Gas usage

  1. Al237 Member

    Messages:
    24
    Location:
    Cheshire, UK
    Using my new R Tech 180 and hobbyweld 5, the 9 l size, and gas has run out before the one job completed. Didn't note actual welding time but calculated that total of 10 feet of weld on mix of 4mm and 5mm box section. Flow rate 10 lpm.which should give 100mins of welding time. In between each welding run, when setting up etc, gas turned off at the bottle. This seems excessive gas use, should I be suspecting internal leak within the welder? All joints tight and no apparent leaks. Previous bottles on Clarke welder lasted much longer.
     
  2. 123hotchef Member

    Messages:
    9,678
    Location:
    Kent
    how did you measure the flow?
     
  3. Jay1st

    Jay1st AdeptusMechanicus wanna be.

    Messages:
    288
    Location:
    South West FRANCE
    You need to take in account for preflow and postflow, on my Kemppi i cannot adjust it.
     
  4. Al237 Member

    Messages:
    24
    Location:
    Cheshire, UK
    Using the pea shooter gauge acquired from R Tech.
     
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  5. Al237 Member

    Messages:
    24
    Location:
    Cheshire, UK
    Good point, hadn't taken that into account!
     
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  6. 123hotchef Member

    Messages:
    9,678
    Location:
    Kent
    the pea shooter should be acurate. Not sure if you can adjust post and pre flow on the Rtech
     
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  7. Al237 Member

    Messages:
    24
    Location:
    Cheshire, UK
    As I was mostly welding box section there are a lot of individual welds so accordingly a lot of pre and post gas flows which may account for the extra usage. On the box section piece there are 10 joints on 60x60 section, so 40 individual welds.
     
  8. Munkul

    Munkul Jack of many trades, Master of none

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    2,632
    Location:
    Cumbria
    It should have breezed that job and had some to spare!
     
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  9. 123hotchef Member

    Messages:
    9,678
    Location:
    Kent
    was the bottle full?
     
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  10. pedrobedro

    pedrobedro Man at Matalan

    Messages:
    10,508
    Location:
    CX Derbyshire
    Which Kemppi mig is that ? My Minarc 180 starts and stops with the trigger. Doubleboost did a video review on Rtech 180 ask him about the settings he used.
     
  11. Jay1st

    Jay1st AdeptusMechanicus wanna be.

    Messages:
    288
    Location:
    South West FRANCE

    Got the miniarcmig 200, has lots of postflow and there is 1/2 sec preflow. When i do some stitching on very thin sheets it consumes gas like hell
     
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  12. Munkul

    Munkul Jack of many trades, Master of none

    Messages:
    2,632
    Location:
    Cumbria
    That's a bit poor... no real need for much pre and post flow on mild steel at all.

    https://www.mig-welding.co.uk/forum/threads/minarcmig-evo-200.49317/

    This thread might help with adjusting it on your machine :)
     
  13. Jay1st

    Jay1st AdeptusMechanicus wanna be.

    Messages:
    288
    Location:
    South West FRANCE
  14. Munkul

    Munkul Jack of many trades, Master of none

    Messages:
    2,632
    Location:
    Cumbria
    It doesn't say anything about it in the manual which is poor IMO, but at least the internet helps :) I keep looking at those machines as a really nice little flux core portable machine, but I don't actually have any justification for it :(
     
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  15. Al237 Member

    Messages:
    24
    Location:
    Cheshire, UK
    Yes, it measured full pressure on the contents guage.
     
  16. Al237 Member

    Messages:
    24
    Location:
    Cheshire, UK
    I seem to recall him setting to 10 lpm
     
  17. Al237 Member

    Messages:
    24
    Location:
    Cheshire, UK
    Before contacting R Tech decided to repeat soap bubble test on all gas joints. Yes! Slight leak from the pea shooter gauge to the regulator connection. Appears to have been knocked and turned slightly which has caused a leak, moving it increased the leak so I think it has possibly been intermittent. Only very slight but a quick nip up stopped the seepage. Can't say how much this has added to the apparent usage, but it can't have helped.
    Note to self - check the ****** obvious!!!
     
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  18. Nauticus

    Nauticus If l let my mind wander, its often gone for weeks!

    Messages:
    60
    Location:
    Lincolnshire, UK.
    I am intrigued to see this flow rate often quoted.

    I was taught MIG welding by BOC. We bought a BOC welder for doing motor bodywork and crash repairs, at the Earls Court Motor Show in the mid 1970's. Up to that time I'd been using gas (oxyacet) and occasional stick. The welder sales package included delivery, commissioning and a day's on-site, hands-on instruction and training. (those were the days when customer service counted)

    One of the first operating instructions from the BOC Technician/instructor was " setting the gas flow to 6 litres per minute" ( litres?? and at that time we hadn't fully gone 'metric'!! Three years earlier we were still using shillings and halfcrowns etc). There was a pea-shooter type flow-meter on the gauges. I have always set that flow rate for mig welding since that day.

    At present I'm welding mostly 3mm mild steel - 50mm angle and flat. Out of habit, I now check my gas flow using a pea-shooter at the start of each welding session - (basically, because I often accidentally turn the wrong knob when shutting off the gas at the end of a welding session and completely mess up the flow setting instead.)

    I'm using the small 'tri-mix' HobbyWeld gas and I will very likely use up a 5 kg roll of 0.8 wire before the gas runs out. I have no problem with the welds - no porosity, very little splatter, flat, smooth, and at least 2.5mm penetration - usually almost 3mm. I am usually welding indoors with no strong drafts to blow the gas away. If I do have to weld in an open doorway I shield the weld with my left hand (in a leather gauntlet of course).

    I have only used the BOC mig welder when I had the garage business, and now a Sealey 150 which I have had for around 15 years, (I had a similar one before that) so I don't have a wide experience of different mig welders.

    I can understand that using 1mm wire and higher will probably require a faster gas flow, but I am intrigued, looking through the messages here, as to why some other welders on 0.8mm wire appear to need a faster gas flow. Is it the aperture of the torch nozzle? or are there other obscure differences in manufacture that determine the ideal gas flow?

    Malc.
     
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  19. metalmelt Member

    Messages:
    373
    Location:
    UK
    From memory the R tech purge on welder switch on and not before every weld, they don't have a post flow and this would unlikely be your issue.

    To an extent it depends on your unbilical and is the 15 or 25 and is your gun nozzle slightly tapered, straight, or wholely tapered as this makes a significant difference on small welders; it also depends on the type of welding you are doing. Look at Nauticus's post, he worked on bodywork where the nozzle would generally be close to the work and this needs less gas and if this is on an MB 15 unbilical this would be less than an MB 25 umbilical.

    We normally use 36's on 1.2 wire and I can use less than 10 LPM on close work and this changes due to the type of work we do, so go through everything and turn your gas right down until you get porosity and turn it up a little at a time until you get weld coverage.
     
  20. s410man trainee dogsbody

    Messages:
    1,159
    wales
    Turn the gas on and look at the gauge to see how much pressure is in the bottle

    Turn the gas off

    Does the pressure dial drop quickly?

    If so youve got a leak somewhere
     
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