Thin Metal Technique Wire Burning To Tip

[geoffsurf]

I don't know if I am right to call myself an intermediate welder but anyway I have a question that I think belongs in this section. I am working on a vehicle, welding using the pause thin metal method on my Sealey 185 Supermig. I am working with 1mm sheet and usually use setting 2 or 3 with the wire speed at around 5.

The problem is that even when I consider the welder set up right and the weld seems good the wire is sometimes burning back to the tip. I then have to use pliers and twist the torch so the wire eventually breaks away from the tip and pushes through the tip again.

This is becoming more and more annoying as although it usually happens on the first contact it can happen during the pause method welding which can then upset my method and joint. I have read that this is normally caused by too low a wire setting. However, I wondered if there is any exceptions to this particularly with the thin metal pause technique?

 

[Shedendman]

What position are you welding in?
What size wire 0.6 or 0.8?

 

[Exuptoy]

Could it be feed roller tension causing the wire to slip? I'm hardly ever up above 5 on my porta.

 

[Jim Davey]

Does the machine have a burnback timer? If so reduce the time (usually turning counter-clockwise does it)

 

[Shedendman]

Does the machine have a burnback timer? If so reduce the time (usually turning counter-clockwise does it)

i dont think that machine does,i know the newer ones have a spot weld timer,i was going to go with @Exuptoy and say the tensioner might be a bit slack but saying that when i use 0.6(and not very often) i give it an extra pinch on the screw and up the speed a tadge, thats on my machine of course

 

[Jim Davey]

Some cheap machines don't have a good burnback characteristic and the only way to counteract the melting back is to pull the torch away from the job slightly as you release the trigger.

 

[geoffsurf]

I don't know if it helps to explain things but when it happens it is almost like the wire makes contact and explodes back to the tip very quickly, it is not like a slow burn to the tip.

I am using 0.8mm wire and the machine doesn't have any burnback timer (I didn't even know there was such a thing). I don't know exactly what you mean by welding position but I am currently just using the torch on top of a horizontal panel and the shroud on the torch is at an angle so if the rim of the shroud touched the panel it would not seal against the metal.

I have the wire feed tensioner set pretty much okay, it doesn't seem to be slipping at all in normal conditions, only when the wire melts to the tip and the wire is stuck. I could try more turns but it doesn't feel like this is the issue. I have recently replaced the wire with good quality Lincoln Electric. I also sprayed some anti spatter spray today on the tip and shroud to see if that would help, it didn't really and the tip ended up looking black like the spray had burnt on it.

I thought it was actually possibly because my torch isn't close enough to the piece of metal. I know others have said keep it close but I think it also happens sometimes when the tip is close to the metal. It is clean metal and I just don't understand why it does it.

 

[Shedendman]

All i can suggest is wire speed not set right,ie up it a little or shorten your distance from the work piece,to long a stickout?

 

[Jim Davey]

Is the tip tightened up into the tip adaptor, they can sieze and cause all sorts of feed problems.

 

[anjum]

Check the wire is not rusty and the liner is clean, I was having the same problem with rusty wire which also contaminated the liner. Cut off all the rusty wire through, cleaned out the liner and no more problems.

 

[Exuptoy]

That should be best practice though, to remove the wire and store it in a dry environment everytime you finish working with it. Would spraying the coil with anti-spatter make any difference to the rusting of the wire when left in the machine. Does it have oil like properties? I've never looked at the properties of the stuff.

 

[EAZEE]

Sounds like too much power and not enough wire speed to me bud

 

[Jim Davey]

That should be best practice though, to remove the wire and store it in a dry environment everytime you finish working with it. Would spraying the coil with anti-spatter make any difference to the rusting of the wire when left in the machine. Does it have oil like properties? I've never looked at the properties of the stuff.

Argh! No, all that will do is attract dust and turn the inside of the liner into a sticky cludgy mess that will need throwing away after the first few weeks.
Dry, clean wire only, no oils or lubricants.

 

[geoffsurf]

I bought a new reel of good quality wire in the summer and it has been in there since then. I checked the wire before starting the other day and it didn't seem to have any surface rust. The tip is tight and seems okay.

I will try turning the wire speed up and see if that helps.

 

[james butler]

i have the same problem with my sealey supermig 150 and its really intermittent when it does it. i found making sure the tip is squeaky clean helps with a bit of tip dip to prevent build up which also led to it sticking.
it is really annoying when it does it as i would have mine set up perfectly for a job and would randomly just stick.
one more thing just check the wire passes through the tip OK, ive had a couple of tips that wouldn't let the wire through easily from new and they used to stick all the time.
i think likewise can happen with a really worn tip as well?

 

[mikejack]

my sealey has same problems at times . I usually find a spatter build up in the nozzle is shorting out to the tip ! I also run at 2/3 for 1mm but speed up at 7 !

 

[Turbo]

I have a sealey supermig 180 and had the same problem, here are my solutions.
When the wire sticks to the tip it often makes the hole smaller. Use a gas nozzle tip cleaner to clean the tip and slightly enlarge the hole.
http://www.ebay.co.uk/itm/like/2626...=9041111&device=c&campaignid=620865095&crdt=0
Use a tip dip wax instead of anti spatter spray, I've found it works a lot better.
http://www.thewelderswarehouse.com/Welding/Tip-Dip.html
But the most effective solution was to move the shroud out further meaning that the tip is recessed more, further from the weld pool so less chance of it sticking.

 

[geoffsurf]

Thanks for the advice on this. Sorry for the delay in reply, I don't think I currently have my notifications turned on to my email. With new wire in place, replacing the tip, cleaning the inside of the shroud well and also using some anti spatter spray it seems I'm having much less instances of the problem.

I will keep the above advice in mind though and if it starts becoming a problem again I will try the above products.

thanks