I’ve got a wave in the middle of a door that’s driving me nuts!

C

CK-2

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I had a couple of spots on a door on my old show car that I wanted to fix. So I sanded down and spot repaired, primered, blocked, sealed, painted and cleared. Wet sanded and cleared again. Now I’ve got a bad wave right in the middle of the door. I’ve sanded with 600 and it’s still there. I’m sick over it and don’t really know how to fix it. I need help.
Whatever I need to do I’ll do it, I just want it gone.
 
Is it a clearcoat wave? If so go back and block the panel again evenly, front to back (or back to front doesn't matter) with the stiffest block you can use on the panel using the 600 wet. If it's a relatively flat panel a doubled up and taped paint stick will work, the narrow durablock will work as well. You want something that is the length of the wet sandpaper you are using. 11" long. Block evenly, do not concentrate on the wave area. Just even blocking across the length of the panel. Make 2 or 3 complete passes that way and stop, clean it off, and wet it down. Wait a moment for the water to disperse and sight down the panel. If it's gone, you're done. If not keep blocking and checking. Doing it evenly across the length of the panel is key. Don't not sand more in one area than any other. Block at a 45 degree angle to the top of the door. If you are really having trouble go back after making a complete pass and block at the opposite 45 degree angle (crosshatching). Don't sand back and forth parallel to the length of the door as it's hard to remove a wave that way.
Hope that helps. Keep asking questions if you have them.:)
 
It’s a wave towards the center of the door that runs vertically up and down the door. I put 4 coats of universal on the door and thought it looked good. I didn’t see anything unless I just missed it. Then I blocked and put more clear on and there it was.
I blocked with 600 all the way to 2000 and buffed and it’s there. Would it help to spray a guide coat on first?
 
I would go back with the 600 do like I said above. Guidecoat IMO really doesn't help on clearcoat waves as much as it does with primer. Key is even blocking with a coarse(er) grit like 600. Block the entire panel evenly with as stiff a block as you can get away with. You can use 2 quality paint sticks, cut them off to 11" in length. Tape them being careful to not overlap the tape, as you wrap the tape, lay the tape right next to each other. This makes a good block for this, if it's a flat panel.

This one is a little shorter and it's 3 sticks taped together but it illustrates how to tape it.
DSCN0644.JPG

Also sand at a 45 degree angle to the length of the panel. If you have to crosshatch by going back the other way at a 45 degree angle. This is the best way to get the wave out. If you sand back and forth lengthwise to the panel it will be much more difficult if not impossible for you to get the wave out. So sand at a 45.
 
Thanks for the help. I have this oak block that is
1 3/4 x 10. Or would I be better off using the paint sticks that have some give to conform to the panel?
Also is it coming to get a wave in one spot like that?
 
Oops forgot to attach pic.
 

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I use a block similar to yours. How you use it is much more important than the actual block, IMO. I've watched a lot of people sand, and one of the most common mistakes is concentrating on one problem area, instead of blocking the entire panel evenly until those imperfections are gone. It will cause exactly what you are describing. The area that gets blocked the most will be the lowest.
 
I usually block the clear with 400 grit dry when I want a true straight finish.
600 gets them really good, but I've used both side by side and could see the 400 did
just a tad bit better, especially for runs.
You need to make sure you use low pressure when sanding, it's easy
to flex the panel a little and keep it from getting straight.
 
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