Same tools, same primer, same techniques, but this paint job looks splotchy

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  #1  
Old 10-11-17, 07:03 AM
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Same tools, same primer, same techniques, but this paint job looks splotchy

I've done several paint jobs before, and while far from showroom quality, they were a lot better than this.
Same compresser, same HVLP gravity sprayer, same 4-1-2 primer-activator-urethane priming.
Only difference was this was a flat black finish, the others were factory colors.

How did it turn out so splotchy and what can I do to correct it?
 
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  #2  
Old 10-11-17, 07:13 AM
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It looks like you stopped to change directions a lot especially near the gas cap. The driver's door & left front fender are far more evenly sprayed.
 
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Old 10-11-17, 10:01 AM
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Either not enough paint applied or it wasn't applied evenly. Flat black can be a little harder to apply. Wet sand and paint again but try to keep a wet edge at all times and maybe speed up some. IF the mil thickness of the paint is thick enough wet sanding alone will help.
 
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Old 04-11-18, 01:00 PM
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I've been able to get the rest of the truck to an acceptable appearance except for the hood and the roof.
At this point I'm going to sand as best I can to see if that'll get it smooth.
After that I'm just going with a different color.

What grit sandpaper should I use to smooth this out? I'd been using the scotchbrite but it's not aggressive enough.
 
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Old 04-11-18, 01:27 PM
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400 grit is about as coarse as you can go under automotive paint. I like to have a garden hose trickling when wet sanding.
 
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Old 04-11-18, 03:26 PM
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Ok I'll get some 400 grit - hopefully that smoothes out those rough areas
 
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Old 05-01-18, 08:12 PM
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After further trial and error I've eschewed the recommendations by folks at the paint shop to continue use of the air sander.
Not sure why I didn't notice this earlier but the sanding pad is concave, not flat. A buddy of mine, whose work I've seen, always hand sands.
400 doesn't do anything. I got 180 sticky, stuck it to my hand and started sanding.
Now I'm at least getting somewhere and things are starting to even out some.
I have a buddy hit the area I'm sanding with the air sprayer as I sand to blow away dust.
Problem is, with all the dust/paint particles, it become hard to tell what splotchy spot to hit next.
If I wipe it down with prepsol, it pretty much spreads the dust and you can see the prepsol wiping "lines". I hose it down at full pressure with the garden hose but still can't seem to clear off all the dust.
Other than time and weather (which is the only thing that's worked so far), is there any way to clear off all the sanded dust so that I can get this job done in a reasonable time?
 
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Old 05-02-18, 02:22 AM
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What kind of equipment were you / are you using to paint this truck with?
 
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Old 05-02-18, 02:54 AM
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180 grit sandpaper will leave scratches that will show thru automotive paint.
If prepsol is smearing the dust around it means you aren't folding/changing your rag often enough.
 
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Old 05-02-18, 08:12 AM
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Take a compressor with a blow gun and air dust it first?

You said you're going for a flat black finish. Are you shooting a single stage, or a basecoat/clearcoat?
 
  #11  
Old 05-02-18, 08:42 AM
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What kind of equipment were you / are you using to paint this truck with?


Is this being painted in a booth with spray equipment or in the driveway with spray cans.

If later regardless of what is done it's not going to look much better.

Helps to know what level this thing is going to!
 
  #12  
Old 05-02-18, 12:17 PM
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I'm using:
a Porter Cable Air compressor
a Vaper HVLP gun
a Husky air blower
an air sander

I'm doing it:
outdoors
between 55 and 80 degrees

I'm using flat black no clear coat.

I've always used the same method described above with acceptable results.
The only difference is the flat black color which, as I've been told, is difficult to spray evenly.
 
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Old 05-02-18, 03:10 PM
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Like, a gallon of Rustoleum flat black? Or a specific automotive flat black? 1-part or 2-part?

Looking at the hood it kind of looks like you've got some tiger stripes. Like, you might not be overlapping enough, or your fan might be too wide or your pressures are off and you're getting dry edges. If you've done this before with different paint, I'm leaning towards you're running the wrong settings on your gun for this new paint.

I'm also wondering if the PrepSol is compatible with what you're using, or is it softening and smearing the paint.

The other thing is, this is a terrible time of year to be painting outside. With the amount of pollen in the air, it's sure to land in the finish.
 
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Old 05-02-18, 04:39 PM
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I know you said you've had this work previously but I have a hard time believing that little compressor is up to the job.
 
  #15  
Old 05-03-18, 03:40 AM
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I question the compressor size also, how much can you spray before the pressure drops?
 
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