Go Back  Bike Forums > Bike Forums > Framebuilders
Reload this Page >

Question for Falanx - suggested steel & filler for a particular fabrication situation

Framebuilders Thinking about a custom frame? Lugged vs Fillet Brazed. Different Frame materials? Newvex or Pacenti Lugs? why get a custom Road, Mountain, or Track Frame? Got a question about framebuilding? Lets discuss framebuilding at it's finest.

Question for Falanx - suggested steel & filler for a particular fabrication situation

Old 05-19-13, 04:17 PM
  #1  
Jmclay
Senior Member
Thread Starter
 
Join Date: May 2013
Posts: 66
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Question for Falanx - suggested steel & filler for a particular fabrication situation

I just stumbled onto this frame-building forum and wonder of wonders have discovered a bonafide materials engineer, with wit, no less! I have read every relevant post submitted by Falanx that I have been able to find on steel tubing. As an ME who's materials knowledge is akin to dividing by zero, and as a keen amateur frame-builder who is hopefully better than that, this question keeps knackering me: Which steel tube set and filler (brass/silver) would be most suitable (and why) for these circumstances and the goal of maximizing toughness (I think that's the goal).

1) Lugs
2) Excellent tube to tube coped joints and lug fit-up
3) Excellent brazing fill/penetration of lug interstices but I take a bit more time to complete a joint and at slightly higher end of a given filler's range.
4) The bottom bracket shell & tubes get two heat and cool cycles, one for DT & ST and one for the chainstays. Actually three, the main tubes get tack brazed and aligned before the main fill. Everything else gets two; tack, align, braze.

I use brass and silver, have read much of the advertising around the "new" bicycle steels/treatments, read Mario Emiliani's article on silver vs. brass and a lot more; I have concluded that I haven't the technical background, by a long shot, to answer my question! Ever. The good news seems to be that all of the usual material players do a pretty good job when handled reasonably well; but I'd like to know what is optimum under the circumstances.

Thanks much,
John

http://www.flickr.com/photos/2162441...7629417200546/

Last edited by Jmclay; 05-19-13 at 07:29 PM. Reason: Added photo link
Jmclay is offline  
Old 05-20-13, 09:03 AM
  #2  
ksisler
Senior Member
 
Join Date: Sep 2012
Posts: 1,720
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
Liked 0 Times in 0 Posts
OP; It is for sure you will get good answers as many outstanding builders habit here.

However, brace youself as you will likely get 3 correct answers from each question, plus several "well it depends".

/K
ksisler is offline  
Old 05-20-13, 11:44 AM
  #3  
calstar 
Senior Member
 
calstar's Avatar
 
Join Date: Mar 2012
Location: santa barbara CA
Posts: 981
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 52 Post(s)
Liked 1 Time in 1 Post
Originally Posted by ksisler View Post
OP;
However, brace youself as you will likely get 3 correct answers from each question, plus several "well it depends".

/K
__________________
"The older I get the better I was" Brian
calstar is offline  
Old 05-22-13, 02:28 PM
  #4  
MassiveD
Senior Member
 
Join Date: Jul 2011
Posts: 2,434
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
- It's a fair question. My first thought with this kind of issue is how to avoid this question ever coming up at all. I don't personally ever want to build a bike that would be close enough to disaster for this to be a factor. With probably 5-10K posts on framebuilding and some huge multiple of more reads, I have never seen a post where a guy was building to real numbers and had some multiple for safety to build to. Apparently we have pretty robust margins to build to.

Other fields like planes (or maybe bikes in the EU), have products engineered, graded materials, certification for doing the joints, inspections, static testing, certification for flight, then inspection protocols. Apparently building bikes isn't that risky. I haven't heard much about EU standards recently, but early reports were that the Walmart type bikes were doing better than the customs, which isn't that surprising, since the weight budget is pretty open ended.

- Heat wise, to paraphrase the old saying about misfortune: 80% of bike tubing doesn't care how hot you get it short of setting it on fire, and the remaining 20% actually gets stronger. Might be missing something.. but not much.

- Materials do mater, stainless for instance, you want silver or something designed to braze it.

- Another thing is heat over heat. If you do heats in stages like when making lugs out of tubing, there may be an advantage to using a higher temp fillers first. Though some people can get by on the fact that reheated filler has a higher melting point.

Also, if you really wanted to get into it, it would probably be important to have some actual stated objectives. The answers might differ quite a bit depending on what the critical, heat, or materials specs were. One can always go nuts and rather than dealing in generalities examine the actual specs that the manufacturer suggest. These might include inconvenient competence suggestions for the maker. It also isn't just filler. It is torch, flux, filler, cleaning, and what combination of all these things.

Last edited by MassiveD; 05-22-13 at 02:43 PM.
MassiveD is offline  
Old 05-23-13, 08:12 AM
  #5  
ksisler
Senior Member
 
Join Date: Sep 2012
Posts: 1,720
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
Liked 0 Times in 0 Posts
Ditto Massive;

- I can see that about 90% of frame builders are still using artisanal processes and procedures in a cottage industry environment and not the (perhaps) more modern, more refined industrial ones.

-- In an industrial activity, the complexity and skills are essentially engineered out of the human contribution and embedded into the machines, jigs, materials, lines, and processes (areas which can be sped up without affecting product). The net intent of industrialization is to increase output, lower total cost per widget, and enable completion of the manufacturing to an adequate product but with fewer, less skilled/training/educated personnel (=cheaper). If one sees robots welding bike frames, it is pretty certain that it is "industrialized" as would a factory where individual workers still weld, but they weld only one specific joint on every frame as the frame proceeds down a production line in a serial fashion. This second case exists only due to the cost of robotics to replace the human workers in areas where labor is cheap and fairly expendable.

-- When I originally visited the Trek and Santana factories in the late 1970's and early 1980's it was clear that a zillion hours of engineering effort had been incorporated. However in both cases, the workers executing the build tasks were still highly skilled individual builders indicating that the shops were still artisanal/cottage activities vice industrial; just increased in scale to get the production numbers up. This is what kept the price per bike/frame for their brands a good bit higher that similar looking department store items (quality issues aside).

-- It is certainly possible to industrialize frame building and some of the ISO certified factories in China probably approach that categorization for high volume frames. Rigid standardization of product has enabled relatively good bikes are very low prices, but at the cost of allow almost no per customer individualization... Thus for customers with adequate disposable income, the custom builders will continue to have a good market segment to feed them.

/K
ksisler is offline  
Old 05-23-13, 08:34 AM
  #6  
ksisler
Senior Member
 
Join Date: Sep 2012
Posts: 1,720
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
Liked 0 Times in 0 Posts
[Partial Quote from MassiveD; Another thing is heat over heat. If you do heats in stages like when making lugs out of tubing, there may be an advantage to using a higher temp fillers first. Though some people can get by on the fact that reheated filler has a higher melting point. Unquote]

Massive; I don't think this has previously been discussed in this forum. Neat. When I have had a need to make lugs for tandems; in the early days the lug parts were just welded together and then the frame was brazed traditionally, once or twice with silver. but mostly just brass. In later days, since the TIG provides a stronger, more reliable joint I have used it to craft the lugs, but again followed by traditional brass or silver to complete the joints.

I can see where brass for the lug construction followed by silver for applying them would make sense from a heat management/staging standpoint as you stated. I would have never thought of brass for both the lugs and for joint itself...

I would like to hear what jointing methods others use to make lugs and then to finish the frame joints off. I wasn't really aware that very many builders fab'd up their own lugs. I know I generally want to avoid it when good lugs are already available from others.

/K
ksisler is offline  
Old 05-23-13, 09:52 AM
  #7  
cycle_maven
Collector of Useless Info
 
Join Date: Aug 2009
Posts: 1,407
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Dividing by zero is infinity... Just sayin'
cycle_maven is offline  
Old 05-23-13, 11:16 AM
  #8  
Jmclay
Senior Member
Thread Starter
 
Join Date: May 2013
Posts: 66
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by cycle_maven View Post
Dividing by zero is infinity... Just sayin'
Actually, dividing by numbers that tend towards zero, is infinity; dividing by zero is undefined. My materials knowledge is better than that but with one course in it and no professional experience I can't own to knowing very much. Falanx is obviously at the other end of that spectrum! I'd like to see through his eyes!

The objective isn't to see how little I can get away with but simply this: Given the available "nicer" steels these days, which ingredient combinations (of steel and filler) will produce the highest toughness (or most attractive combination of yield and toughness) after enduring the brazing cycles typical of building a bicycle frame. For me that's tack and one or two brazing heats depending on the joint, a little on the hot and slow side but flooded interstices and tight joints. Maybe it still boils down to using whatever steel you want and silver if looking for the best result, whether or not it matters much in the end. While I AM curious about the most clever choice of these two ingredients (and the supporting science) I am still perfectly happy to use plain vanilla 9/6 bicycle tubing, brass and pressed lugs. I don't have a silvered frame in my stable right now.

On a practical note, I find Columbus SL attractive because it comes in standard diameters in an 8/5 wall, is easily available and is a bit higher in yield, at least on the front end, than many others. What I don't know is how it responds to brass vs. silver temps. Since it's tiggable I'd assume it's grain structure would be happy with brass temps, but is it even more happy with silver temps, or do the brass temps refine the grain further? But then how about 5 cm farther down the tube?
Jmclay is offline  
Old 05-23-13, 11:39 AM
  #9  
tuz
Senior Member
 
Join Date: Dec 2006
Location: Toronto/Montréal
Posts: 1,193

Bikes: Homemade mixte, track, commuter and road, Ryffranck road

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
It would be interesting to know the toughness. However, unless you crash (in which case all bets are off anyway), you won't be regularly stressing the bike to levels where toughness, yield strength, etc. matter? I'd be more interested in the resistance to fatigue vs. joining method and steel alloy.
tuz is offline  
Old 05-23-13, 12:46 PM
  #10  
ksisler
Senior Member
 
Join Date: Sep 2012
Posts: 1,720
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
Liked 0 Times in 0 Posts
Originally Posted by Jmclay View Post

Actually, dividing by numbers that tend towards zero, is infinity; dividing by zero is undefined. My materials knowledge is better than that but with one course in it and no professional experience I can't own to knowing very much. Falanx is obviously at the other end of that spectrum! I'd like to see through his eyes! The objective isn't to see how little I can get away with but simply this: Given the available "nicer" steels these days, which ingredient combinations (of steel and filler) will produce the highest toughness (or most attractive combination of yield and toughness) after enduring the brazing cycles typical of building a bicycle frame. For me that's tack and one or two brazing heats depending on the joint, a little on the hot and slow side but flooded interstices and tight joints. Maybe it still boils down to using whatever steel you want and silver if looking for the best result, whether or not it matters much in the end. While I AM curious about the most clever choice of these two ingredients (and the supporting science) I am still perfectly happy to use plain vanilla 9/6 bicycle tubing, brass and pressed lugs. I don't have a silvered frame in my stable right now.

On a practical note, I find Columbus SL attractive because it comes in standard diameters in an 8/5 wall, is easily available and is a bit higher in yield, at least on the front end, than many others. What I don't know is how it responds to brass vs. silver temps. Since it's tiggable I'd assume it's grain structure would be happy with brass temps, but is it even more happy with silver temps, or do the brass temps refine the grain further? But then how about 5 cm farther down the tube?
OP; I believe I read that a few tube variants are TIG only...meaning not meant to be torched. It was one of the one for sale from one of the suppliers in the suppliers thread.
ksisler is offline  
Old 05-23-13, 02:37 PM
  #11  
calstar 
Senior Member
 
calstar's Avatar
 
Join Date: Mar 2012
Location: santa barbara CA
Posts: 981
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 52 Post(s)
Liked 1 Time in 1 Post
Originally Posted by ksisler View Post
OP; I believe I read that a few tube variants are TIG only...meaning not meant to be torched. It was one of the one for sale from one of the suppliers in the suppliers thread.
I'm pretty sure I read somewhere the "TIG only tubes" are speced because the tubes have shorter ends before the transition/butt begins. The HAZ of TIG is smaller than that of brazing(at least for brass) so the thicker walled ends do not have to be as long to protect the properties of the tubes. Brazing/torching a TIG only tube would most likey result in overheating the thinner transition/butted section.

Brian
__________________
"The older I get the better I was" Brian
calstar is offline  
Old 05-23-13, 06:45 PM
  #12  
Jmclay
Senior Member
Thread Starter
 
Join Date: May 2013
Posts: 66
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I believe that detail is correct Calstar.
Jmclay is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.