HPA Fittings and Valves

[CraigH]

I suppose I should have known (and sort of did) that fitting would be an issue to get the setup I want.

First 1/8" NPT vs 1/8" BSP - What does GX Pumps use (GX CS3-I)?   Looking at PyramydAir I see the Air Venturi fittings are 1/8" BSP.

Next I want to use a "Gold" filter.   And I want to add shutoff valves at both ends of the filter so I can leave the filter pressurized.   There will be an air bleed between the filter output valve and the airguns.  (A one-way valve could be used as a filter input valve but much prefer a proper shutoff valve as the Tuxing does not have a drain)   Otherwise the filter has to be filled and the volume is rather large.   The valves seem somewhat difficult to find - and they are 1/4" NPT.   This might be needing a number of various adapters.   (Hope to avoid such a situation)

[CK]

My GX CS3-I uses an M10 thread for the female disconnect, and it does a metal-to-metal face seal in the hose almost like a flared connection (there is no Delrin sealing disc or O-ring). The QD does a good job of sealing Foster male fittings so far.  I've only had trouble with it sealing on a JTS "Foster" fitting on an Airacuda.

I cannot help on the shutoffs.  I've thought of doing similar with my Alpha filter, but all I've done is put a Foster check valve on the inlet, and the batch fill my guns so I'm not wasting as much air filling the filter housing.  One thread on Airgun Nation had a link to a shutoff valve on Amazon but it was a plain steel valve and I'd rather have stainless steel.  I was looking for one the other night and it's a pain.  So for time being I'm just living with the 5 minutes or so it takes to fill the housing the first time.

[CraigH]

Yesterday ordered several parts from a few places:

Two 7250 psi hydraulic shutoffs with 1/4" npt female both ends
Ten 5000 psi 1/4" npt female x 1/8" npt female reducers
One 6000 psi inline bleed valve 1/4" npt male x 1/4" npt female
Two 8mm female x 1/8" npt male quick disconnects - working 4000 psi x max 6000 psi

May need a few 8mm x 1/8" npt connectors (male and/or female).

[CraigH]

Perhaps no one reads or cares, but,

"Ten 5000 psi 1/4" npt female x 1/8" npt female reducers"

should be,

"Ten 5000 psi 1/4" npt male x 1/8" npt female reducers"

Those have arrived - awaiting the rest.

[CK]

It sure would be nice to have these sizes available at the hardware store where you could pay them out on the floor to make sure you account for all of the transitions.  I always end up doing that with plumbing fittings to verify my shopping list, and I inevitably find the gaps in my lists

Did you choose brass, steel, or stainless steel for your fittings?  And please let us know how the valves work at pressure.  Some of the reviews I read about the PIC brand valves mentioned that they were difficult to close.  It'd be nice to find a high pressure ball valve at a good price.

[CraigH]

All are steel or stainless steel.

As I understand it, brass is not of sufficient pressure capacity.

[luge007]

Oh, this was read, just not comment on, you have 395 views! 

YES, brass and steel fittings are NOT sufficient for 4500psi + of HPA and likely end in disaster.  Most of the 'hardware store' fittings will work fine for 'shop compressors' at 125psi or so, but for the HPA, it's just not worth the risk of injury or death.

ONLY 416 Stainless fittings rated for 4500+ (typically 6000psi) fittings should be used for anything that might see those kind of pressures.  I suspect most normal hardware stores do not carry those fittings because they are EXPENSIVE and most people do not need them.  I mean, what homeonwer is going to swing by the local hardware store and grab a $25fitting in 416ss when they could grab a $3 brass fitting that will safely do the same job?

Having built an HPA booster pump rated for 4500psi, I can tell you most of the 6000psi fittings are crazy expensive, really have to hunt for them online too.  YES, you need them if you are working with HPA, but dang.  IIRC, I had $350 worth of fittings (and hoses) in the one Booster and that did not include the $140 inline HPA regulator.

CraigH, please post pics of your project during construction or when it's done, always fun to share.     My Booster pic is up in my gallery, probably not worth reposting here, but I'll try to link it, lets see what happens
https://www.gatewaytoairguns.org/GTA/index.php?action=gallery;sa=view;id=9507

Cheers,
M

[CraigH]

Thanks for the post and the great images.   It is difficult to find HPA fitting excepting for a few by vendors for their specific applications.   Many others only rated for 3000 psi.

Turns out there is a third 8mm disconnect thread size (besides 1/8" npt and 1/8"bsp) - M10x1mm to 8mm disconnect (not pipe, but with face seal).

Awaiting the same.

Should have just bought  a 6.8L CF tank and get breathable air from a scuba shop.   

[CraigH]

After a long protracted period with many (non-airgun) problems and issues, I laid out the planned HPA filtration arrangement in (still) unassembled form.

The attached image shows the air flow from compressor to airgun.   In assembled form the right and left sides of the components will (would) be on opposite side of a 1x6 board, with the air hose at the top being the transitioning component.

Some implicit verbs above indicate I may not even complete the project but rather toss the whole pile.   The reasons being some unknown ratings of fittings.

None of the fitting or valves (save the 1/8" x 8mm quick connects) indicate whether their ratings are "working" or "maximum".   If all the rating are "working" that would be all well and good.

Bob Sterne has mentioned using a safety factory of 2.5 to 3.0 for HPA components (I am assuming those numbers being to imminent failure).   Most fitting I have seen have a much lower "working" to "maximum" ratio.   Bob has also mentioned that hydraulic fittings are ok for HPA.   Giving only one example, if the 7250 psi shutoff valve rating is for "working" pressure, by Bob's factor the failure pressure would be around 20,000 psi.   Too many unknowns.

So for now at least, with other concerns at the forefront, the project is quiescent.