(𝘼𝙨 𝙮𝙤𝙪 𝙬𝙞𝙡𝙡 𝙜𝙖𝙩𝙝𝙚𝙧 𝙛𝙧𝙤𝙢 𝙧𝙚𝙖𝙙𝙞𝙣𝙜, 𝙩𝙝𝙞𝙨 𝙥𝙤𝙨𝙩 𝙬𝙖𝙨 𝙬𝙧𝙞𝙩𝙩𝙚𝙣 𝙞𝙣 𝘿𝙚𝙘𝙚𝙢𝙗𝙚𝙧 𝙗𝙪𝙩 𝙙𝙪𝙚 𝙩𝙤 𝙤𝙪𝙨𝙞𝙙𝙚 𝙞𝙨𝙨𝙪𝙚𝙨, 𝙩𝙝𝙚𝙧𝙚 𝙝𝙖𝙨 𝙗𝙚𝙚𝙣 𝙖 𝙙𝙚𝙡𝙖𝙮 𝙞𝙣 𝙥𝙤𝙨𝙩𝙞𝙣𝙜 𝙞𝙩)
November / December 2022
Hi again everyone..
Progress has been made once again with my home build fixed wheel bike, and to be honest,
probably with a little less in the way of setbacks in this instalment.
You may remember, the next challenge was going to be brazing the rear triangle to the main
frame. This in itself, poses one or two problems, as I can’t apply too much heat to them as they are heat treated tubes. With this in mind, I needed to finish the bronze and latterly brass fillet brazing to the bottom bracket, which I had fashioned some homemade lugs to accommodate the chain stays (I needed to do this, as the chainstays are heat treated and I wanted them to get a good strong mount to the bottom bracket shell)
So with fillet brazed BB lugs in place, I was then able to install the heat treated tubing. This
time, sweating them in with silver solder, which in temperature terms, melts at a much lower
point than brass or bronze, but which also makes for some incredibly strong joints, especially
when used in a lugged construction.
I decided not to make a jig in the end to assist with the alignment, as I thought, being a one off, I should be able to get it pretty near?
Once the chainstays were in place, the bike would actually sit up and self support itself.
Suddenly the seemingly fragile tubing was taking on a new lease of life and showing signs of
being pretty strong construction. See photo, of the back end without seat stays added.
I then added the horizontal dropouts, applying small amounts of silver solder to tack into place and compare with my 1:1 plan.
After which I needed to install the seat stays. I held them in place, (you may remember, I want Helenic stays, which come past the seat tube and install onto the top tube. Purely from a cosmetic point of view on my part. GT Bikes often use this method)
I had made some prototype tubing ideas from Toilet roll tubes, as I want an inverted curve
silver soldering into the tube. Easier for you to see the photo than me to explain fully.
I set about cutting the seat stays to length, cut out the section from them and inverted it to
form the fluted effect, silver soldered in place and then to the frame. Already the silver solder
was doing a great job of holding everything together, and the rear triangle looks pretty good!
I can’t say it is fully true, but it looks not bad at all!
Once the rear triangle was in place, I spent the evening looking at the bike with a bit of
disbelief, knowing that I have built it. While currently waiting for some more silver solder, my
curiosity started to get the better of me.
‘Would this bike, in its current stage, support my weight?’
I waited until everyone was out and decided to prop myself up against the kitchen door frame
and gently lower myself to stand onto the cranks. (Seat not fastened yet!)
Believe it or not, it held my weight! Nothing snapped! Nothing groaned! (thankfully neither did
myself!) It just did what I hoped it would, and supported my not so lightweight stature!!
Thank goodness for triangles..
Whether it will have this level of compliance on the road remains to be seen! But in the mean
time, it is looking promising. I still have no idea whether I will have a rideable bike at the end of
all this, but every hour I spend in construction is one hour nearer to finding out!
During this stage of the build, the fillet brazing around the bottom bracket and down tube and seat tube, was pretty poor to be fair, but on sourcing some thinner brass rods, the whole process become much more easier and I was soon able to tidy it up considerably!
The Americans have a phrase for brazing for when the braze forms nice overlapping pools whilst molten. ‘Stacking Dimes’ Mine isn’t quite stacking dimes, but I can now see evidence of that in places. (Some builders would rather fillet braze and smooth it by careful application and grinding techniques in any case)
I have also found that when brazing goes right, much less gas is used in the process, as time is optimised much better. So.. why ‘Bermuda Triangle’
Well I was working on the rear triangle, and it was the most catchy title I could think of!
I am currently typing this blog, waiting for my Christmas cake to come out of the oven. Due
some time around about midnight. I hope you have enjoyed reading these blogs as much as I have reliving the processes I have encountered through the bike build.
The bike is now sat on wheels that I built in 2009 (a radial laced front, based on a DT Swiss 240 which spins forever. I have never trued this wheel since built, and the unusual green back wheel, which to me is more unusual not because of its colour, but because I built it with a 4 cross lacing, which I don’t think you see too often.
Anyway, the cake beckons my attention, see you soon when I hopefully get to the stage of first test drive, adding bottle bosses etc, prior to final colour choice and eventually painting.
Safe riding in the mean time!