How to choose flux core wire?

[Shield Arc]

Can you get a closer picture? Are you dragging the gun? With flux core, or anything that produces slag you need to drag. If you're right handed start on the far left, and weld towards the right. With the gun slightly pointing to the left.

 

[s219]

Can you get a closer picture? Are you dragging the gun? With flux core, or anything that produces slag you need to drag. If you're right handed start on the far left, and weld towards the right. With the gun slightly pointing to the left.

So here's a question for you -- how do you neatly end a puddle when you get to the end of the material when dragging a wire?

Here's a lousy zoomed picture of a typical weld for me (that is two pieces of bar stock butted at a 90 degree angle). I was dragging left to right. End of the weld at the right, the bead always tapers off. It looks OK, but I'd rather have full depth of the puddle to the end. Should I pause and let more wire feed at the very end to fill out the puddle there, before letting go of the trigger? Do not remember this issue when stick welding many years ago.

 

[Shield Arc]

When you're getting ready to stop. Turn the gun 90-degrees to the plate, close up the stickout just a touch, and go backwards 3/8 to 1/2-inch. The crater / stop is the one of the weakest spots in a weld, because of the lack of fill. If you shorten the arc length / stickout it gives you a colder arc, and by backing up will allow you to fill in the crater.

 

[farmer2009]

Neat trick there shield.

When wire feeding how do you keep a constant stick out. I am use to a stick and find myself wanting to feed in as I weld. I am right handed and I did weld that left to right. I'll take some closer pictures today.

 

[s219]

When you're getting ready to stop. Turn the gun 90-degrees to the plate, close up the stickout just a touch, and go backwards 3/8 to 1/2-inch. The crater / stop is the one of the weakest spots in a weld, because of the lack of fill. If you shorten the arc length / stickout it gives you a colder arc, and by backing up will allow you to fill in the crater.

Ah, wonderful, thanks -- Excellent description. I will practice it this weekend!

 

[Shield Arc]

I have to remember to do it my self. Another good habit is to try and never leave the crater / stop on the end. Better to weld one direction, and stop. Then weld from the other direction and stop on top of the first welds crater. Easier to fill the crater / stop that way.

farmer2009 I really pay more attention to the sound of the weld. If you listen to the weld, and change the stick out, you will hear a different sound. I also lean to the left so I can look right at the contact tip, to watch the amount of stick out. Even with the radio on in the shop, if the sound of the weld changes, that gets my attention faster than watching the puddle.

In this first picture you can see where I backed up some to let the crater fill.
The second picture shows the stop in the center.

 

[MinnesotaDaveChalmers]

When you're getting ready to stop. Turn the gun 90-degrees to the plate, close up the stickout just a touch, and go backwards 3/8 to 1/2-inch. The crater / stop is the one of the weakest spots in a weld, because of the lack of fill. If you shorten the arc length / stickout it gives you a colder arc, and by backing up will allow you to fill in the crater.

You've made me curious, how does shortening the stickout, which generally increases the amps slightly, make a cooler arc?
Arc length is set by the voltage, it's not supposed to change with stickout length variations?

 

[Shield Arc]

Give it a try, you'll see.
Mean while down near the bottom of the page.
Miller - Making a Sound MIG Weld

 

[MinnesotaDaveChalmers]

Give it a try, you'll see.
Mean while down near the bottom of the page.
Miller - Making a Sound MIG Weld

Isn't that a short circuit mig page?

I thought this was a flux core thread, which you know is a spray arc.

 

[Shield Arc]

Yes but the same principal applies. Even with SMAW, There are three to four small zones where the voltage changes. I try to set my voltage to hit the sweet spot at about 3/8-inch stick out. To a degree if I want a hotter / more flowing puddle I'll open the stick out to say 1/2-inch. But if I go too far, say 3/4-inch, I'll run the risk of losing the arc. If I want a cooler / stiffer puddle I'll shorten the stick out to say 3/16 of an inch.
Same with SMAW, want a colder puddle jam the rod right into the puddle. Want a hotter more flowing puddle back the rod out some.

With self shielded T-8 wires, and dual shield most of those wires require 3/4 to 1 1/4-inch stick out.