[PSUBS-MAILIST] manifold

Thu Nov 12 19:49:49 EST 2015

Brian,Nice to hear about Lake Diver,  well done!Hankps; keep the name as is :-) 

     On Thursday, November 12, 2015 3:41 PM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Yeah, my one bad experience was with a larger fitting, 3/4 I think, with minimal Teflon tape, the nipple was literally a mangled mess after I finally got it out. Brian 

--- personal_submersibles at psubs.org wrote:

From: Stephen Fordyce via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Subject: Re: [PSUBS-MAILIST] manifold
Date: Fri, 13 Nov 2015 08:02:39 +1100

No worries Brian - it's like a lot of things, where if you have good technique and parts then it's fine. Plus the 1/4" threads are much more forgiving than the bigger ones.I just finished a project (a system for a very large LNG plant for Chevron) where we were not not allowed to use Teflon tape, only paste - and everything was SS. Everything went in fine and sealed, but when we had to make some modifications maybe 40% of the connections were galled to some extent.Damaged threads is something to really watch out for, as that can really ruin your day. This can also happen when a SS threaded fitting is welded onto something and distorts slightly - I had some rather expensive components on a last minute project destroy themselves because of this.Cheers,
SteveOn 13/11/2015 1:58 AM, "Brian Cox via Personal_Submersibles" <personal_submersibles at psubs.org> wrote:

Stephen,   Thanks !   I had one bad experience with galling so I think I'm over reacting a bit ,  I think the multiple layers of Teflon will do the trick ! Brian

--- personal_submersibles at psubs.org wrote:

From: Stephen Fordyce via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Subject: Re: [PSUBS-MAILIST] manifold
Date: Thu, 12 Nov 2015 18:56:00 +1100

Hi Brian,I prefer to use brass for oxygen since it doesn't burn, whereas stainless steel does.  But it's a bit overly paranoid since SS tube is widely used with HP oxygen anyway, and so you have to use SS compression fittings with it.  Plus you have to try really hard to get SS going.
If you use plenty of Teflon tape, say at least 4-5 turns (and make sure it's suitable for oxygen, and none of it ends up in the flow path) the galling risk of SS on SS new threads is very minimal.  Because NPT threads seal on the sharp bit of the threads, they do get slightly more damaged each time they are assembled, so avoid doing it more than necessary, and don't tighten ridiculously hard.  That said, with plenty of Teflon tape you can get away with at least 5 cycles.
It should go in and turn smoothly as you apply torque, if you feel it getting jerky then that's time to think about stopping.  When they gall, it's usually the male thread that's wrecked, so re-tapping the female thread is an option in many cases.
Cheers,Steve
On Thu, Nov 12, 2015 at 2:12 PM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Stephen,                 In your opinion would it be better for me to use a brass manifold if I were to be screwing ss fittings into it , because of the galling issue using stainless to stainless.  Or does it not matter that much it I use some type of anti galling compound? Brian

--- personal_submersibles at psubs.org wrote:

From: Stephen Fordyce via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Subject: Re: [PSUBS-MAILIST] manifold
Date: Wed, 11 Nov 2015 11:59:47 +1100

Hi Brian and all,
Western Enterprises (USA) does a nice and really cheap (~US$70?) 7-port (1/4" NPT) brass block rated to 3000PSI and idea for oxygen - see photo below - would be good if it's inside your sub.  They also do a SS version for several times the price. 
Global SCUBA Manufacturing makes most of the ones that Alec pointed out at Deep Six and they're pretty good too.  Being chrome plated brass they tend to be cheaper than SS, a bit nicer for oxygen service, and are still good for saltwater use.
Both of those places only sell through distributors but you should be able to download catalogues (I can send if needed) so you can at least see what exists.
I may have already mentioned (shameless plug), but I run a small business on the side which largely deals with custom assemblies and high pressure oxygen fittings, hoses, cylinder adaptors, etc. for SCUBA gas mixing and the like (and I'm a distributor for GSM and Western).  My catalogue is here:
www.tfmengineering.com.au/TFM Engineering Catalogue 2015-10.pdf
Much of my stock comes from the USA (to Australia) so it may not be very effective to ship it here and then back again, but if anyone is interested and has a few hundred USD worth of order I can probably arrange to get stuff sent direct from the factory instead.
Cheers,Steve
PS: What I wouldn't for access to McMaster Carr!  They don't ship to Australia :(

On Wed, Nov 11, 2015 at 9:42 AM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Great !   Thanks everybody ! Brian

--- personal_submersibles at psubs.org wrote:

From: Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Subject: Re: [PSUBS-MAILIST] manifold
Date: Tue, 10 Nov 2015 16:34:20 -0500

Hi Brian,
Call George at Deep Six Scuba. Here is the relevant page below, just scroll down and you'll see manifolds. BTW he's a super helpful guy, he's always fishing around and coming up with weird adapters and stuff for my unusual requests. Say hi!
http://www.deep-six.com/page30.htm

Best,
Alec
On Tue, Nov 10, 2015 at 1:31 PM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Hi All,               Does anyone know where I can get a stainless high pressure manifold that would be an off the shelf type item?  I will be needing to distribute HP air to various places ( not breathing air) , also will need ports for gages, probably at least 6 ports. I can always plug any port not it use.   Brian 
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