September 17, 2014 at 1:59 am #47387
I’m finally at the stage with my restoration where I need to blast a few fenders, a trunk lid and a hood/core support in preparation for paint. The panels have some rust and need to be done inside and out so rather than chemically strip them (they’re unknown underneath, but all have multiple coats of paint. I thought I’d just blast and epoxy them to seal them up. I’d like to know what the best practices are for blasted sheet metal (these are old cars, no chance of warping a panel (no sheet metal is below 20 ga).
I’ll be using PPG DPLV (as I can get it). So, should I DA the outside of the panels with 60 post blasting? What degreaser or washes if any should be used? I’ll be handling the panels gloved up once stripped and they will be primed within 24 hours.September 17, 2014 at 3:44 am #47388
Trust me, with a high power diesel commercial sand blaster you can warp some pretty thick metal!
Nonetheless, I assume you will be using silica as the media. Depending on the grade, it may leave the metal coarse. Running paper closer to 180 (by hand or machine) is fine (just a quick go).
You can use a good wax and grease remover, but be cautious if you do, and coarseness left in the metal will just grab lint and fibers out of your towel and make a mess (and tacking won’t help then).
Then just shoot the epoxy as per the tech sheets.
Are you blasting the parts, or having them blasted?September 17, 2014 at 6:11 am #47390
Thanks Ben…I’m blasting the parts and will be very careful of the effort put into it. I’ll buff it all with 180 then shoot it.September 18, 2014 at 4:45 am #47406
I picked up some Norton black ice 180 for the DA and the primer and a few other things…set me back $500! Man, the good products are a bit more expensive, but I’m sure glad that I’m out of the generic lines of paint.
Another stupid question – the TDS for the epoxy says that I need a 1.4 to 1.7 tip (HVLP) to paint this stuff. My Iwata LPH400 is so equipped, but I was thinking that I’d prefer to shoot it with my Sata Jet 3000 RP 1.3. Let me know if this is stupid.September 18, 2014 at 5:29 am #47408
You should be fine with the RP and a 1.3.
It’s not that far from a 1.4, and the RP puts out really well, so you should still get your mil build without any issues.September 22, 2014 at 5:13 am #47432
OK – so blasting panels probably wasn’t completely worth the effort…but I did find a few rust through areas that the blaster discovered. Restorations are like that, for example, my “good” trunk lid turned out to be full of bondo and is basically junk. Had to strip and prepare the original.
I sprayed the last of the evil ProForm epoxy on the parts that won’t go on the car just to seal them up and burn the paint. Then I switched over to the new PPG DPLV – sweet mother of pearl, that makes a difference. Two full wet coats and it’s nice and shiny. Looks great, easy to work with and totally kick the crap out of what I’ve been using. :dnc :dmc So pleased with the results (just doing a panel or two at a time as it’s all I can handle.
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