Hi,

Got recently a new mig welder to replace my old gasless one I burnt out. Question is how do I tell what the gas flow is or whether it's the right amount?? I asked at BOC where I got the gas cylinder for a flow meter (one was hanging on the wall at £27), but they said it wasn't worth buying then handed me a table that shows litres/min...?! what use is that? Considering the price of the gas I'm not to keen on just wasting it. I also don't like the fact that I have no way of knowing how much gas is left.

So is it worth while getting a flow meter and some gauges??

Help would be appreciated.

You do not say what size welder you have, but as a guide I use a 150 amp mig with argon mix and use between 8 and 10 lpm.

I have two ways to measure the flow and both seem to be matching each other to 0.5 lpm.

I have a simple plastic taper tube with a rubber cup and a small metal ball in it, I used that when I only used Co2.

When I went to the argon mix I picked up a duel gauge regulator for about £40 and that shows bar pressure and lpm so I set that t around the 8-10 mark when trigger pressed.

Few things on ebay at present

You can do it without by seeing how the welds go and the amount will also depend on inside/outside/draft etc.

I learnt a lot from this website: -
http://www.mig-welding.co.uk/ and the tutorial on there.

Sorry if this is too basic!

Cheers

Adrian

[Edited on 18-11-07 by AdrianH]

Thanks Adrian,

Good link. New to the use of gas and such a big welder (170 amp, I bought is as I'm going to do some trailers soon). I was missing my wee gasless welder but seem to be getting the hang of this one.

I think the regulator you mention would be a good investment in the long run, I suspected that the guy in the BOC shop was hoping I would blast the gas out like a rocket to be on the safe side and then I'd be back pretty quickly...

Cheers for that.

Hi

I use a flow meter mounted on the regulator. (glass tube & bead)

Far more accurate than a round gauge type.

hth

Paul G
Rescued attachment lotus pics 089.jpg

Turn the wire speed to zero and turn the regulator knob till you can just hear the gas with the nozzle next to your ear. Start welding and if it looks dodgy turn it up a bit. I'm not too good on the hearing bit and if I can hear it hissing there's way too much.

I work on the principle that you can't have too much gas (though my wife doesn't agree after I come back from a beer and curry evening with the boys!!) so whilst I was learning I had the gas on pretty full on. Now that I'm getting better at welding I reckon I can work out when my welding sucks because I've got too little shield gas and when it sucks because I'm still learning!!!

So I'd have it quite high until you know your mistakes aren't due to lack of gas- there are enough other variables to screw up when learning to weld

Too much gas causes turbulence in the weld shield and can be as bad as too little. Plus if you want to get a job finished you don't want to run out of gas in half the time and pay double for the privilege.



[Edited on 19/11/07 by Peteff]

Flowmeter
£12:95 + £3:50 shipping off Fleabay

linky

Not essential, but certainly useful.

BOC are expensive. Also look at Air Products and Air liquide as a Gas supplier.

If you are only using CO2, then look at trying to get a cylinder from your local friendly pub landlord.
Make sure you get pure CO2, and not CO2 with nitrogen. Should be an ALL BLACK cylinder, with no other colours.
A lot of pub gasses these days are not pure CO2. So be careful and Check.
Pay about £10-15 to the landlord.

Argon with 5% CO2 (Argoshield or Cougar) is much better for welding, but more expensive than CO2.
It depends on how much welding you do in a year.
best is to find someone with a BOC or AP / AL account, then get a gash bottle the same size as your mate, then swap out on the account. But you do need to have exactly the same bottle. size, colour and markings.
ie One lot of rental, split between the two of you and two bottles. But its not that easy to get the bottles.

You can have too much gas as well as too little altho you will not probably notice when useing hobby welders.
if the gas flow is too high you can get gas inclusions in the weld pool. As a guide 8-12 Lpm for welding up to 6mm plate depending on weld prep and wind etc What gas are you useing?
Tip: if you are getting porous welds and you have the correct gas flow weld prep etc try covering up you wire when not in use with a cotton rag to prevent moisture

Thanks for all the advice. I'm using BOC's Argoshield, might have spelt that wrong but the gas does seem good as when I get it right the welds look very clean indeed. By the sound of it a set of gauges and a flow meter would be a worthwhile investment. I didn’t know the gas side of things would end up so expensive, just as well the wire is so cheap. This new welder also seems very particular about the settings being spot on, especially the wire speed, where as my old welder put up with any old setting.

I’ll get the hang of it eventually.

Cheers.