help with welding/welder problem

I have a 120v Lincoln Weldpack MIG welder that was giving me some trouble today and I am a bit stumped as to the cause of the problem.
The welder has 4 positions for voltage control and a potentiometer for wire speed. I am using 025 solid wire with 75/25 mix on 1/8" mild steel. I have been welding on this project (outdoors) for the past week and today I experienced a consistent problem that I can't seem to figure out the cause. I have been welding in globular transfer mode but now I seem to only be able to do a short transfer mode (at best). Nothing has changed, that I am aware of. But now I am getting ugly welds with constant balling of the electrode and sticking to the tip. It is as if the voltage has been lowered. I tried all my usual checks, gas (half tank), extension cord (the same one), settings (the same), dirty tip, nozzle, etc (all cleaned), dirty workpiece (cleaned), feed problem (nothing seems to be hindering feed), bad ground connection (reclamped). The vertical welds are causing the most problems, flat horizontal are better but still not as good as a day ago, or this morning. Today was the first really hot day this week, could this have some effect that I can't think of? thanks for all input, rick
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"semidemiurge" wrote: (clip) I have been welding on this project (outdoors) for the past week and today I experienced a consistent problem that I can't seem to figure out the cause. (clip) ^^^^^^^^^^^^^^^ Could there be a little breeze?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

It is not the breeze. I know the effects of the shielding gas being blown away and this is not that. thanks. rick
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The supply voltage could be lower because everyone is using their air conditioners.
Dan
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hi Rick, Here's everything you never really wanted to know about mig setup.
Id start (as i do with any welder that isnt mine) by checking your feed from end to end. Its part of the setup process i go through every time i change a roll of wire, or whenever i have a problem with my welder.
grab your gun, feed out 2" or 3" of wire. Now unscrew your tip. Slid it up and down the wire. How does it feel? any drag at all, or silky smooth? if there is any drag, change it. If you constantly have tip problems, dont be scared to step up to the next size (ie. 1.0mm tip on .9mm wire etc)
Tip ok? next thing is to check your liner. Leave the tip off. Lay out the gun/lead in a *straight* line from the welding machine, no kinks or bends. remove the gun from the welder. Is the gun permanently attached to the welder? then you'll have to get a bit imaginative. unscrew it if it doesnt look like too much trouble. If it does look like too much trouble, then release the spring locks on the roller(s) and grab hold of the bit of wire with your fingers. turn the roll of wire around a bit so youve got a bit of slack. Now try to push the wire in and out of your gun. How does it feel? can you easily slid the wire in and out? If yes, then you're doing pretty good. many liners have a small bit of drag to them. if you have a lot of trouble sliding it, then your liner is probably full of crud. take the gun off the welder, pull the wire out and blow out the liner with compressed air. You do this once a week anyway, right? If you still have problems then pull the liner out of the gun... any kinks in it? change for new. if you still cant clean it or get it to feed smooth then you'll have to rplace it. Many flux cored users have liner problems because of the dusty nature of this wire. The answer is to blow out your liner frequently, and buy a packet of 'wire wipers', these things attach to the wire before it enters the roller and remove most of the dust before it gets into the liner.
alright, now you've got a good tip and a free sliding liner.... time to check the tension on your roll of wire (not the feed rollers yet!) Not all welders have wire roll tension, but its handy if you do have it, especially on 4.5kg roll machines. Look at the spool where it goes onto the machine. imagine that the welder is working away and the spool is turning, feeding out wire... maybe quite fast. When you stop, if there is no tension on the spool then it might carry on turning just for a fraction of a second due to its own momentum. This isnt too bad if there's plenty of sidewall on the spool, but small rolls in particular usually fill that spool up right to the brim. when it carrys on a second, the wire can get enough slack in it that it slips off the spool. now when you start welding again, the wire starts wrapping itself around the spool holder and making a good old tangle of a mess. a minute later your welder jams up. You think you're out of wire, but have a look at the spool, and oh $%#@. All that lost wire.... If you have a spring with a tensioning nut on that spool holder, then that is your spool tensioner. You dont want much tension on it, in fact you want as little as possible. what you want though is for the spool to stop turning _as soon as_ you stop welding. you dont want it rolling on. check it by pulling your trigger for a second and letting go. or just roll the spool a bit with your hand. when this is adjusted with too little tension, you see the spool roll on a bit which gives some slack in the wire. next time you pull the trigger it starts really easy because it doesnt have to pull the spool, but a second later the slack is taken up, just like someone who doesnt really know how to tow a car, giving a 'jerk' to the spool and putting a sudden extra load on the rollers. but because there's no tension, the spool probaby skips ahead a bit, giving a little more slack in the line... etc etc. the end result is an unpleasant start, which can contribute to machine gunning. If your machine doesnt have a tensioner and you constantly have problems because of it then you can try making something up. how you do it depends on the nature of your machine.... some guys put springs in the 'axle', some guys make up special little wheels with springs on them, some guys just jam a bit of rag between the spool and the machine.
so you've sorted out your gun/liner problems, got your spool tension right _only now_ can you adjust your roller tension. roller tension is a critical adjustment on any welder, but its the *last* thing that should be adjusted, because it is affected by every other thing in the system. If you've got friction in your gun/liner then it has to push against that. too much tension on your spool, then it has to pull harder to get the wire going. Sadly though, roller tension is almost always the first thing that a welder adjusts when he has feed problems. A lot of guys crank down on that thing before they even check their tip. Ive seen guys start at a shop, go to their new workbay, and before they even try the welder or pickup the gun they open up that side cover and crank down the roller tension all the way! If your welder has been working fine, and you havent changed anything, then the roller tension should never need changing. If the wire is slipping then something else is causing it.... dont use the roller tension as a fix all because you're too lazy to find the real cause. With roller tension, you want as little as possible, but as much as necessary. The way i check it on solid wire is to pull the trigger, then with only your index finger and thumb, try to stop the wire from feeding through by holding it before it enters the rollers. If you cant stop that wire feeding through no matter how hard you squeeze it (with only your index finger and thumb) then you've got way too much tension! The end result of this is that you are squashing the wire and also wearing out your rollers prematurely. The wire becomes oval shaped instead of round, which effectively increases its diameter. This in turn causes problems in the tip and liner, which means..... you have to turn up your tension more to overcome that extra drag, which in turn squashes the wire more making it even more oval shaped which means.......
too little tension means that the rollers slip on the wire, chewing it out. this happens most often with small diameter wires at high speeds when starting, especially if you have a bit too much tension on your spool. the rollers have to suddenly get the wire moving from stopped to quite a high speed as well as overcome teh initial drag of the spool and the drag in the gun/liner. what happens is the rollers do a little 'burn out' on the wire every time you start. You can see it pretty easily on the wire. The fix, is to slow down your wire speed a bit, reduce your spool tension, increase your roller tension and ccheck your liner/tip. this is a cinstant problem for feeding aluminum wire, but we'll go into that some other time. To adjust your roller tension correctly, simply squeeze that wire with your thumb and index finger then adjust the tension so that you can only *just* stop it from feeding. if you can stop it easily then thats not really enough tension, but its close! another downside to too much tension is that when you have a problem in your tip/liner the rollers will just keep on feeding away. you want them to slip in this case, but with too much tension they just jam that wire right up the works which can destroy your liner, or sometimes kinks the wire betweeen the roller and liner then the wire starts wrapping round the rollers and tangling up there, gets caught in the drive gears etc etc... a real mess. adjusting tension on twin roller machines isnt any more tricky... They usually have numbers on the sping loaded tensioners to let you adjust them the same, but i start with just one roller, adjust it as for a single roller machine, then do the other one, also by itself. then put them both on, and turn them down an equal ammount until i get the 'just slipping with thumb and index' result that i want. twin roller machines need slightly less tension on the rollers than a single roller machine, but a good single roller machine can work just fine. Id take a good single roller machine over a bad twin roller machine any day of the week.
If you cant get your roller tension right, then you may have worn rollers, or the wrong size/type of roller. This is usually what happens with too much roller tension. the groove in the roller gets prematurely worn. there's no easy way to fix this.... new sets of rollers arent too expensive compared to the time you can waste messing around with them, so in this case i usually just get a new set of rollers. you'll be happy with them. if you have the wrong size of roller then most rollers have two grooves. on small machines, one groove is for 1.2mm wire and the other for 0.9. you change them by turning them around. on some small machines, one groove is smooth while the other is knurled. This limits you to one size of wire. The smooth groove is for solid wire while the knurled groove is for flux cored. dont use knurled on solids, or smooth on flux cored!! also, dont try using the wrong size roller on wires... you'll only make a mess of the rollers. Some machines use one knurled (drive side) plus one smooth (freewheeling side) for flux cored, while some machines (usually those with much bigger wires) use knurled both sides for flux cored. Setting roller tension on flux cored is a little bit more 'feely' than on solids due to the knurled rollers. You dont want the roller to ever slip, even if you squeeze it hard with your thumb and finger, but you definitely dont want too much tension which puts bad 'tracks' on the wire and really makes a mess with the dust in the liner. You can tell a lot by looking at the tracks on the wire... but basically you want as little tension as you can get away with here. turn it right down till it slips, then up until it doesnt slip. weld for a while, turn it down a bit if you can...
Diagnosing feed problems only needs a systematic approach, though to look at the average tradesmen in the production environment you'd think it was a high art. Start at the tip, then the liner, then spool tension, then roller tension. Thats all there is to it. If you find a problem in one area, work it out. if you still have feed problems after that, especially machine gunning, or melting tips/clod starts or wires burning back into the tip then you probably need to adjust your ramp up/burn back. Consistent welding starts with having a consistent welder. Its no use trying to adjust your gun technique to suit a welder that isnt feeding properly. Start with a consistent way of setting up your welder, then once you've got consistent gun technique welding is no longer a 'mystery'. If you're not getting the results you want, then its easy to work out what you need to change.
Shaun

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thanks for that. Good post.
Peter
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
semidemiurge wrote:

I would check the following:
1) Circuit breaker - Cycle your breaker on/off a few times. 2) Wire connected to breaker - The cycling of the power for brief times will thermally expand and shrink the connection. Periodically check and tighten the lug or screw. 3) Due the same for the outlet you are plugging your extension cord into. Ditto for the plug at the machine. 4) Check the connections inside the machine that connect to the gun and ground lead. These are often forgotten unless you switch between solid and flux core wires. 5) Replace your ground clamp. Most shipped with the small machines are under sized and prone to corrode. A decent ground clamp can be had for 10 to 20 bucks and save you a lot of hassles. 6) Make sure the fan inside your machine is running and clear of debris. The lack of cooling will shorten your duty cycle and lead to crappy welds fast.
Thats all I remember from the days of my small welder.
Good luck
Jim Vrzal Holiday,Fl.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.