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They’re dozens of ways to build a mixing whip, thought I’d post my solution since I was writing this up for someone else. This is a pretty deluxe solution, costing around $500-$600, $300 of which is in the digital pressure gauge.
All part numbers listed are Western Enterprises part numbers which your local welding shop should carry or at least have cross references for. The analog gauge shown isn’t a WE gauge, but the WE number should be able to get you an equivalent. The only two non-WE part numbers are the DIN fill whip end (always put a DIN fill whip end and put a DIN-Yoke adapter on it to fill Yoke cylinders, it’s a far cleaner solution) and the PSI-Tronix digital gauge.
See the picture at the end of this post while referring to the part numbers below.
62 is the nut that attaches the nipple to the bulk O2 cylinder.
63-SF* is the nipple with filter that terminates in a ¼ NPT male fitting. *Actually a 66-SF or 69-SF will work just fine too, whatever the welding shop can get. The –SF postfix means that the nipple has a filter on it. The above two parts will connect the whip to a “CGA-540” valve.
BST-4HP is a street T
G-2-4000 is a 4000 PSI gauge that will tell you the bulk cylinder pressure. This runs about $20.
SS-130M is a metering valve, otherwise known as a needle valve. This is one of the big-ticket items in the whip, costing about $60.
CV-4M is a check valve. I HIGHLY recommend you put one of these in your full whip to avoid back flushing the SCUBA cylinder contents into your bulk cylinder. Cost about $20.
BST-4HP is another street T
PG-5000 is the PSI-Tronix digital gauge that will read the SCUBA cylinder pressure. NESS part number 80. This gauge costs $300.
PF-4-36 is a 36” long whip that goes to the SCUBA cylinder. It feeds down to reduce stress on the whip. The other side of this whip comes in from the right side of the picture. This is another big ticket item at about $70
B-4HP is a male-to-male connector that attached the whip to the fill whip end.
001 039 (NESS part number) is the DIN fitting. NESS now carries a far more inexpensive fitting than when I bought one, about $40. If you’re going to fill cylinders with Yoke valves, just get this part http://www.northeastscubasupply.com/...s/dintoy_1.jpg which is a standard DIN-reg-to-Yoke adapter from NESS.
Part 415 at the top fits on an inert gas cylinder connection (Helium or Argon) and converts it to a Oxygen connection so this whip can be attached to it. It’s a “CGA-580 to CGA-540” adapter. Costs less than $10.
All the small parts where I didn’t list prices cost on the order of a buck or two.
I’m currently in the process of building a manifold that’ll allow me to mix He and O2 without moving the whip around. However, I decided to make this whip simply attach to the manifold so I still have a portable, stand-alone whip that I can take on the road with me if necessary. I'll post something on that when I'm finished.
Originally posted by ericfine50 a little less $$ than the PSI and just as good.
I bought one just to see how good it was... it wasn't.
Not even close.... sent it back for a refund.
Accurancy is the name of the game:
1% of 5000 is 50 psi accuracy which just isn't good enough for PP blending.
.25% of 5000 is 12.5 psi accuracy which is good enough for PP blending using a PG-5000 PSI-Tronix digital gauge.
.25% of 2000 is 5 psi accuracy which is even better... and that is why I use a PG-2000 PSI-Tronix digital gauge (fitted with a Swagelok QD so that I can swap it out with a 4000 psi dial gauge for coarse fills of argon.)
I'm using the Global stuff that comes turn-key. Not real cheap but I don't have time to build stuff. The mix controler includes the digital gauge (psi tronix) check valve, flow restrictor and quick disconnect. The O2 wip and the wip from the hyper filter are also quick disconnect so I do all the mixing with the same gauge. They also sell all the peices if you want to build your own. I'm not shure of the price difference. For me time is at a premium so I only save money if I save time.
We are currently very partial to the Parker ST series. 5000 psi, straight through unobstructed bores (which makes them suitable for 100%), easily replaceable single O-ring seal, available in SS or brass, and dirt cheap - about $2 for the male plug and $4 for the female QR in brass. McMaster Carr has them (they call them High Flow Pneumatic/Hydraulic Couplings) though for some reason they don't stock the brass males so you got to get them from a Parker store. I got so many of them on my mix gear that you can play with it like legos.
BTW, when it comes to gauges I am more concerned with repeatability than accuracy. Most mixers I know end up using a small fudge factor in one direction or another to get their mix to come out the way they want, so absolute accuracy isn't quite as critical as one might think. I think most newbie mixers would do better to put together a cheap, rugged whip with an decent 4" or so analog gauge, and get some hand on experience before they start trying to build the ultimate whip. Mind you, that's for nitrox - when they move on to deep trimix, then it's time to start worrying about fractions of percents.
But then I always have been partial to analog guages - I like the trend information, for one thing. My current setup used a 12" 5000 psi precision analog gauge!
Originally posted by ericfine50 UP -
PS - I love those Swaglock QDs. Make life very easy.