Thread: Gas Vs Gasless

That amounts to less than $90 worth of flux wire over 2 years which does not cover the cost of a cylinder by a long way.

Don't forget to consider the cost of not having to (extensively) de-splatter and deslag the welds. Neat welds straight off the gun are worth the gas hire I reckon .

Originally Posted by Iggsy

Don't forget to consider the cost of not having to (extensively) de-splatter and deslag the welds. Neat welds straight off the gun are worth the gas hire I reckon .

Maybe my experience from persisting with gasless has paid off in better welds. There is no extensive cleanup activities going on here. A quick, and I do mean quick run over with the wire brush on angle grinder and its done. This is what I consider worth the saving of gas cost.

Everyone has a right to their own opinion. I use welding to make things. Although I regard it as a hobby, everything I produce has a purpose on our small property and also a cost. If I can save some bucks on this job that means more money to spend on the next job. There are plenty of jobs lined up and some of them are designed to enable us to do things easier and so prolong our viable life on this property. I guess what I am saying is that I cannot afford to use gas. If you can afford it then go ahead and use it.

Dean

I've never been a fan of gasless Mig welding, but when the gas rental for oxy acetylene went unjustifiably beyond my means, I bought a cheap (under $100) Chinese AC transformer type gasless Mig welder that is also portable.
After persisting with practice for a whole (0.8kg) roll, I put it away in digust....
I tried it on thin sections and sheet metal and made a mess including lots of burn-through. On thicker sections in 'Hi' mode, it would weld for about 10cm at a time before the 'Overheat' light came on and shut the transformer down. Incidentally, as it cooled down, the gun came 'live' again without any safety interlock. You have to think where you put it down once the transformer is off!

Over the past few days I've been building and welding a fence frame in 2mm thick gal RHS - and we had quite a bit of wind here.
At first I contemplated trailoring my stick welder out there to do the job, but then thought of giving the Mig another go (because its small and light).
This thing has two settings: Hi/Low and wire feed. That's it.
The new roll of wire was CIGWeld pro 0.9mm wire (the initial role was unbranded 0.8mm) - ex Bunnings. (it - like all other gasless wire I've found - is labelled DC Electrode negative. Why do they even make AC gasless welders????)
Halfway through the roll I nearly gave up again, but strated to get the occasional nice weld - so I persisted.
Well, I've gone through another two rolls today and I think I've finally got it
I still dislike the enormous amount of splatter (including on to me and my clothing) and the difficult to remove thin layer of slag, but the welds are now pretty consistently OK.
I even gut up a few to check their safety - penetration, slag inclusions, porosities etc. They were all OK. I impressed myself

I'll continue using the poor little thing on other thin sections and see what I can do with it.

I'm contemplating a contactor on the trigger for the primary side of the transformer and also adding a bridge rectifier. Am I wasting my time thinking about those?

Cheers,
Joe

I think your experience with gasless welding is more to do with a cheap POS welder than flux-core wire itself, and this seems to be a common story.

Put flux-core through a half-decent machine, and it'll produce a very respectable weld. Before I went to CO2 shielding gas I went through a roll or two of Boss flux-cored wire (distributed by Unimig I think) and the light slag cleaned off easily with a (hand) wire brush and any balls of spatter that resisted the brush went with a swipe of the flat end of a chipping hammer.

As for converting the welder to DC, I don't know - you'll get DC, but I don't know whether you'll get particularly good voltage regulation is another question. If it was me, I'd save up for a half-decent inverter combo machine - I've got one and it's invaluable on the farm - copes with voltage drop in the (often long) supply leads with the ability to quickly swap to stick if the application requires it.

Thanks for that clarification and suggestion RustyArc.
I suspect you are right about the POS welder. According to the circuit diagram that came in the "manual" there is no regulation of any kind in this box....
Joe

I'd doubt that your welder is AC on the output. Mig is a DC process. Stick is the best choice for gasless welding on a home type level.

Originally Posted by BenM78

I'd doubt that your welder is AC on the output. Mig is a DC process. Stick is the best choice for gasless welding on a home type level.

You may well be right with second sentence, but these cheap machines are definitely AC only. Essentially a small stick welder with built-in wirefeed.
Stick is definitely my choice for structural welding or thicker sections. No doubt at all.
I just wanted to get the hang of this POS machine instead of just wasting the $100 I spent...... Anyway, gone through 4 rolls of wire now and quite comfortable with its limitations - and my capability to overcome them.

I'll save up for an inverter welder.....

Joe

Originally Posted by jhovel

but these cheap machines are definitely AC only. Essentially a small stick welder with built-in wirefeed.
Joe

How intriguing. Would cost bugger all to put a rectifier in there and have something that might actually work!

I love these kinds of machines, people buy them, can't do anything with them and then pay me to do the welding

Great attitude! I love it.
I intend trying it with a rectifier while I'm saving
Joe

Originally Posted by BenM78

How intriguing. Would cost bugger all to put a rectifier in there and have something that might actually work!

I haven't looked at transformer DC welders - from my background, inverter welders, being a form of switched-mode power supply, are far more familiar designs, but a concern would be regulation, MIG welders being a constant-voltage supply. I'd expect you'd need an inductor to smooth the voltage output, possibly making it a more complicated and expensive exercise. But on the other hand, you might learn a lot trying

Any hints on inductor construction? SInce it may have to carry 130A, it ought to be wound from something like 3/16 dia (~7.5mm2) copper wire or cable around a laminate iron core. Would something like a microwave cor be big enough? And how many turns would this inductor need (or just fill up the available space)?
Cheers,
Joe
(not good at quantitative electricals but good at improvising)

It is going to cost way more than $100 to attempt to rectify your AC output to DC.
You may fing that your power supply is not constant voltage like a mig but rather constant current with a voltage sensing wire feed.
Cut your losses, you will still be left with a POS welder at the end.

If it costs me anything, I wouldn't bother.... I intend to try this only if I've got the bits in my workshop doing nothing.... and only for a learning exercise.
By the way, there is no sensing of any kind in this box: as mentioned before, it has an on/off switch , a hi/low switch, a transformer and a wire drive motor with a rheostat to adjust the wire speed - that's it. The gun trigger switch only operated the wire feed - the wire is always "on" when the box is "on".... As you say "POS"....
Cheers,
Joe

Originally Posted by jhovel

I've never been a fan of gasless Mig welding, but when the gas rental for oxy acetylene went unjustifiably beyond my means, I bought a cheap (under $100) Chinese AC transformer type gasless Mig welder that is also portable.
After persisting with practice for a whole (0.8kg) roll, I put it away in digust....
I tried it on thin sections and sheet metal and made a mess including lots of burn-through. On thicker sections in 'Hi' mode, it would weld for about 10cm at a time before the 'Overheat' light came on and shut the transformer down. Incidentally, as it cooled down, the gun came 'live' again without any safety interlock. You have to think where you put it down once the transformer is off!

Snip

Cheers,
Joe

I am glad My mig works better than that, now anyway. I have yet to have it switch off due to duty cycle limits and I have used it for some reasonable sized welds.

Remember one thing however. Gassless mig are classified as next to useless on thin section metal. I you wish to weld thin sections you have to use gas. I have used mine on 2mm thick galv C - channel etc with no problems at all. I would guess 1mm thickness is ok but any less than that would be an issue.

Dean