Tack weld with Tig

Check out the youtube channel "weldingtipsandtricks" . Jody is a VERY good teacher , and covers all your questions in a series of easy to understand videos . And help support his efforts , buy a tigfinger . I did ...

It is just like any other welding, you got to get both bits hot :-)

But to be a bit more serious, as the upper plate gets hot need to sort of slide over and get the bottom plate hot so that they melt together. Or try heating the bottom plate next to the overlap as it get hot sort of slide over and catch the upper plate.

I learned TIG welding as an aircraft welder where most of what you weld is very thin. The technique was to use a low enough amperage so that you could start the arc and melt a very small puddle, then by manipulating the torch you could move the puddle around to melt both sides of the joint. see:

I have never TIG welded in my life, but I've heard it described as being very similar to gas welding. The first kind of welding I was ever any good at. If that's the case you need to make little circles from one material to the other. Slower on the thicker and faster on the thinner so that they both reach flow temp at the same time. A buddy of mine recently likened repairing aluminum water pipe with a TIG as being similar to gas welding a muffler pipe with a clothes hanger. I know how to gas weld a muffler pipe with a clothes hanger. LOL.

Ok, all the pros can trash me now. I can take it. LOL.

The difference is that the TIG arc will jump to one side or the other and not heat both. After running straight beads we practiced on overlap and then fillet / tee joints to learn how to heat all the metal uniformly. My hands know how but I can't explain it in text.

--jsw

I learned how to gas weld when I was 13. My dad bought a gas welding setup and I taught myself. I found that coat hangers made good welding rod. I weld repaired several lawnmower handles for various neighbors with coat hanger welding rod. I also repaired a couple bicycle frames and the rear brake pedal on my neighbor's Yamaha 175 dirt bike with coat hangers. Good stuff. And the price was right. Eric

No, you are essentially correct. If you ignore the requirements of gas flow, possible need for shielding, etc., it isn't much different at all :-)

In general, heat the bottom plate, not the top plate.

TIG tacking is not almost-instantaneous like MIG or stick tacking, it takes a moment or two.

When you heat the top plate, heat escapes only away from the edge - when you heat the bottom plate, heat escapes in all directions.

So you need to put twice as much heat into the bottom plate.

(well not entirely, but I find it helps to think of it that way, especially with thin sheet)

The arc will usually try to fasten on the top more, and you will have to compensate for this as well. Pulse at 30+/s can help tighten the arc to where you want it.

A sharp tungsten can help you get right into the corner.

-- Peter Fairbrother