[Chips O'Toole]

How far away from a steel TIG weld does rust and filth have to be? Today I tried a lap weld. The top and side of the upper piece were clean and shiny, but the underside, which was concealed, was not. Gas started coming out of the crack between the two pieces of steel, and let's just say the result was not pretty.

[Otto Nobedder]

I always try to clean a 1/2" of the face side of the weld, the end of the leg (for a fillet), and at least a 1/4" of the backside of the weld for insurance against drawing crap into my weld from that area.

Steve S

[Farmwelding]

Cleaning also depends on heat level and thickness of metal. Sheet metal should be cleaned on both sides since heat goes through. 1/4" probably doesn't need cleaned on both sides. But 1/2"-1" away is good for me. Lap welds I clean the edge of the top peice and some on the top and bottom and the bottom plate just a straight line where he weld is.

[Chips O'Toole]

Here is what happened. The weld in the front is MIG. I used this metal for MIG practice, and then I TIGed another piece of scrap to it, after grinding the weld area clean. The TIG is puffy and full of craters. I was pretty happy with the MIG weld.

As bad as the TIG weld is, it's considerably better than what I was doing a couple of weeks back.

[exnailpounder]

How far away from a steel TIG weld does rust and filth have to be? Today I tried a lap weld. The top and side of the upper piece were clean and shiny, but the underside, which was concealed, was not. Gas started coming out of the crack between the two pieces of steel, and let's just say the result was not pretty.

It can never be clean enough for tig. You can get away with being lazy on new metal sometimes but tig is all about precision and the words lazy and precision never seem to mix well. Tig is the elite process in the welding world and the only way to be really good at it is to understand it. Chips, you're welding too cold and jamming in too much filler. Tig welds are always flatter than other process'...your lap weld should be a little concaved. Tig is a slower process than any other...you need to puddle, dip and move ahead a bit and repeat. It's easy and hard all at the same time. One day it will click in your head and you'll wonder why you ever thought it was hard.

[cj737]

And check your gas flow on the TIG welds. Either you are holding too long an arc, or the gas flow is wonky.

[Chips O'Toole]

I am always forgetting to hold the tungsten close. It's like it moves away by itself as soon as I quit thinking about it.

[Farmwelding]

I am always forgetting to hold the tungsten close. It's like it moves away by itself as soon as I quit thinking about it.

Yep. I'm teaching a fellow student to tig weld right now. I'll show him, watch a couple times, go work on something else for a little while, come back and he's got the tig torch 1.5" away from the plate. It's cool to watch-a tornado of fire, but it ain't right.

[exnailpounder]

I am always forgetting to hold the tungsten close. It's like it moves away by itself as soon as I quit thinking about it.

You need to get yourself propped in a comfortable position and then do a dry run with the torch to see how much of the weld you can complete without getting out of position . When you're out of position, stop and re-position and go on. Torch angle and arc length are VERY important and when you get out of position one or the other or both go south and that's where the trouble starts. Try doing shorter welds and really concentrate on arc length and torch angle and when your small welds look good, make a little longer one next time. Keep stacking those little success' on top of each other and you'll be on the road. As you're seeing, there is a lot going on all at the same time when you're tigging so it takes awhile to get the hang of it. One step at a time.

[Chips O'Toole]

I hate metal prep. The flap wheel, knot wheel, and 72" belt grinder are slow. Today it occurred to me that my "needle scalers" might be called "scalers" for a good reason. Is this the tool I should be using?

[Oscar]

I hate metal prep. The flap wheel, knot wheel, and 72" belt grinder are slow. Today it occurred to me that my "needle scalers" might be called "scalers" for a good reason. Is this the tool I should be using?

Cubitron-II sanding disks in a coarse. Everything you mentioned comes a distant second to them. To watch them obliterate metal makes it a pleasure to use actually.

[Chips O'Toole]

Thanks for the reply.

There are about a trillion Cubitron products. Do you mean the flap disk or something for a DA sander?

[Oscar]

The flap disks are good, but no I mean sanding discs that use a backer pad, although they are stiff enough that I sometimes don't use them with a backer pad for quick surface touch-up's, because you can get a really extreme angle on them. Also called fiber disks. They're like a round cut-out of "sandpaper", but they are damn stiff. I have some on my cheap ryobi grinder and will take pics when I get home.

[Farmwelding]

I Believe oscar is referring to these

[Chips O'Toole]

Thanks.

Yesterday I got good results with a fiber paint-stripping disk. Like petrified Scotchbrite.

[Oscar]

Yep, those are the ones.