Argon/CO2 mix for MIG

It certainly has an effect on the welder, i.e. me! Burning paint sets me off sneezing for the rest of the day. (Never weld in an unventilated area.) As for the weld itself, if there's enough wax or paint to melt and run into the weld then it can be detrimental, but small quantities will simply burn off without effecting the quality noticeably.

Incidentally, if you manage to set fire to the underseal or whatever, before running for a bucket of water, remember that you're actually holding a fire extinguisher in your hand. A squirt of MIG gas sent with the trigger pressed enough to release the gas but not enough to switch on the power will quickly put out most flames!

So these cheap helmets are ok are they? I have wanted one of these for a while but keep putting it off as I'm scared the cheap ones will be crap.

I'm still using the handheld thing that came with my welder.

By the way, I use a Migmate 130 as despite what a couple of people have been saying I think it is great. I haven't used any other welders though, but this seems to do the job very well.

Wire feed is improved if you use one of the bigger wire coils, about £10-12 and I disconnect the gas if I'm not gonna be using mine the next day.

Dave

Good question - it's about 8 years old, budget model, I think it's a migmate

130 (does that make sense?) - orange case, black front, bottle at back with a fabric strap, wire speed control, current controls are basically two switches A/B 1/2 yielding a matrix of 4 different settings?

I can't remember, but the manual was next to useless. The regulator has a little "narrowing wedge" marked on it to indicate how far open it is.

It's given me average performance despite my lack of skill with it - but I have had to persevere with...

New nozzle needed 12 months ago, old one fatigue sheered at the where the tip screws in - cost a very unreasonable £24 from the (local) manufacturer. Consider this against the purchase price of £100 (shop display unit).

Trigger mechanism is now dodgy with use - needs regular dismantling to cure wire snags etc.

Wire tension control plastic hinge broke within moments of first use - fixed with a large washer and self-tapper.

If I'm not careful about wrapping the dormant unit in polythene, or at least the wire reel, the wire oxidises making welding impossible (not a fault of the unit obviously, just an observation).

I regularly blast the gas shroud with antispatter spray whilst welding, this avoids the need to keep unbunging the tip or clearing the shroud every ten mins. (I got the spray from

I can tell when I've got a good weld "on the run" 'cos the unit overheats just as I'm getting good! It takes around ten mins to reset :-(

Bottom line is that the unit needs care even for low usage, but then again it would've been entirely inappropriate for me to have bought dearer equipment, my welding is //that// bad ;-)) Put another way: every time I finish the welding task in hand I mutter a "never again" to myself - bit like binge drinking.

The only criticism I have of mine, is that the flip clamping knobs. The ones that hold the helmet in the open position, could do to be stronger and better made. The plastic knobs with plastic screws, are barely strong enough to hold the helmet open. A slight movement of the head and it'll flip down again. I cured that on mine by making new knobs that fitted the screw better, and allowed them to be screwed tighter, but obviously that's not an easy mod to make if you haven't the right tools.

Apart from that the helmet works perfectly, and considering the cost of most of these type of helmets, is still very cheap for a helmet that does the job as well as the ones costing several times the price.

Maybe if I were buying another I'd go for this one:-

Looks to be better made, but not that much more expensive. Works out at about £55 inc shipping, at the $59.99 Buy it now price. It also has the advantage of being solar powered, as against the 4 AAA batteries needed by the one I have. Mike.

I think you'll find they all work that way. The bottle has a valve that must be depressed to open it. The knob has a r/h thread, so turning clockwise screws a pin into the bottle opening the valve. I suppose they could have used a l/h thread, but in general r/h threads are cheaper to manufacture. R/h thread tooling being cheaper to buy, than l/h OTOH stick on labels are the same price, whichever way the arrow points. :-) Mike.

Hmm. Both the handbook - useless - and the arrows on the knob indicate it is clockwise to reduce the flow, anti-clockwise to increase. The handbook says to start with it fully clockwise, then unscrew about 1/2 turn. This results in my getting through a bottle of gas in a few minutes...

Andy Dingley in a very helpful post ;-) indicated that these valves often stick. I'll take it apart (if I can) in a few minutes and see what's what.

I expect I still have my original small bottle adaptor knocking about somewhere if you want it. It'll be a Clarke one, but that shouldn't matter as long as yours uses a push fit onto the pipe. I have to warn you though, that it was never perfect. If it was screwed tight onto the bottle, the valve would be too stiff to turn. Slightly loose and it was fine, though I did always undo it completely to avoid leakage when not using the machine.

I don't understand what he means. I've been regularly using my MIG, plus the one they have at work, for well over 15 years in total. During that time I've never had a valve in a bottle stick, or any trouble with the regulator on either m/c. Even if it were a sticky valve, I can't beleive you could buy 4 faulty bottles in succession. :-) To say they often stick, is not my experience at all.

You can easily check whether a bottle valve is sticking, by simply unscrewing the regulator. If it doesn't leak it aint sticking.

And theres nothing to stick in the regulator, unless the regulator screw seizes up.

If there are any leaks in that area the most likely cause would be a seal failure. Either the regulator to bottle seal, or the 'O' ring, IIRC, sealing the regulator screw shaft. Having said that neither of the 2 m/c's I use has ever suffered from either problem. Mike.

But the regulator hasn't got any valves, so it don't make sense.

Tear the label off. You're confusing me now, with your maximum and minimum :-)

Apart from the mislabeling it sounds like the regulator is working perfectly. Forget the label. Turn the regulator knob so the gas flow is shut off. To weld, turn it slowly in the opposite direction, until you can just hear the gas coming out of the nozzle. Doesn't matter what the book or the knob says, that'll be near enough the correct setting for the gas flow, and I guarantee that you'll use considerably less gas than you've been using so far.

I haven't really examined one, but I think it's more of a flow regulator than a pressure regulator. The volume of gas is all that really matters. With the low volumes needed for shielding, pressure is unimportant. Mike.

It has - a spring loaded one. With a rubber diaphragm sealing its outlet from a second chamber. I'd guess it works by using atmospheric pressure as a reference.

It has arrows on the knob with + and - signs. These correspond to what the manual says - clockwise to turn down the flow, anti-clockwise to increase

- like a normal water tap. But in practice it works in the exact opposite way - I'd say by exerting a direct mechanical load on the bottle valve.

Yes - that's now what I'm doing. Still not getting anywhere. On minimum voltage - which I'd guess it needs for body panels - I can't get a consistent arc. Go to the next setting and I burn holes. I'm thinking I'll give it up. ;-)

I just find it weird it works the wrong way round without apparently being faulty.

Thinks. IIRC, there's a small valve or air bleed that goes to the chamber above the diaphragm. Could be that's stuck. I'll have another look tomorrow.

Therefore the manual is wrong, as you've discovered. Probably a misprint. Throw the book away, or ignore it. So far, all it seems to be doing is adding to the confusion.

I'd say by exerting a direct

The pressure regulator is there simply to keep the pressure from rising high enough to blow the pipes or unions. when you switch the gun off. AFAIK it's output pressure is fixed and is non adjustable. The gas flow is controlled, as you say, by how much the bottle valve is opened by the pin on the end of the regulator knob.

I can't

A fine motto. If at first you don't succeed...... Give up.:-)

It does definitely sounds like the m/c is faulty. I don't believe a man of your caliber could be so helpless at using a MIG. :-)

From what you've said so far. I don't think the wire feed mechanism, or the gas regulator is the cause of the problem. In fact the gas regulator seems to be working perfectly. If you can regulate the gas flow, between off, and full flow, there can't be anything wrong with it mechanically. It's just marked incorrectly.

If you cut the end of the wire, and then trail the gas nozzle along the workpiece, actually touching it, at the lowest power setting you should be able to strike an arc. If the wire feed is too low you'll lose it the arc, because the wire will be melting too quickly, and leave too great a gap to sustain the arc until the wire feeds forward again, so you get a staccato pop pop pop pop. Or, the end of the wire could oxydise so when the wire next strikes the job, it's insulated from making electrical contact. If it's too fast you'll find the wire will probably stick to the job and just get red hot. Preferably starting from too slow a feed, gradually increase it until you get the frying bacon sound. Set the gas flow as I described earlier BTW.

Maybe you've tried all the above, exactly as described. If you have and you still find you're blowing holes, or not sustaining an arc. I think you can safely blame the m/c.

The only way to be sure though is to have someone who can use a MIG, try it out. Mike.

Screwed out it does not let gas through screwing it in should increase the pressure/flow.

I make the assumption that the Sip does not have a regulator gauge. You can save heaps of gas by having one and the correct flow.

If regulators have been screwed in too far they stick or you can wreck the seals. ......................................................................................................

Dave

Reading the thread previous the mix of gas CO2/Argon

Technical Explanation!

It depends on the application this is what's happening.

Straight argon is not desirable for MIG on carbon steel - not enough 'oomph',the welds are pretty but they sit on top and are more likely to cold-cast.

Straight CO2 is very hot, hard to use on thin material, and plenty of spatter. (Flux core wire does this)

You need either 25% CO2 and 75% argon, or a tri-mix which is usually around 80% argon, 15% CO2 and 5% O2 (the mix varies by manufacturer and purpose). Another alternative is 98% argon with 2% O2.

Straight argon is needed for aluminum, and it's usable for stainless steel (better is the 2% O2 mix).

The bottom line is that for most hobby MIG welding 25% CO2 and 75% argon, is the stuff you want.

So you weld thin material then more argon - thick material more CO2.

Then why is the knob engraved like this - which agrees with the handbook?

I'm no expert, but it appears to be a regulator rather than just a plain valve. It has a spring loaded rubber diaphragm which in turn operates a valve.

Is there a plug in the side which you can fit a gauge. Not sure who around here has Sip stuff anymore I have a look tho and see what happens.

I have a CIG mig welder 195 and a proper regulator and run a Argon/CO2 mix suitable for light metal. Usually run the thing at 120/150 amps with .8mm wire (which I can just about run at 100% duty cycle.) The bottle size is E which has 4.2 cubic metres of gas and this lasts about

4 hours welding. The composition Argoshield 52 is 25% CO2 and 75% Argon.

rm

In message , "Dave Plowman (News)" writes

I use one of those outdoor 300W halogen lights when I'm welding, shining straight onto the workpiece. You can see what you're doing then even through a standard arc-welding mask.

I was thinking along these lines. I'll give it a go.

In message , "Dave Plowman (News)" writes

Make sure it's got a strong glass face plate, it'll get a lot of spatter on it.

Yes - although if it can stand the heat of a 300 watt QI bubble, it should be ok.