[Lightning]

Hey, all,

I'm tigging up some home projects using some OLD 1/8" steel (like from the 60s or 70s) that was used in the frame of a travel trailer. Even when I grind off all the rust and dirt down to shiny metal, I find that I'm getting a lot of porosity in the weld, and the metal is bubbling like a volcano and spitting molten metal that sticks to my tungsten even when I don't dip it.

This happens so fast that it seems like I can't weld more than 10 seconds before I need to switch tungstens or grind, because the tungsten gets fouled and my arc starts wandering all around.

I suspect this is due to impurities and maybe a lot of sulfur in the old steel.

Somewhere I saw a Welding Tips and Tricks video where Jody recommended some kind of stainless filler for this kind of situation, I think he said it contained a lot of de-oxidizers that helped clean up the weld.

Does anyone remember which filler Jody recommended for this? Was it 309 ?

Thanks.

[cj737]

Switching filler wire probably won't resolve your dilemma. But 309 is useful for low grade carbon steel though it won't prevent contamination in the base metal from purging out while welding. You could preheat the base to help with out-gassing and then wipe with Acetone, then weld and see if that helps your situation.

Also, you should clean the backside of the metal. Being thin, the heat from welding will draw impurities through the base and to your welding surface.

[Farmwelding]

I feel like that thin of steel off of an old trailer isn't a good plan. Get some better she'll to practice tig on. I don't know where you live but I know here in Wisconsin, we drop enough salt on our roads to make a Dead Sea out of Lake Michigan. This salt and sand gets pounded into car and trailer frames along with other junk so steel like this may still have all of this far pounded all the way through it and is almost impossible to remove on 1/8" without making it 20 gauge sheet metal. If it is a repair I'd do mig. For practice-get better steel to start and then clean it.

[MarkL]

This happens so fast that it seems like I can't weld more than 10 seconds before I need to switch tungstens or grind, because the tungsten gets fouled and my arc starts wandering all around.

I'd make sure you can get a good weld on known clean metal, eliminate the possibility something else is wrong.

[Lightning]

Thanks guys. Yes, I can get good welds with new metal, and I know using old rusty stuff is less than ideal, but I'm stuck with using what I've got.

Tried using 309 filler and cleaning it a little better, and tungstens last a little longer...

[Poland308]

Having to grind the tungsten more often because of the junk from old steel is normal. I've welded on old steam pipe in buildings built before 1890. Lots of that old stuff welds just like your describing no way around it. I keep about 20-25 half sticks of tungsten with both ends ground to points in my case. Just for days like that, when I crap them all up I just grind them all at once. Sometimes it will almost spit metal from the puddle out in big enough globs that you can't get the tungsten out of the collet with out taking it all apart.