About Constructing a Rib

Moon, gluing the gussets on a mostly-finished rib.

Resin, hardener, disposable glue brushes, Popsicle sticks for mixing the epoxy, and measuring and metering devices.

I suck 10 milliliters of resin out of its container and deposit it into the graduated cylinder. Then I pour 1 milliliter of hardener in on top of it. I use the Popsicle stick to mix the two together. Then, I just dip the brush into the graduated cylinder and spread the glue on the joints.

10 milliliters of resin. It looks like a bit more than that due to surface tension. Now, I'll add a milliliter of hardener.

All the pieces of a rib, ready to be glued up.

Adding the tiny nails after gluing to hold the gussets in place while the epoxy cures.

When I first build a rib, I use nails to hold the gussets in place while the epoxy cures. When I glue the gussets on the other side of the rib, after removing it from the jig a day after building it, I place the jig (with a new rib in it) on top of it overnight. The weight from the jig provides plenty of pressure to give good joints.

Rib Number One

After what seems like a long while and lots of waiting, I finally glued up the first rib. I cut out all the pieces of wood for all 28 ribs before starting. I'm hoping to build one rib per day until they're all complete. The epoxy has to set up for about 24 hours, so one a day is all I can do, since I built only one jig.

Cutting 1/4" x 1/4" spruce with my miter saw.

A pile of pieces with a bronze Lie Nielsen block plane in the background.

Some parts in a baggie with the jig underneath.

I clamped this piece of scrap wood to the table on my oscillating belt sander to use as a fence to create steep angles on the cap strips where they meet at the trailing edge of the rib.

Cap strips, ready to go.

Stage one of cutting out the rib leading edges from plywood.

Cutting out the jig for creating the leading edges.

I'm using feeler gauges both in front of and behind scrap blocks made from the spars (.035" and .010") to create a little space where the spars will go. This is because the upper wings are swept slightly, but the ribs run parallel to the slipstream, so there needs to be a little wiggle room for the angle when I slip the ribs over the spars.

Rib number one glued up. I'll glue the gussets to the other side when I remove the rib from the jig tomorrow evening. The epoxy is not at all what I expected. It was white and runny. Doesn't seem right, but that's what Aircraft Spruce sent me and I think I mixed it right. Hopefully, the rib won't fall to pieces when I remove it from the jig tomorrow. I bought a small graduated cylinder to mix up the epoxy. It's a 25ml cylinder and I chopped it in half since I don't need all that capacity and want easier access for stirring and dipping my disposable glue brush. It worked okay as a container for mixing the epoxy, except it was a bit messy pouring the epoxy into the cylinder. Maybe I'll come up with a neater way to pour it in.