OK, primer is taking forever to dry in high humidity, but at least it is no longer tacky. While sandable, it clogs the sanding paper WAY too fast in this state, but it is what it is. Going forward, I think I will abandon my cheapo spray paints, and upgrade to Tamiya primer and paints. Tamiya paints are way more expensive, but at least they dry reliably in 5-10 minutes vs. 1-2 days per paint coat with RustOleum/Krylon.
Now that wings and the airframe are ready, it's time to put them together.
Per instructions, I need to sand the mating root edges of two wings to 45-degree angles so that they fit tightly together on top of the airframe. There is a beveling tool provided, but I worked by hand on a large sheet of 3M sanding paper to speed-up the process. Then sanded the attachment surface on the airframe with 120-grit paper, and mixed the epoxy. Positioning the wing so that the beveled edge sticks out just enough to mate with the other wing is a bit tricky, as is keeping it in place while you clamp the pieces together to dry. I had to re-measure and re-align things a few times to get it right.
6 minute epoxy dries way too fast in the summer, so I will have to use 15 minute epoxy, measured by weight.
Once the epoxy has cured on the first wing, I mixed the second batch and glued the other wing.
And while the second wing was drying, I glued the two vertical stabilizer fins with TBII, to avoid messing with epoxy unnecessarily.
Origami folded and TBII-glued paper canopy turned out way better than I had expected.
Next up - applying glue fillets everywhere (TBII mostly, epoxy along the area where two wings mate together), attaching the rectangular launch lug, and painting.
I will stick with the recommended black background paint scheme, assuming I can find a can of black Tamiya paint in the basement.
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P.S.: A couple of lessons (re-)learned and reflections so far:
- Working with the regular HD/WM (Rust-Oleum, Krylon, etc) paint is really slow and frustrating when humidity is above 50%. Like it is now in NJ.
- Do NOT forget to CA-seal the edges of your balsa wings after you paper them. I hadn't worked with balsa for more than a year, and had totally forgotten this step. Now I have to deal with a few paper edges that are not sticking to balsa as well as they should. So I have to go back and re-glue them again, and again. Not fun, and totally avoidable.
- TBII is great to work with, but still shrinks when drying. I now remember that I have a TiteBond Gap Filling formulation somewhere around the house. I should have used that for filleting.