Brandon Dixon wrote:
>
> These are all very good points, and I'll add one more idea that I thought
> that some of the more experienced TIGers would suggest: It sounded to me
> like you were welding on sheet metal on a vehicle. It is quite possible to
> get contamination of the weld pool from the BACK side of the metal. Any oil
> or grease or undercoat, etc back there can mess things up big time.
This truck has some serious corrosion. I don't expect to be able to
weld over
rust so I grind it clean. But I suspect that I may be running into
contaminants
that are below the consmetically clean surface. If the weld puddle is
as
sensitive to oxidation as Bill says, it sounds like a definite
possibility
is contamination and it may be my welding technique that is bringing it
in.
Insufficient preparation could be a contributing factor as well.
Thanks to all who are contributing to this discussion. There's a lot of
variables to consider in this process and they're not all installed in
my
head yet.
Steve Shipley
>
> Brandon Dixon
>
> -----Original Message-----
> From: Bill Ruof [mailto:1953xk@home.com]
> Sent: Thursday, July 27, 2000 8:22 AM
> To: Steven Shipley; shop-talk@autox.team.net
> Subject: Re: Question about TIG
>
> I have to add my two cents.
>
> Spatter is little BB's of metal. If you are getting a buildup of small
> discrete balls of metal one possibility is that you are overcooking your
> weld pool. The arc and the weld pool should be very smooth. No sparks or
> flying metal.
>
> Take care not to contaminate the tungsten. Once you dip it in the weld pool
> or jam the filler against it you've contaminated it and you will start to
> get a buildup and degradation. Snapping off the contaminated part is OK but
> you still want to grind to shape it. It is best to grind with a freshly
> dressed wheel. Make sure you have a good point to start.
>
> Folks were also dead on the money about being sure that you are using the
> right filler. Gas fillers have LOTS of deoxidizers and result in an
> overactive weld pool if used for TIG welding. Trim your filler after a stop
> and make sure it stays under the gas shielding while you're welding. If you
> pull it out from the shielding while you're welding it will oxidize. When
> you run that oxidized metal in, you destabilize the pool and the arc.
>
> The base metal probably isn't the problem if it is ground to bright metal.
> You have to make sure to get out any pitting too.
>
> If all else fails recheck your gas lines and fittings to make sure you
> aren't drawing in any air along the way.
>
> Welding is SO much fun.
>
> Bill Ruof
>
> > I've encountered a problem. I keep seeing a build-up of spatter
> > that sticks to the electrode and the ceramic cup. As this spatter
> > builds up the arc becomes harder to control. I'm spending a lot of
> > time putting new points on the electrodes.
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