Tungsten prep

Date 11-09-2006 01:16

When welding without high freq. start,(touch or scratch),do you guys prepare your tungstens differently?I am just getting used to this method as I have always had the H.F. luxery,but my inverter is a touch start/lift..whatever.It says to rest the tungsten on the material and wait 2 seconds and lift to iniciate the arc.It doesnt work too good.I end up scratching it to get it going.I am just using 2% thoriated 1/16 & 3/32 electrodes.I usually dont put a flat on the end but in the instructions it recommends this.I have just always pointed mine longitudaly,or balled the pure on a pc of copper .Does anyone know if lanthinated or ceriated will work better for this start method?.I would just try them but dont have any right now.need to go to the weld-mart and do some grocery shoping:):)

By Lawrence (*****)

Date 11-09-2006 12:40

Touch start is nice and a better alternative than scratching.

1. The flat on the end of the tip prep is a very good idea for touch start, this is especially true with the 1/16 dia. electrodes. You risk contaminating the weld zone with little bits of sharpened tungsten when you use a very pointed tip, but even with larger dia. electrodes the flat end prep is the way to go with scratch or touch and won't have a very noticable effect on your welding performance once the arc is struck unless your working on material less than 0.060"

2. I've had better luck touch starting with a little change in my regular technique. Start by laying the edge of your ceramic cup on the work and slowly lower your electrode down until it touches. Then lever it up nice and easy with the edge of your cup as the fulcrum. This will allow you to control the distance your tungsten comes away from the work. You want it to only come up about the dia. of the electrode itself when you lift it.

Thorium, Cerium, Lanthanum, all "should" perform about the same in the circumstances you describe. However, I have found great differences in quality and ductility of lanthanum electrodes from various vendors, but that may be a little more than your asking for today.

Let us know how it works out.

By MNSTRBLDR (**)

Date 11-09-2006 13:16

The way we scratch start ours here is to set the cup on the metal with the tungsten about 1/16" off the metal. Next, use your filler wire to "strike" between the metal and tungsten. Kinda like a match. We save alot of tungsten this way and don't risk sticking the tip to the metal. See if this works once. Henry

By Molten Metal (**)

Date 11-09-2006 15:33

Thanks for the good advice gentlemen.

By jwright650 (*****)

Date 11-09-2006 20:01 Edited 11-09-2006 20:06

Just be sure the filler rod is in good contact with the base material or you may get a little surprise:-)

We've all had helpers that while trying to teach them to strike an arc with SMAW E7018, they hit the plate that they are trying to tack on, rather than the grounded base material and drop the stinger thinking something is wrong with it when it bites them.

By CHGuilford (****)

Date 11-10-2006 14:26

Kinda reminds me of sitting on a jig plate, getting ready to lay down to tack overhead; hot day, working hard and gloves were soaked with sweat. I was breaking the flux back for an easier restrike.
About that time I discovered there was a small hole in the seat of my jeans.

I often wondered if using straight polarity on that 7018 would make me feel it in my fingers instead.

By Dave

Date 11-10-2006 18:20

"I often wondered if using straight polarity on that 7018 would make me feel it in my fingers instead."

Chet,

You know there's an easy test for that. Go ahead and try it and we'll all anxiously await your findings!

Dave

By jwright650 (*****)

Date 11-10-2006 19:07

Yeah Chet...We're anxiously awaiting ;-) LOL

By weldhaus Date 11-12-2006 00:49

I got a kick out of you little saying at the end of your post. It should be the motto of were I use to work because they did so much grinding on handrails instead of laying down good beads. Only me and the other shop foreman could produce welds that needed little grinding at stop and starts, not the entire weld.
Peace
Weldhaus