Dual shield FCAW-G

[joeu235]

I plan on building a 8' x 16' cattle guard soon. 8" channel for the supports and 4.5" pipe. I was originally planning on tacking together with MIG and then stick welding, but this seems like the perfect job for dual shield flux core. I have a Hobart 210 with C25 gas. I know I need different wire, probably Lincoln Outershield 71M. Couple questions.

Will my welder handle this? I assume so since Jody is always talking about the Lincoln 210 MP.
Do I need different gas? Literature I've read says C25 gas is sometimes used but also 100% CO2 is used.
I've seen charts from Lincoln that show voltage and wire feed speed. Since my unit only has dials with unknown positions I know I can hook up a voltmeter. But as a starting point will this take more voltage than regular MIG?

Thanks.

 

[TMGT]

The 71M should be designed for use with c25, it will require higher voltage then short circuit but your 210 should be capable, I was usually around 24v on 1/4" material.
Biggest issue you may have is whether your gun can handle the heat, it gets pretty hot!
My stock gun on the mm251 needed regular cool down time, I was using the .045 71M

 

[Shield Arc]

This is Lincoln's .035" 71M. I didn't write my numbers down, the spec sheet says.
Volts, 20 to 33. AMPS, 95 to 215. I ran this weld with C25 gas, and 3/4" stick out.

 

[Big Barn]

Here's Lincoln's .045 " 71M on my very first try a few years back. It's pretty easy to run......

According to my notes/ 40CFH--24-27 Volts--250 IPM. Bernard 350 amp gun. Approximately 3/4" stickout.


I haven't had occasion to mess with it since, so I can't say my skills have improved .



Terry

 

[joeu235]

Thanks for the info everyone.

Wow, they think very highly of those Bernard guns.

 

[MinnesotaDaveChalmers]

You could just use 71t-11 self-shielded flux core instead. Your door chart would help you with settings for that.
(no shielding gas to cool the gun though)

Curious why you have chosen dual shield for this job - is the metal thicker than your mig will handle with solid wire?

 

[joeu235]

I'm not a welding expert but...

Cattle guards take a lot of stress when a tractor, loaded equipment trailer, or occasional cement truck run over them. I was planning on using 7018 stick to get a strong but ductile weld but from what I've read/watched, dual shield is just as good but quicker.

 

[Big Barn]

I'm not a welding expert but...

Cattle guards take a lot of stress when a tractor, loaded equipment trailer, or occasional cement truck run over them. I was planning on using 7018 stick to get a strong but ductile weld but from what I've read/watched, dual shield is just as good but quicker.

You're probably right about the speed. I rarely have larger projects anymore and prefer "zoning out" using stick.

I find the experience mildly therapeutic. Maybe it's just me...

 

[MinnesotaDaveChalmers]

You're probably right about the speed. I rarely have larger projects anymore and prefer "zoning out" using stick.

I find the experience mildly therapeutic. Maybe it's just me...

Stick and TIG are good for that

 

[Shield Arc]

Dual shield is very fast:thumbsup:! You have the best of both worlds, slag, and gas coverage. We used 1/16-inch dual shield to splice these 1-inch wall, 10-feet in diameter piles in the Columbia river.