September 26, 2007Finally got back to work on the kit after returning from Singapore! But I've only a limited time because I'm off to my parent's home at the end of the week, for at least a week. [as it turned out, for 2 weeks].
As noted above, I had already fixed edge defects with putty and did some sanding.

Next up: prepping the wood strips that have to take the clamp pressure and resist the epoxy (don't want any nasty strip permanently attached to the box!). I used some scrap 1/4" ply for the strips and wrapped them in light paint drop sheets.
I mixed up about 60ml of epoxy (and still had some left when done) to use for the joints and the feather on the inside corner. Oops! I had run out of acetone and had to quickly go get some. [I never made a good Boy Scout.]
Although I had been planning on performing the glue-up with my wife, she was still at my parents without any clear return date; so, I decided to do the corner-by-corner glue method and hope for the best.

Painting the finger joints with epoxy was pretty tedious but it went right along and I was soon finished. I applied the required 2 clamps along each side, 8 in total, and then checked for square. Not a perfect first try - the two corners were about 1/4" different. I had a long clamp in reserve and put it across the top (by necessity) of the long diagonal and applied just the slightest pressure. I had two equal diagonals virtually instantly.
I then used most of the rest of the epoxy to feather in a fillet on the inside corners, using my fingertip as a spatula. Then, cleanup and waiting for 48 hours for the epoxy to fully set.
October 23, 2007I stayed away from home for 2 more weeks, helping my parents. The box was left with clamps on, so it was 'good and set' when I got back! No ill effects of being clamped up that long, as I had protected the wood with scrap very well.
I went to work at routing the edges flush, getting rid of the small raised portion of the finger joints (planned in by Astro Systems) and the extra epoxy. Initially, I tried doing this on a router table but quickly decided that the way to go was to make an edge guide from scrap and use the router "by hand" with a long straight bit.

Since that worked well, the next step was to use a similar setup and round over the edges with a guided round-over bit. Finally, the machining marks on the edges got sanded down with 120, 180, and 220 grit paper, on an orbital finishing sander.
One more item for the mirror box right now - the cover. I thought this step was misplaced in my instructions, but that is probably due to the fact that this was a custom kit. Anyway, I did sand and finish the cover now, but I haven't put any of the hardware in place yet.
Dec 22, 2007
My fears were justified about the fitment of the Primary Mirror Cell into the mirror box (see below). I'm thinking that because AstroSystems switched to 1/2" plywood for the mirror box, that there was some warping inward due to the clamping pressure when the box was assembled. I did that just before I left for Asia and the box was left clamped for 2 weeks or so. That made the side panels take a bowing set inwards. The box was also slightly out of square (maybe 1/16") but the bowing of the sides was much worse (contact and needed about 1/8" sanding).
So, long story shortened, there had to be considerable sanding done to get the PMC to fit reasonably well into the box. I didn't want to sand the edges of the PMC, so, instead, the bottom of the box was sanded down a ply layer in a couple areas. There is still a little contact, but I'm sure that screwing the PMC into the lower blocks will help square things up.

Today, I glued up the bottom of the lower truss clamps to the main body of the clamps and set them aside to dry in a warm room. The epoxy is very reluctant to flow when its cold so the containers are set in a pot of warm water for 30 minutes before I use it. It also gets very stiff after mixing if it's cold, so glue-up is being done in the house rather then the garage.
Dec 23, 2007 
With the epoxy on the bottoms of the lower truss clamps well cured due to the overnight in a warm room, it was time to epoxy the clamps to the top of the mirror box. I took the advice of the manual and put some 3/4" brads through both arms of the clamp. It was necessary to make a pilot hole using a brad in a power drill because nailing into the edge of the plywood is difficult with a light nail like this. I set the brad's head below the surface with a finishing nail set.

Working one corner at a time, I spread the epoxy on the outside of the arms, placed the template across the corner, pushed the clamp body in and up against the template, worked some gymnastics to tap the brads with a hammer in one hand while keeping the clamp in place with the other, placed the inner part of the clamp in place, and, finally, applied a woodworking clamp around the entire corner assembly. You can see that two of my clamps were applied with the clamp screw inside the box; this was because the screw-end clamping surface for these particular clamps is gimballed and won't work against the outside box corner.

The glue-up for the clamps took about 1.5 teaspoons of mixed epoxy. I had about 0.5 teaspoons left in the mixing cup, so I went ahead and glued the dowels into the tops of the truss poles, as per directions. Here's one about to be stood on its end for the epoxy to cure. Don't neglect to test the fit of the dowels into the poles before you start gluing! One of my dowels was a bit oversized and required a little sanding to get it inserted.