Ok, Mig welding sanity check....

   / Ok, Mig welding sanity check.... #11  
Esab makes a flow meter that goes on the nozzle to check gas flow at the arc but they cost about $30. There's a very slight possibility that the gas solenoid on the machine is malfunctioning and/or leaking. Being the liner was damaged, it sounds like the problem is in the gun cable. It would help to know what machine it is.
 
   / Ok, Mig welding sanity check.... #12  
What the others have said, you can for sure hear the gas at 20cfm ,could you ask your dealer to swap out your gun to check and see if that solves it, also check the connection at the machine may be leaking at the seal
 
   / Ok, Mig welding sanity check....
  • Thread Starter
#13  
Ok, did some more testing a few hours ago. First I pulled the replacement liner and blew out the gun cable with compressed air, nothing came out, it was clean. I hooked the linerless gun cable to the machine, turned on the gas and checked for flow, it was good. Re-installed the liner, and the tip (no wire in the liner) checked for flow, good again. Fed the wire into the liner and figured I'd do a few test welds, here are the results.

IMAG0108.jpg

A multi pass fillet weld done last weekend without porousity problems (yes I know its very ugly)

IMAG0107.jpg

Single fillet weld done last weekend with out porousity (yes I know its very ugly)

IMAG0106.jpg

Lap weld done today done a few hours ago, porousity at start (left side) smoothed out at the end.

IMAG0105.jpg

fillet weld that started alright but got nasty for the remaining 2/3rds.

IMAG0104.jpg

fillet weld, 2 starts, both started ok, then got nasty at the end.

Definately leaning towards the gun cable here, I did a leak down test on the hose and reg. Turned off the unit, without bleeding down the pressure and watched to see if it lost pressure over 15 minutes or so, no noticeable leaks (at least up to the machine solonoid.

For those that asked, I have not posted a machine brand because I dont want the manufacutrer to get a bad rap for a mistake I might be making. The machine is under warranty so I will take it up with them once I have a consensus that its not something I am doing wrong. Thanks again for the input and help.

Chris.


Chris.
 
   / Ok, Mig welding sanity check.... #14  
Something for sure is not right, it looks like you are running out of gas coverage You are sure the cable is hooked up right in the cabinet make sure its not set up for fc wire but if you have some fc wire try it that would eliminate if its the machine or not. Also grind your joints to a bright finish before trying to weld them. see if that helps .If its a hobart mabye some millers put the control on purge and try to see if the gas coming out is consistant; purge will not let wire feed, also make surre theres no oil or anythig like that around they area of the weld.
 
   / Ok, Mig welding sanity check.... #15  
Honestly, I think it looks like you are varying your gun height, and angle and not readjusting as you travel (or readjusting to correct as the case may be). It's going to be one of the 2 oar 3 import brands here. It could be a cup size issue. All units have issues...but some have charachteristics that lend themselves to checking certain things before checking others. Without a knowledge of which brand it is, it is hard to say exactly.


The other main issue you have is the total lack of metal prep. Contaminated metal alone can cause porosity.
 
   / Ok, Mig welding sanity check.... #16  
It could be a pinched hose or some other gas flow problem, but I kinda agree with mark here that your joint is not prepped. Oil or other surface contaminants can cause porosity just like that.

Try it again with proper joint prep (a grinder is your friend) and see if your results improve.
 
   / Ok, Mig welding sanity check....
  • Thread Starter
#17  
Ok, been testing for the better part of 2 hours and have found the problem. Let me start by saying I started out trying the same setup as described before but with metal ground clean and shiny and had the same result, randomly porous welds.

To back up a bit, this all started with a kinked liner. There was some impact on the hose, likely in shipping or assembly, that caused the original liner to be kinked and was causing random wire feed issues. Me being gung ho to continue my project I went to the LWS and purchased a Binzel liner because I had been told it was an equivalent to the Trafimet liner (not by the manufacturer of the unit btw, shame on me for not checking). The only place I could find Trafimet liners was on European web sites. Anyway, the Binzel liner was a drop in for the Trafimet with one distinct difference, the Trafimet liner has a heat shrink tubing of sorts from the wire feed end up to within a foot or so of the gun. And it dawned on me, that was likely to direct the gas up to the gun end and not let it seep between the liner coils and out the feed end of the gun cable.

So in with the old liner, and back to beautiful?!?! non pourous welds. Gas flow was much improved, I could feel it flowing when I tested before but it was now much greater now that the original (and correct) liner was back in.

Problem solved, I am an idiot

Chris.
 
   / Ok, Mig welding sanity check....
  • Thread Starter
#19  
Another multi pass weld with the correct liner...

IMAG0109.jpg
 
 
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