Argon surge suppressor

**Krunch** · 09-14-2010, 07:51 PM

I'm a new tig weldor and this may be useless info, but I thought I would pass it along for discussion or ridicule.

I read in Minnick's "GTAW Handbook" (thanks for the recommendation, Glen) that if you do a lot of short stop-and-start TIG welds, you will often get a surge of Ar when you hit the pedal because the pressure "backs up" between the solenoid gas valve in the tig machine and the regulator/flowmeter upstream.

Anyway, Minnick said that you could save a lot of gas if you do a lot of stop-and-start welds if you use a "gas surge suppressor" which would temper the surge when you first step on the pedal.

Minnick said such an item would quickly pay for itself in saved argon.

I looked high and low on the internet and didn't find anything until I found a Smith flow restrictor (you can see it on page 11 of this pdf) which (if my calculations are right) would limit flow to 35cfh at 50 psi (they say 21 cfh at 30 psi and I extrapolated from that).

(I know 35 cfh is a lot, but I have a "Y" attached to the front of the machine in case I ever want a back purge line, so 35 would give me 20 + 15...)

Most places where I see them talking about that part (Smith P/N: 15001-20) they're talking about MIG and not TIG, but I installed mine, and I swear when I step on the pedal I don't hear nearly as much of a WHOOSH as I used to. But then again, I still have 2400 psi of Ar.

I installed mine on the back of my Sync 250 but I may move it to the front and see what happens there, as well.

The part costs $13 so even if it's equivalent to a "gas line magnet that doubles your mileage by breaking down the molecules," I haven't lost that much.

FWIW and let the abuse begin.

**B_C** · 09-15-2010, 09:22 AM

Wow you must have read my mind because I have been wondering about this for a while. I experience the same WHOOSH from my torch when I do stop and start jobs and wondered if there was a gadget I could buy to stop it.....You got any pics of it installed?

**usmcpop** · 09-15-2010, 10:14 AM

Here's a patent that is worth reading. All the guy apparently did is incorporate a small ID delivery hose with a surge orifice. That apparently takes care of both the surge and the wasted gas.

http://www.google.com/patents?id=OkUOAAAAEBAJ

**Krunch** · 09-15-2010, 03:34 PM

Originally Posted by B_C

I experience the same WHOOSH from my torch when I do stop and start jobs and wondered if there was a gadget I could buy to stop it.

B_C, I heard there's an even cheaper workaround for this problem:

Find the brown bottle and turn the valve handle clockwise until it stops.

Definitely makes the gas last longer!

**Krunch** · 09-15-2010, 04:47 PM

B_C, At first I thought you were giving me a hard time, but now I'm not sure.

Anyway, here's what the gizmo looks like on the back of a MIG machine...I have it on the back of my Sync. Same idea. It's maybe 1.5" long. Basically it's just a brass fitting with a tiny .026" diameter orifice in it.

**usmcpop** · 09-15-2010, 05:44 PM

B_C, put one of those IV drip tube clamps on your hose and just crank it down until the surge stops. Or stuff a MIG tip into the hose.

That patent I mentioned seems like nothing more than an orifice and a really skinny ID hose that prevents the hose from becoming a surge reservoir (source). Makes sense. A very short hose would help.

**B_C** · 09-16-2010, 11:49 AM

would you want the restriction closer to the machine than the regulator? that seems like the way to do it because you would still have a large volume to feed if you put the restriction near the regulator?

**usmcpop** · 09-16-2010, 12:14 PM

The restriction needs to be near the destination (welder) so the built up gas in the supply line doesn't all rush out at once.

**Roger** · 09-16-2010, 02:18 PM

How much gas are we talking about? In the hose is very little gas. I once calculated the volume. Might be more low pressure gas in regulator. I decided starting flow surged flushed out any Air diffused into torch or MIG gun and wasn't worth worrying about. If using expensive Helium it might be worth trying to save every cubic centimetre.

**usmcpop** · 09-16-2010, 02:45 PM

I think it's a twofold problem. You only need so much initial surge to purge the line. Anything more may just mess up the flow of gas at the business end. High volume users, especially those using the more expensive gasses and long lines from a manifold or tank, may actually save $$ by some simple plumbing.

In B_C's case using Helium, it may help prevent him from talking in a high-pitched voice.

**calweld** · 09-16-2010, 04:02 PM

Originally Posted by Roger

How much gas are we talking about? In the hose is very little gas. I once calculated the volume. Might be more low pressure gas in regulator. I decided starting flow surged flushed out any Air diffused into torch or MIG gun and wasn't worth worrying about. If using expensive Helium it might be worth trying to save every cubic centimetre.

It seems to me you would want that initial surge, for the second or so of preflow, saturates your weld area with inert gases. Unless it creates a vortex effect, pulling in atmospheric gases, of course. Doubt it would save much money, unless one was constantly making one or two second tack welds all day long.

**B_C** · 09-16-2010, 05:42 PM

Yeah it's also giving me a head ache thinking that I have use the machine the way it is now for 15 years....I think I'll pour a drink of Rum and coke and think about it...

**B_C** · 09-16-2010, 05:44 PM

The MIG tip is a good idea though......what size you think would be right?

**B_C** · 09-16-2010, 05:57 PM

OK I had a drink and decided to go look at the welder and I did notice something that is probably working against me.....Notice how long the feed line (Gas) is ....I think I might shorten it a bunch and see what happens?