It is Easter and I am loving the amount of time I’ve had in the workshop this weekend. I’m getting stuck into a couple of projects. Today is the turn of SB6560, a 531c 1984 Services des Courses frame that needs a small frame repair. I prepped the frame for this repair a few weeks ago and now have some time to finish the job.
This is how I left it…
I’d removed the poorly fitted transfers and took care of the stubby remains of the gear lever bosses, taking things back to the bare 531 tube.
Today was the day I actually got around to doing something with those bosses. It’s been a good while since I did my frame building course with Dave Yates but I’m sure everything I needed was still in my brain! First thing to do was transfer the location of the boss. I had taken a measurement before the earlier work, measuring from the boss to the head lug. I marked this location on the bare steel with a sharpie.
Once every part is cleaned, I flux both the frame and the boss and position them into place. When I’m happy with the position of both sides, I’ll then cover everything with lots more flux.
Small repairs like this don’t require much equipment. They especially don’t require any oxy/acetylene equipment. I’m using Silver to join the boss to the frame and Map gas is ideal for this. The torch I am using on this bottle doesn’t really have any type of flame control, it is either ON or OFF, but it works ok for what I need.
Fixtures needn’t be fancy or specially made either. When I did my course, Dave’s fixtures were all home made. Like me, you start with a requirement such as a repair you need to do, you make something to deal with it and before long you have a set of useful stuff. My fixture for the lever boss placement is just two steel strips supported either side of the top tube with slots to control the position. I can wind up the wing nut to put pressure on the boss to hold it against the frame. The fixture also has enough clearance to allow me to get in with the flame and silver.
The principle is straight forward, but practice is definately needed. Applying heat in the right places and watching the flux react, while remembering that Silver melts quickly and makes a mess if you aren’t careful and control how much you are putting in and where it is going. Once both sides are done the frame needs to sit and cool. Make sure you switch the gas off and go and switch the kettle on!
The results after a basic clean up with emery cloth and files…
It needs some more work, especially around the base of the boss, and the existing paint needs to be feathered before I can mask up and prime, ready for new paint.
I’m happy that I’ve been able to keep paint loss to a minimum, just a small amount, and that is mainly from the clean up with the emery and file rather than due to the heat of the torch. I’m going to need to cover a few inches of down tube and at least the bottom head lug, but that is for another day as I’m running out of weekend!