When referring to an "old fart welder" I'm not talking about equipment but an individual whose has been holding a stinger 10+ hrs a day for 40+ years. This process is all about procedure which presents no challenge for those with that experience. I machined and fit up the components and closely observed the old fart who does this:
1. Warm the casting gently to 200-250 f. Just enough to get the sweat out of it and get the molecules moving as he said. An oven can be used which will heat it evenly as dwelling in one spot with a torch can induce brittleness/cracking.
2. He used a stick welder with UTP FN-85 rod and if IIRC it was 1/8" dia.
Here's the product info on the filler material. The elbow is steel so this is a case of joining dissimilar metals and possibly why this particular rod is the ticket.
3. Beads were short; no more than 3/8" long and immediately he would peen the weld as well as the surrounding area with an air hammer set very low with a blunt tip. He would actually "push" the weld to flatten/spread/shape it as it cooled but the primary purpose was to prevent stress buildup.
4.Welding/peening were both done in about 20 second bursts for probably 100 times. He paced himself in such a way that each bead he put down was maintaining preheat for the next.
5. When he finished I wanted to dress it up a bit with a grinder and was told that the breeze/exhaust could potentially ruin it and that it had to immediately be wrapped in a welding blanket and left undisturbed for a minimum of 6 hours. (burying it in kitty litter or vermiculite are acceptable alternatives). He had some type of muffler/diffuser? on his air hammer to prevent blowing on the part and didn't want open doors or fans anywhere near the process.
6. As the welds were shaped with the air hammer there wasn't much to do to smooth it out. I just used a rat tail file to blend the elbow to the casting.
This process worked flawlessly several times so I hope some of you can make use of it successfully.
