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Main Section => Welcome to our virtual Pub Meeting ... => Topic started by: MikeT on January 10, 2021, 11:02:53 AM

Title: Mig gas set up
Post by: MikeT on January 10, 2021, 11:02:53 AM: Need advice on gas set up on my MIG.
I know the gauge on the left is bottle contents and the gauge on the right is LPM.
Read somewhere its best to start with 14 LPM, if I set the gauge at 14 LPM the flow meter only goes up to 10 LPM any help gratefully received.
Title: Re: Mig gas set up
Post by: Davidss on January 10, 2021, 11:25:28 AM: The gauge seems to be calibrated in Cubic Feet per Minute, is your conversion to Litres per Minute correct?
What are you adjusting to 'set' it to 14 LPM?
Rephrasing, is there something other than the gauge that is calibrated to show the flow?

I suspect the outer ring of figures on the 'flow gauge' is PSI, although I can't see a legend that says that.

My gauge set only shows the Line Pressure in PSI; I would never set mine at the 14 PSI that yours is set at, as it's much too wasteful of gas. The precise setting can be influenced by what wind is present (non if working inside, slight to strong if working outside).

Regards.
Title: Re: Mig gas set up
Post by: ChrisJC on January 10, 2021, 11:35:06 AM: I would turn it right down, try welding (and fail dismally as it will spatter horribly). Turn it up a bit and try again. When it starts to weld nicely, you know you've cracked it.

Chris.
Title: Re: Mig gas set up
Post by: Robin on January 10, 2021, 11:36:58 AM: I set mine at 7lpm at the nozzle for my MB15 torch, unless I'm welding outside in a breeze when I wind it up to suit (don't bother trying if it's more that a breeze - the shielding gas just gets blown away!).

I use a 'pea-shooter' gauge to check and adjust the flow at the nozzle rather than relying on the gauge.
auction: #143784811803

You can set the flow according to the weld results - pinholes in the surface means not enough gas, but setting it too high just wastes gas! Though of course, that's assuming all your welds are identical - for 'hobby' type welding most of our welding jobs will be on different steels and different positions (but, whereas in industry a lot of welds will be repeating the same job over & over.

Robin.
Title: Re: Mig gas set up
Post by: Robin on January 10, 2021, 11:41:09 AM: Ah, the picture didn't come up for me at first (probs with our broadband this morning!) - I see you have a flow gauge fitted - what is that calibrated in? Is it possible that is cfh, not lpm?
Title: Re: Mig gas set up
Post by: MikeT on January 10, 2021, 12:54:15 PM: Interested you set your MB15 torch at 7lt its the same torch as mine. I cant find where I read 14 LPM,
2 more pics showing the gauge and flow meter more clearly.
Title: Re: Mig gas set up
Post by: Robin on January 10, 2021, 01:11:44 PM: Your round gauge is calibrated for lpm on the outer edge, and your flow meter (pea shooter type) looks like it's marked with graduations of 2, 4, 6... up to 14lpm.

Your round gauge is currently showing 18lpm, but that's because there's no flow - once you open the bottle valve and operate the torch that will drop to a more realistic level.

Apart from a rough setting, you can ignore the round gauge as the pea-shooter meter will give you a more accurate flow rate, and with the torch button held in you can adjust the valve on the gauges until the 'pea' in the pea-shooter hovers around 7lpm.

Just be aware that each time you operate the torch there will be a big flow as it releases pressure built up in the hose, so you should be reading the flow once it settles down after a second or so.
Title: Re: Mig gas set up
Post by: Serious Series on January 12, 2021, 11:37:20 AM: The right hand gauge on the regulator is normally a pressure gauge but if it has a small orifice in the regulator after the gauge can be calibrated for the flow that will pass through the orifice at a certain pressure. This is to allow you to work without the pea shooter unit .
As said pea shooter will be more accurate.
I used to work for Air products industrial gas so got may gas cheap the cylinder I am currently using does not have a regulator fitted externally comes with push fit connection and the push fit adapter is sized for the flow the customer needs. Pressure reguation must be built in to top of cylinder.
When I switch to Argon for Stainless steel or alloy normal cylinder regulator and pea shooter gauge to set up my flow.
Title: Re: Mig gas set up
Post by: MikeT on January 12, 2021, 01:30:30 PM: Im now set up and getting plenty of practice, gas set at 7LPM, the only problem Im having is actually seeing the end of the wire, so Im struggling with welding straight lines. once I have started welding Its just luck if I have actualy welded the seam/join. The Wire sticking out about 10mm and mask set at 9.
Is there a certain position I should be looking, directly over the top of the torch or from the side?
Title: Re: Mig gas set up
Post by: Craig T on January 12, 2021, 01:40:36 PM: I always look from the sides and get pretty close too.

Another thing is if you are dragging or pushing the weld. Pushing the weld makes for deeper penetration but pulling the weld can be useful for thin material. That can alter where you look but still, get in there pretty close.

What type of mask do you have? As you say it is set to 9 I'm assuming it's an electronic auto dimming one?

Craig.
Title: Re: Mig gas set up
Post by: MikeT on January 12, 2021, 02:08:34 PM: Its a scan auto darkening solar powered. I was given it a few years ago, so uncertain if its quality or not.
It has 2 settings in side for one sensitivity and one for delay on the outside it can be set from 13 down to 9
Title: Re: Mig gas set up
Post by: mrutty on January 12, 2021, 03:16:56 PM: If its an old mask don't forget to replace the splatter screen as it will have a huge impact on your welding (speaking from experience)
Title: Re: Mig gas set up
Post by: Gres on January 12, 2021, 03:22:06 PM: Illuminate the area to be welded with a decent bright light, older halogen work lights are also lovely and warm at this time of year! As long as the light source isn't directed at the helmet then it won't trigger the auto darkening.
Title: Re: Mig gas set up
Post by: alchad on January 12, 2021, 03:31:43 PM: I have exactly the same problem in seeing the weld. As has been said, get the best lighting you can on the weld and make sure the front and rear screen in the helmet are as clean as possible. Try using new screens, they're relatively cheap.

Regards

Alchad

PS If you wear glasses that's an added buggeration as you seem to get a double reflection
Title: Re: Mig gas set up
Post by: Old Hywel on January 12, 2021, 07:22:23 PM: I need stronger ‘reading’ glasses when welding than for other close work.
UV light refracts differently, perhaps enough to make it noticeable.
Title: Re: Mig gas set up
Post by: MikeT on January 13, 2021, 08:49:19 AM: Interesting comments regarding wearing glasses, I'm wearing varifocal glasses, will try using reading glasses, see if that helps.
Title: Re: Mig gas set up
Post by: mrutty on January 13, 2021, 10:52:00 AM: My lecturer recommend them for TIG work. Just a cheap pair from Boots
Title: Re: Mig gas set up
Post by: Tim_Moore on January 13, 2021, 11:01:26 AM: Quote from: MikeT on January 10, 2021, 11:02:53 AM
Read somewhere its best to start with 14 LPM

way too much gas at 14L/m, you will need this much if you are welding outside with a slight breeze.
Inside the workshop with no air movement you can comfortably run 7-10LPM. If you are spot welding alot (typical car stuff) then be mindful that this will burn even more gas as the pressure will build up the first pull of the trigger will dump a "puff" of gas until the flow regulates until equilibrium is established. as soon as you stop this pressure builds again resulting in alot of wasted gas!

if you go for spot welding try keep momentum of the pulses to reduce the build up of pressure!
welding gas cost can add up quickly!