Success! Got the array put back together. It puts out about 12ma under the light of a 60 watt bulb. That's as good as gold for one of these early solar arrays.
The solder used on this array was not low-temp by any stretch of the imagination. My little Hakko iron would not generate enough heat to melt the solder to sweat the joints back together. It was like trying to melt aluminum. I ended up using a Weller micro-torch. Worked great and it didn't damage anything. While I was at it, I touched up all the joints, since quite a few of them exhibited some flex. Afterwards the whole thing was good and solid, and flat.
I could not find the correct thickness of black foam for the backing, so my wife Janet took a 1/2" thick piece of extremely soft small-celled black foam and cut it down to 1/8" thickness with a wide blade X-Acto knife (she ALWAYS helps during a restoration, whether it's a radio, TV, tape-deck, old truck or motorcycle). I put the back on and sealed it with GC Vinylite cement, which appears to be the same stuff Hoffman used to close it up.
Now on to the radio and speaker.....
