Wednesday, July 16, 2008

Breathing life into Bob's Yo...a resto project

This is one of those heart string resto projects I tend to accumulate. I love the old mountain bikes from the hey days of the sport and have always had fun bringing them back to the glory days to be ridden and enjoyed again.

Bob sent me his Yo (seems like a looong time ago) that admittedly, had seen better days. A Krylon blue paint job and some roughly applied rack braze ons had sullied this fine machine. The task before me was to remove the bosses, clean her all up and put on a nice new finish.

The bosses did not really cause me much concern until I finally gave her a good look. The welds that were holding these in place had clearly undercut the foundation of the tube and I began to worry about what I would find once I cut them free and exposed the underlayer.

Here's a shot of one of the bosses with the paint blasted off. The weld undercuts the tubing in the center of the boss and then there is too much build on the uneven balance that I'm surprised has not caused a stress riser failure before now.

Once the rack braze on was removed, you can see what was left behind. A nasty hole from too much heat on the thin tubing during welding. This was the aftermath on 3 of the 4 pieces...oh boy :(
I basically had two viable options; replace both stays or work some creative metal new stays would have busted the bank on this guy, I pulled out the wand ;)

I closed up the holes with some carefully applied tig welding. Heat control and filler application is crucial as the thin tubing wants to melt back away from the torch, creating a much larger problem. Fortunately, I've played with lots of hopeless repairs and I was able to close up all the holes pretty smoothly. Boo-yah!

The next shot shows the filled areas under some fresh flux, ready for a bit of silver to level out the surface area and give a nice transistion from original to repaired area. I could have used some poly fill (bondo) to smooth things out under the paint, but want the piece to be as bomber and high quality as possible, so there you go ;)

Here's a shot with the flux still cooling and some 45% silver built up over the area. I used the 45% as it is not as viscous as the more common 56% and could be counted on to reliably stay put rather than run away around the tube.

I should make note that all this was done fairly quickly, from tig to braze, so that the area never really cooled down, allowing me to repair the area with as little heat application as possible, retaining the strength of the material.

And finally, one stay filed and sanded smooth, one ready for some attention. It's a lot of effort to expend for an almost 20 year old frame, but it sure is sweet to see it all fixed up right.

This guy is going to get a SWEET paint job...gulf stream orange and blue with white and black trim. Should be killer. Bob, I hope you got some spiffy parts for this bad boy just waiting in the wings :)

I also busted out some of the July Luvs today, a little later than I wanted, but it is what it is.

I'm gonna be starting a straight 72 hour shift tomorrow at the FD, so I'll be hitting the email and getting back to some of y'all during some down time.

Thanks for the patience,


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