Gluing up a wing spar

Yesterday I headed over to Stu’s to glue up all of the pieces to the aft face of the upper right wing spar. There are two full length spruce spar stiffeners, four pieces of plywood at the wing root, spruce blocks placed at each rib location, and four plywood pieces for the flying wire attachment brackets. Then I’ll get to flip it over and do the same on the other side.

When I was building wing ribs, I found that a total of 8 ml or so was about right to make two ribs. Since I did that a lot, I got used to mixing up small batches of T-88 epoxy. Yesterday was the first time I have had to mix relatively large quantities — I went through two 20 ml batches, which is about the most I can do in the little medicine cups I bought for this. Even that left me slightly short. There are a couple of plywood attachment pieces that I didn’t get installed yesterday. System Three makes auto-mixing dispensing cartridges, but they’re substantially more expensive to use. As in, over six times the cost. I think I’ll be sticking to mixing cups. I may need to get some larger ones, though — mixing up 20 ml at a time isn’t going to work for a lot of this stuff.