April 12, 2020
Priming day is a lot of work, today it was two batches due to the number of parts. First, a few hours with soapy water and Scotch-brite pads cleaning all the parts. We decided to skip the Alumiprep and Alodine and just mechanically strip everything down with Scotch-brite. It’s an intense scrub down to get the oxide layer off the parts and then there’s only a ~2 hr window to prime the parts before the oxide layer reforms. Since the scrubbing takes off the marker too all the parts had to be re-labeled after scrubbing.
After the scrub everything gets one final wipe down with Acetone, which again removes the marker and requires re-labeling to keep everything straight. The marker shows up well through the primer, so this is the last time they need to be labeled. At the same time the two-part epoxy primer gets mixed up and has to stand for 30 min before it’s ready to spray.
Finally all the parts go into the booth and Paul dons the bunny suit. We’re using the 2 part epoxy primer from Akzo Nobel. Expensive stuff, but really seems to be strong once it’s dried (unless it’s attacked with a bucking bar…). The spraying itself only takes 10 min or so and goes pretty smoothly. The hardest part is making sure all the flanges are sufficiently coated. It’s easy to get the flat surfaces but the flanges, which are often the actual mating surface are easy to miss. We’re spraying everything with a $10 Harbor Freight LPHV purple gun and it does a decent job.
Cheers,
-Kacy
(Total Build Time: 124.0)