flag: United States
      Quote Originally Posted by Tsaints1115 View Post
      Proper paint adhesion is proper paint adhesion. And collision repair is a huge chunk of the market compared to anything else so the last thing they'd want is warranty claims on any paintwork.
      Yessir! Sounds like you’ve painted a lot of cars and you know your stuff….
      1969 Camaro - LSA 6L90E AME sub/IRS
      1957 Buick Estate Wagon
      1959 El Camino - Ironworks frame
      1956 Cameo - full C5 suspension/drivetrain

    7. #7
      Join Date
      Feb 2019
      Location
      Kankakee IL
      Posts
      285
      A baker's dozen or so.
      Tracey

    8. #8
      Join Date
      Aug 2004
      Location
      San Bernardino, CA
      Posts
      852
      Quote Originally Posted by dhutton View Post
      Any quality 2k urethane should fill 180 scratches. I use SPI Turbo primer. Not sure I would trust the job to Eastwood/Kirker 2k.

      Also would not apply that poly on bare metal. Quality epoxy only on bare metal.

      Don

      I unfortunately live in California and about the only SPI products I can get my hands on are Epoxy and waterborne wax and grease remover. I have SPI epoxy on hand. I didn't strip the car to bare metal because of how pristine the existing old paint was. I just hit the car up with some 80 grit and shot the poly over it. The trunk deck had one tiny ding in it I used some glaze on.

      The 2k urethane high build I have on hand is Upol system 20. its 4:1 and was recommended to me by my local auto body supply.

      so the task at hand... do I stop at 180 and shoot the 2k high build or sand the poly as far as I can go?

    9. #9
      Join Date
      Nov 2006
      Location
      Mountain Springs, Texas
      Posts
      3,801
      Country Flag: United States
      It’s not in the tech sheet but it should easily fill 180 scratches imho. Hopefully the paint god will approve….

      https://www.u-pol.com/files/31617/up2253v-TDS-EN

      Don
      1969 Camaro - LSA 6L90E AME sub/IRS
      1957 Buick Estate Wagon
      1959 El Camino - Ironworks frame
      1956 Cameo - full C5 suspension/drivetrain

    10. #10
      Join Date
      Feb 2019
      Location
      Kankakee IL
      Posts
      285
      Quote Originally Posted by dhutton View Post
      It’s not in the tech sheet but it should easily fill 180 scratches imho. Hopefully the paint god will approve….

      https://www.u-pol.com/files/31617/up2253v-TDS-EN

      Don

      Name:  300px-Buddy_christ.jpg
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Size:  21.7 KB
      Tracey

    11. #11
      Join Date
      Nov 2006
      Location
      Mountain Springs, Texas
      Posts
      3,801
      Country Flag: United States
      The last Paint God on here went to prison….

      Don
      1969 Camaro - LSA 6L90E AME sub/IRS
      1957 Buick Estate Wagon
      1959 El Camino - Ironworks frame
      1956 Cameo - full C5 suspension/drivetrain

    12. #12
      Join Date
      Feb 2019
      Location
      Kankakee IL
      Posts
      285
      Nothing wrong with consulting directly with the manufacturer. Even a rattle can of Rustoleum has the prep, spray, recoat, and drying specs on it.
      Tracey

    13. #13
      Join Date
      Aug 2004
      Location
      San Bernardino, CA
      Posts
      852
      I ended up taking the entire thing to 320. I was pretty amazed how easy it was to remove 180 scratches with 320. Only gripe is my spray on guide coat clogged the 320 pretty bad. All in all I am happy with it, feels glass smooth. Poly is pretty much transparent, I have a few metal spots showing but its getting coated in 2k urethane primer tomorrow. I will try to wet sand it with 400 some time in the future. I am still working on the rest of the car.

      should I use rattle can etch on the metal? my Upol primer states its DTM.