Troubleshooting a mig welder

I periodically use a miller wire feed welder at work but lately it doesn't work so great.
I am not an ace welder by any means but usually I can weld something if I can
position the workpiece that doesn't embarase me.
We use .035 copper clad wire, a co2/argon mix for shield gas.
I don't get that frying bacon sound while welding but instead get a sound that makes me think the wire is burning up in flight if that makes sense. I've played with wire speed and voltage (yes, this thing has voltage instead of current markings).
I used another welder in another part of the shop and the difference was like night and day. I don't know where to start troubleshooting this thing. Ideas?
Wes
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Wes wrote in rec.crafts.metalworking on Mon, 11 Oct 2010 18:46:50 -0400:

Check the tip where the wire feeds out of the gun. It unscrews, and will need to be replaced from time to time. Then check the drive rollers that feed the wire from the spool. They can get gunked up, and cause poor feeding. Also, check your ground clamp and wire. If you don't have a good ground you won't get a good arc.
--

Dan H.
northshore MA.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Wes wrote:

First of all what make and model of welder? Can you watch the voltage as you are welding? A bad connection somewhere in the loop is a likely problem, but it could also be something internal in the welder itself. I would compare the voltage reading while you are welding with the other good working welder. You can feel is the wire is not feeding properly. I would look over the tip and make sure that the holes for the gas are open and there are no leaks in the feed system.
What does the weld itself look like? It could be possible that the gas you have is not what it should be. I've seen tanks filled or labeled wrong, it doesn't happen very often but it can happen.
John
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
My own thinking: to make good welds, you need to have a good technique (you already have it), correct voltage at all times, correct feed speed, and proper gas flow.
So. You already have a good technique and check the remaining factors.
Get your buddy to help.
1. Have him monitor voltage while welding 2. Have him monitor feed speed by watching the spool turn, to see if it feeds unevenly. 3. Stick a flowmeter in the gas line to see if the flow is consistent with what you want it to be.
Somewhere above you will probably find your answer. Check the liner too.
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 11 Oct 2010 20:57:45 -0500, Ignoramus23519

I would suspect slow feed, no gas or wrong gas, but in any case Ig's troubleshooting procedure looks right to me.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thanks. No gas would still let him "weld", but the weld would immediately be characteristically rusty looking (in addition to being bad). I welded with no gas just to test a bunch of welders for sale, that is how I know.
i
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 11 Oct 2010 23:37:02 -0500, Ignoramus23519

I do it every now and then when I forget to turn on the gas. But it doesn't sound right when I do that so I stop to see what's wrong.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Sorry for asking a question and not getting back with details. This week I've had days where I focused on one thing or another and had to stay with it all day to get it done.
I'm not getting signs of no shield gas, I know what that looks like, I get high welds no matter what I do. By high, I'm not getting penetration. This is a welder where I normally set wire speed to a certain number, voltage to another setting and generally weld away with minor tweaking.
The welder at the other end of shop is same model so I can do some comparasons like monitoring voltage during welding as suggested.
I'm only working 1/2 a day tomorrow and covering for another tech that will be out while convering my areas so I may not get back to the welder until next week.
Thanks to all for the various suggestions,
Wes
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

No shielding gas will give spongy black welds. A high profile means too cold. If you turn it up and it's still a high bead, something's wrong inside, or with the power level controller. Or circuit board. Or all. Sounds like time for a trip to the welder hospital.
Steve
Heart surgery pending? Read up and prepare. Learn how to care for a friend. http://cabgbypasssurgery.com
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Wes wrote in rec.crafts.metalworking on Thu, 14 Oct 2010 23:04:16 -0400:

Did you move this welder to another location in the building? A long run of marginal wiring might not supply enough power to the machine.
--

Dan H.
northshore MA.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I'll add that my Century can reverse the polarity. If yours can reverse, make sure it's correct.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Can you give a little better description of the sound, or what the wire is doing? Is it burning back to a globule on the end of the wire? Are you feeling the wire poking the base metal? The first is if the speed is too slow. The second too fast.
What do your finished welds look like? Do some on the flat and see if you can arrive at a happy medium. On most makes, there is a chart on the inside of the door that will give you some guidelines and parameters.
A problem with MIGs is the control board, that senses what the machine is doing while welding and makes adjustments. It also stops the machine if something gets too far out of kilter. This is one of the most common things electronically that can go wrong with it.
Other than that, how old is the liner? If very old, go to a .045 liner no matter what size wire you run, it can be oversized and not make a difference. Check the tip as stated by another poster. Check the rollers for looseness. Check the nut on the reel so it's not too tight. Several basic things, but once they are all okay, it's time to have it checked electronically by someone who knows.
My buddy just got his Miller fixed, and it was $250 for a new control board. Hope yours is something simpler.
Steve
Heart surgery pending? Read up and prepare. Learn how to care for a friend. http://cabgbypasssurgery.com
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

First of all...what is the brand and model?
Gunner
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.