Welder issues???

[drcoastline]

Hi all,

I joined some time ago but have not posted much. I have been reading and trying to learn MIG techniques.

I have a Lincoln 135 Gas welder. It has 4 heat settings A,B,C,D. A being the lowest. It also has infinite speed settings 1-10.

I have set the machine on heat setting B with a wire speed of 3-4 as the graph on the machine more or less states. I have wleded in several patch panels with what I believe are favorable results.

I have been practicing and welding on 20Ga. steel. The photo below is a patch panel on a car fender. The arrows show various welds. The Yellow arrows identify flux core welds I did many years ago. Some of those welds have failed and rusted which is what has prompted the new repairs. The blue arrows identify what I think are good welds with a nice even pool and good penetration. I did a few repairs prior to this piece and the welds looked very similar to those identified by the blue arrows.

I began this piece with a few quick tacks and then began at the blue arrows. After making the 5 wleds I moved to the lower right. Suddenly the welds seemd to be sitting on top with a slight pop and spatter. It seemed as though the wire wasnt feeding fast enough and the weld was cooling before it could penetrate. The welds identified by the red arrows do not penetrate and the line between the two pieces is clealry visible on the back side. I checked my hose for kinks and tried again. Same thing. I increased my wire speed slightly no better. If you look to the right side of the weld you can see I used a flapper disk to start to knock those welds down.

I then checked my gas flow. 150lbs. in the tank 20lb. @ the tip. Still no better.

I shut the welder down and turned the tank off. I cleaned the tip and checked the wire feed. After about 30 minutes I turned the tank back on ensured gas flow at the tip made sure the wire was moving through freely. I tried again. The weld was still sitting on top, the weld was popping and spattering. Top left and bottom left welds.

I switched to a scrap piece of steel and turned the heat to D I could not get the weld to burn through the scrap.

The purple arrow identifies my last attempt for the day. I put the welder back to the original settings and tried again. Now it is making a sizzling sound and the molten wire is pooling up into a bead on the end of the wire.

Are there any suggestions as to what is happening?

Thanks you in advance.

DRC

 

[shenion]

Sounds like a poor connection somewhere. Could be work lead.

otherwise, the welder may have blown a one or more of the rectifier diodes.

 

[drcoastline]

Thanks Scott,

I will check all the connections tomorrow. Where would I find the diodes and what do they look like. Is this a repair I can make?

 

[shenion]

The diodes will be on large aluminum plates in the welder. Usually from 4 to 16 of them.

They would need to be checked with a meter after the wires are disconnected.

 

[knoba]

Just a thought...

...occasionally, with older welder machines, when the user changes the torch angle (to make more welds from another position), the resulting re-positioning can produce tight radius’s in the torch lead. This can give the wire a harder route to travel through, impeding the wire speed slightly & making it's progress through the liner jumpy.

Try to keep the torch lead as straight & as unstressed as possible, by re-positioning the welding machine, for the location & position you are welding in, to ensure consistent results.

 

[drcoastline]

Thanks Knoba,

The welder is only a few months old. But your suggestion was one of my first thoughts. As it seemed to me the wire was binding. So I made sure the hose was staright. I am still not convinced that binding is not part of the problem.

Of course that does not explain why the wire is now sizzling at the tip and the molten metal is balling at the end of the wire.

 

[drcoastline]

Ok, I checked all connections. I think I had a bad ground (?) The clamp piece that attaches to the work. I checked all other connections that were required when I put the welder together and all looks to be ok.

I made a few welds on some scrap. The first thing I noticed is it is still making a sizzling sound, it also appears the wire is melting above the surface? Again creating a ball on the end of the wire. It aslo seems as if there is an arching before the wire contaects the surface. The good side is it appears that the weld is now making good penetration after about 3 to 4 seconds. Is this normal? It doesnt feel right but appears to be doing the job. I am concerned about heat build up and warping. There also appears to be more brown residue then before. Sorry for the blury photos.

I look forward to your opinions.

 

[shenion]

Wire speed may be a bit low. Too slow and the wire will burn back.

May be less than ideal gas coverage. Too low a torch angle or torch too far from work can cause issues.

 

[drcoastline]

Scott,

Can you expalin "less than ideal gas coverage"? and how do I correct that?

I will try increasing the wire speed and various tip angles to see what happens.

Thanks.

 

[shenion]

Gas flow should be 20CFH or 10LPM.

Too low a torch angle will cause air to be drawn in. Torch too far away will also diffuse the gas more. Should be 1/2" or so.

 

[Jackson]

I have a Linclon SP_135T and I don't know if this helps but a few times when I haven't welded for a while and I start it up I encountered the same problem. I added a little more tension on the wire feed roller and made sure the wire spool was turning almost free ( checked with my hand, not loose but not to tight). This seems to fix my problem.

 

[drcoastline]

Scott, Knoba and Jackson,

Thank you all for your input. I have gone through all of your suggestions. I am not sure which one or if it was a combination of all of your suggestions but my wleder is working again and producing welds with good penetration. In fact I may even say it is working a little bit better.

Thanks for your in put and helping me work thru this issue.

Regards.

Donovan