TheSamba.com :: View topic - Flux core welding with heavy metal : bead appearance.

Tue Oct 28, 2014 4:08 pm

I use flux core whenever I can and the situation I have is when I weld 1/4' steel with the voltage turned up ,the puddle activity is so active that the bead looks really bad.

If I turn the voltage down and move the nozzle really slow , I get a much better looking bead.

Is this an issue with using .030 gauge wire on a high setting or is flux core done with a much slower nozzle motion?

Thanks for your expertise!

Wed Oct 29, 2014 8:18 am

sometimes if the heat is too hot for the base metal the wire & flux will boil. The width of your weld should tell you if you are moving too fast or slow & if you have too much heat. Post a picture of your welds, there may be others to help on this.

Wed Oct 29, 2014 7:29 pm

My camera is not really good. :lol: If I set voltage for maximum penetration ,the weld pool is way too active. I'm usually trying to weld hot enough so I don't have a big comfort zone of not burning through.The bead looks like the surface of the moon. I have to set voltage for a decent looking bead which of coarse limits penetration.

I figured that the only bad thing about welding too hot was burn through. Is this wrong? Should I weave to get more penetration if the weld pool is too active and leave the voltage down.

Wed Oct 29, 2014 10:30 pm

Sometimes yes, turned up too high and you'll overhea the weld puddle but base metal is too cold?? yes it can happen.
1/4 thick in one pass may be beyond the limit of the machine, and wire too. Could in a situation where going with bigger wire would be good, but sometimes the machine won't necessary put out any more amps so it doesn't help. You can look up the amp range for the wire, but also look at the door chart, see what they recommend.

Just have to use the highest setting that works well.
Vee it out bigger, therefore more room for deposit metal to go, and you can and travel slower. Or can do two or three passes if a T joint.

Wed Oct 29, 2014 11:17 pm

I just discovered that the sticker inside the cabinet knows more about welding than I do. :oops: I'm actually welding 3/16ths as well.

How can I have lousy penetration but a pool that is too agitated? With mig it is usually better to error by being too hot but I guess it is the opposite with flux core. I usually try to use a low wire speed with flux core so as not to create a cloud of flux fumes. I'll turn the wire speed way up next time and see what happens.

I find it perplexing that if I have the voltage turned way up, I get good penetration but the weld puddle to too damn hyper.

Thu Oct 30, 2014 1:06 am

The flux can overheat too, flux-core is a whole different animal!

Thu Oct 30, 2014 6:35 am

You need to drop down the wire speed & adjust the heat. Is the wire new? I only ask as if flux core wire is not stored properly it will oxidize & not weld properly.

Thu Oct 30, 2014 6:15 pm

I'm still learning and altering my methods as a my skill progress. I just figured penetration/burn-through would be the best limiting factor to "weld to".

A lot of general welding rules don't seem to strictly apply to my machine. Like turning up the wire speed makes for a hotter bead until a certain point and then it actually cools the pool down. Sometimes dragging does not make a difference to pulling with mig.

I keep my wire in ziploc bags and it does not sit around for that long. I don't seem to even come close to a contaminated wire situation. Sometimes I think the electrical grid I'm on is not up to par. If I mig upside down ,it can go from easy to difficult with out changing anything. :?

I'm getting some mint looking welds with the same wire but I'm welding by 'bead appearance' and not 'maximum penetration'.

Edit: Usually I go light on the wire speed because of the flux cloud in creates. :D

Fri Oct 31, 2014 5:50 am

Welcome to the world of small welders and flux core wire; if you want the convenience something else is going to have to suffer. Modok is spot on about V grooving your joints and making several passes. If you want to just do it in one shot with the machine on full blast, AND get a nice looking bead, you're going to have to get a bottle of gas and convert the machine. Sometimes preheating the part helps, but heating it and keeping it clean can be difficult. I always used gas around the shop with my little buzz box, and swapped to flux core when I had to drag it out to a job and didn't want to haul the bottle.

Fri Oct 31, 2014 6:27 am

Sorry to ask this basic question, but you are switching polarity when you run flux core?

Also, what do the settings recommend? I would go with the recommended settings and adjust technique to suit.

Fri Oct 31, 2014 11:00 am

Northof49 wrote: Sorry to ask this basic question, but you are switching polarity when you run flux core?.

Very good point, and often overlooked.

Fri Oct 31, 2014 11:24 am

I have the polarity switched. It seems contradictory to do a pass on each side of a butt joint ;for example , when I have the heat to do it in one pass but the bead is uncontrollable. :D I'll experiment with higher wire speeds and report back.

Fri Oct 31, 2014 11:56 am

What diameter of flux core are you using? My Lincoln came with a small roll of 045 flux core that works very well on 1/4" steel. I set it precisely by the chart and it pumps out the perfect weld. If the joint style dictates more penetration, such as a T where I need to get to the root, I move up one unit on the settings to the next heavier gauge specified on the chart.

Fri Oct 31, 2014 3:05 pm

I'm using .030. My mig is a 120volt 130 amp welder. The instructions say it's for .025-030 gauge wire. I don't think my welder would benefit from a thicker wire because it only has the amps for .030 in my opinion. With a thicker wire ,I think I could only max it out with a very slow wire speed with no other benefit.

Sat Nov 01, 2014 5:40 pm

Not trying to be rude but it doesn't sound like you have a understanding about welding. Research wire speed and volts relationship plus multipass groove welds.

They weren't trying you to weld both sides, make a bevel (ends up a groove) and lay down more than one pass to fill the groove. However if you really want penitration you run a groove weld on one side and grind out the backside until all the black is gone and its clean metal then run a bead. That's full penitration.

To get penitration you need a bevel. I run .052" wire all day and I still bevel anything I can.

Cranking the volts up and having the wire speed down will cause undercut and a poor weld appearance. The wire speed actually increases amps. Flux is smokey, making it run with less smoke is only hurting quality.

Did you change your contact tip to match the wire size? Also correct size drive rollers?

If there's slag you drag, it keeps it out of the puddle. I only push uphill vertical because gravity pulls the slag down.

Without a pic its hard to say what's going on. My guess is lack of wire speed.

Sun Nov 02, 2014 1:26 pm

I got a chance today to investigate what could have been the problem.

I could not find the piece I set up on but for some reason welding at the highest voltage setting was making the pool hyper active. I turned to a lower voltage and got good looking but narrow beads.

Today when I go through all the parameters I can do no wrong so I'm inclined to believe there was a flux content issue.

Question: As flux core has a huge variation on wire speed that will work how ,should I set wire speed, just under stubbing the weldmet or what? I notice that if I use a slower wire speed that the stick out rapidly fluctuates. Is this a factor I should consider?

Sun Nov 02, 2014 4:00 pm

I would set the speed somewhere along the limits that produce a consistent sizzle and the desired amount of heat. The voltage has to match or move in step with the wire speed to produce a good arc. Try a test bead with one hand on the speed control and vary it as you run a bead. Experiment and find a good wire speed for the voltage setting.

Mon Nov 03, 2014 9:33 pm

Yeah ya just gotta play with it.

If the wire is burning back then you have too many volts and not enough wire speed.

I don't like the arc so short it almost stubs out. Having the arc a little longer seems to smooth the bead out.

You can crank the volts up to weld thick metal but ya gotta have the wire speed up too. I use a respirator with hepa filters btw because its smokey.

Your stick out had alot to so with voltage too. Longer stick out decreases volts, can even be to the point that the wire hits the puddle because the volts are so low. I've read threads where people say the opposite but they're incorrect. The voltage is sent through the liner to the contact tip. If you increase the stick out the extra wire has resistance so the voltage at the puddle is less.

The biggest problem I see with welders is having the machine properly set up. The company I work for flew up some guys that can't set thier machines so they grind all thier welds.

Keep tinkering, you'll get it. Flux core is pretty amazing.

Oh and you have it set on straight polarity right (electrode neg)?

Tue Nov 04, 2014 2:34 pm

I just read the instructions to my camera so my welding should be improving. :lol: It has a lot of features and adjustments I was not aware of. :oops:

When I get some hyper weld pools I'll take a picture of the bead. My biggest problem with flux core is trying to see the pool around the white arc. :evil:

Tue Nov 04, 2014 4:18 pm

Yeah, that's a draw back to flux core, you don't see the molten pool clearly like you do with gas welding. Angle the torch slightly away from the weld (10-15 degrees) and move in the direction you are angled towards. "Drag with slag". Watch the edge of the weld where the wire is feeding into the pool and you are dragging the nozzle away from it. The view should be clearer than if you push the electrode and experience a larger pool of slag in front of it. Drag away from the pool.