Go Back  Bike Forums > Bike Forums > Folding Bikes
Reload this Page >

Welding cast Al Brompton rear rack.... info please.

Notices
Folding Bikes Discuss the unique features and issues of folding bikes. Also a great place to learn what folding bike will work best for your needs.

Welding cast Al Brompton rear rack.... info please.

Old 08-25-19, 12:18 PM
  #1  
tmac100
Senior Member
Thread Starter
 
Join Date: Dec 2007
Location: Doha, Qatar
Posts: 940

Bikes: More bicycles than I can ride at one time: 2 custom made tourers, a Brompton 6-speed, and an Indian-made roadster.

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 124 Post(s)
Likes: 0
Liked 3 Times in 3 Posts
Welding cast Al Brompton rear rack.... info please.

My friend's Brommie rear rack was damaged when it was checked in wrapped in bubble wrap inside an Ikea Dimpa bag.

We didn't check the bike for about 6 months after the flight, so no "culpability" with the airline.

The rack is broken at the bolt hole where the front of the rack is attached to the frame. Anyone ever welded cast Al successfully? Should be able to fashion a new "attachment point" on the rack instead of buying a new one and throwing the old broken one away.
tmac100 is offline  
Old 08-25-19, 01:53 PM
  #2  
2_i 
Senior Member
 
Join Date: Sep 2005
Location: Michigan
Posts: 2,513

Bikes: Trek 730, Bike Friday NWT, Brompton M6R*2, Trek 830, Trek 720, Dahon HAT060, Dahon HT060,...

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 352 Post(s)
Liked 13 Times in 11 Posts
Car racing acquaintances weld aluminum regularly. The welding equipment is large and expensive and you must be skilled to operate it. You might check with garages that specialize in motorcycle customizations. While getting a new rack might be the simplest, there might be some learning benefit in trying to fix it, for you and us reading about your or your friend's experiences.
2_i is offline  
Old 08-25-19, 09:50 PM
  #3  
tmac100
Senior Member
Thread Starter
 
Join Date: Dec 2007
Location: Doha, Qatar
Posts: 940

Bikes: More bicycles than I can ride at one time: 2 custom made tourers, a Brompton 6-speed, and an Indian-made roadster.

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 124 Post(s)
Likes: 0
Liked 3 Times in 3 Posts
Sorry if I implied this was a DIY project. Welding is the technique best left to the experts. Thanks for your supportive suggestion. Next stop is the Al welders...
tmac100 is offline  
Old 08-25-19, 10:24 PM
  #4  
2_i 
Senior Member
 
Join Date: Sep 2005
Location: Michigan
Posts: 2,513

Bikes: Trek 730, Bike Friday NWT, Brompton M6R*2, Trek 830, Trek 720, Dahon HAT060, Dahon HT060,...

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 352 Post(s)
Liked 13 Times in 11 Posts
For hobby car racers it is DIY. The welding equipment is pretty central to their hobby. However they will also have a lift to take the engine out of a car - pretty abnormal for most people .

Myself I tried soldering alu, following two different processes in the market, and I would not recommend it to anyone. The chances of destroying the soldered items was at 50% or so. If a joint was achieved, it would not be strong. Welding of alu is, of course, done regularly and correctly done joints hold well.
2_i is offline  
Old 08-28-19, 11:05 AM
  #5  
mconlonx 
Str*t*gic *quivoc*tor
 
mconlonx's Avatar
 
Join Date: Jun 2007
Posts: 7,553
Mentioned: 45 Post(s)
Tagged: 0 Thread(s)
Quoted: 7004 Post(s)
Liked 42 Times in 31 Posts
Burned through plenty of aluminum learning how to TIG weld it. By the end of a class I took, I very inexpertly welded a cast piece of someone's ATV, a fender brace or something. Definitely no an expert, no longer have access to the correct equipment, and someone correct me if I'm wrong, but I also remember hearing that it's a good idea to heat-treat aluminum after welding to make it less brittle and prone to breakage. IOW: take it to someone who knows what they are doing.

If I was going to go DIY and didn't care about the aesthetics, I might try some of that carbon wrap where you wet it down, wrap the repair area, let it do magic, and then it is repaired. But ugly.
__________________
I know next to nothing. I am frequently wrong.
mconlonx is offline  
Old 08-28-19, 11:46 AM
  #6  
tmac100
Senior Member
Thread Starter
 
Join Date: Dec 2007
Location: Doha, Qatar
Posts: 940

Bikes: More bicycles than I can ride at one time: 2 custom made tourers, a Brompton 6-speed, and an Indian-made roadster.

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 124 Post(s)
Likes: 0
Liked 3 Times in 3 Posts
Originally Posted by mconlonx View Post
...... take it to someone who knows what they are doing. ...
Yup, see the last sentence of my last post (#3). Some "things" are best left to acknowledged/professional experts who do those "things" for a living 😉
tmac100 is offline  
Old 08-30-19, 04:10 PM
  #7  
2_i 
Senior Member
 
Join Date: Sep 2005
Location: Michigan
Posts: 2,513

Bikes: Trek 730, Bike Friday NWT, Brompton M6R*2, Trek 830, Trek 720, Dahon HAT060, Dahon HT060,...

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 352 Post(s)
Liked 13 Times in 11 Posts
The car racer, Jessi Combs, who perished while this thread was active, had a distinguished metalworking career. She was accomplished as a welder and created her own line of welding gear for women.

https://www.discovery.com/motor/jess...d-record-crash

https://www.bbc.co.uk/news/world-us-canada-49504222
2_i is offline  
Likes For 2_i:
Old 08-31-19, 12:39 PM
  #8  
tcs
Palmer
 
tcs's Avatar
 
Join Date: Mar 2007
Location: Parts Unknown
Posts: 5,952

Bikes: 1980 Mike Melton, 1982 Stumpjumper, 1982 Santana, 1984 Alex Moulton AM, 2008 BikeFriday tikit T-11, 2010 Dawes Briercliffe, 2017 Dahon Curl i5, 2019 Surly ˝DT14

Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 569 Post(s)
Liked 63 Times in 49 Posts
Originally Posted by tmac100 View Post
Anyone ever welded cast Al successfully?
Depends on the alloy.

Or perhaps it could be brazed.

Should be able to fashion a new "attachment point" on the rack instead of buying a new one and throwing the old broken one away.
Adding additional material to bridge the break is perhaps advisable, and in such case, there are some metal-epoxies that might accomplish repair depending on the future duty of the rack.

If in the future this rack will be loaded with 'around the world' dunnage...just buy a new rack!
tcs is offline  
Old 08-31-19, 05:00 PM
  #9  
Schwinnsta
Schwinnasaur
 
Schwinnsta's Avatar
 
Join Date: Dec 2006
Location: New Orleans, LA
Posts: 930
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 165 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
In 1987 or so, I had an aluminum engine block on a VW Rabbit diesel welded successfully.
Schwinnsta 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.