The SAGA of my Trieste...
- Last Fall I bought a Trieste from Simonbeans and reported on it in this forum. I dove it twice... Once down to 20 ft in the lake out front and once down to about 120 ft in Fortune Pond. I found that it breathed surprisingly nice... Which surprised me considering all I had heard about the Trieste being a hard breather due to it's small and dome shaped diaphragm.
- Well, I couldn't leave well enough alone and wanted to try out the Scuba Museum's large diaphragm Trieste cans. This required me to take my Trieste apart and transfer the guts to the larger cans. And in the process, I discovered that my Trieste had been fitted with a very sensitive, handmade silicone diaphragm. No wonder it breathed so nice! BUT... The previous installation had rolled one edge under causing it to crease and become un-useable for re-installation. Not to mention, it was just barely sealed on that edge and I'm considering myself lucky it didn't let go when I was diving it. Bill said the Trieste diaphragms were notoriously hard to position during installation... A fact I would experience personally, later.
- I sent this photo to AntiqueDiver and asked if he recognized it. Bill was making diaphragms for the Trieste several years back. He used a nylon stocking for reinforcement, a large fender washer, and liquid silicone. He said it looked like one of his. Allan apparently made some of the same design so it might have been his, too. It's kind of fun to know the history of this reg includes three of my vintage diving friends, Allan, Greg, and Bill.
- So I ordered a new Trieste diaphragm from the Scuba Museum and in the meantime tried installing the guts in the large cans with a large silicone diaphragm. This I dove a couple of weeks ago in 12 feet of water at the local pool (its winter here). Breathing ease was excellent. I tried it swimming hard and it fed me plenty of air... AS much as I needed. BUT, I didn't like the idea that I couldn't put a Trieste label on it (none of the stick-on labels say Trieste). AND ANYWAY, I wanted to keep my Trieste as original as possible. So I planned to take the guts back out and reassemble it. The new diaphragm arrived. It's soft and the dome shape isn't as pronounced as expected. I had high hopes for it.
- Next, I spent two evenings trying to install the new diaphragm in the original Trieste cans. No matter what I did, it would end up either misaligned or would pop loose with a hard inhale. At this point, I'm pretty sure the band clamp isn't squeezing it tight enough. And it's screwed as tight as it will go. I'm beginning to think the handmade diaphragm might have been secured with liquid silicone... glued in place.
- About this time I remembered that Allan sells replacement regulator labels and he has them for the Treste. They're a little larger in diameter than the label recess in ScubaMuseum's cans. But it occurred to me that I might glue one of these labels over the label recess with silicone sealant. The sealant will fill the label recess behind the label with good enough rigidity. And that appears to have worked quite nicely.
- Nothing is broken or modified (yet) in the original Trieste cans configuration so I can still restore it when I want. I'm going to think on solutions for my diaphragm installation issues... Ask around, get advice, suggestions, etc. Maybe even make my own diaphragm. Meanwhile, I am very happy with how the large plastic can conversion has turned out. Here are some more photos: