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 The inside of the cable has a liner which should be withdrawn regularly to clean it and inspect it for cleanliness and kinks.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
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