[PSUBS-MAILIST] manifold

Thu Nov 12 16:02:39 EST 2015

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,
Steve
On 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
> <http://www.tfmengineering.com.au/TFM%20Engineering%20Catalogue%202015-10.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 :(
>
> [image: Inline image 1]
>
>
> 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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