Color sanding blotchiness

[TinCanFab]

Hi guys, I just sprayed some single stage/non metallic- L345 light grey (a khaki looking tan grey) on my single cab's doors.

First, I layed 4 wet coats over scuffed dark grey sealer ( 2K barrier coat as per PDS instructions) that I let sit overnight. I knew I would be buffing out any imperfections so that's why I put a few extra coats on.

I got a new gun and it took a little getting used too. The paint came out real even with no runs or bugs. It did have a few tiny specks of dirt and about six very very small fisheyes. The PDS sheets say I can start sanding with 1500 within 48 hours, so I have. I also read through the sticky about wet sanding and buffing.

The slight orange peel has been knocked down with 1500 and 2000 grit wet, by hand only. The peel spots that have been sanded look much darker than the rest of the smooth areas. This is my first time doing this with single stage.

I went at the fisheyes with 800, wet and by hand. I got the them to dissapear but the areas I sanded are much lighter in color- leaving a brighter looking blotch. Medium grey, a ring of slightly darker grey, then a center with a bright grey.

My question: I don't have a buffer or the compounds yet. Am I wasting my time going at it with a buffer, or do I need to spray more paint over these areas? If so, how long should I wait to respray?

I'm pretty sure I haven't burned through the paint. The sealer is 20 times darker than my paint color.

[schell '59]

sounds like she is light..sorry bro'.

i would rescuff it with 600 on a block and recoat it...then block it with 2k only...make sure you apply 3-4 coats wet.
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[TinCanFab]

OK, thanks. Can I shoot more on it right away? It's only been 3 days.

[schell '59]

yep..just make sure you put enough on if your planning on blocking it down for color sanding as it's gonna remove your color again...also be careful you don't overcoat it too as it will flashback on you and cause dye back and solevent pop...make sure each coat flashes well.

how many coats did you put on the rest of it as well?...your doors with more color than the other panels will look deeper than the shell if your not careful..

hope his helps.
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[TinCanFab]

Actually, I haven't sprayed any other panels yet. I'm thinking my first 2 coats were to light because I was still getting the feel for the volume of paint coming out of the cap and the playing with the adjustment knob.

My compressor is small so I will be doing the whole truck in panel sections. For that reason, I used a capful of accelerator. Bugs weren't an issue because I sprayed at 8 am. I live in an orchard and was surprised they didn't attack it.

I'm not looking for a show job, just an original look. I'll practice a little more until I get it down. It's also getting done in my garage, but I think the fisheyes were from forgetting to scrub it real good with dish soap before painting. I might just wear rubber gloves too while handling the loose panels.

If I scuff it down real good with 600, do you see any problems with my other panels matching? Any other suggestions?

[schell '59]

nope the 600 wet grit will give your the re opened adhesion you'll need plus knock any imperfections down as well.

panel painting is not a problem either so don't worry just remember the EXACT amount of paint,coats,and air pressure you use...even when the compressor has to cycle back up...ty not to spray when the compressor is trying to keep up with you to many times...this will kill your paint transfer ratio and can make your paint go on thicker in areas vs the other panels...

a 5hp standard size compressor,like a craftman style stand up for instance,will work and not cycle to much while spraying a roof or a side panel of a bus or a roof of a bug...then let it catch up and do another...

run a gun bulb,wear gloves,if you don't have real good wax and grease remover(panel prep) you can use real nice glass cleaner and denatured rubbing alcohol. don't for get to at least tack rag it first beefore you spray just for that last bit of cleaning.

water down your floor or driveway and have at it...one panel at a time,day by day if that's what it takes..remember the more that compressor runs,the hotter it'll get and the more moisture will get into your line and gun,hence the gun "bulb"...this will stop much of the dirt and moisture from the hose and compressor.

good luck!
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[TinCanFab]

Thanks a lot for the help. I actually took the time to route 25 ft. of 3/4" galv piping to a big Sharpe oil/water trap on the other side of my garage. I seem to be getting clean dry air at all times as long as the compressor doesn't run for a couple hours straight. I even bought a new air hose that I only use for paint. My rear apron came out fantastic.

I've been using your other techniques as well. I'm now learning that a few runs with wetter coats is better than too light, as long as you plan on buffing it later.

I'll pop back in with some pics when it's all assembled. It's going to be several months though. I've still got tons of bodywork to do on the rest of the truck.

[schell '59]

try not to "run" it though single is a tricky system when you run it as it tends to load up and darken the color and also lightens when it sanded and buffed.
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