Four kinds of frame welds?

[Kontact]

Reading the Merlin thread and having seen some videos about ti production got me thinking about this. I hope someone can straighten me out about this.

Are there four types of welds or welding steps used?

1. Tack weld. Small spot welds used to hold tubes together for further joining. Do they use filler rods?

2. Fusion welds. Welds made without filler. Some builders do this as a first pass to get a deep weld between mitered tubes before the final weld for greater strength. This may also be the kind of weld used when joining a seat tube collar to a seat tube that is pressed in, like Moots and some others do.

3. Filler weld. A weld made with a filler rod to leave behind a slightly beaded fillet. This is the final weld for most brands, and can be the only weld in "single pass" welding.

4. Puddle weld or smoothing weld. Another fillerless fusion weld made over the filler weld to smooth it. I believe this is what Merlin's puddle welds were all about. It melts the little bumps out of the fillet for a more brazed look.


While I doubt anyone uses all four passes, they certainly could. But this list seriously confuses the idea of "double pass" welding, because there are more than two passes to choose from, and some go before the big weld, some after.

Can anyone confirm the above list, or correct me (mis)understanding?

[Wimpy]

I think Ti bikes are Tig welded.

Check here (http://www.hobartwelders.com/elearning/) for you need to know about Tig welding.

[oliver1850]

Tack welds can be made with or without filler.

When I have seen double pass welds done it's been with filler on the first pass. The second pass is then done either with a continuous motion to make the weld as smooth as possible, or puddle/move/puddle/move to get the ripple effect.

Generally speaking on the race car work I did, we did single pass welds (after tacking) unless there was something ugly that needed touched up. Most welds were with filler, but sometimes made a fusion weld without it.

[Kontact]

I think Ti bikes are Tig welded.

Check here (http://www.hobartwelders.com/elearning/) for you need to know about Tig welding.
All the welds I'm talking about are TIG welds. The question is just when and how the TIG welder is employed.


Oliver, I saw a video for maybe Stork where the first pass was a fusion weld without filler. Then he did a single filler pass. That's where I got the idea of for #2.

[oliver1850]

I think you have a pretty good grasp of the different processes. A lot of the work I see on bike parts is much nicer looking than is seen on most race cars. When you have a driver take a brand new car and put it in the fence the first time out, it takes some of the incentive out of making everything look perfect.

[Chance]

All the welds I'm talking about are TIG welds. The question is just when and how the TIG welder is employed.


Oliver, I saw a video for maybe Stork where the first pass was a fusion weld without filler. Then he did a single filler pass. That's where I got the idea of for #2.
In the highlighted part did you mean to say when is a filler rod used? If it's a TIG weld wouldn't a TIG welder always be used? :confused:

[Chance]

While I doubt anyone uses all four passes, they certainly could.
P.S. -- It's doubtful many people would consider tack welds a "pass". A step for sure but pass probably means the entire circumference.

[oliver1850]

You use a tig welder to make all 4 types of weld. Think of it as an electric heat source, or an electric version of a brazing torch. It just provides heat to melt the base material, any filler has to be added manually (although there are robotic tig machines). The tig torch also supplies shileding gas around the electrode, which not only keeps the electrode from frying, it also shields the weld area from atmospheric "pollution".

The filler rod is held with your left hand if you're right handed. You feed the rod into the melt area, withdraw it, then move the torch. This is what makes the ripple effect in the finished weld.

[Wimpy]

I think you have a pretty good grasp of the different processes.....


The terminology in his OP is not even close to standard weld speak. With the exception of tack welds. He does seem to grasp that. Other than it is not considered a "pass"

Beyond that it sounds like he has not a clue.

[oliver1850]

I understood what he was talking about, in all 4 examples. You could do all 4 steps in a single joint, but like the OP, doubt it is often done.

We would normally do steps 1 and 3.

We would sometimes do steps 1 and 2.

We would sometimes do steps 1, 3 and 4.

I could see where doing steps 1, 2, and 3 might be advantageous, but have never done it myself.

[Kontact]

The terminology in his OP is not even close to standard weld speak. With the exception of tack welds. He does seem to grasp that. Other than it is not considered a "pass"

Beyond that it sounds like he has not a clue.
He has plenty a clue. I'm not a professional welder, so I'm not using pro welder speak. But I have accurately described the processes used so that anyone equipped to discuss this can answer the question. The fact that a TIG machine is used was a given - sorry I didn't spell that out for you.

Anyone who wants to refine the language is welcome to. Anyone who just wants to throw around insults is not welcome.


And I referred to a tack as a pass simply because frame builders who do not use tacks sometimes say that they "only use single pass welds". If you would like to contact those builders to straighten them out, go ahead. I'm sure they will also be delighted to speak with you.

[Kontact]

I understood what he was talking about, in all 4 examples. You could do all 4 steps in a single joint, but like the OP, doubt it is often done.

We would normally do steps 1 and 3.

We would sometimes do steps 1 and 2.

We would sometimes do steps 1, 3 and 4.

I could see where doing steps 1, 2, and 3 might be advantageous, but have never done it myself.
Thank you Oliver. Who is "we"?

I wonder if anyone ever does 2, 3 and 4? A real weld lover might want the fusion pass for strength and the 4 for looks.

Are those seat post welds with or without filler rod? And what is the correct term for a fillerless weld? I had heard "fusion", but would appreciate a more accurate term.

[Ahneida Ride]

I think .... (note think) this is how the perfectionist that does the
Bedford Tig (Ti and steel) does it.

1.) the join is tacked (so the tubes don't move all over)

2.) First pass .... fill in as much as possible and only where needed.

3.) then do the actual welding ..


obtaining a fillet like end result takes real talent.

[oliver1850]

Thank you Oliver. Who is "we"?

I wonder if anyone ever does 2, 3 and 4? A real weld lover might want the fusion pass for strength and the 4 for looks.

Are those seat post welds with or without filler rod? And what is the correct term for a fillerless weld? I had heard "fusion", but would appreciate a more accurate term.

"We" refers to various places I've worked, building cars for several of the North American professional road racing series, CART, and USAC (Indy 500).

Not very often that you can weld something without tacking it. Welding pulls things around much more than you might think. Tight fit of parts in the weld area helps tremendously, but the cooling weld always shrinks. As it does, it will tend to make the joint gap somewhere else, so you generally tack everything.

Generally we would worry much more about the strength than the appearance, so wouldn't often take another step just for looks. Bikes are a bit different, I'm sure appearance is more important. The interesting thing is that the smooth welds appeal to some, while others like the look of perfectly uniform ripples.

I'm not sure what seatpost weld you're talking about, would have to see it.

There might be another term better than fusion, but that one works for me. Perhaps one of the framebuilders, or some other professional welder will comment.

[Kontact]

Here's the weld I'm talking about. The one running around the circumference of the seat tube at the bottom of the top tube join. It's a lipped piece of Ti that is pressed into the seat tube then welded. Just wondering if filler is needed for such a weld or not.

http://redkiteprayer.com/wp-content/uploads/2011/06/IMG_3845.jpg
Before assembly:
http://www.paragonmachineworks.com/PDGImages/MS0009.jpg

[zank]

There might be another term better than fusion, but that one works for me. Perhaps one of the framebuilders, or some other professional welder will comment.

Autogenous.

[Kontact]

Thanks to Oliver and Zank's PMs and posts. I've really learned something and enjoyed your expertise.

[Wimpy]

.....
And I referred to a tack as a pass simply because frame builders who do not use tacks sometimes say that they "only use single pass welds".


When they say single pass they are not talking about not tacking. They simple mean that they get full penetration and sufficient filler with a single (root) pass of welding.

Multiple pass are required with thicker materials when there is not realistic way to lay enough filler down with the root.

Companies like Moots uses a second pass simply for looks.

The crap about a "fusion weld" followed by a "filler weld" followed by a "puddle weld" is just that, crap.

I don't know where you got it and I hope no one is really doing it with the thin tubes used for bikes.

[Tyler Evans]

Here's the weld I'm talking about. The one running around the circumference of the seat tube at the bottom of the top tube join. It's a lipped piece of Ti that is pressed into the seat tube then welded. Just wondering if filler is needed for such a weld or not.

http://redkiteprayer.com/wp-content/uploads/2011/06/IMG_3845.jpg
Before assembly:
http://www.paragonmachineworks.com/PDGImages/MS0009.jpg

That is a pulsed fusion weld. No filler wire. No filler wire needed if the fit up is perfect.

[Kontact]

When they say single pass they are not talking about not tacking. They simple mean that they get full penetration and sufficient filler with a single (root) pass of welding.

Multiple pass are required with thicker materials when there is not realistic way to lay enough filler down with the root.

Companies like Moots uses a second pass simply for looks.

The crap about a "fusion weld" followed by a "filler weld" followed by a "puddle weld" is just that, crap.

I don't know where you got it and I hope no one is really doing it with the thin tubes used for bikes.
Why are you being so condescending? Are you a frame builder or professional welder like several of the people that have replied to this thread? How did you graduate from "I think ti frames are Tig'd" to lecturing everyone in three posts?

Darren Crisp is an example of a builder that uses a fusion pass followed by a filler pass. Moots and Merlin are examples of filler passes followed by cosmetic fusion passes. What are you calling "crap", exactly?

You seem to be implying that there is might be something wrong with making multiple passes. But, as a frame builder who PM'd me says, titanium is pure enough to allow multiple passes. Heat damage to tubing happens because of the length of time at temperature, not the number of times if the area has cooled in between. 3 correctly executed welds shouldn't damage quality titanium any more than 1 will.



Thanks for the response, Chothen!

Everyone else, this is fun. Thanks again. Here's an interview with Darren Crisp from Pez that has some nice captioned photos of his tack, fusion, filler method:
http://pezcyclingnews.com/default.asp?pg=fullstory&id=8138
He also has some interesting commentary on weld temps and penetration. Worth reading and enjoying the pictures.

[Mtmooradian]

Tack welding is just a term for making a small fillet to hold your tubes in place untill youve taking the frame from the jig. I do four tacks per joint. After that it's up to the welder to judge what and how his passes are going to be. All that a pass with TIG is, is just a bunch of tack welds stacked up on top of each other. A seat tube joint can be fusion welded because the joint fits inside of the seat tube backing up the weld area and 100% penatration is possible without the filler. If two tubes were to be butt welded without filler there wouldn't be enough metal between them to keep a uniform thickness. Pulse isn't needed. All that pulse does is allow you to weld with putting as much heat to the metal. I have five different machines and rarely need to use the pulse function. If your mitered joints are perfect then a single pass using filler may be possible. Sometime after checking the alignment it's safer to use a light pass to pull a tube then to try and manually align the tube(cold set).

[Wimpy]

........
Everyone else, this is fun. Thanks again. Here's an interview with Darren Crisp from Pez that has some nice captioned photos of his tack, fusion, filler method:
http://pezcyclingnews.com/default.asp?pg=fullstory&id=8138
He also has some interesting commentary on weld temps and penetration. Worth reading and enjoying the pictures.


Now I understand your confusion!

This generally requires higher temperatures as the fusion is being created between the rod and the tube. It’s a pretty solid weld if you get enough heat, but as I’ve described, it is not a joining of the tubes to each other.

You are doing your research via a frame builder trying to distinguish his brand. Not a welder.

Unless he is using Schd 80 pipe to make his frames, I suspect Darren knows the statement above is not true.

[jr59]

I think all on this post are wrong;

There are 2 types of welds;

Good ones and less than good ones! :p

[Carl Strong]

Are there four types of welds or welding steps used?



I'm late to the party but though because I do this everyday (as does the Chothen One) I'd throw in my 2 cents based on my experience and my relationships with other builders and referring only to titanium.

To answer your specific question:

Most builders use a double pass. The tack does not count as a pass. The first pass we call fusion (homogeneous) without filler, although is same areas of the frame the welder will add filler, usually a smaller size than will be used on the second pass. Then on the second pass filler is used. This is called the dress pass. The fourth pass you suggest is done but rarely and only by a couple of builders and is also done in some rare cases with the pulser on. Some builders only do a single pass on Ti just as they would on steel. Nobody (that knows what they're doing) double passes steel.

[Kontact]

Now I understand your confusion!



You are doing your research via a frame builder trying to distinguish his brand. Not a welder.

Unless he is using Schd 80 pipe to make his frames, I suspect Darren knows the statement above is not true.
I suspect Darren and Oliver and Zank know a lot more about welding titanium than you do.

Darren qualified his statement by saying that low amp, small welds do not penetrate all the way through to the base of the tubing. And from examples I've seen in ti, that seems to be completely true.

Darren is not saying you can't get full penetration with one pass. He's saying that he doesn't like to heat the tubing up enough to get that kind of penetration in one pass.

The "distinguishing" he is guilty of is claming that either higher temp welds or shallower welds are not as strong as his. Clearly, there are many single pass welds (the way he defines them) that have lasted for decades. But just as clearly, nearly every Ti frame failure I have ever seen involved a crack that was either centered on the weld or started in the Heat Affected Zone. And while contamination is a likely culprit for many of them, shallow penetration or high amp heat damage probably account for the rest.

I am not "confused". Crisp's method is just that; a method. He is probably not the only one doing it, either. And aside from whatever claims he makes about strength and penetration, his welds are clearly smaller than average because he's using lower amps and less filler by going two step.

What's your experience with Ti welding again?

[tribuddha]

not sure this will add anything to the conversation but it seems like maybe the jargon used is diffrent although the steps seem similar.. just my two cents.. :beer:
as a long time superintendent for a general engineering out fit I have worked on more then my share of industrial welding jobs. some included exotic metals with a variety of sophisticated welding machines that removed the human error that occurs in the process. most of the projects required some form of inspection ( xray etc) and all my welders had to be certified on the type of weld we submitted during the approval processes.

we didint tack much.. these tacks are suspect in quality and required the welder to grind or re-weld these "imperfections" we used jigs or clamps.

the first pass is the root weld as noted by some in early posts it was usually with smaller rod

the second pass was the hot pass this was to float out any impurties from the root

the pass(es) were for filling the weld
after the weld each welder stamped the weld and then they were x-rayed to assure they met spec

welding at some of the other clients was performed by machine.. these welds left no bead- were full penetration welds and were remarkable in quality they had no porosity and were really a nice finished product. these were almost exclusively for high tech companies or for biotech etc.. the machines are expensive as are the components...