Changing tips

[Stegel]

Hi. First try at MIG welding today and I could do with some advice please. Using an Oxford 240, Argoshield Light, with a Binzel torch. First few goes on 1mm steel went surprisingly well, but then thought I'd try 3mm angle. I'll admit to getting the coarse and fine power adjustment knobs mixed up with the result I managed to get such blobby welds that I blocked the tip of the gun. Unscrewing the tip was difficult, I guess because the wire was welded to the nozzle, and the second time was so difficult I then couldn't insert the new nozzle as the adaptor thread was damaged. So, no more welding until an order of new adaptors arrive.

How do I prevent this happening again (or am I just being clumsy?). Should I file the tip down to release the wire before removing the tip? I hope as I improve, and now I know which knob is which, it won't be such an issue!

Many thanks in advance.

 

[123hotchef]

get some tip dip! cant you nip it off flush with some cutters then unscrew the tip

 

[Sparkey]

Helllooo and welcome to the forums
With the adapter you mean the gas diffuser right? What type of binzel torch issit?
First things first....was your tip sticking out of the shroud or not? And yes normally it's best to remove the blobs before trying to unscrew the tip (i never leave without a small pair of cutting pliers, quite handy for that)
Do you have any pics of your torch and welder? We looooove pics here on the forum! Makes it easier to give you some tips about your setup etc.
Sparks

 

[Stegel]

Hi, and many thanks for the prompt replies - the torch is an MB25, and yes I suppose I do mean the diffuser! The first time I unscrewed it, the diffuser came off with the tip, but I screwed the former in a little tighter so the tip alone unscrewed next time. I have some welding pliers but it was not possible to snip off the blobs, and I could feel it fighting the wire as I unscrewed it.

The tip does protrude beyond the shroud - everything is standard and tightened up / pushed on fully home.

I'll get some tip dip (didn't know it existed - as with most new hobbies, a learning and spending opportunity!) and try not to repeat my errors. I'll post some pics up next week when the diffusers arrive - the set-up is in the naughty corner of the garage at present, although really it's my wrong-doing!

 

[Sparkey]

MB25 ok, normally your tip has to be inside the shroud...i know there are other members on here who like to use it when the tip comes out of the shroud but for normal use i would say keep the tip inside the shroud. The main reason for that imho is to prevent this kind of trouble. So maybe you should get a new shroud as well...how does it look?

 

[Stegel]

The shroud looks a little worse for wear, but has cleaned up ok. I bought the welder via Tom Orrow and he threw some shrouds in, so I can change it easily - I presume I just don't push it fully on, but leave it projecting flush with the tip? The advice is much appreciated - I gas welded on several cars 35 years ago, and got reasonably good at it, but I'm having to acquire a new skill-set after many years absence!

 

[norlander]

Get some MIG pliers, and some tip dip. Pull the trigger to advance the wire if you can before removing the tip, if its really stuck, try to free it with the edge of a coin. If no go, grab the wire before the wire feed, cut and make it fast, take off the shroud on the torch, unscrew the tip and pull the wire through, fit a new tip and refeed wire.Shrouds come off and go on clockwise normally.
You should know where your knob is by now at your age, but in regards to the machine, there might be a settings chart on it. If not,
The coarse knob will give you the main juice for the material, on a 240, maybe set that tween 7 and 9 o clock to start with, fine setting, 3 o clock maybe (I'm totally guessing here, never seen an Oxford MIG).
Then set your wire speed on a piece of scrap and see what you get-and, make sure, that you have a good contact for the return/earth/ground or you are urinating into the wind.
Nice kit the Oxfords, learnt on oil cooled Oxfords in my yoof, totally brilliant kit.
Good luck, someone with an Oxford will probly be along to put you right on the settings.
Get the tip inside the shroud, to start with, you might have a cut back shroud.

 

[Stegel]

Thanks for that advice - it was well and truly welded to the tip, so the idea of cutting it off at the feeder seems a sensible move.

Knobs - indeed, old enough to know, not old enough to have forgotten. There's a two setting course switch and a six setting fine - completely accidentally (eyesight / inattention) I was welding 3mm angle at the full 240 amps!! I was welding 1mm at 1+1, for 3mm I'll go for 1+2 / 1+3.

 

[Sparkey]

Thanks for that advice - it was well and truly welded to the tip, so the idea of cutting it off at the feeder seems a sensible move.

Knobs - indeed, old enough to know, not old enough to have forgotten. There's a two setting course switch and a six setting fine - completely accidentally (eyesight / inattention) I was welding 3mm angle at the full 240 amps!! I was welding 1mm at 1+1, for 3mm I'll go for 1+2 / 1+3.

Haha yeah 240 amps + the tip sticking out = a mess! Looking forward to see some of your welding
Sparks

 

[WorkshopChris]

I have some welding pliers but it was not possible to snip off the blobs, and I could feel it fighting the wire as I unscrewed it.

If you can't cut the blob in the future you basically have two options:-
1, Remove the shroud so you can hold the tip on the corner of the vise jaws and file the blob until you are back to the copper, normally the wire pings and pokes out the end as it releases.
or
2, Open the cover release the wire tension, cut the wire, then remove the tip complete with the wire from inside the torch., replace with new and start again.

If you try to unscrew the tip with the wire attached as you found it gets tighter as the wire twist inside the torch, then if you replace with a new tip if you don't remove any twisted wire or the section that might of been damaged as it pulled through the feed roller it may jam in your new tip.

Luckily its something that only occasionally happens if the wire burns back as a empty reel runs out.

 

[Stegel]

Thanks for all the advice - diffusers, tips and tip dip arrived this week, and I reflected on last week's performance.

A few practice welds on sheet this morning, and then on with the dog cage - new (additional) dog means a twin cage required!

First few real welds rather than practice; the last one is a box section, not as neat as the angle iron welds, but rather pleased as my mitre cutting was not that accurate for the bend so I had to make up some material with weld.