Pandemic Bug; Tiny Doubles (Pics)

[Cio]

My pandemic bug was tiny doubles, I am starting to assemble my creations.

I have just about always dove with a pony, pretty much required in NJ, and never liked it from a logistical point of view. I tried different mounts, all worked fine, but not great. There is always something awkward.

Didn't take much to find out that tiny double are a thing so I bought a bunch of tanks, probably too many, and designed my onw bands.

This pandemic was a long and lonely one and left to my own devices in the basement, well, this happens;
I got enough tanks to make the following tiny doubles;
AL40, OMS45, Heiser45, LP50, ALu63, HP80, ALu 80 (I know the last two aren't all that tiny)

I intended to weld the bands, just like the ones you buy are, and got to thinking, why are these always welded? I put them together and although I need one extra nut and washer to make assembly simple, I don't think there is a need for the welding. These seem super ridged and I can't imagine wanting to weld them at this point. (the back of the weld is just a place for corrosion to grow on the unpassivated weld.

Anyone know of any reason these would need to be welded? I design and make things for a living so I can't see why but maybe someone with doubles experience knows why, it's easy enough to weld but why do it if you don't have to?

I still have 7", 5.25" and 5.5" to assemble. all are 8.5" CC which I kept even for the small diameters thinking it would keep them close to the body and hold the wing in a good spot.

 

[Compressor]

I can't answer your questions about welding. But I see that you have done a very nice job with the doubles,

Thanks for the photos.

 

[BoundForElsewhere]

Nice fabrication. very clean. I want your garage.

 

[johndiver999]

Very nice, ALMOST makes me want to dive doubles. I wonder if there is a market out there for people who would like to dive double Al 40's independently - if there were a reasonable set of bands available?

 

[Cio]

Very nice, ALMOST makes me want to dive doubles. I wonder if there is a market out there for people who would like to dive double Al 40's independently - if there were a reasonable set of bands available?

I think the AL40s will be awesome, they are basically the same weight as an 80 and with the manifold should improve buoyancy characteristics and be super streamlined. I'm hoping I can make the work with an OxyCheq 30# singles wing. I have enough material for 10 or so sets of the 40s. I'll need to bend some up and see how they work out first though, I' a little concerned the gap may make them unstable and require a Rev B. I added holes so they can be independently bolted, hopefully they work, making them wasn't easy.

Here's the model of them

 

[johndiver999]

Good luck. I was sorta thinking out loud, that people who have one or two 40's might like playing around with doubles rigged independently, especially if they didn't have to get a special manifold, but I assume your design provides the proper separation for the use of a "normal" manifold?

 

[Akimbo]

It is easy to limit minimum spacing, which also forces cylinders to be parallel, with plastic spacers.

It is also easy to make your own bands with little more than a drill, hammer, and vise. Go to an HVAC or sheet metal fabricator and buy some thin stainless about 50mm or 2" wide. 20 gauge or 0.8mm works fine. Instead of stiffening plates for the bolt, take some aluminum round stock about 20mm or 3/4" in diameter and cut it in half the long way to make 2 half-moon profiles. Drill a hole and wrap the thin stainless around it in the middle and the two ends. I'll try to get a photo if this description isn't clear.

 

[captain]

I used the split round stock to make triple bands for a triple 30's vintage replica set..

 

[rob.mwpropane]

It is easy to limit minimum spacing, which also forces cylinders to be parallel, with plastic spacers.

View attachment 649986​

It is also easy to make your own bands with little more than a drill, hammer, and vise. Go to an HVAC or sheet metal fabricator and buy some thin stainless about 50mm or 2" wide. 20 gauge or 0.8mm works fine. Instead of stiffening plates for the bolt, take some aluminum round stock about 20mm or 3/4" in diameter and cut it in half the long way to make 2 half-moon profiles. Drill a hole and wrap the thin stainless around it in the middle and the two ends. I'll try to get a photo if this description isn't clear.

Photos would be great.

I've thought about making my own bands, I don't think it would be hard to copy the ones I have. My problem is time, just can't seem to find enough for all the projects I already have.

 

[OTF]

i love the triples!