Confused over which gas for welding...

[Diamondpilot]

I run 25/75 myself on both my welders with great results for general fab work.

Chris

 

[Transit]

There is plently to search on this but I am still confused.
My wire welder is a Lincoln 170T (220) that I have used with flux core wire for farm welding and rusty metal welded outside.
Now I want to do attractive welds on new metal or clean hot rod frames or other new metal than is in the area of 1/8" yhick. Maybe thinner, maybe some thicker.

I do not understand which gas I should use and know little about it. Which wire size? What size bottle to buy for infrequent use? The kit I bought has the regulator, etc and says I can use different wre sizes. I presumed I would just use argon and was not aware of blends.
The welding class I took covered all this but I need some practical application. Thanks in advance.

Take your pick;

MIG Welding Wire Charts - Airgas.com

http://www.terracesupply.com/WIRE & ELECTRODE SELECTION CHARTS.pdf


ER70s-6 is the most common used.

 

[sixdogs]

Thank you all.
I'm going to use Lincoln .035 wire, buy a 125 C25 gas tank and take my time. My last car had a unique fiberglass body but I'm getting the itch to build something from scratch again. Thanks.
Hey Transit--great charts.

 

[Jeff H]

I have the Lincoln 170 also. I have been happy with Stargon gas. Argon-Carbon Dioxide-Oxygen Mixtures -- Praxair's <I>Stargon® CS</I> Blend My bottle is the same size as JaySte's .

 

[Jim in ICT]

The welder should have a chart with suggested settings for heat and wire feed speed for the thickness to be welded. It should show the recommended wire size also. That would be a good place to start, then adjust only one setting, amperage or wire speed. If you adjust both, it can be more difficult to tell how the adjustment affected the weld. Try to get a sound almost like the sizzle of bacon without the popping. Look inside the sheet metal cover where you load the wire for the chart. The 75% Argon / 25% CO2 mix (or 80/20), will provide the best appearing weld. Straight CO2 will have more penetration, but will require more grinding to clean up the spatter.

 

[smfcpacfp]

I have one welder (Millermatic 211) and I weld both aluminum and steel, mostly steel. I own one tank which is filled with argon, because aluminum requires it. I am not aware of a problem using pure argon except it costs a bit more for steel. Having a tank with argon and another with some separate mixture for steel would cost quite a bit more, however.

 

[mjncad]

I use 75% argon, 25% CO2, and 0.030" wire and so far, so good for my work.

However, good quality wire like Lincoln's made a big difference in weld appearance and quality over Airgas' mediocre Radnor house brand.

 

[czechsonofagun]

I have always perferred .035 hardwire with C25 gas. Probably 1/8" is max with one pass. CO2 will leave you with worm holes, but it is cheaper. I don't trust mig enough to weld hot-rod frames, even though I have been certified in it.

We use Mig to weld frames for custom Corvettes, no problems ever. Welding is the last thing, the design is also important; how you triangulate and put it together.

 

[sixdogs]

Thanks to all of you. I'm getting ready to go beyond the flux core welding of farm stuff to building or altering a hot rod frame. After some practice first. Good advice here.

 

[ModMech]

Flux core wire is what you WANT for dirty/breezy conditions. You can add gas as well for even better welds, but it is not required.

I've gone thru dozens of large bottles and a number of 40# spools using CO2 without any real problem. It was not until the LWS suggested I try C25 that I discovered how nice it is to weld with. I'm not one to use flux wire, if I need to weld dirty stuff in the wind, I will use a stick. Too much work to restring the MIG and change polarity for a "quick fix" to get back to work.