Now that all my structural components are done, it's time to start putting it all together.
First up is the fin can. Unfortunately, I couldn't stop to take pictures as I was spreading in the epoxy, but there wasn't anything special to see there. I followed the steps I outlined earlier:
1. spread a ring of Rocketpoxy just above where the fin slots end.
2. insert the fin can until the first centering ring was in and just before the second one was in the tube
3. spread a ring of epoxy just below the fin slots.
4. push the fin can in until the 2nd centering ring was a few inches in the tube
5. the last smear of epoxy was near the bottom of the tube.
6. insert the fin can all the way in
7. push in the thrust plate so the fin can is at the proper height.
Note: a ring of silicone grease was spread on the aluminum thrust plate so it didn't get accidentally epoxied in. It will ultimately be bolted on to the bottom centering ring.
Here's the whole thing left to cure overnight.
Looking down the tube, it appears that I have good filets set up on the upper centering ring. I did a check of all four quadrants. Looks complete.
I use a cheap borescope to check the internals. The centering ring just below the fin slots also looked good. A quick wipe with an isopropanol-soaked paper towel made sure the slots were clear of epoxy. Here's a phone cam shot looking inside one of the slots. The filets were good, and the fin slots were clear of epoxy drips.
While the fin can was curing, I finished up putting together all my fiberglassed 1/8" Batlic Birch bulkheads for the payload bay. These were clamped together and left to cure.
The image above shows the upper and lower bulkheads clamped together. They aren't epoxied together though. I took the assembly apart this morning, and it all looks good. The bulkheads are hard as a rock. Since they have to take a large shock on deployment, I test my bulkheads by balancing them on a wood dowel and standing on the ends. If it bends even the slightest, I'd be concerned. This didn't budge.
Since each plywood disc was first wrapped in fabric+epoxy before putting together the sandwich, I get 2 layers of epoxied fabric between each layer of wood. Those were then epoxied together and clamped.
So...
Each bulkhead is a multi-layered sandwich of:
fabric
1/8" birch 3-ply wood
2 layers fabric
1/8" birch 3-ply wood
2 layers fabric
1/8" birch 3-ply wood
2 layers fabric
1/8" birch 3-ply wood
fabric
The fabric is cheap, but is soaks up a lot of laminating epoxy! The downside is that each bulkhead weighs about 300 g. Not an issue for this large rocket, though.
Tonight, I'll epoxy on the switch band.
Then, it's time to make the fin alignment jig.
Onward and (hopefully) upward.