Marking SS for TIG...

So I'm about to start on a piece for a friend, going to practice a bit first on some scrap of the same size/material, but there are two welds I'm just not sure about.

This is for a cooling fitting, lower radiator hose goes on each end. I need to run a bead around, to replicate the flare on the original. Not a big deal, surface, no through penetration needed, just keeps the hose on, but it does need to be the same distance all the way around.

I thought about making a fixture for the torch and then rotating the piece on it's own fixture, but it seemed like a PITA for two welds. Started thinking about the best way to mark it so I could follow it visually, but was concerned about introducing anything into the weld area. What should I use to mark it, a nice scratch, soapstone, sharpie... something else? Or do you think it's not overkill to fixture it and rotate the piece and manipulate the filler under a fixed torch?

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Originally Posted by Trip59

So I'm about to start on a piece for a friend, going to practice a bit first on some scrap of the same size/material, but there are two welds I'm just not sure about.

This is for a cooling fitting, lower radiator hose goes on each end. I need to run a bead around, to replicate the flare on the original. Not a big deal, surface, no through penetration needed, just keeps the hose on, but it does need to be the same distance all the way around.

I thought about making a fixture for the torch and then rotating the piece on it's own fixture, but it seemed like a PITA for two welds. Started thinking about the best way to mark it so I could follow it visually, but was concerned about introducing anything into the weld area. What should I use to mark it, a nice scratch, soapstone, sharpie... something else? Or do you think it's not overkill to fixture it and rotate the piece and manipulate the filler under a fixed torch?

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Depending on how you can position it in a vise or on the bench, I usually just stack up a few pieces of wood to prop my torch hand on so I can hold a set distance. It's a quick and dirty way of getting a semi fixed torch height. I weld through sharpie marks all the time with no signs that is does anything on either steel, stainless or aluminum. I doubt I could reliably see a scribe mark anymore. :(

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Originally Posted by Rambozo

Depending on how you can position it in a vise or on the bench, I usually just stack up a few pieces of wood to prop my torch hand on so I can hold a set distance. It's a quick and dirty way of getting a semi fixed torch height. I weld through sharpie marks all the time with no signs that is does anything on either steel, stainless or aluminum. I doubt I could reliably see a scribe mark anymore. :(

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Appreciate it!

I was thinking of setting it up almost like a hand turned welding lathe, propping I can handle and just do it in a couple repositions.

I know what you mean about seeing, it's a lot harder to see than it was 13 years ago, going to try with my reading glasses next time, see if that helps, else I'll buy some cheaters.

I'll give the sharpie a try. I tried welding a straight line the other day and it was straight, but I missed my endpoint by 1/3 the distance, wound up drawing closer to me regardless of how I positioned.

How thick is the metal roughly?

The bead takes the place of a hose barb? If it is and you need it relatively smooth, you could just lay the bead and then give it a "wash" with the torch, where you just run the torch over your bead to give it a fused-like finish. If it's getting machined into a barb then just put on lots of filler: it doesn't matter what it looks like as long as you don't undercut or miss something.

I use sharpies too. They seem to sort of disappear as you get close to them. If that's a problem, I would "scribe it" with an angle-grinder & cutting disk, Giving it a nice easy to see mark. Soapstone is kind of useless for stainless.

Yup, but not a barb per se, we're talking about 2" diameter pipe, this is just the flared bump like you have on radiator bungs on cars. I don't have a bead roller, nor do I know anyone with one and a die that small, so I figure a 3/32 or so bead around the outside would do what I need.

If I could machine it, I would, but it's a bent pipe to begin with and my lathe doesn't swing 3' would be nice though :)

Good info on the sharpies, if you're saying it's not an issue, I'll run with it. Like I said, these aren't full penetration welds and the bead is less than critical, so all is well.

Ha! Swinging a radiator, that would be something to see eh?

I think for what your doing it'll work no problem. No need to fixture it: just do a few short welds. Stainless is pretty easy, just only a little harder to do than steel. It insulates more so heat builds up in the weld area faster. It also expands more than stainless with heat. Those gang up on you and cause warping, and makes welding thin stuff a little difficult. Shouldn't be an issue with what you're doing though.

The only thing is if you penetrate to where the stainless gets to melting on the back side, ugly, nasty "popcorn" will form without a back purge (argon on the back side). If the wall thickness is over ~1/16" it shouldn't be a problem for someone with a little experience.

I did the same thing for some steel turbo plumbing with large tubes. The guy I was working with came up with a slick way to make them come out nice and even. We just took a piece of 1/8" filler rod and bent it into a ring that fit tight on the pipe, then welded it right where the rod met the open end of the pipe. With good control of the heat we were able to avoid breaking down the outer edge of the ring, so it came out great and was very consistent. Something else that just occurred to me, since your's is stainless, is that by welding from the edge like that you will have argon shielding flowing over both the inside and outside, so you won't need to backpurge, and will keep the corrosion resistance intact.

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Originally Posted by Rambozo

I did the same thing for some steel turbo plumbing with large tubes. The guy I was working with came up with a slick way to make them come out nice and even. We just took a piece of 1/8" filler rod and bent it into a ring that fit tight on the pipe, then welded it right where the rod met the open end of the pipe. With good control of the heat we were able to avoid breaking down the outer edge of the ring, so it came out great and was very consistent. Something else that just occurred to me, since your's is stainless, is that by welding from the edge like that you will have argon shielding flowing over both the inside and outside, so you won't need to backpurge, and will keep the corrosion resistance intact.

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Are you saying you put the ring right on the edge? I was going to space it in about 1/8-1/4" to match the original. I had the thought of wrapping a piece of filler, but figured it'd melt down to a point of wasted effort as I went around it.

Paul, for this bead, I wasn't going all the way through, just building up on the surface. The two bungs I have to add, I was going to back with copper, since I do not have another flow meter to allow me to purge. I was thinking, it's odd that some company hasn't come up with a cheap material that could be used to fill pieces and take up the space, to save on argon purge volume... or someone has and I haven't come across it.

I have a tool I made out of vice grips that I use to form a bead around the end of tubing. You have to work your way around a couple of times with it, just moving a little bit at a time, but it gives really nice results and is perfect for just doing the occasional one of these. Looks like it was rolled with a bead roller (yet takes up far less space to store.) It works well for tubing that's about 1/16" thick. Let me know if you are interested in pics

PS - be aware that welding directly over sharpie on aluminum can indeed cause some contamination (specifically on aluminum, some small bit of porosity that would otherwise not be there without the sharpie.) For that reason, scratch a line might be better. You can weld pretty close next to a sharpie line without problems though.

You could pretty quickly make a precise scratch or sharpie guide line by tightening a hose clamp to the tubing, and using its edge as a guide to make your mark. I'll often use sharpie (because it's so convenient, and also so easy to see) scratch lines, or even a combination for marking things for general fabrication and welding. I pretty much also use sharpie as a substitute for prussian blue whenever I have the need.

Hell yeah I'm interested! I have a flanger from HF and have used manual ones similar. I'm sure I could come up with a design, but you've already been there, done that, and I'm sure you're an iteration or two past where I'd be starting.

Thanks for the info on the sharpie, glad I asked.

The thought I had tonight was to take my chop saw and cut a few thin sections of the extra pipe I asked for, slit them and place them over the pipe (like the filler idea, but I don't have any 1/8) Then weld them up, wash over them and just add filler in the small gap.

Looks like this, and two more projects coming up this weekend, unfortunately, only one is a paid gig, the others are starts or continuing projects for me.

Found it!
Attachment 8361

I used 7" long vice grips to make it, but if I did it over again I might use 10". I think I used the cut off head of an eye-bolt to make that. The steel is a little bit soft but it works fine for thin-gauge tubing.

Using it is not real fast, but is kind of fun and gives great, professional results. The trick is to insert the tubing a consistent amount (I used a marking on the tool to tell how deeply to insert the tubing) and also it's important to keep the tool parallel to the tubing. Then you just clamp it, open it, move it a little bit sideways, and repeat that until you've gone all the way around. (Then, maybe tighten the vice grips a bit if a more pronounced bead is desired, and repeat around another time.)

I've had this for several years and used it on several projects. I've even used it to form beads in tubing in place (an intercooler left installed in an engine compartment) - can't do that with a bead roller!

In follow-up to the above post, I found a decent looking bead I formed into a tube with the above tool, and got a pic for demonstration purposes. It's 2" diameter, .065" 6061-T6 boost tubing that I took off my race car; and the formed bead allows a standard style worm-drive hose clamp to reliably retain a rubber connector with ~28 psi boost pressure.
Attachment 8454

I've formed beads in mild steel tubing with about the same difficulty as 6061-T6 for the same tubing thickness. Stainless I may have not actually tried, but would work OK I think as long as it's one of the ductile alloys (like 304) and is in an annealed state. (work hardened that stuff can get so crazy hard and might crack before it forms... but if it's mandrel-bent tubing, it's probably annealed prior to bending.) I've also formed some beads in some much softer alloy aluminum tubing that was definitely a lot softer than 6061 (although not sure, I suspect it was 3003).

Awesome! I can't imagine it wouldn't be a 300 series, 303, 304, 312, etc. I've seen some others like 327/347 but I've never run into them other than on manufacturer's sites.

I actually came up with a design based on yours but using a pair of 24" bolt cutters with custom made jaws. Same action that can cut a hardened bolt ought to be able to put enough force to deform 1/16" stainless...

Waiting on him to get back into town, his nephew was supposed to get me the raw materials, but the kid is kind of a dunce.