what size welder ???????????

I've got stainless wire and haven't yet had the excuse to play with it. But I have mig'd aluminium. It worked, but ye doGs its difficult. Definately

*skill* required.

Gas does it for me. Argoshield light and a bit of clean metal is a joy to weld. Theraputic almost. hmmmmm. Beth

On or around 26 Sep 2003 10:39:26 +0100, Beth Clarke enlightened us thusly:

oh yes... and an excellent liner and a good wire feed and not to many sharp corners in the "snake"...

right boodly tricky so 'tis.

Well blow me (traditional meaning intended). I never thought of that. Wonder if I could get Machine Mart to swap it for a gas Mig? :-)

-- David

I've acquired BOC's Industrial gases price list 1/1/03

Unfortunately I cannot decipher what the letters for sizes relate to but their CO2 shieldpak refills cost GBP8.81, rental GBP39.19/annum, fixed charge per transaction collected GBP10.52. Prices differ for argoshield in refill cost at GBP24.56. Overall it looks similar to my deal with Air Products, it still makes the fire extinguisher refill the most attractive kosher method for a small, irregular user IF flux cored wire is markedly inferior.

AJH

AIUI flux-cored wire is, in effect, just very thin and flexible "stick" welding. It's not proper MIG at all.

Yes I think so, as I understand it manual metal arc welding is effectively the same as auto feed metal arc welding, though the method of metal transfer is more flexible with the auto feed.

When the "inert" [1] gas is used it protects the molten metal from the outside atmosphere until it has cooled below a temperature at which it will react. The flux coating on arc welding rods both creates a non oxidising atmosphere for the weld metal and acts as a flux to combine with impurities in the weld and float them to the surface, where they then solidify as a glassy slag, which needs to be chipped off. To my mind this chipping off is a large disadvantage of stick welders over auto feed gas shielded ones.

A flux cored wire does the same but the flux has to be inside the wire as the outside metal is needed to conduct the current from the tip. Never having seen any results of a "mig"[2] with flux cored wire I don't know if it needs chipping off?

[1] There's not much inert about CO2, I assume those molecules in the arc dissociate but CO" being a lighter molecule tends to be favoured over any metal oxide at the higher temperature as they recombine. [2] Another case where the merkin usage of the english language is probably more descriptive? They don't use "mig" but I forget the precise term.

AJH

In my (limited) experience, there's far less slag than you get with MMA, and it comes away easily with the excess metal when I grind back my grotty welds :-)

On or around Sat, 27 Sep 2003 21:56:06 +0100, Andrew Heggie enlightened us thusly:

well, it presumably has flux. The coating on MMA rods is flux as well, and the flux is there partly I think to reduce oxidation during the welding process.

Gas-shielded welding using CO2 or CO2/Argon mixture is now referred to as MAG, Metal Active Gas, IIRC - works better on steel than argon, apparently. Genuine MIG uses pure argon, and is used for stainless steel and aluminium.

And to help sustain the arc.

Ah well. From my admittedly amateur readings the gases have quite an effect on the weld pool than "inert" would suggest. Take TIG welding as an example: TIG uses pure argon. WEll yes and no. For some specialist applications Helium is added (I can remember why without looking it up). And even oxygen. With MIG, you often see Argon/CO2 mixes. I have Argoshiled light, which is

5% CO2. This helps the 'wetting' of the metal and filler wire, so it doesn't just sit on the piece you're welding but gets incorporated properly. Like solder flux. Adding more CO2 to the mix, say 25% aids weld penetration. So for a given current you can weld thicker metal. The downside is you cant then weld stainless or aluminium as the CO2 contaminates the metals too much. In practice 'Mig' welding with CO2 allows you to weld muckier/rusty bits of steel, which on a landy is no bad thing! With Argon and bright clean metal it's a complete joy. Very different sound, not so much splatter, and the weld pool is very precise.

The Haynes "Automotive Welding Manual" is a pretty good reference and practical guide.

Beth

On or around 29 Sep 2003 11:29:55 +0100, Beth Clarke enlightened us thusly:

I'll go along with that. 5% stuff in use here, though it's called coogar 5. Used to use plain CO2, in silly little bottle, but that was a pain.

Mind, the 5% stuff seems to allow of welding the same metal with either a lower power setting or faster wire feed than the plain CO2 did.

Wassamatter Austin, my posts getting too long and boring for you to read? ;-) snipped-for-privacy@4ax.com para 3.

MAG makes sense, so does what Beth says about how different mixes affect the weld. AIUI on a migmagautofeed you set the voltage with the switch and *effectively" the current with the wire feed AND/OR distance from tip to weldpool. Changing the gas could also vary the voltage across the arc.

AJH

CO2 cools the weld pool more, so you need more amps to keep a puddle. As you say ArgoShield or whatever is better when welding thinner stuff as a result.

Regards

William MacLeod

On or around Mon, 29 Sep 2003 22:22:25 +0100, Andrew Heggie enlightened us thusly:

nah, I had a ton of messages over the weekend while I wasn't here, and they got rather sketchily read.

but still, 's a fine old usenet tradition for several people to post the same answer :-)

Hi There

I would recomend going for the MIG set as it is far eaiser to use.

If you want any unbiased advice on machines then contact me snipped-for-privacy@weldingonline.co.uk I run a welding repair centre and always give honest straight advive even on equipment we dont sell. I also have several second hand MIGs available.

Regards

Steve (TD5 Commercial)