13 replies to this topic

[CityEPete]

I'm getting to grips with my mig welding slowly but surely (on my minor rather than mini), I've converted to the 9l hobbyweld 5% bottle and a 2 stage regulator, it was around 200psi when new and it's now down to around 75psi, is that over half empty now or does the pressure drop off as it goes or am I about to run out?

Second question, after reading suggestions that around 10lpm is about right for mig welding with the 5% stuff I've been doing that, should I set it to around 10 on my gauge or have it as I have now where I'm showing 10 when it's flowing, am I wasting gas do you think?

I've just switched from 0.6 to 0.8 wire and tip and I'm happier with that, should I just reduce the gas until I feel it's not welding well? What's the first sign of gas starvation?

Thanks, Pete.

[sonikk4]

As a rule of thumb when welding inside a draught free area then all you need to hear from the shroud is a gentle hiss, not a howling gale. I have used this rule for years as I originally broke the gauge on my old regulator.

Yes less than half left, should still run for a little while but needs changing very soon. 200 psi to start with is rubbish, are you sure it's not Bar??

My bottle from BOC although considerably larger comes with 3000 psi as standard.

[sonikk4]

If it's Bar then you have at least 1100 psi left.

[CityEPete]

Thanks guys I'll go and have another look at the gauge.....

I've probably got it too high then, what lpm would you suggest and do you set it when flowing or stationary? Stationary seams obvious but I'm a noobie.

[CityEPete]

It's bar! I've got around 60 bar left, will that run down at the same rate as it started?, must have been about 200 bar to start with.

[sonikk4]

Providing you have the regulator set correctly then yes. The flow is minimal. If you have a howling gale emanating from the shroud as i already mentioned then you will use it very quickly and pointlessly.   

[CityEPete]

Thanks I'll see how it goes maybe the second half of the bottle week last a lot longer now!

What sign should I look for to show the gas is too low?

[sonikk4]

Thanks I'll see how it goes maybe the second half of the bottle week last a lot longer now!

What sign should I look for to show the gas is too low?

 

Poor welds, porous welds will be the biggest indicator.

[CityEPete]

Ha I'm managing those anyway!

Thanks I'll see how I get on tomorrow night now then.

[Daz1968]

The hobbyweld is supposed to be 137 bar fill, I used to use them and I never got a bottle with much more than 110 bar, boc bottles are 230 bar on y sized bottles which is what I use now.
10 lpm is what I set to but I use a flow meter after the gauge as they are inexpensive and easy to read and set up.

[CityEPete]

Thanks Daz I'll look into flow meters too then.

[tiger99]

A quick indication if using a mix that is about 90% argon or more is that the fresh weld will be a silvery colour if there is enough gas, or too much, while it will have at least brown patches of oxide if it is insufficient. CO2 tends to give a duller weld, more grey than silver, but should still not show rusty streaks.

Not very scientific, I know, but short of destructive testing of a sample of welds (which you should do anyway from time to time) there is no other obvious DIY method of assessing adequacy of gas flow.

I would suggest running a few short welds on clean offcuts of 0.9mm steel with the flow set at various levels from 0 to 10 lpm and see how the welds vary. If in doubt, post some photos here. Also, ask at the MIG welding forum if in doubt.

[CityEPete]

Thanks tiger

[CityEPete]

I have got a new bottle and it was indeed 2000psi so that's all good, I have solved my issue of worrying about it running out by smashing the regulator after the bottle fell over......time to make a bracket to hold it to the wall as I planned all along, lol. the flow meter survived though so I am not replacing it.