Why is butt welding ok now?
#1
Banned
Thread Starter
Join Date: Apr 2010
Location: Lincoln Ne
Posts: 9,924
Bikes: RANS Stratus TerraTrike Tour II
Mentioned: 46 Post(s)
Tagged: 0 Thread(s)
Quoted: 3352 Post(s)
Liked 1,056 Times
in
635 Posts
Why is butt welding ok now?
Up thru most of the 80s if you bought a bike book, you were warned that a butt welded frame was junk. You needed to buy a lugged frame brazed or silver soldered at low temperature. The snobs basically said cyclist ride a lugged framed bikes, and the unwashed rode junk.
Does anyone have a scientific engineering reason why butt welding doesnt weaken tubes now?
Does anyone have a scientific engineering reason why butt welding doesnt weaken tubes now?
#2
Senior Member
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 33,656
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 2026 Post(s)
Likes: 0
Liked 1,095 Times
in
741 Posts
Because welding techniques have improved immensely, newer tubing alloys and shapes are better able to take the welding heat and brazed lugged assembly has gotten too expensive.
#3
Banned.
Join Date: Apr 2011
Posts: 937
Bikes: CCM Torino 76
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
I may be wrong, but...
I seem to recall a study done in the mid/late 80s that showed, I think, improved strength from joints or material around joints (the heat affected zone, or HAZ) heated at the higher temperatures required for welding, but for less time, compared to the longer time spent at lower tempertures to ensure brazing material filled all the joints or built up a good fillet. I think Keith Bontrager was involved with, or conducted, this study.
I seem to recall a study done in the mid/late 80s that showed, I think, improved strength from joints or material around joints (the heat affected zone, or HAZ) heated at the higher temperatures required for welding, but for less time, compared to the longer time spent at lower tempertures to ensure brazing material filled all the joints or built up a good fillet. I think Keith Bontrager was involved with, or conducted, this study.
#4
30 YR Wrench
Join Date: Aug 2005
Location: Oxford, OH
Posts: 2,006
Bikes: Waterford R-33, Madone 6.5, Trek 520
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 3 Times
in
2 Posts
The tubes used prior to the availability of air-hardening steels weakened significantly when exposed to the heat of welding. The only way to compensate was to make the tube thicker, therefore heavier. The new classes of steels actually get stronger with the heat, so the tubes can be quite thin. My welded Waterford R-33 has a downtube that is .7MM at the welds. Amazing. And the frame itself, made of S-3 steel weighs 2.9 lbs. Also, with the advent of laser tube mitering, tubes can be cut to fit precisely together, so that a very small weld bead is required.
#5
Banned.
Join Date: Apr 2011
Posts: 937
Bikes: CCM Torino 76
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
The tubes used prior to the availability of air-hardening steels weakened significantly when exposed to the heat of welding. The only way to compensate was to make the tube thicker, therefore heavier. The new classes of steels actually get stronger with the heat, so the tubes can be quite thin. My welded Waterford R-33 has a downtube that is .7MM at the welds. Amazing. And the frame itself, made of S-3 steel weighs 2.9 lbs. Also, with the advent of laser tube mitering, tubes can be cut to fit precisely together, so that a very small weld bead is required.
Here are some comments made online by Keith Bontrager:
https://search.bikelist.org/getmsg.as....9911.0067.eml
Basically, the pertinent info presented here is that welding does weaken tubes, but since the heat is applied and removed quickly, the HAZ is small and easier to deal with. Brazing requires either heating a larger area (generally with lugs) or heating for a longer time (as with fillet brazing).
Last edited by DCB0; 03-09-12 at 09:55 AM. Reason: splelign misteak
#6
Banned
#1, TIG , Tungsten Inert Gas.. welding is not Butt welding .
Where the spark from the tip of the torch with the tungsten point in the center,
there a fillet of wire laid down around the miter. with the heat joining all 3.
Where the spark from the tip of the torch with the tungsten point in the center,
there a fillet of wire laid down around the miter. with the heat joining all 3.
Last edited by fietsbob; 03-09-12 at 05:03 PM.
#7
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,671
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5767 Post(s)
Liked 2,541 Times
in
1,407 Posts
A combination of all the reasons above, including mainly materials and techniques.
The issue with welding in the past is that, with the steels in use, a weld created a weakened area just beyond the joint, making the joint radically stronger than it's surrounding area and therefore prone to cracking there. The welds held up fine, and the tube would crack adjacent.
We still see that from time to time, but not all that often because the current materials and techniques manage it much better. It should be noted that during the same period that bike buyers were warned against welded bikes, motorcycles, airframes, auto roll bars, and all sorts of critical strictures were being welded very successfully.
There's also a bit of confusion in that many of the "welded" bikes of the period in question, weren't in fact welded, but had brazed butt joints without benefit of filets or lugs. These so-called frames were very common at the low end of the spectrum, and while usually OK, prone to failure.
Current mat
The issue with welding in the past is that, with the steels in use, a weld created a weakened area just beyond the joint, making the joint radically stronger than it's surrounding area and therefore prone to cracking there. The welds held up fine, and the tube would crack adjacent.
We still see that from time to time, but not all that often because the current materials and techniques manage it much better. It should be noted that during the same period that bike buyers were warned against welded bikes, motorcycles, airframes, auto roll bars, and all sorts of critical strictures were being welded very successfully.
There's also a bit of confusion in that many of the "welded" bikes of the period in question, weren't in fact welded, but had brazed butt joints without benefit of filets or lugs. These so-called frames were very common at the low end of the spectrum, and while usually OK, prone to failure.
Current mat
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#8
Old fart
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,779
Bikes: Several, mostly not name brands.
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3583 Post(s)
Liked 3,395 Times
in
1,929 Posts
#9
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,671
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5767 Post(s)
Liked 2,541 Times
in
1,407 Posts
Max temp is only part of the story, and higher isn't always worse. Different alloys respond differently to heating, and much more importantly cooling. Often the rate of cooling is the most important consideration.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#10
Senior Member
Welding techniques and joinery got better. So did tubing.
Did the same books from the 80s also pooh-pooh butt brazed joints, i.e. fillet brazed "butt" joints? Didn't think so...
Plus it might be that the books you are reading weren't based on the most awesome science and technical knowledge... They might have just been bringing their preconceived notions of aesthetics into play instead of sound technological know-how.
Did the same books from the 80s also pooh-pooh butt brazed joints, i.e. fillet brazed "butt" joints? Didn't think so...
Plus it might be that the books you are reading weren't based on the most awesome science and technical knowledge... They might have just been bringing their preconceived notions of aesthetics into play instead of sound technological know-how.
#12
Senior Member
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 33,656
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 2026 Post(s)
Likes: 0
Liked 1,095 Times
in
741 Posts
Expanding on FBinNY's posting above, so-called "fillet brazed" joints made without lugs were used on both ends of the quality spectrum. Some very high quality custom frames were made using that technique as well as low quality cheap ones.
#13
Senior Member
Join Date: Jul 2006
Posts: 425
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I think the only mass produced bikes with actual butt welds were the Electro-forged Chicago Schwinns. Not considered a top line bicycle, but I think history has proven the strength of the welds. Otherwise, the frames during that time (the 80s) were most likely TIG welded. Tig welding has a long history in aircraft structures. It is a proven joining technique.
Last edited by krome; 03-09-12 at 10:38 AM.
#14
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,671
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5767 Post(s)
Liked 2,541 Times
in
1,407 Posts
...
I think the only mass produced bikes with actual butt welds were the Electro-forged Chicago Schwinns. Not considered a top line bicycle, but I think history has proven the strength of the welds. Otherwise, the frames during that time were most likely TIG welded. Tig welding has a long history in aircraft structures. It is a proven joining technique.
I think the only mass produced bikes with actual butt welds were the Electro-forged Chicago Schwinns. Not considered a top line bicycle, but I think history has proven the strength of the welds. Otherwise, the frames during that time were most likely TIG welded. Tig welding has a long history in aircraft structures. It is a proven joining technique.
Butt weld refers to the type of the joint, namely 2 members meeting end to end, or at an angle with no overlap or reinforcement save the weld itself.
TiG welding refers to the welding process itself, which uses an inert gas to protect the weld area from harmful exposure to the surrounding air.
Whether TiG welded or not, most modern welded frames are butt welded though it would probably to refer to the joints as "T" joints (though nobody I know in the bike world ever does).
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
Last edited by FBinNY; 03-09-12 at 10:51 AM.
#15
Senior Member
Join Date: Jul 2006
Posts: 425
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
You're mixing terms with different meanings.
Butt weld refers to the type of the joint, namely 2 members meeting end to end, or at an angle with no overlap or reinforcement save the weld itself.
TiG welding refers to the welding process itself, which uses an inert gas to protect the weld area from harmful exposure to the surrounding air.
Whether TiG welded or not, most modern welded frames are butt welded
Butt weld refers to the type of the joint, namely 2 members meeting end to end, or at an angle with no overlap or reinforcement save the weld itself.
TiG welding refers to the welding process itself, which uses an inert gas to protect the weld area from harmful exposure to the surrounding air.
Whether TiG welded or not, most modern welded frames are butt welded
You are correct on the nomenclature, a butt weld is a geometry, but the electro-forged process is not the same as most other welding techniques. It is more akin to spot welding, in that it did not use filler material and it was a resistance weld.
As far as I can tell, the techniques used in mass produced metal bicycle frames were thus:
Fillet brazed
silver brazed with lugs
Tig welding
Schwinn's Electro-forged
Adhesive bonding with lugs
And I'm not sure of MIG welding, but I wouldn't be surprised if it is used in the mass production of consumer aluminum frames today.
Last edited by krome; 03-09-12 at 11:04 AM. Reason: added adhesive bonding.
#16
Banned
its the big rooms with a thousand people in Asia doing skilled hand welding
for low cost per unit produced, of a million frames that make it OK..
for low cost per unit produced, of a million frames that make it OK..
#17
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,671
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5767 Post(s)
Liked 2,541 Times
in
1,407 Posts
brass brazed with lugs, internal or external
brass brazed of mitered tubes with little or no built up filet save for the bit that occurs naturally due to surface tension.
furnace brazing with copper, often used for attaching steerers to crowns as a sub assembly.
Also note that while Americans and British were brazing with gas, the Italians were doing very nice work with induction heating which produced very clean joints.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#18
Senior Member
Join Date: Aug 2005
Location: Pittsburgh, PA
Posts: 33,656
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
Mentioned: 39 Post(s)
Tagged: 0 Thread(s)
Quoted: 2026 Post(s)
Likes: 0
Liked 1,095 Times
in
741 Posts
I don't think lugged silver brazing was ever used on mass produced bikes, they are lugged brass brazed. Silver brazing is an expensive technique used mostly by custom builders dealing with particularly temperature sensitive tubing as uses lower temperatures than brass brazing.
#19
Senior Member
Join Date: Sep 2007
Location: Gaseous Cloud around Uranus
Posts: 3,741
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 38 Post(s)
Likes: 0
Liked 11 Times
in
7 Posts
1: Bicycles don't have butt welds,they have fillet welds.
2:CroMo,Tig and fillet welds,as a team, have been around since WWII,we understand them pretty well by now.
3:CroMo work hardens as you use it,so the HAZ zone actually improves in strenght as you use it.
4:The only difference between now and then is the internet,more crap get spread around.CroMo,Tig and butt welds made alot of things before bicycles.....like airplanes and race cars/bikes,buildings...ect.
5:Tig welding was a "black art" for many many years.Ask most machanic types about tig welding in 1960-1970, they would look at you like Nipper the RCA dog! Hell,most of them STILL think it's magic.
6: Really,the only difference between Tig and OA, is one has a flame and one has a lightening bolt to melt the metal,short of the sheilding,and that can be cured with flux.
7:Before 1940 they has CroMo and they used to OA it together to make airplanes,it's a wonder they didn't fall from the sky......They welded aluminum with OA also.....how did they do it without TIG.....I think all of the smart people died.....
2:CroMo,Tig and fillet welds,as a team, have been around since WWII,we understand them pretty well by now.
3:CroMo work hardens as you use it,so the HAZ zone actually improves in strenght as you use it.
4:The only difference between now and then is the internet,more crap get spread around.CroMo,Tig and butt welds made alot of things before bicycles.....like airplanes and race cars/bikes,buildings...ect.
5:Tig welding was a "black art" for many many years.Ask most machanic types about tig welding in 1960-1970, they would look at you like Nipper the RCA dog! Hell,most of them STILL think it's magic.
6: Really,the only difference between Tig and OA, is one has a flame and one has a lightening bolt to melt the metal,short of the sheilding,and that can be cured with flux.
7:Before 1940 they has CroMo and they used to OA it together to make airplanes,it's a wonder they didn't fall from the sky......They welded aluminum with OA also.....how did they do it without TIG.....I think all of the smart people died.....
Last edited by Booger1; 03-09-12 at 11:51 AM.
#20
Senior Member
Most (all?) of the connections on an electro-forged Schwinn actually have an internal sleeve and are not butt-welded.
#21
Banned
Yea there was a spigot in the headtube, the main tubes went over.
those were punched out and butt welded themselves .. edge to edge.
it was the BSO of the era , that cranked up the power
and the end of the tube was hot enough to
stick in a spot welding like situation, no filler needed.
those were punched out and butt welded themselves .. edge to edge.
it was the BSO of the era , that cranked up the power
and the end of the tube was hot enough to
stick in a spot welding like situation, no filler needed.
Last edited by fietsbob; 03-09-12 at 12:47 PM.
#22
Old fart
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,779
Bikes: Several, mostly not name brands.
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3583 Post(s)
Liked 3,395 Times
in
1,929 Posts
#23
Senior Member
Join Date: Feb 2012
Location: You have really nice furniture
Posts: 821
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
When I first saw the title I thought he was talking about welding a butt and I thought that would never be OK.
#24
Senior Member
Join Date: Jul 2009
Posts: 11,128
Bikes: 1986 Alan Record Carbonio, 1985 Vitus Plus Carbone 7, 1984 Peugeot PSV, 1972 Line Seeker, 1986(est.) Medici Aerodynamic (Project), 1985(est.) Peugeot PY10FC
Mentioned: 22 Post(s)
Tagged: 0 Thread(s)
Quoted: 150 Post(s)
Likes: 0
Liked 34 Times
in
27 Posts
There's also a bit of confusion in that many of the "welded" bikes of the period in question, weren't in fact welded, but had brazed butt joints without benefit of filets or lugs. These so-called frames were very common at the low end of the spectrum, and while usually OK, prone to failure.
Current mat
Chombi
.
#25
Senior Member
Join Date: Jun 2011
Location: Sunnyvale, California
Posts: 1,180
Bikes: Bridgestone RB-1, 600, T700, MB-6 w/ Dirt Drops, MB-Zip, Bianchi Limited, Nashbar Hounder
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I was under the impression that little in terms of welding technology has changed much, with exception of robotics being very consistent in quality and repeatability. That said, I was told by one maker that for their mass production steel frames, they were now getting cheaper tubing that was "super-butted" and pre-formed for their frames and this allowed them to butt weld simply because now the tubing at the joint was thicker. And the use of robots to do the welding made the work much faster, cheaper, and more precise than could be for average humans. So this reduced the HAZ issues that might migrate out of the super-butted region.
For aluminum, I think the extrusion technology has really been the key and we see curved frames and not straight tubes even with customized joint designs for frames because robots can TIG weld extremely well. I think that's what makes the biggest difference. In the old days of working in the machine shop building pressure vessels, I learned to TIG weld and stick weld and braze. And it wasn't easy to lay down a fine bead consistently, and every time I had to stop and itch something and took the inert gas off the bead and restart, it weakened the joint especially with aluminum. I think the real difference here is in robotics and automation of the process that has enable butt welds to achieve strength. They were always strong if done right, only humans were flawed and only a few could do it right consistently. Machines have changed that.
For aluminum, I think the extrusion technology has really been the key and we see curved frames and not straight tubes even with customized joint designs for frames because robots can TIG weld extremely well. I think that's what makes the biggest difference. In the old days of working in the machine shop building pressure vessels, I learned to TIG weld and stick weld and braze. And it wasn't easy to lay down a fine bead consistently, and every time I had to stop and itch something and took the inert gas off the bead and restart, it weakened the joint especially with aluminum. I think the real difference here is in robotics and automation of the process that has enable butt welds to achieve strength. They were always strong if done right, only humans were flawed and only a few could do it right consistently. Machines have changed that.