The weather has come and I can’t assemble the kayak outside because the plywood will get wet. I was able to go to the hardware store. I bought polyurethane (to waterproof the plywood), some sandpaper, a box of rivets, and some aluminum that I will use to make the seat support.
I decided that today might be a good day to start riveting the connecting sleeves to the tubes. It’s a fairly simple process but works well. To rivet the sleeves to the tubes the first thing to do is drill a hole through the sleeve and the tube inside. Then insert the rivet into the hole and squeeze the gun until the rivet ‘pops’. Two become one. Easy right? Not so, I figured the first step would be the easiest; to drill a hole, but I was sadly mistaken. I set the drill on the first outer sleeve and pulled the trigger,the drill spun dutifully around…. and around…. and around. It seemed to be taking too long to get through such a thin piece of metal so I stopped to check. 
Finally!
I lifted the drill and blew away the metal filings. There was barely a scratch. I figured I must have had the drill in reverse (it wouldn’t be the first time). So I checked but no, the drill was rotating in the right direction, what gives? I tried again but the drill was going nowhere. Maybe the bit was dull? I tried a different drill bit and the same thing happened, the stubborn metal just wouldn’t give. After about 15 minutes of drilling the drill finally made it through the outer sleeve, a mere 1/16th of an inch thick. It then punched straight through the aircraft grade aluminum of the inner tube in a couple of seconds.
I have no idea what the sleeves are made of but it sure is tough. When I was at Alco Metal pulling out tubes that were marked 6061-T6 (a high strength aluminum) I found this thin wall tube that fit almost exactly over the 1 inch aluminum tube. It was perfect for the connections. The guy even gave me it for free. I should have known when I was cutting it with the hacksaw, it was very difficult to get a cut going and there was a lot of screeching, a sure sign of a hard metal. 
After you make the hole riveting is a snap, or pop. Just squeeze while applying pressure until the nail of the rivet breaks.
So after drilling for several hours and only getting four rivets done as well as breaking a couple drill bits I was like well f@#$ that, and built a terrarium.
