Been using my shiny new MigMate to varying degrees of success....
And my CO2 ran out. B&Q only had Argon (80%) and CO2. So i used that
seems to give better results, but whats the difference? why use one or the other? different materials?

on an associated note, the canister didnt last that long, maybe two hours of on/off welding... so where do I get bigger canisters? can i refill the one ive got?
at 7 quid a pop, not cheap either....

If you have ever let off a CO2 fire extinguisher you will know that it freezes what it is directed at. Same thing happens with the welder, the pulses of moulten metal tend to 'gel' as they hit the weld pool. This means you need higher amps, you get a harsher weld and you get lots of spatter caused by non moulten metal being flung out of the weld pool.

If you dont use the welder very much, the disposable bottles may be your cheapest option because BOC prices are quite high for rental and the actual contents of the bottles. If you usage is higher, check out the BOC prices, or there is a company in some parts of the country called (I think!) Cougar, their rentals are more but the refils are cheaper.

unless you get the propper bottles from boc thats whats gunna happen,i use co2 pub gas

not an expert but....

carbon dioxide/argon mix tends to be the preferred choice i think (correct me if I am wrong).

Small bottles work out to be really expensive, so hire a large one then all you pay is to get it filled. Also means your wleding isn't interrupted every day by running out of gas.
Am sure some of the others will post with help

[Edited on 19/10/03 by 9904169]

i agree with all of the above, unfortunately CO2 bottles are bigger the the mix ones at MM. The bottles are shite, last about 3 or 4 days each. Gotta remember to turn off at the valve cos the torch leaks it overnight.

if i ever find my motivation im gonna get a big bottle...

I agree with Conrod, I use CO2 pub gas. Cheap at about £8 for a large bottle.

Just make sure you get the pure CO2 stuff not the CO2 / nitrogen mix they put in stuff like Guiness or Murphys.

It's the soft drink gas if I remember correctly.

You will also need to get an appropriate adapter to connect your welder to these type of bottles.

Good luck

where do you get them there pub bottles from? and how much gas is in em?
i tend to use co2 as i find it lasts longer, it cools the weld more than co2/argon mix so can have the flow lower, and i try to set it as low as possible and it lasts quite a long time.


Russ.

In the long term a big CO2 bottle is much cheaper, seems to last forever, and is cheap to fill.

A small amount of Argon, say 10% mixed with the Co2 will usually give a flatter weld although exact results depend on your technique. Higher percentages of Argon are not appropriate for welding mild steel (too hard to explain why).

You should be able to get good results with pure Co2. and once you have a decent sized bottle, its real cheap to run.

Bigfoot

Jumpy,

As you're going to be doing a lot of welding as you're building your own chassis I'd strongly recommend a large bottle ASAP!

Look up your local welding supplies place in Yellow Pages and get a size 'X' bottle of Argoshield from your local BOC supplier. All the bits and deposit and stuff will cost you about £80-100 but it works out a lot cheaper than loads of small bottles!
Ok, it's not as cheap as pub gas but it's much easier for inexperienced welders (I should know! ) and you'll get a better looking weld with better penetration and have less spatter to chip off!

You can then practice with it by building a wheeled welder trolley that will stop the bottle falling over! If it does fall over there's a good chance it'll smash your nice shiny new regulator so chain it up if nothing else!

HTH,

James

CO2 bottles for MIG welding have a dip tube fitted so the gas is drawn off as a liquid. This is to prevent H2O (water) content of the gas increasing as the gas is used up. I don't think the pub bottles have the dip tube. But you could always hold the bottle upside down....
Professional MIGs have a heater to prevent the tap icing up.
BTW This info is tens of years old so things might well be different now!

Get the pub gas CO2 from local pub / brewery suppliers or catering suppliers. Some won't supply if you tell them it's for welding others won't care. I've never had the tap ice up don't know if others have. I have also tested my welding to destruction using the vise and a large lump hammer - no problems with it.