Dual shield rookie

[Pony]

Puts down a nice weld.
What gas mix are you running with it-

 

[.RC.]

It is an 80% Argon, 20% CO2 mix. Can also use it for solid wire I believe, but not tried it yet.

I have been building a few of these and welding them with self shielded flux core is a pain.

 

[.RC.]

Done some more experimentation with Dual Shield. I found horizontal fillet welds with 1.2mm (0.45) wire, you need heaps of amps 250+ to get it to penetrate into the root as the deposition rate is to great if you go too slow you end up having the arc on the puddle rather then the leading edge.

Vertical up's are like cheating though. Just hold it straight and zip it up and it is counter intuitive in that you want fast wire feed for vertical up, not slow.

Here is a cut and etch when I finally got things sorted out.

 

[Willie B]

Done some more experimentation with Dual Shield. I found horizontal fillet welds with 1.2mm (0.45) wire, you need heaps of amps 250+ to get it to penetrate into the root as the deposition rate is to great if you go too slow you end up having the arc on the puddle rather then the leading edge.

Vertical up's are like cheating though. Just hold it straight and zip it up and it is counter intuitive in that you want fast wire feed for vertical up, not slow.

Here is a cut and etch when I finally got things sorted out.

View attachment 312049

My last machine Millermatic 252 was crank voltage very high, turn up the feed speed a LOT. Imediately I burned up my hand, then I burned up the gun. Bought a massive Bernard gun & heat shields for my hand. Heat shields melted.
Dual Shield is a HOT process! it also gives nearly certain bond with parent metal. For me, its ability to give certain bond while running a lot of deposit uphill makes it very desireable. It has not been easy for me to work the bugs out. I've watched many videos, none addressed the problems I had.

My problems were birdnesting, a snarl around the feed rollers, and porosity. Several people on Welding Web contributed, especially Oscar. I still never made headway.

Maine Oxy manager figured out the wire I was using needed 85/15 gas. sold me different wire for 75/25 gas. He sold me little felt cylinders & lubricant to put on the wire as it entered the feed rollers.
I tried in vain to figure out what liner my gun needed, then discovered a "jump liner" I already had.

My birdnest problems are solved. My porosity problems are solved.

 

[Welder Dave]

Done some more experimentation with Dual Shield. I found horizontal fillet welds with 1.2mm (0.45) wire, you need heaps of amps 250+ to get it to penetrate into the root as the deposition rate is to great if you go too slow you end up having the arc on the puddle rather then the leading edge.

Vertical up's are like cheating though. Just hold it straight and zip it up and it is counter intuitive in that you want fast wire feed for vertical up, not slow.

Here is a cut and etch when I finally got things sorted out.

View attachment 312049

Curious why your welds have a pinhole at deepest part of the root? I ran .045" dual-shield and didn't find it that hot using a 300 amp Bernard gun. If you want hot burn some 3/32" Innershield NS3M E70T-4 at 400 amps+. You need the heat shield on the gun. Even the smaller guns for self shielded flux-core come standard with a heat shield. I think I've seen optional heat shields for standard guns though. The biggest Lincoln Innershield gun is rated at 600 amps for burning 1/8" wire! That's got to be pretty insane.

 

[Tyler d4c]

Curious why your welds have a pinhole at deepest part of the root? I ran .045" dual-shield and didn't find it that hot using a 300 amp Bernard gun. If you want hot burn some 3/32" Innershield NS3M E70T-4 at 400 amps+. You need the heat shield on the gun. Even the smaller guns for self shielded flux-core come standard with a heat shield. I think I've seen optional heat shields for standard guns though. The biggest Lincoln Innershield gun is rated at 600 amps for burning 1/8" wire! That's got to be pretty insane.

I wander if it isn't a small slag inclusion considering it's past the edge of the plate

 

[.RC.]

That is the major issue with dual shield at lower power levels.

I had endless trouble with root penetration, and further research revealed it is a common problem with horizontal fillet welds.

The fix is to get the arc on the leading edge by going faster and do not put the arc on the puddle.

Here is a photo showing what was happening when I started out doing some testing. Also here is a video showing the problem with dual shield flux core on horizontal fillet welds if just done in a blase manner.

 

[Old Doug]

I built and repaired RR cars with it . I thought it was a very good thing . I often thought if i could have dual shield at home i could speed up some projects.

 

[digger doug]

That is the major issue with dual shield at lower power levels.

I had endless trouble with root penetration, and further research revealed it is a common problem with horizontal fillet welds.

The fix is to get the arc on the leading edge by going faster and do not put the arc on the puddle.

I have an old edition of the Lincoln welders bible, there was a loose insert about a technique developed during the early stages of WW2, that showed just what you did with etching. run fast enough to use the arc force to dig into cold steel.

Arc force blowing on the liquid puddle is absorbed much shooting a gun into water.