Weld porosity HELP... Options

[ONTHEGRIND]

So I have a Lincoln hd 3200 mig that hasn't been used in a year or so.. I went and got a bottle filled last week argon co2 mix using solid .025 wire with the correct brand new tip welded on brand new steel tried the l/min from very low to very high always welds the same. I can here gas exiting the gun ground is clean here is a photo of what im working with.. The welds are very black be a wire brush on a die grinder makes a pass over them..

The top weld is c 5 settting what it recommends bottom is b5

(IMG:http://www.914world.com/bbs2/uploads_offsite/img.photobucket.com-9738-1387250279.1.jpg)

[Jeff Hail]

Oh boy! So much for aiming for a stack of dimes!

I can sense your frustration from here. Works on 16 gauge but not this - so its not a gas flow issue. I doubt you got a slugged bottle. You would not know it anyways until you used up most of the shielding gas then it would get funky - not when its full.

Unplug the unit and pull the cover completely off so you can get to the back of the drive motor. Check all the terminal connections to the drive motor and remove them one at a time. I think they are spade connectors on this unit so squeeze them with a pliers and reconnect them. Give it a try. The welds in the picture do not appear to be a wire speed problem but simple diagnostics cant hurt. While you are in there check the hose to the gas solenoid and the one out to the gun. Make sure they are not leaking.

If that doesn't solve your problem check all the connectors on the heat setting switch. Pull each one, squeeze the crimp and reconnect.

Few questions: Is the gun head getting hotter than what would seem normal? If so check the wire liner to make sure its tight at the connector where the spool feeds into it. I think this unit has an allen set screw -make sure its tight and the brass nipple on the end of the liner is seated correctly all the way in. There is an o-ring on the brass nipple, make sure its not rotted away and sealing correctly. You can cut the wire and blow the liner out while you are in there -wont hurt.

Check the drive wheel orientation. Make sure the groove is in the correct position for the wire size you are using. Does the wire speed stay the same when you turn the speed control up? Tighten up the tension so when you feed out wire from the gun a few inches off the ground it should not slip. It should curl when the wire hits the ground.

With the unit on troubleshoot the wire speed potentiometer, turn it all the way down. Squeeze and hold the gun trigger, as you turn the wire speed up does the drive motor speed up. You should hear it wind up faster. The wire should run out faster as the motor speeds up. If the drive motor does not speed up the potentiometer is bad or has a loose connection - try crimping the connectors tight on this also. Worse case the PWM controller on the board took a dump but that is the last thing to check since failure is rare on the smaller Lincolns.

As far as gas flow a CFH gauge will work fine it that is all you have.
Rule of thumb on the flow by nozzle size with trigger depressed is:

Nozzle inside diameter - 3/8 inch -Minimum flow 15, typical 18 to 22, 30 max

1/2 inch -Minimum flow 18, typical 22 to 27, 40 max


If the nozzle is 5/8 I.D or bigger its too large for thin sheet metal and a waste of shielding gas. Try to use a conical shaped nozzle.


Let us know when you have chance to report.