Capillary pull alongside the weld

[keith]

Originally Posted by BTromblay

Hi,

The under cutting along your weld seam is more than likely caused by being to hot. Try an initial TIG welding setting of 1 Amp per thousand of an inch, example (.040" thick= 40amps) if in a aluminum add 10% to your current setting. For the use of filler rod in 19 gauge steel, I prefer a 1/16" diameter rod with a 1 to 1 dip rate approximately. 1to1 example (1" of filler rod for every 1" of travel).

I recommend to people that I have trained in the past, to start with a test coupon approximately 12" square, sheared in half. Weld, evaluate, shear, weld, repeat and so on. You want to verify that the heat affect zone (HAZ) / (the discoloration) is consistent and parallel to the bead and that you have full penetration on the backside. The larger coupon is used to give you a realistic result when building bigger parts. Small coupons heat up quickly and require more accurate temp control on behalf of the operator.

With practice and some basic instruction you can make a consistent weld bead that is fast, clean, full penetration and no under cutting that can be planished and fully disappear.

Let us know how you do. Hope it helps.

Bill

Bill,
That is great information. I had never thought or heard the term 1 to 1.


Thanks for the insight.


keith