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Post by technidiver on Jul 4, 2019 9:50:33 GMT -8
Mossback, are your tanks painted or just plain galvanized steel? Just another research question. Heard that the painted tanks were more prone to failures due to the inside being rust prone, etc.
My LDS has no problem with the older pipe thread Teflon tanks and from what I've gathered they can take as much and more abuse than the o ring tanks.
TD
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Post by nikeajax on Jul 4, 2019 10:28:59 GMT -8
Heard that the painted tanks were more prone to failures due to the inside being rust prone, etc. TD It's my understanding that that is only half true: it's when people repaint their tanks and do a bad job and not neutralizing the rust. As with auto refinishing, it's all about the primer, don't use paint on top of he old stuff... JB
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Post by Deleted on Jul 4, 2019 11:00:32 GMT -8
Mossback, are your tanks painted or just plain galvanized steel? Just another research question. Heard that the painted tanks were more prone to failures due to the inside being rust prone, etc. My LDS has no problem with the older pipe thread Teflon tanks and from what I've gathered they can take as much and more abuse than the o ring tanks. TD My 72's are factory galvanized....never bothered painting them....just left them as they came. My two twins; both were coated with plastic at one time.......one, the USD 1800psi jobber still is.....the voit I scraped the plastic off, had it nickel plated..(crappy job, the nickel only took to the high points and left the valleys from sanding untouched. I didn't know much about plating preparation way back in the late 70's) so I primed and painted those with refrigerator paint.....it has held up for many years.....see photo.........the Voits have seen a lot of use and abuse......I rarely use the USD so they aren't near as beat up........by the by.......the Voits are 1/2" necks, the USD are 3/4".......the o-ring in one of the USD tanks allows air to leak and I have to, sometime this year, take them apart to fix that........never had any issues with the 1/2" jobs. Voit tanks: Untitled by Michael Story, on Flickr USD tanks with plastic coating still on them. Untitled by Michael Story, on Flickr
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Post by SeaRat on Jul 4, 2019 14:27:50 GMT -8
It looks like two different Mossback Mk 3 regulators on those tank sets. I'm going to dive mine again soon
John
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Post by nikeajax on Jul 4, 2019 14:40:01 GMT -8
It looks like two different Mossback Mk 3 regulators on those tank sets. I'm going to dive mine again soon John As well as a Waterlung octo... JB
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Post by SeaRat on Jul 4, 2019 18:42:48 GMT -8
I have been around here awhile, and so I started reading through the thread about the "Mistral" regulator from 2005. It goes through details and experimentation concerning the Venturi, and hose-within-a-hose concept. Then I came across this post by me which addresses the use of the Mistral on high pressure tanks (3000+).
I think this affirms my hesitancy on using the Mistral on a high pressure system. I still have that publication in my library, and I'll see whether I can find it.
John
PS, yes, I do still have this paper, and the figures and tables are very interesting.
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Post by Deleted on Jul 5, 2019 7:02:52 GMT -8
It looks like two different Mossback Mk 3 regulators on those tank sets. I'm going to dive mine again soon John Actually no. The USD twins have the same regulator as the Voit hanging on it, just different hose. The USD photo is a older photo, back before the MB-Mk3 was born.........the USD photo regulator, a 66 RAM, is festooned with my first design, the Hookah port nut adapter with a 3 way splitter and a HP banjo. The Voit photo was taken in the summer of 2010, this was the first testing on the Mk3 at Lake Whitney. The yellow hoses were the ones I was selling for a while, when no one else would. Yep, the Sportways is a rebuilt 2nd stage. I could not find a replacement diaphragm so the LDS had some sizes from several brands and I got one that was close to the correct diameter, trimmed it down and vola!......been using that reg as a octo for years also. My first reg. was a sports-diver 2, even though I trained on a Healthways DH.....still have it but just keep it with my Nimrod oval dive mask, my first mask. I think I was 14 or 15 then when I bought the mask at Leonard Brothers Sporting Goods in Ft. Worth.
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Post by snark3 on Jul 6, 2019 12:09:37 GMT -8
TD- Just my humble opinion but using Johns calculations on the previous page on a set of doubles you'd be gaining 30 cuft. Rather than risking the potential problems with over pressurizing your tanks why not just mount a 30 cuft pony. You would end up with roughly the same air and have the added safety of a separate air supply if you were to have a catastrophic reg failure.
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Post by technidiver on Jul 6, 2019 15:00:26 GMT -8
TD- Just my humble opinion but using Johns calculations on the previous page on a set of doubles you'd be gaining 30 cuft. Rather than risking the potential problems with over pressurizing your tanks why not just mount a 30 cuft pony. You would end up with roughly the same air and have the added safety of a separate air supply if you were to have a catastrophic reg failure. That's a good point Skippy, I might end up doing that. For the price of a 72 compared to a pony, I could sling a 72 as a backup. Now that's interesting! Luckily, my back doesn't give me many problems, and I'll continue to (ab)use my back until it does so. I consider myself fortunate, I've had to carry double 130s for a friend who can barely lift an 80! He's good once he gets in the water though. TD
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Post by SeaRat on Jul 6, 2019 15:09:42 GMT -8
Well, today I used my Mossback Mk3 with my twin AL 45s, which have a service pressure of 3000 psig. My starting pressure was 2912, so pretty close on a dive at High Rocks on the Clackamas River. My max depth was 23 feet for this dive, but I did dive in fairly high current too. I really love my Mk3, as it has all the things a modern regulator needs. Mine is hooked up with a Cobra dive computer, LP inflator and a USD octopus (Calypso second stage). It worked flawlessly throughout my 45 minute dive. The Mossback Mk3 has an entirely new first stage, balanced, and based upon an Aqualung first stage, which Ol' Mossback made and marketed a while back. It is made for higher pressure, and is a completely balanced first stage. The second stage, and box, are DA Aquamaster. I took my Hope-Page mouthpiece off, and based on the below paper, put the USD hose system back on, as it did breathe better with the original hose/mouthpiece in place. I've talked about the problems with the Mistral at high pressures. Here's the graph from that paper* I told you about. Graph of Mistral:bar001 by John Ratliff, on Flickr John *Nyman, R.J., and J.G. Van Der Walt, "An Attempt To Link Objective and Subjective Perfromance of Sport Divers' Regulators, Science Diving International, Edited by N.C. Flemming, Proceedings of the 3rd Scientific Symposium of C.M.A.S, published by B.S.A.C., 8th-9th October, 1973.
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Post by nikeajax on Jul 7, 2019 11:42:47 GMT -8
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Post by technidiver on Jul 7, 2019 12:29:27 GMT -8
Well, now that's a practice that isn't encouraged or allowed today. But hey, they just gave away $8 of air!
TD
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Post by nikeajax on Jul 7, 2019 12:53:21 GMT -8
But hey, they just gave away $8 of air! TD Steele's only charges 5bux a pop: think of all the money you'd save if you came here to fill you tanks JB
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Post by technidiver on Jul 7, 2019 14:51:49 GMT -8
But hey, they just gave away $8 of air! TD Steele's only charges 5bux a pop: think of all the money you'd save if you came here to fill you tanks JB $16 for my doubles. Even with the exchange it would be cheaper to pay Steele's prices, but the transport cost might be prohibitively expensive Funny question, does Steele still use steels? TD
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Post by nikeajax on Jul 7, 2019 15:46:29 GMT -8
Jim used anything that's handy, just like me! Seriously: if you take any of Jim's classes no telling what gear you'll use if you don't use your own! If it works he'll send you under with it: Dacor Olympic-400, Voit MR-12, Conshelf-XII, etc and it doesn't matter the tank either, steel 72's or the dreaded aluminum widow-makers! If Phil or I are in his shop he will always brag on us JB
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