Question number one- Welds

[Sandy]

I often read posts which state how great the welds are on certain bikes and how poor they are on other bikes. I would think that there are two different considerations on tig welds- The important issue (to me) is how well are they done as a functional matter relating to structural integrity, durability,strength, longevity, etc. A second issue, not really too important to me, is the aesthetics of the weld.


The welds on my Ottrott are very neat, smooth, and uniform, but certainly not nearly as pleasing as on any Spectrum that I have seen, for example. But Spectrum ti bikes are made by Merlin, and I would think that the superb finish of a Spectrum tig welded bike is more a function of Spectrum's efforts after the bike is sent by Merlin to Spectrum in Pennsylvania.

Can one really tell, by simply looking at the finished product, what the functional quality of the welding is, or is one really looking at the aesthetics of the finished welding in giving an opinion? In other words, can one really tell about the quality of the welds, without a more invasive type of approach, sort of like sawing the critter into little pieces??

Looking for a job welding at Saratoga Springs,


Sandy

[dbrk]

Welds have two functions not directly related to one another: structural integrity and aesthetics. When working in titanium the structural integrity issue is merely exaggerated by the requirement of creating an "uncorrupted" weld, that is, one made by purging the environment of oxygen which would otherwise make the weld brittle. There are heating issues as well but these seem less vital since I have seen plenty of "burnt" welds (on Serottas, btw) that hold up fine. As we see on many "sloppy" welded ti bikes (and there are many!), the welds can hold up just fine, the issue is cleanliness and O-free welding environs.

As for aesthetics the Moots welds are what I call "one breath" (though I am told they are not actually) inasmuch as they lay up seamlessly one upon the next in tiny toothpastey ways. Most Serottas that I have seen, to be honest, are just not as clean and even and correct as the Moots. Some are better than others but few break (and, yes, Serottas do break b/c I have seen that too). When you make a lot of bikes there are mistakes, part of having a handmade bike is that it is _handmade_! I have seen Ibis and IF welds that are pretty amazing and sometimes Seven. Moots wins hands down for consistency. As I see it, you buy Serotta for the ride, design, tubes but not reallllly for the welds though they are fine enough.

Spectrum does no finishing work on the welds in Pennsylvania. The smooth, filet-brazed look comes from Merlin that way and always has, whether it was Cambridge/then Sommerville built or, now, Tennessee built. I think it has to do with going over them more than once. Some might argue that this compromises integrity but that's proven to be nonsense since they don't generally break any more commonly than any other finely made ti bike. "Stronger" welds in titanium is a ruse: they are plenty strong enough if they are just not corrrupted, such is the overbuilt nature of titanium.

dbrk

[Orin]

Welds have two functions not directly related to one another: structural integrity and aesthetics. When working in titanium the structural integrity issue is merely exaggerated by the requirement of creating an "uncorrupted" weld, that is, one made by purging the environment of oxygen which would otherwise make the weld brittle. There are heating issues as well but these seem less vital since I have seen plenty of "burnt" welds (on Serottas, btw) that hold up fine. As we see on many "sloppy" welded ti bikes (and there are many!), the welds can hold up just fine, the issue is cleanliness and O-free welding environs.

<SNIP>

Spectrum does no finishing work on the welds in Pennsylvania. The smooth, filet-brazed look comes from Merlin that way and always has, whether it was Cambridge/then Sommerville built or, now, Tennessee built. I think it has to do with going over them more than once. Some might argue that this compromises integrity but that's proven to be nonsense since they don't generally break any more commonly than any other finely made ti bike. "Stronger" welds in titanium is a ruse: they are plenty strong enough if they are just not corrrupted, such is the overbuilt nature of titanium.

dbrk

A couple of things. Got to keep the nitrogen out too for the same reason as the oxygen.

The smooth look is easily achieved by doing a second pass without adding filler. This of course doubles the chance of O2/N2 contamination and the additional heat cycle may affect strength. A second pass may increase strength by removing stress risers caused by the edges on the "row of dimes" look of a single pass weld.

I agree it's probably all a ruse. Either way is plenty strong as long as it didn't get contaminated.

Orin.

[cpg]

I think you guys got it right from a real world perspective, but if I was to split hairs (of which I don't have too many to spare) the smoother the weld without undercutting the stronger the weld. But ulitimately, once it's strong enough, making it stronger doesn't do much. As a technical side, a second pass on ti requires additional rod to be added or the weld looks smeared. With all that said, aesthetics matter. Anybody that says that they don't, I'd welcome that debate.

Curt

[slowgoing]

Welds don't affect the ride. I had a Colnago CT-1 with semi-ugly looking welds but it was a fantastic riding and handling bike. And in my experience, after you buy the frame and put up pictures on some web site to show off your welds, very few people will notice them again, even on group rides. In my opinion, how purty the welds are isn't really a reason to choose one frame over the other. Whenever I hear people say how purty Moots' welds are, I always say to myself, "Who cares? How does it ride?"

[OldDog]

"Spectrum does no finishing work on the welds in Pennsylvania."

Hmmm.....my Spectrum is of '95 vintage, went to see Tom and ended up getting a "stock" Merltrum Road, for considerable savings ( it even fit!) over a custom. At the time Tom indicated he would have the frame in a few days as it was stock at Merlin. He explained the finish work as sanding the welds, as well as a fine sanding to the overall frame in prep for a clearcoat paint. Clear coat only frames, receive a different level of finish vs. color painted frames.

The benefit of purchasing a Spectrum over a Merlin at the time was receiving a detailed frame prep and paint of your choice.

Tom - maybe you will see this and chime in, thanks.

[Tony Edwards]

As dbrk points out, in typically wise fashion, the apparent cleanliness of welds is not direct evidence of their strength (and, to the extent it is, that strength is generally greater than it needs to be anyway, when titanium is the medium being welded).

I have always thought the welds on my Serotta ATi were beautiful, and still do. The welds on my Moots VaMoots are, well, somewhat more so. Both are more than adequate in aesthetic terms, and, no doubt, in terms of their strength as well. It's honestly amazing to me that a welder can lay down a bead as nice as what I see on my Serotta, and nearly unbelievable that my Moots is welded by a human being.

[Steve800]

As for aesthetics the Moots welds are what I call "one breath" (though I am told they are not actually) inasmuch as they lay up seamlessly one upon the next in tiny toothpastey ways. Most Serottas that I have seen, to be honest, are just not as clean and even and correct as the Moots. Some are better than others but few break (and, yes, Serottas do break b/c I have seen that too). When you make a lot of bikes there are mistakes, part of having a handmade bike is that it is _handmade_! I have seen Ibis and IF welds that are pretty amazing and sometimes Seven. Moots wins hands down for consistency. As I see it, you buy Serotta for the ride, design, tubes but not reallllly for the welds though they are fine enough.

dbrk

Good point,

Does anyone here know how many welders there are at Serotta?

Steve

[Tom Kellogg]

I do try to avoid adding to threads on this forum since it really isn't my business (or at least my forum). But OldDog asked...

Just a few things. I am not aware of any "real" US Ti builders active today who do not weld as well as they need to. ie. there aren't any more hacks out there. From our point of view, the smoothness, or consistency of the welds has nothing to do with function, but it can indicate the experience of the welder and how much they love frames. Laying down the kind of welds that we all see on a Moots tells us that the torch guy out there in Colorado has welded up LOTS of frames and that he really loves his creations. That style of weld does require somewhat more heat than most other welds, but high end alloy titanium tubing, handled properly is not much effected by the extra heat.

Keep in mind that Seven, IF, Merlin and our Spectrums are all stuck together with double pass welds as are a number of other high end frames. Double pass welds do take a lot more time, but they are done that way for purely aesthetic reasons. A welder can end up with a cleaner bead with a second pass. In our case, the second pass does not get more filler. All of the filler is applied during the first pass and the second pass is simply a washing pass.

Finally, in an attempt to clear up some misunderstandings floating around. The Spectrum welds that one of our customers ends up with are "as welded." We don't remove any material. In the early days of Merlin, we did, on occasion remove some weld material. That practice was eliminated once Seven split off from Merlin and we no longer had to "clean up" some irregularities. We haven't touched a main tube weld since. Oops, we do use nylon brushes on them to give them that brush finish.

Anyway, for the most part, welds are welds. Some look different, and if that matters to you, wonderful. Eddie's or Tyler's or Tim's work is appreciated. And they appreciate that. But that is all it is.

Peace to all...

[rnhood]

Nice posting gentlemen. I certainly learned something about welding today. Now I need to learn about making more money so I can buy a new bike.

[Jeff N.]

Right on, Mr Kellogg. But not long ago I spoke with Bill Holland about single pass vs. double pass. Double pass is quite evidently more aesthetically pleasing than single pass. But I asked him about strength. He said that stress tests on his custom STEMS revealed that single pass-welded stems failed easier than double-pass welded stems....time and time again. Guess which method Bill uses? Right. Just like you and nearly every other custom Ti frame builder.
Double-pass welding takes more time...you essentially weld twice all the way around. The big-boys are into the NUMBERS. Thats the only reason, I would think, that a company would chose single pass over double pass. But I guess it depends on who you talk to. Jeff N.