What's causing this?

bill3337

Member
Hi,

First I'll confirm I am a rank amateur painter. This is the second car that I've taken from bare metal to finished paint. I've used HOK jet black base and their show clear. I started the wet sanding with 1200 and stiff block, then to 1500 and 2000, all by hand. I have a d/a with trizact discs, but wanted to make sure I was getting this as flat as possible. I'm not finished polishing in this photo, but have finished the passes with 3M #1. This will be followed by #2 and #3. While the picture looks pretty good, when you move your head around you can see "distortion" in the image, as if a distortion in a mirror. To me, it appears to be below the surface, like maybe orange peel in the base? I suspect there's nothing I can do about it, but I'd like to know what the experts think. Thanks, Bill in Victoria, BC
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yes you can see through clear to the base. it's why i dont clear black. unless the black is flat it will always show peel.
 
Yes, likely the case. The reason I wanted to stick with base/clear, is that I've never sprayed single stage before, so wasn't sure what I'd run into. I have friend with a black single stage Buick and he has a similar condition in his reflections, but may not be as apparent. I'll have to compare his side by side.
 
ss is just clear with pigment. one thing i have seen over the years and most disagree with is that you can burn paint. especially with a dry pad running 2500 rpm. paint will take on a leather surface look. it will not polish out. excessive heat when buffing will destroy the finish .
 
Ok, been doing some more experimenting. I had hand blocked these panels starting with 1500 and a firm (but not hard) rubber pad, then carried through with 2000 by hand and 3000 triact pad on my 3M sander. Because the initial orange peel blocked off and the surface was uniformly sanded with no shiny spots, I assumed the panels were flat, but I was wrong. I was thinking I was seeing the orange peel in the base through the clear. Today I took a balsa wood block (not as hard as oak, but stiffer than a firm rubber block) and lightly sanded over the polished surface with 1000 grit. It really showed up what I believe is known as urethane wave. I've re-sanded half the roof with the balsa block and 1000 grit and it has flattened the surface out a lot better. I should probably started with 800, but nervous of sanding through, even though I sprayed 4 coats of clear. I've attached a couple photos of when I lightly passed the 1000 grit over the previously blocked and polished area. This area only had one pass with the polisher, but it was enough to pick up the waves. The photos look pretty disgusting, but that's like 2 light passes with 1000. The waves sand out quite easily once I start actual sanding. This is the roof of my '37.
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I don't think you are going to cut wave with 1500 for the same reason you don't block filler with 400 grit. You are just polishing the wave not cutting it. Also need a hard block, not firm.

Let's see what the experts say.

Don
 
I'm starting now with 1000 grit and a wood block (balsa wood) harder than a firm rubber block but not as hard as oak. It appears to be knocking off the high spots, but won't know if it got it all till I buff it up again. A small sample looks pretty good.
 
You can cut the wave with 1000gt it will just take longer. It is best to let it sit for awhile sand then let it breath and harden again, the sun does wonders. Hit it again let it sit again the sun does wonders. If done properly you can proceed to the next grit like 1500 and sand let it sit go to the next grit like 2000 do it again keep doing this till you reach the final grit let it sit then polish. If you sand and polish only to sand again you re doing more harm then good you could and should have started with something like 600 and just got it over with you would have cut the clear less by doing so.
 
i have a collection of hardwood blocks i have made from scrap.after 1000 i use 1200 then 1500 to get rid of the 1000 scratches.
 
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