So, this was a big day - first time I was shooting primer and it's been a solid 5+ years since I've used a HVLP spray gun. Lots going on today, the summary:
1. Cleaned the parts
2. Build the spray table
3. Shot Primer
4. Cleaned Up
Of course, there was a bunch more involved in all of this, I'll likely post a longer-form blog post, but procedurally, here's what I did:
1. Cleaning: For all parts, I sprayed them with PreKote, used Gray scotchbrite pads to scuff and work the prekote into a lather, then immediately rinsed with a bunch of water, and set them on the table to airdry. Note: I only did a single prekote application, instructions want two, but based on other's procedures I've read and a thorough scrubbing, my dice-roll of a single application worked fantastically!
2. Spray table: I build a 5' x 3' frame made from 2x4s, and then made a couple of propped-up legs to give the frame some angle (intention is that the frame can be set on folding tables for spraying. I then covered the frame with hardware mesh leftover from our chicken coop.
3. Shooting Primer: I'm using Azko's 2 part Epoxy Primer (namely: 463-12-8 and CA-116). After much deliberation, I chose this due to it's fabled durability, despite the safety procedures it requires. This is an industrial coating with nasty stuff (isocyanates) which demands a powered-air respirator and full coverage of skin. The usage of this product is straightforward enough - a 30 minute induction time post initial mix, I let it sit for about 40 minutes after mixing - I used clean stir sticks for each part, mixed in the PPS cup I was using, and then sealed the PPS cup. I extracted liquid from the cans using clean syringes, which I'll dispose of after each use. I mixed to line '3' on the PPS cup, which yielded 8oz of primer for my project today (a SWAG, that actually was pretty accurate). I sprayed using the 3M PPS 2.0 gun and it worked surprisingly well; the only challenge I had was spraying the VS skins (I had funky glare from the sun that made seeing what I was spraying a challenge). Aside from that, the only other challenge was the fact that my angle aluminum parts for the rudder blew around from the spray air). After spraying, I let parts dry a few minutes, then flipped and sprayed the other side.
4. Parts were allowed to cure outside for approximately 4 hours before I moved them indoors for the night. I used the TR-19 thinner to clean the few parts of the gun that needed cleaning, and packed up my respirator, gun, tables, etc.
Results: Overall, I'm quite pleased with my first priming session - I had very few runs, and only a couple of misses. There was some dry-spray that I hit the VS with, but again, that's being critical and it was solely my fault for bad lighting (I was spraying outdoors in 80F and about 65% RH. The parts turned out great, and I'm excited to move along to dimpling and shooting my first rivets for the plane!