Welding Tips and Tricks

Just changed out to a dual gauge in place of a gauge and ball column style regulator. Noticing after shutting off bottle then returning the next day the control side gauge pressure reads about 40 psi. So today before shutting off welder I shut off the bottle and hit pedal to bleed off pressure to solenoid in welder, then turned off welder. Good practice? Waste of argon? What do you think?

If you're happy with that do it.
It will bleed to zero eventually anyway.
How long it holds pressure is a good indication of leaks as well.
You aren't wasting argon bleeding it down, its basically unusable whether you bleed it off or it bleeds itself off.

Cheers

bruce991 wrote:So today before shutting off welder I shut off the bottle and hit pedal to bleed off pressure to solenoid in welder, then turned off welder. Good practice? Waste of argon? What do you think?

I always bleed mine because I've often wondered if the temperature goes up a lot and the gas expands in that trapped volume, whether it can damage the solenoid or any components. Sometimes I don't weld for a long time, if I put it away in February when it's 20F, and it goes up to 100 in June, I'm not sure if that hurts anything.

Bruce, are you saying you went from a flow meter to a pressure gage? If so, why?

LtBadd wrote:Bruce, are you saying you went from a flow meter to a pressure gage? If so, why?

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Yes I did just because the later came with this newer welder and wanted to see if it was more accurate. I have flow still, it worked just fine. Do you have a preference? Flow is what I have used for years. So was curious mostly.

I've got a couple flow meters with the ball. Also have 3 or 4 pressure gauge style ones. Has bottle pressure on one dial and flow rate on the other dial. I don't think it makes a huge difference accuracy wise.

Might be able to see the ball and where it is in the column from a distance unlike the gauge. Never heard of a plausible advantage to either.

I guessed a column style was more basic, like a manometer and could produce accurate readings in a low tech format. Dial type may need a more delicate touch during construction to make sure its accurate??

Pressure gauge type are less accurately tell you if you have flow. They are a bourden tube style gauge that acutely tells you pressure but not flow. The ball type shows flow, that's why the ball only moves when the gas flows. The gauge relies on a known size oriface and a set pressure to determine flow. But it will show you have flow even when you don't. The ball type relies on an adjustable oriface, i.e. Needle vale. This is the most accurate way to control gas flow. Gauge style ones do have there place. Accuracy is acceptable for most applications I use one on my mig welder. But I won't use them for tig.

I've mentioned this before but in my opinion by far the best is a pressure gauge type with a floating ball flow control screwed on the outlet - open the needle valve completely - adjust the regulator pressure to get maybe 10% more flow than you intend to use - now trim the flow on the needle valve - this will gives the least excess pressure for your desired flow & the minimum gas surge on demand & the most stable flow ( a 2stage low pressure type is the best )- the flow type gauges are pressure set at anything from 50 > 80 PSI giving ridiculous surge every time the trigger is pulled - it's not necessary & if you paid UK argon prices I doubt you'd like them so much - there has also been endless discussion on micro bore pipes & restrictors to help alleviate this problem - I have a floating ball flow control on the output of my machine to set total flow plus one each on the argon & helium bottles so blending is easier to judge when needed.

Sounds like I might have started a debate. I do like the flow and column ball type, and will probably switch back, but I also find no need to adjust the pressure one once set I ck it at first and forget it.

Both styles are "single-stage" regulators, and the low side will creep up, especially when the bottle is low.

I prefer the ball type, as there's no ambiguity about flow, but have found good accuracy and repeatability with the dual-gauge type, so I won't take a side on that.

Steve S

I would always have a floating ball for visual check on flow & more consistent setting by trimming the needle valve but am convinced that an adjustable pressure gauge is better - when possible use a twin stage - they are hard to find marked up for argon but it's very easy to find them as low pressure oxygen regulators intended really for gas welding not cutting - this gives much more accurate flow at low pressure - don't worry what the outlet pressure gauge reads - just adjust for desired flow on ball - you can always swap an argon pressure gauge onto it if you are that bothered - most of us have boxes of old regs to pick through even if the necks are bent or broke from bottle mishaps ! most " old school " welders can set flow pretty well just by sound - putting the cup to the ear to set ( on post flow to avoid HF ! )

So I guess I will bleed pressure off if not going to weld for a day or so. Find I have to activate solenoid anyway for flow verification so argon is going to be wasted a bit either way.

Back to the original question, There is nothing technically wrong with leaving the pressure in the line after welding. I believe, but could be mistaken, that the solenoid in the machine can handle 200 psi (??) and your regulator/flowmeter puts out 25-50 plus and that is it. Your hose should be able to handle 200 psi and most of the brass fittings in this line are either 200 psi or 3,000 psi capable. Point is you shouldn't damage anything with that little gas that is in there.

However, I have read about OSHA dinging companies for leaving that gas in the line. What their exact basis is behind that I am not sure.
Jonathan

I never bleed off argon - have never worked anywhere that did & see little benefit ( other than BOC profit ! ) in doing so - I like to see how long the pressure will stay when not in use as an indicator there are no system leaks - now if it were oxygen / acetylene or other fuel gases I get it - there is some potential for safety issues - but not with an inert gas - I guess if it's a habit you have there is no harm in it - seems more likely it's taught at school as a blanket advice on all gas without the need to explain why you're doing it or identifying the situations it is good practice.

I always bleed off, then back off the regulator adjuster so there is no pressure on it when I turn the gas on the nest time. Habit...

At home and at work. I shut the tank valve and call it good. No more no less. Oxy acetylene setup I blead off pressure after I shut off the tank but no more than that.

I just decided shut of the bottle and leave regulator as is, see no harm in either way I figure.

bruce991 wrote:I just decided shut of the bottle and leave regulator as is, see no harm in either way I figure.

That's what I do, and my argument is simple. Positive pressure in the lines means no moisture or atmosphere can get in. Not likely in any event, but it sounds good, so I say it.

Steve S

No need to bleed. The only issue with dual gauge flow meters is they won't show no flow if you have plugged or obstructed lines. The Dinse connector hose on my 200 DX has been kinked a time or two

Always shut off the tank valve but that is it. I made the habit of turning off the power after closing the valve.