Andrew R Stewart
Top Tube Replacement
Here's a link to an 8 shot album of a practice TT replacement I did recently. I chose to grind out the tube from the lug, opposed to replacing the lugs too. Things went well enough but it's easy to grind too much out and end up with a loose fitting new tube... I was concerned about the brazing in the new tube. The old was done with silver as was the seat cluster. In the long ago past i'd had problems with heat control and remelt when doing mulitple brazing steps on top of previous ones. This time the brazing went very well. No remelt of existing filler. Good fill and lug lines. Clean up went fast.
Now that this is behind me I will say that I was very focused during the grinding, prep and brazing steps. I took my time and played out the process in my mind over and over before moving on to the next step. Once again i find that you learn more doing a repair then a full up build. Andy.
Very good -
Is there is reason you chose to grind the tube out instead of heating it to liquify the filler and slip it out? I've never tried grind one out.
Andrew R Stewart
Dave- I was nervous about damaging the seat cluster, remelting the existing filler (remember it's silver for the SS caps and attachment). The reason I ground out the head lug was to not have to duplicate the OE lug's shape. But the next time I feel like experimenting I'll consider pulling the tube with heat. I have done this many times with drop outs and crowns. Since I don't do this for a job i don't have the heat control chops that some have. Andy.
I think you would find it's easier than it might seem to slip the tube out.
The seat lug is thick as are the stay caps and it will take a good bit of heat to get that stuff to fall apart. If you focus most of the heat on the tube to be pulled (no worries about cooking it for obvious reasons) and let that heat soften the silver I think you'll find you can pull that tube without worry of dropping the stays off.
You can also put a heat sink in the seat tube (a crap post is perfect) and this will pull a lot of the heat away from the stays.
Best of luck to you - keep up the good work.