November 15, 2019

Primer test

Before I decided to buy a kit plane, I had no idea that there were so many choices for priming metal parts (or even to prime at all!). But given the New England weather, I decided I’m going to prime mating surfaces. I’m going with SEM Self Etching Primer for a few reasons:

  • It comes recommended from the Van’s community thread (another one)
  • It comes in a rattle can, eliminating need to buy paint spraying equipment
  • I can get it locally at O’Reilly Auto Parts, as well as on Amazon and other online sites
  • Price is moderate – about $21 a can, and one estimate I read is that I’ll need about a dozen cans in total

I made a little test coupon, first cleaning the aluminum with Simple Green Extreme and then 3 light coats of the primer; the result was pretty good. I’ll try some scratch tests after it dries for a few days. I like the green color – it makes it very easy to see what’s been primed.

To me it also feels like a real, big-boy airplane touch – I’ve spent a lot of time at the Beech factory in Wichita, where they used zinc chromate / zinc phosphate as a primer, giving the new planes on the assembly line their characteristic green color.

I also did some more wood working over the weekend: I had enough materials left over to make another work bench similar to the EAA standard work tables I made last week. This one is smaller, but I figure it will make a nice side bench for my drill press.

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