What's a good general purpose MIG wire?

ER70S-6 is what you want and what you get most any place that sells mig wire.

I like .023" wire better as my standard as it works better on thin or small parts particularly any sheetmetal work, it should drop right in with no issue.

The flux core works better outside if there is any breeze and actually makes better welds too, you just have to clean them off and work in a ventilated area.

Straight argon is required for aluminum and it does work for mig welding steel, but is not the best. For steel you want and argon/co2 (5%-20%) blend and a little O2 (up to 2%) makes it a little better yet. Straight CO2 also works well on steel too, the welds don’t look quite as nice as the Ag/CO2 blend, but they are much better than straight Ag.

I had a harbor freight mig for years. The one problem I had (before I fried it that is) is the wire feed gear box fell apart after less than an hour of use. The box was molded plastic and the pins that help the gears a bit short, causing the pins to destroy the holes in the molded housing and then the gears no longer engaged and no wire feed. I made a new aluminum housing and that out lived the rest of the welder.


Happy welding.

 

I agree with Mark, I use thin wire with CO2 gas on sheetmetal or any small stuff and .030 flux core when I'm doing anything over .100 thick. Either way metal has to be very clean or the welds will look horible. If you are using the flux core you will have to chip the slag off before you start welding again if you stop. Lincoln tech told me to "drag slag, push gas" meaning if you are using the flux core lean the tip over and back away as you are welding and if you are using solid wire with sheiding gas, weld in the direction you have the tip pointed.

You have to look at the puddle to weld, with the flux core you will see two puddles. One is the flux and one is the filler and they will be a different shade of red. For both it is important to have your face close to the weld so you can see what your doing. A cheap pair of reading glasses from the drug store helps so you can have your face 10 inches from the weld. You will only have the one puddle with the solid wire but you must still have your face in close to see what you are doing.

Depending on the amperage of the machine you bought you may want to grind V notches in the base metal when you prep the pieces you want to weld. Also make sure you have the polarity correct for the wire you are using.

 

sorry, but I have rarely seen satisfying results with 220V welders. I have used one in the past and after much excercise I didn't get any great results. At least not on thicker steel. Sheetmetal is controllable for some experienced welder, but for thicker steel you just need a current, which 220V transformers simply seem to not deliver long enough.

Then I purchased a 400 V / 250 amps welder which is capable of welding 12mm (~0.5") steel, though sensitively adjustable in the lower range for sheetmetal.
But still excercise and routine is all. When I didn't weld for a longer period, before I start again, I first have to adjust wire feeding and current on some comparable piece of scrap metal before heading to the actual job.

Best Regards from Germany

Martin

 

This is all very interesting. I am thinking about buying a welder. Realistically I don't need it - there is a machine shop very near to my garage and my needs are infrequent. It just looks like fun and something that I want to do. I was thinking that I should take some training before I fry myself as my knowledge is really zero. Anyone recommendations for a good introductory book

 

I'm self taught MIG and TIG.

First tip...buy a lincoln or miller. A good welder will give you the potential for good results. Get a welder with enough power for what you weld mostly.
2) use the right wire
3) use auto darkening helmet
4) practice
5) practice
6) practice

Here is a roll cage weld I did with fluxcore on 120 wall DOM. It was my first cage. I think that is about as pretty as you can get a flux joint. I completely converted to TIG for the pretty joints.
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Everybody seems to like "Welder's Handbook" by Richard Finch. Excellent primer on all kinds of welding. If you're only going to own one welder, my preference is TIG. It's slow for some kinds of work, but you weld just about anything. You can do very fine welds on steel, stainless steel, and aluminum, and the welds are very good looking.

 

Very impressive job. Thanks for the pointers. I will research what machines are available in Hong Kong

 

Anything I weld inside I tig these days, it's just SOOOO much easier to do a nice job. I keep flux core in the mig for outside work when in comes up. A mig is a lot cheaper and can do good work, it just takes more practice. I use mine so seldom I almost always do a couple set-up/practice beads on scrap before I hit the real parts.

 

thanks. I'll have a look for this book

 

Lincoln and Miller have a lot of good tech stuff on thier web sites as well. I love my TIG but if you have never welded anything before and have a budget of less than $500 or so the MIG is easier to learn. I don't know about Miller but the small Lincoln MIG welders now have an optional spool gun for doing aluminum. The gun is about $150 option that fits on the 120v and the 220 volt machines. You can get yourself a 185 amp mig with separate spool gun for aluminum for under $700. I've used them and they work great.

The TIG is much harder to use and the setup time,prep and dollars to get started are bigger. Figure at least $2K buy the time you get a small machine, extra electrodes, gas and filler metals. That said I love my TIG and the learning curve wasn't too bad for me since I did a lot of Oxy/Acet welding before I got the TIG.

Main thing with the MIG as I stated before you need to have your face close to the work at you have to see the puddle of molten metal. No other way to get a decent weld. If you watch the puddle you will get an idea of how fast to move and how to adjust the wire speed.

 

I know a lot of people that agree with you on this, but I actually find TIG to be easier than any other welding. You can take your time, and if the weld is ugly, you can always reheat it and make it look good. If I haven't TIGed in six months, I can still lay down a perfect bead immediately, but with MIG or stick, I have to practice for a while. And the best stick welder I've ever known can't TIG worth a damn. Interesting, eh? -Steve

 

Same here, I find Tig much easier than any other kind of welding. I bought a used 400amp machine with a foot pedal, chiller and water cooled torch for $1300 on ebay. It will weld anything.....even head stud holes in V12 blocks