Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

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.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 07-27-16, 09:00 AM   #1
chased
Junior Member
Thread Starter
 
Join Date: May 2016
Location: Spartanburg, SC
Bikes: otobecane Mirage Road, Schwinn Sprint Fixed Gear, Panasonic Track Bike, Townie
Posts: 11
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Thin wall practice

Hi all,

I am about to start building my first steel bike with bronze fillet joints and looking for a bit of practice on thin wall tubing. I have built a good amount of bronze-brazed steel furniture, but it has all be pretty thick stuff (1/16-1/8") and I'm afraid of blowing a hole through the tubing or scalloping a joint. I just want to get a little bit of practice making sure I make good joints before ruining any good tubing.

What materials should I pick up for this practice? Should I buy a couple tubes from a supplier and chop them up to try to fit them together? Other ideas?

Thanks
chased is offline   Reply With Quote
Old 07-27-16, 09:37 AM   #2
David Tollefson
Senior Member
 
Join Date: Dec 2012
Location: Puyallup, WA
Bikes: Many... Up to 9 in the stable now
Posts: 58
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Aircraft Spruce has grab-bag tubing ends (usually just slightly less than 12") that are good practice pieces. Or just get some straight gage 4130 tubing in whatever length you like. Or dumpster dive some trashed frames and cut them up for practice.
David Tollefson is offline   Reply With Quote
Old 07-29-16, 02:04 PM   #3
OshkoshBiker
Member
 
Join Date: Oct 2015
Location: Oshkosh, WI
Bikes: DB Haanjo Comp, Trek 1.2, Murray MTB, Framed Minnesota 2.0
Posts: 41
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Quote:
Originally Posted by David Tollefson View Post
Aircraft Spruce has grab-bag tubing ends (usually just slightly less than 12") that are good practice pieces. Or just get some straight gage 4130 tubing in whatever length you like. Or dumpster dive some trashed frames and cut them up for practice.
Is the tubing from Aircraft Spruce the same stuff as what bikes are made from? I have the same question, however, I was going to give TIG welding a try.

Kind regards,

OshksohBiker
OshkoshBiker is offline   Reply With Quote
Old 07-29-16, 03:58 PM   #4
dsaul
Senior Member
 
Join Date: Jan 2013
Bikes:
Posts: 472
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
Get a few 4 foot lengths of .035" 4130 tubing. You can cut them up and make a bunch of T-joints to practice brazing/welding. I found it easiest to leave one tube fairly long and cut the other into small 2-3" pieces. Miter the end of the long tube and weld/braze a small piece to it. Cut that joint off and miter the end of the long piece again for the next joint. This way you can put the long tube into a clamp or vise to position it during welding/brazing.

And, yes, 4130 is the same stuff bike frames are made of.
dsaul is offline   Reply With Quote
Old 08-01-16, 08:17 AM   #5
chased
Junior Member
Thread Starter
 
Join Date: May 2016
Location: Spartanburg, SC
Bikes: otobecane Mirage Road, Schwinn Sprint Fixed Gear, Panasonic Track Bike, Townie
Posts: 11
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
That sounds good to me. However, my local supplier only has mild steel in .065; would this work for practice? It is a little thicker, but seems like it might do the trick. It is also A LOT less expensive than 4130. 24' for $28 and I could use the leftovers for some project down the line - or build a heavy townie with it.

Quote:
Originally Posted by dsaul View Post
Get a few 4 foot lengths of .035" 4130 tubing. You can cut them up and make a bunch of T-joints to practice brazing/welding. I found it easiest to leave one tube fairly long and cut the other into small 2-3" pieces. Miter the end of the long tube and weld/braze a small piece to it. Cut that joint off and miter the end of the long piece again for the next joint. This way you can put the long tube into a clamp or vise to position it during welding/brazing.

And, yes, 4130 is the same stuff bike frames are made of.
chased is offline   Reply With Quote
Old 08-01-16, 03:12 PM   #6
randomgear
Senior Member
 
Join Date: Jul 2006
Location: beantown
Bikes: '89 Specialized Hardrock Fixed Gear Commuter; 1984? Dawes Atlantis
Posts: 877
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
When you switch to thinner wall tubing for an actual bike, you might be surprised at just how fast it heats up.
I've been playing with tubing off a gas pipe bike, that is about 0.065" with my Bernzomatic propane torch - it takes forever to heat up and I get impatient. I don't have nearly as much frustration with 0.035" tubing.
randomgear is offline   Reply With Quote
Old 08-01-16, 03:52 PM   #7
dsaul
Senior Member
 
Join Date: Jan 2013
Bikes:
Posts: 472
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
.065 mild steel will help you with brazing around round joints, but it will still be different than thinwall chomoly tubing. The biggest difference is going to be how fast it gets up to brazing temp. Your concerns about blowing a hole in a thinwall tube are not something to worry about. You would have to really ignore the sparkly red metal to actually melt a hole in it with the torch tip sizes commonly used for bicycles.
dsaul is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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



All times are GMT -6. The time now is 06:29 PM.