The completed 8-can-pipe. Notice cat inspection and the associated feline brain power.

Prior to putting the components together I laid this out to show how the hot band would slip over the stopper and then the cold can with "PAM" would be tapped into the band, stopping at the wood insert. Notice that I had 4 pairs of can's with narrow bands joining the cans bottom-to-bottom. Now it is time to join these pairs of cans with wide bands, with the cans oriented top-to-top.

I only ran into troubles when I attempted to tap a set of cans into place, but I tapped against a band. They are just not stiff enough to take that abuse and that resulted in a split band. Always start with any can combination as shown above, and then connect groups of cans by tapping them together, with the band between the cans.

Although the "pipe" is meant to just be a ventilation duct, there is benefit to the pipe being able to at least maintain it's shape. As a test, I wrapped the 4 x 4 wood block in a towel and hung it at the mid-point of the cans as they were supported on each end by the chairs. There was very little deflecton so in the hot environment of a solar collector, just supporting it's own weight, which for aluminum is pretty light, I suspect these "pipes" made without glue, fasteners or tape will do quite well.

More details on cutting the bands and connecting the cans...

I made some supports and stops to help position the can in the most favorable locations. The "C" shaped stops under the Dremel allowed for a smooth surface along that cut side and the blocks on either side provided lateral support. The can is supported vertically so it is just within the range of the cutting wheel. I added a piece of coarse sandpaper to fine-tune that vertical support plus the bar code on the paper served as a visual guide while turning the can. The wide and narrow bands already cut are visible. I used a sanding disk to de-burr those bands prior to use.

The support for the joining operation is shown here. Shown is the end result of joining 4 pairs of cans (bottom-to-bottom) with narrow bands. On the left the circular disk is the detachable stop to help insure the can is inserted to the mid-point of the band. The bands were put into the oven at 400-degrees F. The bottoms of the cans had been sanded off and "PAM" was smeared along the area where the band was to be located. The cans were then put into the freezer. I would pull out a band and slip it over the round stopper, then take the cold can and place it on the support. Using the wood block and hammer I tapped the can into the band. This process of joining one can to one band may have taken 30 seconds.

I put the can/band combo back into the oven and waited a couple minutes for them to heat up. With the round stopper removed I pulled out the hot can/band and then the cold can was positioned to go into the other side of the band and tapped. The end result would be one of the four pairs as seen in the photo. Again this took perhaps 2 minutes for all 4 pairs to be completed. Besides working extremely well, the only issue was the tendency to "tap" too hard, somewhat compressing the can in an unfavorable way. The 8 cans, when lined up as four connected pairs are exactly the same length as the 8 cans when positioned tightly end-to-end.

Although tempted, I will not test the final 8-can-pipe to see if it is watertight, but by selecting cans without the dimples, and insuring the cans were inserted to the midpoint of the bands, I'm sure these will be water-tight. Next operation will be to grind out the tops of these cans so I can then repeat this process with the three wide bands and therefore complete the 8-can-long pipe.

Interesting observation....

I have been working on a system to better slice 'n dice my cans as well as a support to help improve the process of joining cans with these bands. Doing so had led me to the discovery that at least half the cans I had set aside had the same small dimple where I had the previously mentioned pinhole leak. I have done a better job of can selection by restricting the cans to non-dimpled versions.

Some of the cans will still be used for bands. By using a wood dowel I can work out some of the minor indentations but still, I'll try to limit the use of cans that are not in the best of shape, so to speak.

With many issues cropping up in December, work has been slow but it has been cold in that lab as well. Now if the sun were out and the collector was working, and I could cut a ventilation hole into the side of my house..................