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Thread: Sand scratches after cut and buff

  1. #1
    Join Date
    Aug 2020
    Posts
    5

    Default Sand scratches after cut and buff

    Hi All

    Iím wrapping up a spray job on a motorcycle and and am having difficulty getting rid of the sand scratches after buffing. The parts in question were sprayed a purple nightshade pearl over jet black base - so very dark in color. I waited about a week to wetsand and buff.


    The process Iíve used is as follows:
    1500 wet by hand with a soft block over the entirety of the parts until flat with no peel.
    2000 wet by hand with a soft block over the 1500 scratches. Both these with x pattern.
    3000 trizact on da damp
    5000 trizact on da damp
    Meguiars 105 with lake country orange CCS with 7424xp
    Meguiars 205 with lake country white CCS with 7424xp

    A few theories I have are:
    Cheap sandpaper.. Iíve been using the duragold sheets that TCP global sells.
    Not enough time spent with 2000 grit after 1500
    Not soaking the paper for very long - only soaked the paper for about a minute before starting

    Any other suggestions would be appreciated.

    I also ordered some meguiars m100 and a couple yellow CCS pads to try.
    Should I just throw down and invest in a rotary with wool? As with most beginners, that ones a little daunting.
    Should I trash the duragold sandpaper?

    Thanks!

  2. #2
    Join Date
    Nov 2005
    Posts
    42,557

    Default

    Are you sure that the scratches are in the surface and not in the pearl coat showing through the clear. Sometimes, if the surface wasn't sanding with a fine enough sandpaper before the color and pearl are applied, the pearl or metallic can lay in the scratch and is impossible to remove by buffing the on clear coat.

    However in most cases it's very difficult to see the sanding scratches left by a fine grit and sanding with a finer grit may not have removed all of the previous scratches. Then when the surface is polished it brings up a gloss on the surface but doesn't remove the previous sanding scratches.


  3. #3
    Join Date
    Aug 2020
    Posts
    5

    Default

    Quote Originally Posted by Len View Post
    Are you sure that the scratches are in the surface and not in the pearl coat showing through the clear. Sometimes, if the surface wasn't sanding with a fine enough sandpaper before the color and pearl are applied, the pearl or metallic can lay in the scratch and is impossible to remove by buffing the on clear coat.

    However in most cases it's very difficult to see the sanding scratches left by a fine grit and sanding with a finer grit may not have removed all of the previous scratches. Then when the surface is polished it brings up a gloss on the surface but doesn't remove the previous sanding scratches.


    While I am new to this, I'm fairly certain the scratches aren't from the pre basecoat sanding. The surfacer was finished with 600 wet (as I felt 400 was a bit too coarse) and the scratches were nearly totally gone by the second coat of base, and completely gone by the third. I finished with a fourth wet coat of base after that.

    My assumption is that the scratches still left after buffing are the 1500 grit used to flatten the peel.

    My question now is should I:

    Sand with 2000 again thoroughly, then the 3000 trizact again, and so on.

    or

    Try the yellow lake country pad with meguiars 100 on the da. Will that cut 1500 scatches?

    or

    Buy the rotary ive been contemplating buying and using that with a lake country twisted wool along with m100.


    Also I only sprayed one medium wet followed by two full wet coats of clear.. should I reclear before trying any of the aforementioned ideas?

    Thanks again for the help. It's really appreciated.

  4. #4
    Join Date
    Nov 2005
    Posts
    42,557

    Default

    Quote Originally Posted by Agould650 View Post
    While I am new to this, I'm fairly certain the scratches aren't from the pre basecoat sanding. The surfacer was finished with 600 wet (as I felt 400 was a bit too coarse) and the scratches were nearly totally gone by the second coat of base, and completely gone by the third. I finished with a fourth wet coat of base after that.

    My assumption is that the scratches still left after buffing are the 1500 grit used to flatten the peel.

    My question now is should I:

    Sand with 2000 again thoroughly, then the 3000 trizact again, and so on.

    or

    Try the yellow lake country pad with meguiars 100 on the da. Will that cut 1500 scatches?

    or

    Buy the rotary ive been contemplating buying and using that with a lake country twisted wool along with m100.


    Also I only sprayed one medium wet followed by two full wet coats of clear.. should I reclear before trying any of the aforementioned ideas?

    Thanks again for the help. It's really appreciated.
    Before re-clearing I'd sand and get more aggressive with some wet 5000 grit. Sand an area where it's easy to see the existing scratches then polish it to see if that solves the problem. If more sanding and polishing doesn't do the trick then sand it with some 2000 then re-clear it.

  5. #5
    Join Date
    Aug 2020
    Posts
    5

    Default

    Quote Originally Posted by Len View Post
    Before re-clearing I'd sand and get more aggressive with some wet 5000 grit. Sand an area where it's easy to see the existing scratches then polish it to see if that solves the problem. If more sanding and polishing doesn't do the trick then sand it with some 2000 then re-clear it.
    I should sand with the 5000 trizact? Would that remove the potential existing 1500/2000 scratches? Should I try the 3000 trizact that I have?

  6. #6
    Join Date
    Aug 2020
    Posts
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    Default

    I ended up spending some more time with the 3000 and then 5000 on the da followed by the 205 with the white pads and ended up getting the scratches out. It also polished to a deeper shine without the hazing. Your diagram breaking down what happens with the sand scratches really helped me realize what was going on. Thanks again very much!

  7. #7
    Join Date
    Aug 2020
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    5

  8. #8
    Join Date
    Oct 2007
    Location
    NORTH JUAREZ
    Posts
    3,152

    Default

    Quote Originally Posted by Agould650 View Post
    Hi All

    Iím wrapping up a spray job on a motorcycle and and am having difficulty getting rid of the sand scratches after buffing. The parts in question were sprayed a purple nightshade pearl over jet black base - so very dark in color. I waited about a week to wetsand and buff.


    The process Iíve used is as follows:
    1500 wet by hand with a soft block over the entirety of the parts until flat with no peel.
    2000 wet by hand with a soft block over the 1500 scratches. Both these with x pattern.
    3000 trizact on da damp
    5000 trizact on da damp
    Meguiars 105 with lake country orange CCS with 7424xp
    Meguiars 205 with lake country white CCS with 7424xp

    A few theories I have are:
    Cheap sandpaper.. Iíve been using the duragold sheets that TCP global sells.
    Not enough time spent with 2000 grit after 1500
    Not soaking the paper for very long - only soaked the paper for about a minute before starting

    Any other suggestions would be appreciated.

    I also ordered some meguiars m100 and a couple yellow CCS pads to try.
    Should I just throw down and invest in a rotary with wool? As with most beginners, that ones a little daunting.
    Should I trash the duragold sandpaper?

    Thanks!
    Dura gold is decent paper for the price keep in mind its similar to Norton in that its a little course grit then 3m so basically 2000 is more like 1500 grit.. on something with those curves I'd finish with 2000 dura gold then trizact 3k then 8k..

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