SF Cyclotouring

Ride reports and other ramblings from a San Francisco cyclist.


A Sort of Frame Repair

A few months back, towards the end of a short weekend tour, the BB on my trusty Trek 400 started creaking with each pedal stroke.  Poking and prodding at the bike, I discovered what looked like a crack on the edge of the downtube-to-bottom-bracket lug:

Crack maybe?

I posted to the Framebuilders' List about this problem, and while most agreed that it wasn't worth it to replace the down tube on this old, off-the-shelf frame, I got some recommendations to try to patch the area.  So that's how I proceeded.

First I stripped the paint off the frame in the affected area.  Then I cut and shaped a triangular patch out of an old chunk of fork steerer tube:

Trek 400 Repair

Next I brazed the patch on as best as I could, trying to make sure that brass filler fully penetrated between the patch and the frame tube, as well as building up a blob of brass across the patch and the lug to strengthen that area:

Frame fix

This was harder than I expected, because the BB shell really sucks up any heat you apply to the lug socket.  You can see the black spots on the patch where the flux got overheated and scorched.  In retrospect, I should've used the largest tip on my torch, instead of the same one I use for rack-building.  However, I posted the results back to the Framebuilders' List, and got some encouraging comments that my repair looked fairly OK.

Then I sanded and primed the repaired area:


And then painted the area with white spraypaint:

Painted BB reinforcement

The result looks a little blobby up close, but from 6 feet away, you'd never notice it.


I reassembled the bike with a new cartridge BB since the previous one was starting to feel a little notchy.  So far, the bike's been as good as new, and the creak is gone!  I've since ridden this bike on a couple of mixed-terrain rides, plus another weekend tour, and it seems to work as good as new.


Oxy/Propane Brazing Torch Equipment

I just realized I never documented the components of my oxygen/propane brazing torch setup.  I spent a lot of time researching this stuff, so I want to post it to hopefully help the next person seeking something similar...

  1. Hoke Jeweler's Torch, Oxy/Propane, with 5 tips ($42.50)
  2. Premier Industries 2300.510 LP regulator ($64.00)
  3. 12' of 1/4" T-grade hoses with B-fittings at one end ($34.00)
  4. Flashback arrestor set ($75.00)
  5. Nellcor Puritan Bennett 590 Oxygen Concentrator (~$250 used)
  6. 20lb propane tank (~$60, or borrow from your BBQ grill)
(Total ~$525)

You can find better, light-weight hoses -- or cheaper prices on similar hoses -- but I didn't want to spend the extra overhead of buying multiple items from multiple vendors.  Premier had the regulator I wanted -- plus everything else -- so I just bought everything from them to keep things simple.  I bought the oxygen-concentrator via my local Craigslist.  I already had the propane tank, but you can get one from someplace like a Blue Rhino tank exchange for about $60.

Setting up


Introducing The Potis Strap

This is a brilliant idea that I wish I'd thought of, but didn't.  It came from the mind of Mr. Potis.

1. Bungie-cord loop through strap-loops on the bottom of your rando bag. (I just tied off the bungie cord with a simple square knot.)
Potis strap

2. The bungie-cord loop fits through the front loop of your front rack, and over the backstop.
Potis strap

3. Then you fit the bag on the rack as usual.  The bungie cord keeps the front of the bag nice and snug to your rack!
Potis strap

Easy on-and-off.  Brilliant!


Nitto Rack Wings

Nitto Rack Wings by jimgskoop
Nitto Rack Wings, a photo by jimgskoop on Flickr.

Made a friend's Nitto M-12 rack wider to eliminate Berthoud bag sag.


Nice Rack


Hoke Torch Tips Sizes

Nowhere on the 'net is there information about the actual sizes of tips for the Hoke Jeweler's Torch!  So I've measured and posted them here.
  • Propane Tip #1A - Drill bit size #60 - 0.040 inches
  • Propane Tip #2A - Drill bit size #57 - 0.043 inches
  • Propane Tip #3A - Drill bit size #54 - 0.054 inches
  • Propane Tip #5A - Drill bit size #49 - 0.073 inches
Here are some Victor tip sizes for comparison:
  • Victor #00 - Drill size #70 - 0.028 inches
  • Victor #0 - Drill size #65 - 0.035 inches
  • Victor #1 - Drill size #60 - 0.040 inches
  • Victor #2 - Drill size #56 - 0.046 inches
  • Victor #3 - Drill size #53 - 0.060 inches
  • Victor #4 - Drill size #49 - 0.073 inches



HokeOxyCon!Torch StuffSetting upFirst lightPortable
First Braze AttemptBrazin'

Oxy/Propane Brazing Torch, a set on Flickr.

Finally, after quite literally wanting one for ~20 years, I have a proper brazing torch rig! Now I have to learn how to use it, since this works very VERY differently than my simple MAPP/air torch.