Welding Tips and Tricks

I'm a newbie teaching myself how to TIG weld. I'm using 3/32 2% Lanthanated electrode, 3/32" ER70-S2 filler, on 3/16" hot rolled steel and some 14 gauge hot-rolled steel as my practice coupons. I've ground off the mill scale using a grinding disc to bare metal (not just shined up mill scale with a flap wheel, been there done that).

I'm doing the steel welding drill that Jody discussed. Laying beads. Getting seat time. As suggested in the video, after a few beads, quench the piece in water. What I have found is that after a few quenches I can no longer get a decent bead. Nothing sticks. Looks awful. I wiped it down with acetone and still no change. Today, after having this problem show up again, I took the flap wheel to the remainder of the coupon and took off any discoloration. Back to shiny silver metal. Voila, good beads (relatively speaking).

So am I missing something? As I'm quickly learning, TIG needs clean surfaces but I didn't think I was going to have to re-grind the surface after quenching.

Am I missing something?

thanks,

newbie Steve
Houston, TX

It's possible that when you dunk the hot metal in the bucket that any oil on the unground portions is creating a film on the top of the water. When you pull the part out of the water it is redepositing oil on the whole part.

Or it could just be oxidation building up from the repeated dunks.

Steve,
The water causes an oxidation layer on the surface and it changes the temper of the metal. It shouldn't take much to get it clean enough to weld again. A better suggestion might be to set up multiple coupons and rotate through them while the others are cooling.

Len

Welcome to the forum Steve.

thanks for the suggestions. I'll probably just rotate multiple coupons as I practice.

I found that the mill scale comes back after repeated heating and cooling and you need to re clean your coupon (sander, grinder, etc.). I also found that if you are doing this drill, you get farther if you use a larger/thicker piece of steel.