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Grahame Collins
23rd Jan 2008, 10:31 PM
Hi Everyone
Given that talk about migs and mig torches has been raised on the forum I thought it timely to offer some useful info on tuning up your mig .

If a mig is going to fail or at least suffer a problem ,you can be 99.5% sure that the problem will be mechanical.
Use this as a basis to solve most problems .

Any mig to run needs to feed the wire from the spool to the arc SMOOTHLY. Amperage setting is relative the wire speed-more speed –the more amps. Lets look at things which slow down or impede the travel of the wire. We will start at the spool.

1. The spool should be equipped with a spring, one which places just enough friction on spool spindle to prevent spool over roll once you release the trigger. Some times this spring is wound way too tight by those who would twiddle with such things without knowing the effect. The effect is to bind up the roll and make for weird happenings at the arc. Your judgment is required to work out, how tight the spring setting needs to be.

2. Next to examine is the inboard side wire guide,- it’s a little sleeve that fits over the wire- between the spool and wire rolls. The wire guide serves a very good purpose in aligning the wire with the little groove in the wire rolls. You are looking for the wire to run straight into the groove in the bottom roller at the same time when the upper one is released. If you have not got a wire guide ,we will deal with this later down the page.

3. Make sure that the rolls are aligned with the wire as above. Some rolls are double sided with 2 sets of grooves for different diameter wires. Of course check if your running .8 mm wire that the rolls are marked .8mm as well. Wire rolls can be set at the correct tension by following this procedure. Grip the wire between your thumb and forefinger in an area between the spool and rolls. Set the rolls tension with your other hand. Get someone else to pull the torch trigger (put the earth return clamp out the way for obvious reasons) You should be just able to make the rolls slip by hanging onto the wire. If the wire does not slip loosen the tension a bit more, and so on until you are satisfied that the wire just slips under thumb and finger tension.

4. The other side of the wire rolls there is sometimes another wire guide to the torch cable end. The inside of the cable has a liner which should be withdrawn regularly to clean it and inspect it for cleanliness and kinks. Different torches come apart in different ways so I’m sorry ,you have to read the instructions. Most wire liners are like café curtain spring wire or Teflon tube for aluminium Once you get the liner out run it through your fingers from one end to the other. If there is a kink you will feel before you see it. Rolled up liners can be cleaned by swishing around in a bit of kero in the bottom of a 20 litre bucket. Thoughtfully dispose of the kero and then repeat the treatment with metho.Liners can be replaced if kinked and the off cut can be used as a wire guide as in paragraph 2

5. Check your gas diffuser( the bit the contact tip fits into) for arc and spatters. Check your insulator is not worn as it can suck in oxygen if loose. Don’t forget to change your contact tip once in a while –they wear and don’t transfer current efficiently when worn. The shroud should be set about level with the contact tip. If your shielding gas line has any O rings it is wise to check those on a regular basis as well.

Other pro welders are encouraged to chip in ,I am bound to have forgotten something.

Happy migging

Grahame

Vernonv
24th Jan 2008, 11:08 AM
There's some great info there Grahame.

I'm currently having a wire feed problem with my Kemppi MIG. It seems to have occurred since finishing the spool of wire that was in there (unknown brand - got with the MIG) and changing to a new one (CIG brand).

I get erratic feed (where the wire sticks and the rollers slip) or if I up the tension, I get wire kinking and feeding out the side of the welder:((.

I have a feeling that it's either an issue with the liner or that the wire is "sticking" to the contact tip when it arcs (or maybe a combination of both:?). Ive replaced the contact tip and it didn't seem to fix it. It's getting very frustrating:C.

I will try and find some time with weekend to have a good look at the points you've raised and hopefully I can get it sorted.:2tsup:

Dean
24th Jan 2008, 12:36 PM
awesome info thanks

Cliff Rogers
24th Jan 2008, 01:08 PM
'tis worth adding a link to this thread on MIG selection (http://www.woodworkforums.ubeaut.com.au/showthread.php?t=25774)as a reminder.

Also this one on current set up for you MIG (http://www.woodworkforums.com/showthread.php?t=33549).

And there are lots of good links in the thread on Novice Welding Question (http://www.woodworkforums.com/showthread.php?t=54116).

Thanks Grahame. :2tsup:

pipeclay
24th Jan 2008, 02:02 PM
ernon sounds like you need to change your liner.

Grahame Collins
24th Jan 2008, 02:26 PM
Hi Vernon.

I suspect the wire may have surface rust on your spool of wire . Usually what happens is that the rust occurs on the upper surface of the roll after it sits unused for a time.

When the welder is used next, as the roll is fed through the rolls it alternately slips and then grips on the rolls.
Wipe a balled up tissue over the roll surface .You will see if its rusty. If it is turf it and get a new one.After it is used, store it in a plastic garbage bag with some moisture absorbent salts (can't think of the name - they come with my blood pressure tablets)

It also deposits the loose rust and crud inside the liner.The cleaning process as described earlier works well and will be ok for all but the very worst of examples.Liners for the Kemppi are available without too much trouble.

Go over the tightening of the roll procedure carefully. Most wire snarls around the rolls are caused by bad, wire /roll alignment, poor infeed ,rolls tension too tight wrong rolls groove size.

Don't forget to shout yourself a new contact tip.

Hope it helps

Grahame

Vernonv
24th Jan 2008, 04:56 PM
Thanks Guys.
As I said I will open it all up on the w/e and give it a good going over. I've been absolutely flat out over the last 6 months and haven't managed to find the time to really sit down and properly investigate the problem.
So I'll keep everyones comments in mind as I strip it down and give it a good clean and inspection.:2tsup:

Vernonv
28th Jan 2008, 09:14 PM
Well I finally got a chance to have a good look at my MIG. Using Grahame's info as I guide, I cleaned out the liner.

I used turps instead of kero (I didn't have any kero) and used a 20ml syringe to push turps through the liner. I was amazed at the gunk that came out:oo:. It turned the turps black. I continued squirting turps down the liner until it cam out clear.

I then did the same thing with the metho, allowed it to soak for a bit, then dry, before reinstalling it.

Prior to re-threading the MIG wire I check the condition of the drive and idler rollers. They were both fine and alignment was spot on.

I then fed the the wire and noticed that it was still "sticking" every now and then, so I had a closer look as the spool tensioner. I played around with the tensioner, but even fully unwound, it didn't seem the ease the sticking.

I removed and refitted the spool and then suddenly it all seemed to work fine:?. I think that the spool might not have been fitted quite right and was binding as it turned.

Anyway, it working fine now, so I'm happy :D ... just need to find something that need welding.

Grahame Collins
28th Jan 2008, 10:09 PM
I have just had some thoughts triggered by Vernons post.Yes! another rush of sh_t to the brain.

Intermittent slippage can be caused by rust on the top half of the spool as it sits stationary for a long period of time and the atmosphere gets to it-ergo it rusts.
The wire feeds nicely on the unaffected bottom half and fits and starts and slips on the rusty top half and so on it goes.

Rust is really noticeable when you happen to live close to the sea or in a humid climate. Before you race out and dump the spool of affected wire, you might try running it out and attaching a fairly big weight to the end of the wire.

Take out enough turns out to strip off the top layer of wire. If it is really rusty just cut it off and dump that bit.

Running out the wire also check that the spool is not choking itself.That is to say that one wrap of wire has not gone UNDER another layer.

It's something that happens at times when you inadvertently let go of the unrestrained cut off end of wire before you manage to feed it through the rolls. When you get it sorted sometimes one lay of the wrap has gone under another. It can be deceiving and allows quite a few turns before the bast---d strangles itself.

The reason for the weight is that its a way to to keep tension on the wire while you re spool and feed it evenly onto the reel.
At the same time use a clean piece of steel wool between finger and thumb to clean off the light rust.The rust is what makes the rolls slip on one half of a spool revolution and the other grips because the rust was only on one surface.
Those problems can be frustrating for the new fellas to mig work to diagnose and sort out.

Don't forget when all is clean and works smick to store it in a garbage bag with some desiccant- (now I remember that word)

To cap off then you are :


Checking for strangled wire.
Cleaning off loose rust.
Re spooling the wire for even feed.
Storing with dessicant in a garbage bag for long periods of non use.


Grahame

Andy Mac
29th Jan 2008, 10:56 AM
Good thread as usual Grahame.:)
Further to Vernon's troubles, have you made sure the wire diameter is the same as the original spool, in that it matches the roller, the liner and the tip?

Cheers

Vernonv
29th Jan 2008, 11:22 AM
Well I definitely purchased 0.6mm wire from BOC (not CIG as I originally said:-) and am using the same liner, rollers and tip as the old wire. Having said that, I will double check the new wire thickness with the micrometer when I get a chance (just in case).

Note that the welder is a Kemppi Trigger 1000 that is specifically setup/designed to run 0.6mm wire (i.e. it won't run any other size - not successfully anyway).

So I think the problem was a combination of the misaligned/incorrectly fitted spool and the gunked up liner - but I will double check wire size.

Riley
15th Feb 2008, 01:44 PM
Particularity with ally but also thin steel wire : Keep your lead straight , don't stand on it and ideally elevate your feeder above you. These will help you get a consistent feed rate and cut down on birds nests, The feeders do well especially when you consider its like pushing string ,so give it all the help you can.

Nozzle gel is good to inhibit splatter build up, (spray on cooking oil is heaps cheaper than anti splatter and works well)

As Grahame said look after your contact tips,take them off and regularly ream out the hole. Whilst there are files for them I prefer a "Pin Vice" like shown here:
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=270211103001&ssPageName=MERCOSI_VI_ROSI_PR4_PCN_BIX_Stores&refitem=250213007237&itemcount=4&refwidgetloc=closed_view_item&refwidgettype=osi_widget&_trksid=p284.m185&_trkparms=algo%3DSI%26its%3DI%26itu%3DCR%252BUCI%26otn%3D4%26ps%3D42
and small diameter drill bits ,
your hole is usually about 0.1mm bigger than your wire. Ie if your using 1.0mm wire use a 1.1mm drill bit .
Whilst some machines wont take different diameter wire most will , obviously use what wire is appropriate but endeavor to utilize the thickness wire you can as its easier to live with and behaves better.

Wombat2
17th Feb 2008, 10:32 PM
I read somewhere about tieing a loose loop of toweling cloth about an inch wide around the wire before it goes into the rollers to wipe any dirt off and keep everything clean - anyone do that ?

Grahame Collins
17th Feb 2008, 11:43 PM
Wombat 2
After the rollers, is usually the go, as it gets messy if the cleaning medium comes adrift and heads under the rollers.

As well as that, a professional fix is industrial felt is used held by a clip or for you cheap rses a roll up type ear plug with a cut length ways held in position by a peg.

This slows down the interval that the liner shall need removal for cleaning.

For humid crappy weather like you have now in some parts,slip a garbo bag over the spool to stop spot rust when not using your mig.

Grahame