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kommisarrex
Contributor
To stay on topic, can you say if DSS bladders are made in similar size proportions to the outer shell as the DGX pic above?
Giant Bladder (BP/W)?
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To stay on topic, can you say if DSS bladders are made in similar size proportions to the outer shell as the DGX pic above?
cool_hardware52
Contributor
No. DSS bladders are only very slightly larger than the shells they are used in. Keep in mind that "double bladder" wings, (*not* redundant bladder) meaning those with a sewn outer shell and rf welded inner bladder, the bladder is a "2D" design, like a mylar ballon, and the shell is typically made from multiple pieces, like a tailored suit of clothes.
2D means two flat sheets are rf welded around the perimeter. RF welding dies look like a giant brass cookie cutter. A 2D bladder will never inflate the same as a 3D shell. That requires the Overall outline of the bladder to be a bit larger than the pattern of the shell when deflated.
To avoid stressing the welded seams of the bladder designers have long used bladders larger than the shell. Laminate bladders also don't stretch at all, and this requires even more "extra" bladder to insure the shell is fully filled.
DSS uses custom blown 30 mil urethane. This material does stretch, and is very robust. One could actually use just the bladder with out a shell. We do not recommend doing so, but we have tested it. Years ago when 12 mil urethane was the norm if you inflated a 12 mill bladder outside of a shell it would likely burst before the OPV vented. Not so with 30 mil.
With these properties in mind, i.e. some compliance and very robust welded seams DSS need not oversize our bladders much.
Because we produce our own wings, and weld our own bladders, and produce our own RF welding dies we can control this relationship quite closely.
The advantage is an easier to vent wing.
Welding dies cost money. Producing and stocking multiple sizes of bladders cost money. It's not uncommon for a RF welding "job shop" to have fairly large minimum production run requirements. Those realities lead to one size of bladder being used in multiple wing shells. Most of the time this works ~OK, but the downside can be gas trapping.
Tobin
cool_hardware52
Contributor
Some of our welding dies.
cipherbreak
Contributor
How it's made: SCUBA wings.
I have both a DiveRite Voyager (35 lb lift) and Travel (25 lb lift) wing, and from talking with DiveRite, both use the same exact zip out bladder, with the volume controlled by the outer shell. Through my own stupidity and carelessness, I managed to put a hole in my Voyager wing, called up DiveRite, and bought a replacement inner bladder. Since the time I originally bought my Voyager wing, DiveRite changed the material from urethane or vinyl to what your picture shows, which I think is coated nylon. I patched my old inner bladder with TearAid and figured I'd keep it as a backup. I haven't dived with the patched bladder, but did manage to place patches on both the inside and outside. I also patched my outer shell by gluing some ballistic nylon on the inside with AquaSeal. See TEAR-AID® Repair Patch Official Site - For Fabric And Vinyl Repairs for details. YMMV.
I'm not sure AquaSeal will hold up to patch your wing, as air pressure could push the patch off, unless you manage to put AquaSeal on both the inside and outside
My only other experience with TearAid is patching a vinyl rear window on a convertible top for my car. It's held up just fine for several years, saving me the cost of replacing the window, so the product seems to work quite well
I'm not sure AquaSeal will hold up to patch your wing, as air pressure could push the patch off, unless you manage to put AquaSeal on both the inside and outside
My only other experience with TearAid is patching a vinyl rear window on a convertible top for my car. It's held up just fine for several years, saving me the cost of replacing the window, so the product seems to work quite well
I happily dove a DiveRite Transpac with 25 lb travel wing for many years. I decided I wanted the full modularity of a BPW with 1 piece harness and got DR backplate with Oxy 30lb wing.
I liked that better, but both wings did not vent as well as I wanted. Towards the end of the dive I always had to position myself vertical and tilt my left shoulder up to vent air on my safety stop. This was the case with both wings. Vent hose located on left shoulder of both and both apparently use oversized bladders vs their shell. Coincidence ?
I then got a DSS 17 lb wing and my venting problems went away. It could be the smaller capacity, the center location of the vent hose, the shape of the wing, the size of the bladder vs shell, or all of the above.
I liked that better, but both wings did not vent as well as I wanted. Towards the end of the dive I always had to position myself vertical and tilt my left shoulder up to vent air on my safety stop. This was the case with both wings. Vent hose located on left shoulder of both and both apparently use oversized bladders vs their shell. Coincidence ?
I then got a DSS 17 lb wing and my venting problems went away. It could be the smaller capacity, the center location of the vent hose, the shape of the wing, the size of the bladder vs shell, or all of the above.
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