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Post by technidiver on Oct 10, 2020 19:42:23 GMT -8
John, I think a point crucial to the DBE’s argument is that it does not require force to expand. With the duckbill, you have to blow to get it to stretch and expand and to exhaust. I haven’t done much work studying either, just a thought.
Work of breathing on a rebreather is probably the most important feature, it has to meet a very strict criteria set by the industry and divers. Improper use and poor breathing techniques have led to several incidents of CO2 buildup which are often fatal. The Navy has got better toys to test their theories than the whole lot of us combined, so I’m gonna have side with them on their use of mushroom valves.
But that’s just my opinion, most of you folks here have a lot more diving and technical expertise than me.
Would anyone know the size of the mushroom used on the Mentor? I suppose it’s listed somewhere. I’ll do some digging.
Before this goes off topic too much, I think that this is an excellent addition to the arsenal of parts to the DH Diver. Splendid work done by James and Phil.
TD
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Post by technidiver on Oct 10, 2020 19:44:01 GMT -8
Different design of the mushroom on the mentor, perhaps this would be possible to do on some plastic cans?  TD |
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Post by SeaRat on Oct 11, 2020 10:07:31 GMT -8
Luis,
I was not starting an argument; I was stating a preference, and asking if a different design could be made using the new 3D printing technology. It was exciting to me to see this work that James and Phil have accomplished. I love this adaptation of new technology for our vintage diving community.
Now, there is a difference between rebreathers and open circuit double hose regulators. On the extreme exhaust side, the valve (mushroom or duckbill) on open circuit have an air/water interface. This affects how each type of valve opens and functions. Rebreather mushroom valves don't have this air/water interface unless they are semi-closed circuit, and even then it is different that an open circuit scuba.
I'll leave it at that, but I do prefer a duckbill to a mushroom valve for this function. Both work; the duckbill has been shown to work somewhat better.
John
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Post by cnotthoff on Oct 11, 2020 10:45:13 GMT -8
I seem to have missed the genesis of this thread. I've been using 3-D printing to create zoom gears for housed cameras. www.facebook.com/photo.php?fbid=10213564404779172&set=pb.1674140460.-2207520000..&type=3A friend of mine (a much better uw photographer) started using some Nikon lenses that are not commonly used for uw photo. He was JB welding pieces of gears together to operate the zoom on these lenses. I created 3-D .stl files of these gears and sent those off to be printed. I started by researching materials for 3D-printing. Since the gears I designed are supposed to stay dry inside the housing, water resistance wasn't one of the design criteria. Only PETG and polyproplylene are listed as water resistant. Commonly used materials like nylon can absorb water. What material was used to print your cans? Have you used those cans in water? If so have you noticed an adverse effects? Good Dives, Charlie |
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Post by nikeajax on Oct 11, 2020 11:54:24 GMT -8
...It is amazing that you are still arguing about the old duckbills... Luis, I was not starting an argument; I was stating a preference, and asking if a different design could be made using the new 3D printing technology. It was exciting to me to see this work that James and Phil have accomplished. I love this adaptation of new technology for our vintage diving community... John Because it lets/makes/forces people to think: revisiting old ideas allows people to come up with new ones. How often have people set things aside because they believed that they were of no further use, and then further on another person augments that idea to something revolutionary. Case in point: how similar is the technology in a scuba regulator to that in a soda-siphon--very! Besides this; any voice on this forum is a good thing: funny how people will read and glean information from this site, but can't be bothered to participate  Jaybird EDIT: How long ago was it that people honestly believed that a DH-reg was old fashioned and totally useless for diving: how many people still believe that, and yet... |
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Post by james1979 on Oct 11, 2020 13:14:55 GMT -8
What material was used to print your cans? Have you used those cans in water? If so have you noticed an adverse effects? Good Dives, Charlie Charlie,
I printed those in PETG (and Phil is tracking that these are un-tested, "use at own risk" kind of parts). For anything functionally critical I only use ABS and now PETG (just started using it the last couple weeks). The only other in water use thing I've printed other than those 2 materials is the DivAir cover for Phil. That one is PLA, but is also just a protective shell.... it could fall apart (not that I think it would) and not cause a functional issue.
Respectfully,
James
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Post by vance on Oct 11, 2020 15:01:48 GMT -8
...It is amazing that you are still arguing about the old duckbills... Luis, I was not starting an argument; I was stating a preference, and asking if a different design could be made using the new 3D printing technology. It was exciting to me to see this work that James and Phil have accomplished. I love this adaptation of new technology for our vintage diving community... John Because it lets/makes/forces people to think: revisiting old ideas allows people to come up with new ones. How often have people set things aside because they believed that they were of no further use, and then further on another person augments that idea to something revolutionary. Case in point: how similar is the technology in a scuba regulator to that in a soda-siphon--very! Besides this; any voice on this forum is a good thing: funny how people will read and glean information from this site, but can't be bothered to participate Jaybird EDIT: How long ago was it that people honestly believed that a DH-reg was old fashioned and totally useless for diving: how many people still believe that, and yet... I love the back and forth. It can bring up feelings, but we all, including me, need to step back and realize it's all about exchanging information. Arguments do happen, but they don't have to be personal. |
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Post by nikeajax on Oct 11, 2020 15:15:37 GMT -8
I love the back and forth. It can bring up feelings, but we all, including me, need to step back and realize it's all about exchanging information. Arguments do happen, but they don't have to be personal. And this is my point... EXACTLY!
JB |
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Post by cnotthoff on Oct 11, 2020 15:25:33 GMT -8
What material was used to print your cans? Have you used those cans in water? If so have you noticed an adverse effects? Good Dives, Charlie Charlie, I printed those in PETG (and Phil is tracking that these are un-tested, "use at own risk" kind of parts). For anything functionally critical I only use ABS and now PETG (just started using it the last couple weeks). The only other in water use thing I've printed other than those 2 materials is the DivAir cover for Phil. That one is PLA, but is also just a protective shell.... it could fall apart (not that I think it would) and not cause a functional issue. Respectfully, James
Very cool. I've been toying with some other designs that need to get wet. Do you have your own printer? I've been sending the files off to a company that creates the parts. Shipping often costs more than the part. As for exchange of ideas, I'm thankful you haven't thrown me out for mentioning things that were made after 1990.  Good Dives, Charlie |
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Post by SeaRat on Oct 11, 2020 15:43:30 GMT -8
Okay, what this discussion has prompted me to do is to scan my March 14, 2013 study from my logbook. I maintained a logbook for years with various studies, both professional and personal, along with notes of meetings, etc. Here is my Regulator Resistance Study from that date. I used an instrument from my workplace at the time, and don't have it now so I cannot reproduce this study. But here goes:  Regulator Resist Study001 by John Ratliff, on Flickr  Regulator Resist Study002 by John Ratliff, on Flickr This is the exhalation resistance study. Note that the Mossback MkIII study was with a Hope-Page mouthpiece, with silicone mushroom non-returns inserted in the mouthpiece, and that the bottom box was the DX Duckbill exhaust. Both the DX Overpressure regulator and the DA Aqualung regulator had the removable exhaust that I like.  Regulator Resist Study003 by John Ratliff, on Flickr This is the inhalation study I conducted on these same regulators. These were most of the intact, usable regulators I had at that time. This will take you a bit of time to digest. But I'd be interested in hearing your thoughts about this study. Obviously, I have not written it up and/or published it before. I did this mostly for my own information about my regulators. But this discussion made me realize that a lot of others may be interested in it too. John |
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Post by james1979 on Oct 11, 2020 16:01:52 GMT -8
Charlie, I printed those in PETG (and Phil is tracking that these are un-tested, "use at own risk" kind of parts). For anything functionally critical I only use ABS and now PETG (just started using it the last couple weeks). The only other in water use thing I've printed other than those 2 materials is the DivAir cover for Phil. That one is PLA, but is also just a protective shell.... it could fall apart (not that I think it would) and not cause a functional issue. Respectfully, James
Very cool. I've been toying with some other designs that need to get wet. Do you have your own printer? I've been sending the files off to a company that creates the parts. Shipping often costs more than the part. As for exchange of ideas, I'm thankful you haven't thrown me out for mentioning things that were made after 1990. Good Dives, Charlie Charlie, Indeed I do have a printer... It's smallish (those cans are pretty much the limit in the x and y axis) and single print head, but I make do! Mostly I use ABS, TPU (95 duro Urethane), and now PETG. I suggest, though, that further discussion on this vein move to PM or the thread on 3d printing process I started a while back so as not to derail this one further! Respectfully, James |
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