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View Full Version : Odd Problem with my SP-175



KSky
08-23-2005, 11:48 AM
I moved up from a Lincoln SP-135 that I had for years and never had
any problems with, to a SP-175. It worked well for a while, but
now I cannot get a good bead with it. I am running solid wire and
C02/Argon mix. I get a lot of hissing and the bead balling up on the
wire. I have even had the wire ball up so bad it stuck to the tip.
Tried getting a new tank of gas, but it made no difference.

The bead it makes is pretty flat and shiny (not dull like I was out of
gas) and there is a lot of splatter.

Gas is set to 15lbs pressure and I can feel it blow out the tip, tried
various settings but it doesn't help. Pretty frustrating.

smithboy
08-23-2005, 01:02 PM
Sounds like you aren't getting good flow of gas from tip of the gun to workpiece. Hissing may mean turbulence or blockage and either means that your coverage is not uniform and maybe not complete. I'd check the gun consumables (diffuser, tip and the like) to see if there were any obvious problems like a piece of metal clogging up the works or damage from heat. How good is the flow at the end of the gun? Can you blow dry your hair with it or is it barely perceptible? I'd start by turning up the flow to get better coverage, so as to rule out a flow problem. If turning it up works better, you probably have a flow problem. If you are blowing a lot of gas and still not getting it done, it might be the gas (try another supplier). You probably also want to post to the general question forum, cause more folks read there and this sounds like a general problem not specific to lincoln welders.

Hammack_Welding
08-23-2005, 03:49 PM
just something else to check is the polarity. Make sure the cables are in the correct position. Is the wire feeing out at a steady rate or is it possible that it is feeding irratically? If so it could be a contact tip, or cable liner. Does the weld have porosity to it? (Pin holes) all thru the weld? I had a tig machine once that was acting funny, and we finally found out that there was an air leak somewhere in the regulator/line that was contaminating the shielding gas. it like to have run us crazy before we found it. Good luck, Jackson

smithboy
08-23-2005, 06:02 PM
That's a really good point, jackson. A hole in the liner under pressure could suck air right into the hose and blow it right on the weld. Contamination city. That might also explain the sound. KSKY, you might cover the end of the gun with something kinda air tight and run the gas purge to see if you can hear a leak. You might find a little burn hole or something that is sucking air. If you do tape it up and try to weld.

TEK
08-23-2005, 09:28 PM
KSky, welome!.. :waving: ........You should also check that you are not getting any binding in the liner by making sure that it's pretty straight when you weld. If the whip is tied in a knot you will get an erratic feed rate and THAT will make you crazy. Check too that the contact tip doesn't have a burr or a booger on the end of it. That will also cause inconsistant feed rates. If you were to grab the wire and pull the trigger at the same time youre pulling the wire you should feel a nice smooth feed, no dragging or scratchy feeling. I take a torch tip cleaner to mine on some occasionsjust to get some of the junk out of it. Dont waller it out, just make it smooth. Hope this helps. Good luck. :cool:

KSky
08-23-2005, 11:29 PM
Thanks for the hints. I tried cranking up the gas flow to as high as it would go and it seems to help, so maybe we are on the right track there. I have a friend with a Sp-175 and I am going to go over to his house and swap out parts and see if I can get it to weld right.
When I get it figured out I will post what it was.