Are you using too much $$$ gas?

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I cut my gas flow rate from 15 cubic feet per hour (CFH) to 3.75 CFH with no perceptible difference in arc or weld quality.  I'm saving 75% on gas costs because I set myself free of the tombstone 'recommendation' of the welding manufacturers.  Want to save $$$? - read on.I looked at the operators' manuals for three typical MIG welders:- Lincoln SP-125 Plus- Millermatic 140, 140 Auto−Set, and 180- Hobart Handler 187Their 'recommended' gas flow rate is typically stated as:- 15 – 20 cubic ft per hour (CFH) (7 – 10 I/min)- use 20 – 25 CFH (10 – 12 I/min) when welding out of position or in a drafty locations. If like me, you follow that 15 - 20 CFH 'recommendation' you will have good welds.However, I found I could get the same good welds with 1/4 of those gas flow rates.I have a Lincoln SP-175T.I am particularly sensitive to gas usage because I use small 20oz CO2 tanks for portability.A 20oz CO2 tank contains 10 cubic feet of CO2.At a 'recommended' flow rate of 15 CFH, one tank in theory lasts me 40 minutes.That is not very long.In reality, I get rather less than this - maybe 25 - 30 minutes tops.  Why?With start/stop welding, like tacking for example, the pressure builds in the line behind the gas solenoid valve because the single stage regulator (used by 99% of us folks) only regulates well with continuous flow.  When you click the trigger on, you can hear a burst of higher pressure/high flow gas out the nozzle - much louder than the sound of continuous (trigger pulled) gas flow rate.Try it yourself.Note: Release the tension on your wire feeder SO NO WIRE WILL STICK IN YOUR EAR!Pull the trigger.  You will hear a 'Poof' of gas followed by a 'whooshing' reduction until you reach a constant barely audible 'whooo' of continuous gas flow.With such small gas tanks, I had an urgent need to economize on gas flow.  In stages, I kept reducing the gas flow rate from 15 CFH until I reached 3.75 CFH - which is the limit that I can reasonable control with my regulator.  Everything was just the same!Note:  You can tell you went too far - if it looks like you are welding with little or no shielding gas:- arc quality reduces (sputtering)- porosity appears in your weldI'm certain to be target for many who will shout - Heresy!You can't break one of the 10 Welding Commandments handed down from Mount Lincoln/Miller/Hobart.Do so at your peril!The Tombstone Tablets say 15 - 20 CFH and that's that!  Burn Him! On the other hand... Want to save some money? Try it yourself.  Try reducing your gas flow rate and see what happens.Maybe like me, you will discover you can weld just fine with far less that the 'recommended' flow rate.Up to 75% saving can await the Courageous.Rick V
Reply:I use 9oz paintball tanks for other purposes (powering air tools, carbonating water, etc).Get yourself a decent sized CO2 siphon cylinder (I use a 20lb).  If you can find a CO2 fire extinguisher at a garage sale like me, you can trade it in for the cost of a refill+hydrotest.Then get a two-valve fill station with a muffler.  They can be had on eBay for around $40.Now, you can refill your paintball tanks for pennies as often as you like.
Reply:If it works for you, go for it!!! I know what you mean. I call them welding miracles. I worked in a shop where we had a big alum. wheel rim that was MIG welded with LA-S6 to mild steel flat bar, so it could be bolted to our bending table. Now that's just plain old witchcraft!!!!! Guess no one told her you can't do that!200amp Air Liquide MIG, Hypertherm Plasma, Harris torches, Optrel helmet, Makita angle grinders, Pre-China Delta chop saw and belt sander, Miller leathers, shop made jigs etc, North- welders backpack.
Reply:There's a lot you can get by in still air with close stickout.  However, have you had your flowmeter calibrated?  It may very well be reading lower than your actual output.
Reply:I first started i used 20 all the time just lately i backed it down to 15CFH i may try lower yet i weld inside no air movement at all.HOBART IronMan 230 MIGSmith Lifetime WH200 HD O/A Torch
Reply:Stated by the PO:In reality, I get rather less than this - maybe 25 - 30 minutes tops. Why?With start/stop welding, like tacking for example, the pressure builds in the line behind the gas solenoid valve because the single stage regulator (used by 99% of us folks) only regulates well with continuous flow. When you click the trigger on, you can hear a burst of higher pressure/high flow gas out the nozzle - much louder than the sound of continuous (trigger pulled) gas flow rate.
Reply:So I take then that you are using the type of flow meter with the ball and not the the dual meter flowmeter, right?Looks like you set your flow so low that you are using the burst you get on startup somehow to make it through your complete weld because the ball type is very inefficient on stop start for wasting gas.Would like to see more though with argon/co2 how low you can go.The best way of consumming less with this setup is to go with a smaller supply line.
Reply:I think someone else stated turn your reg down so your welds start having holes in it then bring up pressure just enough so it welds correctly,that's your sweet spot.HOBART IronMan 230 MIGSmith Lifetime WH200 HD O/A Torch
Reply:Originally Posted by damanI think someone else stated turn your reg down so your welds start having holes in it then bring up pressure just enough so it welds correctly,that's your sweet spot.
Reply:Originally Posted by BurningMetalthat's a good way to tell when you don't have enough gas.I used to be concerned with my mig gas....until I started tig welded.  Damn!!!!!   I go through alot of argon!
Reply:Thanks for the interesting reply posts!Maybe I got lucky becasue as Supe said, There's a lot you can get by in still air with close stickout.
Reply:How do you get the gas from the jug back into the tank?HH187Harris O/AInfrared thermometerHalf a dozen angle grinders
Reply:How do you get the gas from the jug back into the tank? - paulinkansas
Reply:Originally Posted by paulinkansasHow do you get the gas from the jug back into the tank?
Reply:at my work, on the big bottle system it's set somewhere really high. somewhere around 45-50 cfh if i recall.feels like a hurricane coming out of the cup. Messes up the puddle a slight bit, but there's nothing much I can do about it since I'm just a nobody there... and to them more gas = better!
Reply:Here read this it will confuse you some more, I read it twice and I still don't quite get the full explaination so I printed it out and I am studying it more.I have both types of regulators.Don't like the fact that some numbers did not print well.http://www.netwelding.com/Shielding_...l_Download.pdfWe might be hearing more about gas waste in the future considering co2 is considered a greenhouse gas, I dunno thought trees needed co2 for photosynthesis?Two ways of preventing gas waste and that is to stop making unnecessary stops and starts,so prep your work well, understand what you have to weld, get 'er done and this will eliminate those high pressure bursts that are gas wastin, and keep your supply hose the smallest inside diameter you can get it if you ever have to replace it.
Reply:My settingsWith Binzel Alpha torches I set to 12 - 22cfh with Co2 (with higher energy, lower settings quiet the puddle). With C10 I (for pulse or spray) I set to 16 to 32 cfh (the pulse needs less).Roundabout welder with Miller torch, flows go from 24 to 36 (this setup uses Co2 and Argon bottles and various mixes are used for the best arc performance through a manifold).Kemmpi torch is set to 16cfh with Co2 and 20cfh with C25.WP-18 Tig torch with gas lenses  6 - 12 cfh (lower with deep crack repair, K-joint and large torch angles).WP-9 Kemmpi with gas lense 6 - 12 cfh, without 12 -18cfh.Gantry bore welder (miller torch) usually set to 20 cfh with Co2Boa 308 borewelder is set to 12 - 18cfh with Co2 or C25Torch angle and puddle size both can affect arc performance vs gas flow. I have needle and seat flowmeters on all setups and am nuts about how I open the gas bottles (quick opening can damage the pressure regulators, and then you get the real big poof when flow starts).MattLast edited by Matt_Maguire; 04-24-2010 at 08:54 AM.
Reply:Hey pistolnoon, that is an interesting article - Thanks!In my view, the author does a delicate balancing act between:- Professionally and clearly explaining the problem,  and- Offering his murky explanation of his patented solution for sale.Here is the 'essence' of what I think the article says.Explanation of the ProblemThe shielding gas delivery hose, between the cylinder gas regulator/flowmeter and the internal gas solenoid/valve in the welder, is subjected to increased pressure when the solenoid/valve cuts the gas flow to the welding nozzle.He used the example:For an 80 psi regulator/flowmeter and only 3 psi needed to achieve the desired flow rate, 5.3 times the physical hose volume of excess gas is stored in the hose when welding stops. e.g. (80 psi+15 psi)/(3 psi + 15 psi) = 5.3XAlso, a standard ¼ inch ID gas hose expands about 13% when subjected to these pressure levels.The amount of excess gas is 5.3 (due to pressure) X 1.13 (due to hose expansion) = 6 times the physical hose volume.Every time the MIG gun switch is pulled this excess gas is rapidly expelled out the gun nozzle; most of it wasted.Patented Solution for SaleThe Gas Saver System (GSS) is patented device consisting of an 1/8 inch ID heavy wall hose instead of the more typical 1/4 inch thin-wall hose.  The hose includes an orifice at welder gas solenoid/valve end of the hose to limit surge flow rate and avoid excess turbulence at the weld start.SummaryThat's it.  In layman's terms, the solution offered is a two-fold: a small diameter, thick wall hose - containing an orfice at the welder end. 1 Small/stiff ID Hose:  The idea of the small/stiff-wall hose is to keep the internal hose volume small between the regulator/flowmeter and the welder gas solenoid/valve.  Saves maybe 13% on gas because of limted volume and little expansion of the hose.2 Orifice: An orifice (pinhole) inside the hose just before the gas solenoid/valve of the welder.  The idea is that the pressure build up in the hose can no longer rush out of the over-pressurized hose when the welder solenoid/valve opens because the orifice restricts the flow.  Save the other 87% on gas.What's this mean for us?My hose is 1/4 inch ID, only 8 inches long and quite rigid (old rubber gets hard!)I could benefit somewhat by shoving a plastic liner inside my gas hose to reduce the internal diameter.  This may be more of a challenge for users of longer hoses but certainly feasible. Add an orifice!  That seems to be where the big gas savings lay.  Maybe one could use one of the gas orifices that Benzomatic sell for their propane torches?  You can find those parts for sale at many hardware stores.  Likely the hole in the orifice may be too small but a set of tiny 'number' drills could be used to drill out/expand the existing hole.Interesting...Rick V
Reply:Originally Posted by Rick V Add an orifice!  That seems to be where the big gas savings lay.  Maybe one could use one of the gas orifices that Benzomatic sell for their propane torches?  You can find those parts for sale at many hardware stores.  Likely the hole in the orifice may be too small but a set of tiny 'number' drills could be used to drill out/expand the existing hole.Interesting...Rick V
Reply:Originally Posted by thecheese429I have thought that a MIG contact tip would work well for an orifice because of its known diameter.... I wonder what size would be good? I have no idea how to calculate gas flow through an orifice
Reply:My reg is set up with a .032 for C-25 75/25.HOBART IronMan 230 MIGSmith Lifetime WH200 HD O/A Torch
Reply:Originally Posted by Rick VA good idea!  I know I have diameters like 0.023, 0.030 and 0.035 available!Re: calculate gas flow through an orficeI did a quick search in Yahoo and, before the 'trojan' messages stomped me out, I saw only complex math and no simple calculation - even the on-line calculators don't seem to be set up for our needs.  Maybe someone else will have more luck with a search.Alas, this looks like only a tedious trial and error approach may work.What works for you may not work for me since everyone has a different machine with different gas flow restrictions:- downstream of the gas solenoid/valve input, and- different inlet pressures to the gas hose from the regulatorThe solution is going to iterative: learning at each step and adjusting orifice diameters and regulator gas pressures as you go.You try orifice 1 - if the flow rate is way too low, you use a bigger-hole orifice.You try orifice 2 - if the flow rate is somewhat too low, you can try increasing your regulator pressure to see if you can reach the wanted continuous gas flow rate.  Then see if gas still 'poofs' a blast from the nozzle when you trigger the gas solenoid/valve on/off.You try orifice 3 - if the flow rate is somewhat too high, you can try reducing your regulator pressure to see if you can reach the wanted continuous gas flow rate.  Then see if gas still 'poofs' a blast from the nozzle when you trigger the gas solenoid/valve on/off.etcetera.......Hey, one size of orifice must be a ballpark fit for most applications else how could the GSS be marketed?Rick V.
Reply:Originally Posted by lars66If a smaller orifce is the solution I wonder why mfgs. just wouldn't put smaller orifces in the gas difusser and have a big selling point for thier guns.
Reply:I notice they sell some nice fibre tig hose covers also.
Reply:I shoved some clear plastic (vinyl) tubing inside my existing 8 inch long, 1/4 inch ID (actual 14-15/64) gas hose.The tubing I used was about 14/64th OD and 7/64th ID.  See - 1.I also had two brass fittings at the entry to the welder with large internal diameters.  I stuffed these fittings with short lengths (some cut at 45 degrees) of various diameter tubing - both took two tubes (one inside the other - co-axial).  See - 2 and 3.The picture below shows where I placed the tubing in locations 1, 2 and 3.THE RESULTS???Well it seems better.  Is it really?  Who knows.Before: Pull the trigger. You heard a 'Poof' of gas followed by a 'whooshing' reduction until you reached a constant barely audible 'whooo' of continuous gas flow.Now:  Pull the trigger. You defintely hear a smaller 'Poof' of gas followed very quickly by a briefier 'whooshing' reduction until you reach a constant barely audible 'whooo' of continuous gas flow.In theory, I have reduced the internal diameter of the hose from 14/64 to 7/64 - by half.  This is a volume reduction proportional to the ID^2 = 4X.I also reduced the internal volume space in the fittings by a factor of 4.Thus I should have 1/4 the volume of gas subject to pressurization in the hose.  That can't hurt and should make things better.Do I have definitive data?  No.Did I add an orifice?  No.It is really better?  After all my work... Sure!Rick V