TIG Welds

[MikeB]

Since taking up frame building I have been an admirer of the perfect weld joints some of the Pros around here can produce. That concentric stack of dimes look that Carl, Drew, Tony, etc, seem to produce look machine made at times (and that is a complement).

My welds, however seem to flow more smoothly, and tend to resemble a small filet when painted. So the question is, I'm I doing it wrong? Is the "stack of dimes" purley assetically pleasing, and add no structuall value? Is one preferable over the other?

An example of my finish work.



Thanks in advance.

MikeB

[Proparc]

Stop right there and start building!!!!

[Dornbox]

The stack of dimes is more of, but not exclusively, a pulse thing either by foot or machine. Many of the welds you see are also flat just like yours but the color from the heat makes them looked stacked. The weld in the pic, while not as stacked looking as the others you mentioned, has a little of the look but once the color was gone, it's was dead flat like yours. I like my welds to go away under the paint. The stack of dimes is aesthetic and very common when you have bulky welds that can't be hidden like on aluminum -atmo. Nice weld by the way, with the right paint technique, it should look exactly like a small fillet.


IMG_2448 by DORNBOX, on Flickr

[Archibald]

Since taking up frame building I have been an admirer of the perfect weld joints some of the Pros around here can produce. That concentric stack of dimes look that Carl, Drew, Tony, etc, seem to produce look machine made at times (and that is a complement).

My welds, however seem to flow more smoothly, and tend to resemble a small filet when painted. So the question is, I'm I doing it wrong? Is the "stack of dimes" purley assetically pleasing, and add no structuall value? Is one preferable over the other?

An example of my finish work.



Thanks in advance.

MikeB

IMHO, you're cooking the joint. That dingy gray color is a dead giveaway. That particular joint is either overfed with filler or it's two passes. Either way, don't do that. :)

Stack of dimes as most folks understand it is not that desirable either. Each one of those ridges is a stress riser; ideally what you really want is for it to all flow together smoothly.

My advice: watch your puddle. Turn down your heat or speed up your travel. Don't worry about stack o' dimes, worry first about evenness and parallel borders tying in the parent metal. Don't starve the joint (undercut) but don't overfill it either. The conservative rule of thumb for the right amount of filler is when the cross section of the throat of the weld is at least equal in strength to the parent metal. This means that if the material you're welding has a tensile of 100K and the filler metal you're using has a tensile of 50K, then the throat cross section has to be twice as thick as the parent metal.*


*yes, you do get mixing/alloying of the filler & parent metal where they both can obtain mechanical/physical properties from each other but since you don't know the result, it's best not to rely on it, i.e., be conservative.

[Dornbox]

Don, I never realized how much you can tell just by a picture of a weld! So much to learn. -Chris

[Proparc]

A LOT of the highbrow tig welding you see on bikes is done with pulse. This weld looks like it was done manually and to my eyes, looks like a VERY good start,( I assume he is starting out). I personally like his "flow out". I can see no reason why he should't start to rock and roll on a bike. A slightly smaller bead starting out wouldn't hurt, but I still would advise him to gets to building,(and hang out at Carl Strongs site). Obviously, don't start taking orders for a million frames, but man, start building bikes for your own use like now!!!

[MikeB]

Thanks for all the responses everyone.

I'm actually building my fifth bike now, so hopefully the work I've completed is adequate for safe travels.

Upon further introspection of my technique, I decided my use of mostly .045 880T (topic from another thread) could be part of the problem. Per Arch's direction, I tried some .035, and moved a bit faster, trying to use less heat. Welded up the front triangle of #5 tonight. What do you think??? :

[Dornbox]

Looks better than my first bike and that bad boy takes a lickin and keep on tickin! I'm guessing that if you didn't wire brush your weld, you still have a little too much heat into it, but that's a guess based only on the lack of color in your beads. Certainly enough material there to be stronger than the tubes though. I'd ride it!

[Archibald]

Thanks for all the responses everyone.

I'm actually building my fifth bike now, so hopefully the work I've completed is adequate for safe travels.

Upon further introspection of my technique, I decided my use of mostly .045 880T (topic from another thread) could be part of the problem. Per Arch's direction, I tried some .035, and moved a bit faster, trying to use less heat. Welded up the front triangle of #5 tonight. What do you think??? :

That's better but still too hot. Work on how you tie your beads together too. When you come to the end of a weld segment, starve the joint just a little so you get a nice concave surface. When you start the next segment tying into it, start near the tip of the concavity and then back up until your new puddle matches the old, then start adding filler and move on. You really have to watch the puddle and see that it's matched up to your last segment before you start moving & feeding again. If you're on top of your game, it's very hard to see where you started and stopped.

[Proparc]

Thanks for all the responses everyone.

I'm actually building my fifth bike now, so hopefully the work I've completed is adequate for safe travels.

Upon further introspection of my technique, I decided my use of mostly .045 880T (topic from another thread) could be part of the problem. Per Arch's direction, I tried some .035, and moved a bit faster, trying to use less heat. Welded up the front triangle of #5 tonight. What do you think??? :

The top tube head tube joint is indeed too hot. Believe it or not, I would bet 20 bucks that you are holding the torch too far away from the work. The farther away you hold the torch, the more you disperse the beam, and the more heat you have to put into the joint. Manual tig welding done well, is actually very difficult. Think of it as manual brain surgery.

A TIP-get a bunch of .035 ER70s rod and practice, (here’s that word again) making perfect evenly spaced, (approximately stagger 50% apart) joints on flat plate joints and then around a tube. The ER70s rod will make this more difficult because it tends to be significantly less forgiving of mistakes. Try to keep the joints around 2.5 millimeters in diameter all the way around the joint.
Pay special attention to your tungsten grind.

[Dornbox]

A TIP-get a bunch of .035 ER70s rod and practice,<snip> The ER70s rod will make this more difficult because it tends to be significantly less forgiving of mistakes. <snip> Pay special attention to your tungsten grind.

AMEN to that especially the Tungsten grind! After a little over a years worth of arch time, I've finally mastered my tungsten grind and it was night and day when I hit the right angle.-Chris

[Archibald]

The top tube head tube joint is indeed too hot. Believe it or not, I would bet 20 bucks that you are holding the torch too far away from the work. The farther away you hold the torch, the more you disperse the beam, and the more heat you have to put into the joint. Manual tig welding done well, is actually very difficult. Think of it as manual brain surgery.

A TIP-get a bunch of .035 ER70s rod and practice, (here’s that word again) making perfect evenly spaced, (approximately stagger 50% apart) joints on flat plate joints and then around a tube. The ER70s rod will make this more difficult because it tends to be significantly less forgiving of mistakes. Try to keep the joints around 2.5 millimeters in diameter all the way around the joint.
Pay special attention to your tungsten grind.

880 wets out better than ER70s2 which is the industry standard filler for steel bikes, but the reason for using 880, or at least why I use it, is because of its mechanical characteristics. I've never found ER70S2 harder to weld with. Are you really keeping your weld segments 2.5mm/.100" across? There's no way I could get the throat I need with a bead that narrow in most cases and not have excessive convexity and what you want is concavity so the welds surface is in tension.

[JFW]

AMEN to that especially the Tungsten grind! After a little over a years worth of arch time, I've finally mastered my tungsten grind and it was night and day when I hit the right angle.-Chris

Could you share some insight here?

Cheers,

El'Trulso

[Carl S]

Wow! That's purdy

[Dornbox]

Could you share some insight here?

I believe the rule of thumb is your tip/point can be up to 2X the diameter of the tungsten. Using a 1/16 tungsten, 2X is actually a fairly long tip which is how I was sharpening mine since day one . I recently started using a steeper angle and really focusing on consistency (I sharpen my tungsten on a grinding wheel then polish them on a diamond wheel, all with a drill) and my beads aesthetics not only improved but their consistency has as well. Nothing like Don's though. That $hit is like black magic voodoo to me. Even though I'm fairly busy welding bikes, I still chop up 4130 and run a few practice beads in hopes of being able to get in the ball park of his welds. When I see welds like Don's it feels as though I'm still playing kick the can and everyone else is playing in the Super Bowl.

This is my latest bead.


IMG_0509 by DORNBOX, on Flickr

[Proparc]

880 wets out better than ER70s2 which is the industry standard filler for steel bikes, but the reason for using 880, or at least why I use it, is because of its mechanical characteristics. I've never found ER70S2 harder to weld with. Are you really keeping your weld segments 2.5mm/.100" across? There's no way I could get the throat I need with a bead that narrow in most cases and not have excessive convexity and what you want is concavity so the welds surface is in tension.

Given who you are and your skill level, (you make our jigs for crying out loud) I most certainly believe you when you say you weld just as well with ER70S2 as the other stuff,). But, you hit the nail on the head with your opening sentence. 880 and most of the stainless rods, wets out better than ER70S2 and that is exactly IT.

ER70S2 is even more difficult for newbie’s to control ESPECIALLY around a joint. I personally have found ER80S2 tougher still. And, that is the idea; practice, practice, practice with the harder rod. The advice about the bead size is for (again that word) practice. Remember, the advice was for .035 4130 sheet AND .035 tubing. We don’t make bikes with .035 sheet.

You wouldn’t necessarily do this on a real bike but, this gentleman’s main problem is heat. And the advice given was to try to help him learn heat management, which I believe, is vital if he wants to make long term safe bikes for other people, ( I am assuming he eventually wants to make bikes for other people).

[Dornbox]

Are you really keeping your weld segments 2.5mm/.100" across?

I actually have a half dozen or so practice samples where I have nice flat even beads about 2.5mm wide dead on on pieces of .035 tubing. I believe it was a combination of a very pointy tungsten and keeping it pretty much on the tubing so the arc was hyper focused. I've also seen some Waterford's welded like this.

[meech151]

I do fillet-brazing on all my frames but am interested in learning to tig, mainly for stainless dropouts but also just to learn. Are any of the small, affordable tig welding setups worthwhile for frame building? I have only mig and stick welded. Can anyone recommend any particular model if
you were only gonna buy once. Thanks in advance. The photos are excellent, you guys do some nice work.

[anthonymaietta]

Are any of the small, affordable tig welding setups worthwhile for frame building? Can anyone recommend any particular model if you were only gonna buy once.

In my mind these are conflicting statements.

This is my welder:



Its a Miller Maxstar and the whole setup was $1500 (back in 2006). It was all I could afford at the time and I have made every frame with it. It does a decent job and it does have the high frequency start and auto-cooling fan. However, it doesn't have all the features I want and will be replacing it down the road.

[meech151]

Yeah, I follow you. That looks very similar to the one I was looking at. Which one are you gonna get next?