Hey, looking for some tips/tricks/information here.
Getting ready to get my engine bay into primer. Long story short, once it’s in primer, it’s likely to sit like that for 12-18 months… life is complex right now.
Engine bay is mix of factory paint, factory primer, and bare metal.
Plan is to scuff everything with 80-120 grit on the bare metal, 300 scotchbrite on the factory paint/primer areas. Mask the rest of the car with a mix of Painters tape and painters plastic. Cover most of the shop in plastic so I don’t kick up as much dirt/dust/etc.
Planning on using a PPG Epoxy Primer (DP90LF) and a DeVilbiss FLG4 HVLP gun with the DeKups setup. (Have a 6hp, 60Gal Kobalt compressor, DeVilbiss Filter/Regulator, and dedicated hose for between the filter/dryer and the gun.)
Any tips/suggestions/other information you’d share?
*I have painted with an old school suction gun, but that was so many years ago it wasn’t even funny, I haven’t played with the HVLP stuff yet, so this will be my first attempt. The reason for the good equipment is that I’m a firm believer in buy quality once instead of crap 10 times. I know I’m going to end up using everything again later when I come back apply the filler and spray the engine bay/entire car.
Verify your HVLP Tip Size. It’s been a while but 1.2 mm and 2.0 mm sticks out. Refer to the MFG of the Primer.
Primer is pretty hard to fuck up. Spray and leave it. DO NOT scuff, knock down, blend, or blah-blah-blah the primer if you don’t plan on putting your base coat on for a while. If anything just cover the bare metal. You will need to break it open and possibly re-build before you paint. You will not be able to just “shoot” color after 48-72 hours anyways. You need to scuff.
I would maybe put an extra 1/2 coat and sand when you are ready to shoot.
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Let me clarify…it will be hard for You to fuck up as you have experience painting. If anything make sure you get a consistent coat. Adjust your feed accordingly. Practice on cardboard. If you can spray a box you can spray a firewall. The only tricky thing with HVLP is make sure you have a good mix in your cup. But, that’s true with all systems.
I downloaded the spec sheet from PPG, 1.5mm tip size at 10psi cup pressure. 2 coats. Mix, let catalyze 30 mins before spray, 72 hour cup life after mixing.
I still need to do all the filler work plus more grinding later… so it will all be scuffed and sprayed again. I just need something to seal the metal that I don’t need to worry about it rusting and at the same time will be ok to put filler over (as a lot of people recommend filler directly onto bare metal, this is a primer/sealer that can/is suggested to be used under the filler).
The plan is to spray this, let it cure for a week, then throw the front end of the car back together and get her rolling and ready for a move… she maybe (90%) be getting hauled across the country on a trailer again within 3-4 months…
You’ll be fine with 2 coats. It’s ok to go a bit heavier on the first coat if your worried about coverage. Second coat should always be lighter IMO.
Ugh…I don’t know WHY sooooooooo many people still follow this rule. 1970 is over. High Solids Primers are THE SHIT and are designed for bare metal applications while still allowing skim coatings to be applied. I’d take the Pepsi Challenge with it any day.
Here is one tip…Tint the primer. DARK. The darker the better. Reason being once the primer sits for a while you’ll need to scuff it a little harder from sitting to be able to get the color to bite again, right? Well, what does dull yellow and light gray primer look like after it’s scuffed? Dull Yellow and Light Gray. If you can get it Darker or even BLACK it will be much easier to tell what needs to be sanded when you go to lay your color. Ask PPG if you can add pigment.
That should work out nicely. I can’t suggest the “best” practice for surface prep months from now as I’ve never waited more than a day or two. But, I can’t imagine it being any different other than be sure to scuff every square inch.