"New tip needed" symptoms?

[Kat M]

Hiya

Half the fun of learning to weld is in recognising what you need to do when something goes wrong.

I really haven't been at this long, either; still not finished the first 0.7kg of wire.

So, a few times yesterday, I pull the trigger, the wire moves, touches the work-piece and... nothing. When I have managed to get going it's sometimes "stuttered" mid-weld and once or twice just stopped dead with the wire stuck to the work. This is with nice clean shiny metal as well.

I hadn't the foggiest what was going on at the time and gave up for the day. It's literally only just dawned on me what the problem could be. Total newb, see... but wanting to learn

Time for a new tip? If I'm understanding things correctly, the only path for current to the wire is via the tip. If me orifice is getting a little mucky (ooh er!) I lose all me current and this would explain the symptoms above, yeah?

How long do the things last? (I suppose that might be an "it depends"...)

...and, being as I'm a complete cheapskate, provided t'orifice isn't worn, can they be cleaned out somehow? (I'm thinking "chemical" rather than "abrasive" as one wouldn't want to enlarge one's orifice, would one..?)

Cheers, Kat

 

[marknotgeorge]

I presume you've checked t'other end (as in the earth cable), and made sure that's on clean shiny metal, too?

If it is indeed an orificial problem, you can purchase new tips quite cheaply (£2-3 for 5) from various emporia, including the renowned Weldequip, who you will find on this very forum.

 

[Wozzaaah]

Doesn't sound like a worn tip Kat, if thre arc suddenly stops then it sounds like power is intermittent to the tip. It does sound like the wire stops feeding at the same time as the arc stops so it may be as simple as a faulty trigger switch in the torch or it may be something more serious. First thing to do is check all the connections you can, inside and out of the machine, make sure your return lead/clamp is in good order and that the clamp is nice and 'grippy'. A new clamp is only a few pounds and well worth renewing if it's one of those flimsy jobbies. Also, take the torch apart and check the connections, including the switch contacts (assuming you have a gas valve you should be able to take it apart and clean it).
The main cause of tip failure is wire burning back and sticking, once that happens only a replacement tip will sort it though they do wear out over time.

 

[Kat M]

Hmm... well, the machine's "hardly used" so I wouldn't expect loose connections but... you never know. I'll have a look.

I've pinched the earth clamp off the arc set I forgot I had. It's one of those chunky cast ones with a spring at least twice as strong as the pressed steel thing which came with the SIP. It was on shiny metal, there's now quite a bit of that on the car

Torch switch... it consists of a couple of bits of bent metal and would be what I'd describe, technically speaking, as "pants." I'll check that too. As replacing the torch is financially out of the question for now, I may devise a way of replacing the bits of bent metal with a decent microswitch.

The wire has been burning back and sticking (before I modified the wire-feed and fitted a steel liner), but not completely; I've been able to unstick it... hopefully it'll happen less often now.

Cheers, Kat

 

[runnach]

Another possibility Kat, you say you are still on your 1st spool of filler wire, even though it is copper coated, it can still corrode a tad (if you have had it a while), I fired up my wee 140amp mig a wee while back, achieved similar symptoms you describe, usual checks, finally opening up the side, good wire, bad wire ect, chucked on a brand new spool n bingo, prob solved!!

 

[malcolm]

New tips aren't expensive. I'm extravagent and buy them in bags of 10, together with a couple of new shrouds. Well worth sticking one on as a cheap first step when the welder starts playing up.

They can last a long time, but always a short time whenever someone else uses my welder. I do tend to put a new tip on afterwards. They can deform as well as enlarge, and occasionally the cheap ones don't even work out of the box.