DIY Single Tank Adapter

[wunat]

I am thinking of making my own STA, does anyone has drawings and/or details on it? Thanks a ton!!!

[Mambo Dave]

My friend thought about it, and came up with using a cut piece of 2" or 3" PVC pipe. It makes sense to me, and I may do it if I switch to a longer tank that would give me first-stage head-bonks.

Bolted in place it should work to center and space a single tank if the BP has the slots for the tank straps.

[amascuba]

My friend thought about it, and came up with using a cut piece of 2" or 3" PVC pipe. It makes sense to me, and I may do it if I switch to a longer tank that would give me first-stage head-bonks.

Bolted in place it should work to center and space a single tank if the BP has the slots for the tank straps.

wouldn't the pvc pipe have to much flex and eventually crack and split from wear and tear?

[Hank49]

I just made one for my Oxycheq 30 wing. I used 1/16" (I think that's the thickness) of stainless steel sheet and cut it 13" by 3 1/2". The middle is 1" wide and the sides are bent at 30 degrees and about 1 1/4" long. The tank straps go around it and aren't threaded through it like some are. We have a sheet metal bending press too. That's important. Bolted it to the Halcyon plate with the tapered, flat head screws that came with the plate. Used a press to push to screws in to make the tapered holes in the STA plate. The sheet metal bending press seemed to bow the sides out a tiny bit so I had to grind them a bit to make it even. Filed off the sharp edges. I used it yesterday and it works great. Saved me US$60.

[mddolson]

Here's mine

regards

MIke D



I am thinking of making my own STA, does anyone has drawings and/or details on it? Thanks a ton!!!

[Mambo Dave]

amascuba, I would guess it would have flex to it. The flex I'm thinking of would open the "U" a bit upon the loading of the tank straps, but not be otherwise problematic. It probably wouldn't last years, but a year of open water diving out of it sounds plausible.

[dumpsterDiver]

I made one out of a piece of 8-inch diameter PVC pipe I found as scrap at a construction site. It is very thick and extremely strong. I made it nearly as long as the plate and only 2.5-3.5 inches radially on each side from where it bolts into the plate from the centerline. (In other words. it is less than a semi-circle in cross-section) It is slightly negative and the total weight is probably less than 2 lbs. The pvc pipe is thick enough that it allowed me to countersink the two bolts which hold it to the plate.

A jigsaw cut the pipe easily. I put tabs of silicone sealant on the side of the pipe which contacts the tank to increase friction and allow me to use a single (scubapro) tank cam belt. This allowed me to assemble the plate and wing into one semi-permanent configuration using just two bolts to attach it to the plate. It took me 20 minutes and most of that time was spent looking for bolts and finding the remanant tube of some silicone caulk that was drying up in the garage.

[wunat]

Thanks alot!!! They are all very useful.

Next thing would finding myself a workshop to get things done!!!

[Mambo Dave]

DumpsterD, what size tanks are you using? I ask only because it seems that a 7.25 diameter tank would have wiggle room in the curvature of an 8" pipe, while an 8" diameter tank might not.

[dumpsterDiver]

I use 80 aluminum, 100 aluminum, steel oms 121 they all fit perfect. (Not sure what their respective diameters are) It serves to cradle the tank and prevent it from rolling side to side. The PVC pipe is bolted tightly to the plate, so the exact diameter of the pipe does not really matter since the pipe is less than a semi-circle. I'm reasonably sure it will work for nearly any size tank.

[Mambo Dave]

80AL's are 7.25 I believe.

I was considering using a smaller diameter, cut much like yours, to rest the tank upon. The tank would rest on the two top-inner ridges of the semi "U." In retrospect this seems like a bad idea as the PVC "U" would/could flex the ridges out in some situations, and this, in turn, would leave some slack in the tank straps.

I now think the 8" diameter you used may be the best option. Having the tank rest upon the bottom-most inner part of the "U" would leave no material that could flex between the tank and the plate.

Sidenote about PVC: I don't ever use the larger diameter PVC pipes on jobs I do, but in the smaller ones I have seen and felt there to be two different white plastics used. Some pipes are more stiff, and seemingly more brittle (though I don't know this for sure). I'm not sure what the different types' names are, but I would think one would want the typical PVC material over the more dense & less flexible stuff.

I'll take a look at 8" PVC the next time I go to Home Depot.

I'm thinking PVC might be workable somewhat like Delrin, and that I could dremel off the corners of the STA for safety and ease of use. Has anyone sanded or ground PVC?

Best,

Dave

[Hank49]

PVC thickness is rated in numbers. Schedule 40 is pretty standard for house plumbing. Schedule 80 is high pressure and thick walled. 80 is usually gray in color vs 40, white. I would think 2 inch cut in half might work....ok for a while. It would space the tank an inch away from the wing. (radius of 2 is 1) and if you use schedule 80 I doubt it would give at all as far as bending out. But having a round bottom on the mount, it won't be as stable as a piece of bent sheet metal that is flat on the bottom. It may try to roll and crack or pull the screws loose.

And yes, you can grind and sand PVC no problem. Smooth the edges, shape the edges, make little moon shapes...haha

[FatRob]

I used 4" UHMW PE U channel section and recessed it for all the grommets/eyelets in my recwing... made a sex nut to hold it on... works great

R.e. deterioration of PVC... only in sunlight, and not likely within a few years... can break in very cold weather, overflex in very hot. UHMW does not break when cold like PVC. CPVC would be more sunlight resistant. Or paint it.