Thread: MIG gasless welding - wire sticking inside

Hi Lyle,

Are you running negative on the torch polarity nd positive on the job clamp? Also have you tried oversizing your tip by 0.1mm. For example if you are using a 0.8mm wire try using a 0.9mm tip

Regards
Pete

No, I think the workpiece clamp is negative and the torch positive (I'll have to have a look at the machine) but it is how it was supposed to be setup. The tip is for the 0.035"/.9mm wire. I have run a drill bit through it quite a few times so it is probably oversize by now.
Useing a bigger tip diameter will not affect the electrical contact of the wire to the torch?
You don't think it is wire feed speed and or voltage, or distance of the torch from the job????

Thanks for the hint.
Lyle.

Hi Lyle ,

For gasless you run postive on the job and negative on the wire, the heat is therefore biased to the job, for gas it is the opposite. A slightly oversize hole won't matter but if it is too big it may reduce the friction and therefore conductivity between tip and wire.

Occasional burn back, if that is what is occuring, is caused by irregularity in wire feed rate. A balanced setup should maintain a steady feed after the initial arc is struck as the MIG should be voltage sensing and adjusting speed slightly to maintain arc length. If the feed drops off for a split second then the wire will burn back to the tip.

Also check the brake on the wire spool is not too tight or else creating irregular drag on the spool as it unwinds as this too can create a slow down in feed rate on lower small feed mechanisms.

Have you seen a pattern when this occurs? For example, does it occur after you shorten the radius of the torch itself? Are you perhaps running too long a torch?

Regards
Pete

HI,
I agree with inverter_weld. I use a Knurled 'V' Roller when I am using Gasless Wire. The Wire size I use is 0.9mm and I prefer to use a 1.0mm Contact Tip to help prevent jam ups due to the knurl marks on the wire. I would also be looking at the Tightness / looseness of the Wire Feed Rollers ( I just seen You have already checked the Tension). What Feed Rollers are You using 'U' are for Aluminium, 'V' are for Steel and Knurled rollers are for Gasless Wire. A 'V' Roller can be used for Gasless Wire as well.
Are You Welding in the Right Direction ?. When using Gasless Wire with a Mig Welder You Drag the Mig Gun like You do when You are using a Stick Arc Welder. When You're Welding with Gas Wire (Shielded with a Gas) You Push the the Mig Gun.
I hope we've been of Help to You.

Wow, seems there are so many things I'm doing wrong
I have been pushing the torch when welding. That is what I was taught at TAFE, but that was for a gas setup.
Haven't checked the rollers, but they were as on the machine when I got it.
Will recheck the wire tension and brake setup.

At least I have stopped blowing holes in the steel now.

I have some more welding to do on the weekend when I get some more steel delivered.

Thanks heaps for your help. Greatly appreciated.
I'll try and post some pictures of the wood storage rack when finished.

Lyle.

Lyle,
When you say it sticks "after a longish weld" do you mean when you try to start the next weld the wire is stuck to the tip?
If so your burn back time maybe to long or you are holding the tip to close to the weld. If you don't have burn back adjustment try lifting the touch as you let go of the trigger or holding the tip further away.
(coming from a guy thats never used a gasless mig, maybe things have changed in these new fangled welders)
Stuart

I think the main problems were, in no particular order pushing the gun instead of dragging, wire feed too slow and voltage too high.
I think what was happening was the wire was burning back up into the nozzle tip.

I have lowered the voltage and increased the wire speed a bit and am trying to improve my technique for the nozzle distance to the weld pool and the angles etc.

I've still a way to go. But the wood storage rack has been finished and hasn't collapsed under the weight.

Thanks for the tips

With flux-core wire I both push and pull with identical results - the choice is a matter of ergonomics for the particular weld. I suspect the main issue would be polarity - DCEN is the go for flux-core, the opposite for gas.

Originally Posted by Lyle

I think what was happening was the wire was burning back up into the nozzle tip.

What I should have asked is "Is it sticking while you have the trigger pulled or far you let it go?"
If its sticking will you have the trigger pulled its not burn back time.

Stuart

P.s. for those who may not know what burn back time is. Its the time the current is kept on after the trigger is released. The wirefeed is switched off but takes a little while to stop. If you switch the current off at the same time as the wirefeed the wire will be connected to the weld. If the burn back time is to long, the wire burns back to the tip and welds to it. Not all small welds have an adjustment on the front panel.