GiovanniLiCalsi

I’m restoring a 1971 Marinoni bicycle and would like to replace the rear brake bridge, at a slightly lower position. When new, it had a MaFac center-pull and I would like to use Campagnolo Nuovo Record brakes, so the original bridge must be replaced and a new one positioned lower.
Is there anyone that can supply me with a new bridge, with a Colnago style bridge, so I can use a recessed nut?
Thanks!
Giovanni

bulgie 

I have lots of bridges for recessed nut, but I don't know what Colnago style means. Can you share a photo or link? Colnago probably used different styles over the years, though I must admit I never really followed them, not my cuppa (after about '72, pretty nice before then).

Also, do you know about the drop bolt for the Campy brake, allowing it to reach 6 mm lower? There are other tricks too, to get even more drop, but the Campy drop bolt is the officially-approved way, done on a lot of nice bikes BITD. Less damaging to the frame, though replacing the bridge can usually be done plenty safely enough. It'd be a shame to repaint it just to get the bridge lower, but that's moot if you're repainting it anyway for other reasons.

Mark B in Seattle

unterhausen

I agree with Mark, a drop bolt is a great idea.

I was thinking maybe a "Colnago style bridge" was the biconical ones, but then I googled for the term and it looks a lot like the ones that Paragon makes
https://www.paragonmachineworks.com/...ke-bridge.html

JohnDThompson 

I agree, a drop bolt is the easiest way to address this, if you can find one or fabricate one.

Otherwise, I have some Gipiemme brake bridges that might be suitable:

GiovanniLiCalsi

I’m planning to strip paint and restore frame, so will silver-solder a new bridge in. I have many years experience silver-soldering, just new to the bicycle frame silver-soldering.
Silver Solder is more fluid than Braze and works by being drawn into the joint by a capillary action. ... Silver Solder is used with a Flux, which chemically cleans the metal and keeps it clean during the Silver Soldering process. Silver Solder is also know as Silver Brazing.

Kind regards,
Giovanni

bulgie 

OK, as long as you know that soldering is not strong enough. Even silver-bearing solders are not strong enough for a brake bridge. You need to silver braze a bridge. But a lot of bikies call that silver soldering — it's sort of a traditional jargon in the bike world that's technically inaccurate, but it's fine as long as you actually braze it!

Most silver brazing alloys are a bit on the "runny" side for a brake bridge, but they can work if you're careful, with good fit-up, prep, cleanliness, the right flux and flame etc. The higher silver content fillers, 56% for example, tend to be the runnier ones, not good for fillet-building, so I would choose a bit lower silver content, say 45%.

Some bridges come with reinforcing plates that have a little spigot that goes up inside the bridge, like an inside lug, very much increasing the "wetted area" for the silver to grab onto. While that is not strictly necessary, I think with silver it's a good idea. It can help with the safety margin, in case your fit-up, prep, flux or brazing skill are anything less than optimal.

Mark B in Seattle

GiovanniLiCalsi

https://youtu.be/no-OWfC5-RY

unterhausen

That video shows brazing a lug, so it doesn't seem to contradict bulgie at all.

I also think silver is somewhat questionable for this application. There are high-build silver fillers, and they are plenty strong. Fillet pro is an example. These fillers are somewhat tricky to use properly. But it's much better to use brass for a bridge that has to withstand braking forces.

GiovanniLiCalsi

I’m planning to order some Fillet Pro.
https://www.cycledesignusa.com/silver/fillet-pro
I have used lots of slfos. What do you think?

https://blog.lucasmilhaupt.com/en-us...r-and-plumbing

Andrew R Stewart 

There's very little advantage to use silver braze for a brake (or BB) bridge, compared to using bronze/brass. But if you know how to swing a silver hammer then use it. If you know how to swing a bronze hammer then use that. I suggest bronze. Andy

GiovanniLiCalsi

The Fillet Pro looks very good. I’m going to order 1 troy oz. and try it. I’m going to buy a Meco oxy/propane torch kit. I have several torch combos, but like the Meco. I have the tanks and valves.
Aircraft chrome moly frame builders use this torch and also jewelers. I’m into both.

bulgie 

I'm also a fan of fillet pro. As @unterhausen mentioned, a little tricky to use, but done right it makes nice silver fillets, especially useful on stainless. The silver flux from Cycle Design is also top notch.

I just tried an older Meco Midget for the first time the other day. It came (well-used) with a gas fluxer I bought used a few years ago, but I never got around to hooking it up and sparking it until the other day -- I think I really like it. It's almost comically small. I got the longer tube from the handle to the tip, puts your hand a bit farther from the flame, good for the bigger tips like rosebuds.

I also got the propane tips from Paige Tools, recommended. They have multiple orifices arranged in a circle around the main one, which is supposed to keep the flame from blowing out. I haven't used them much yet, but so far so good, flame completely stable.

I also recommend the ultralight hoses from TinManTech. The hose is so light and flexible you hardly notice it's there, more dexterity and less fatigue on your torch arm. Not very durable though, so make sure you never walk on it or drop blobs of molten metal on it. I have heavy duty hose from regulator to gas saver, and ultralight from the gas saver to the torch, with the UL hose suspended so it doesn't even touch the ground.

I just noticed Smith makes different gas savers for acetylene versus propane. Mine's the acetylene model, got it used many moons ago (it was actually Mario Confente's originally) so I never realized how expensive they are — I'm seeing almost $200 new (ouch). So I won't be buying a second one for propane! Anyway mine works OK for propane, it's just a bit harder to get the pilot light lit. The flame blows itself out unless I set it really low, but once I get it burning it works %100 throughout the day, good enough for me. Super convenient if you frequently set the torch down between bouts of brazing, because the valves stay adjusted. Just pick it up, light it off the pilot flame, and your flame is already adjusted however you left it when you hung it up..

Mark B in Seattle

bulgie 

Just a reply about my mention of a separate gas saver for propane — after a tiny bit more research I found this, just the pilot replacement part for the Smith gas saver, says it's for LP gas but I bet it'll work with propane too, and only $25 w/free shipping. I'll know soon.

Mark B

GiovanniLiCalsi

Brilliant!
Thanks for sharing your knowledge and experience!
Hope I get an opportunity to meet you.
I’m learning so much, on this thread!
Regards,
Giovanni

GiovanniLiCalsi

With Fillet Pro you can join stainless steel to chrome-moly and vice versa.

• For fillet brazing at below 1200F.
  
• Ideal for use with Martensitic SS (953) and XCR, Cycle Design SS Dropouts and G.P. Wilson 17/4. Paragon and other SS tips and parts.
  
• Beyond any brass in finish strength at silver temps.
  
• Excellent for tips and fork crowns or loose fits.
  
• Capable of joining without support with 100% joint integrity.
  
• Fillet Pro is being used Worldwide for SS and Steel fillet frames by Top Builders.
  
• Joining with Fillet Pro results in distortion free construction.
  

Anything that can be done with LFB can be done with "Fillet Pro" and more...


https://youtu.be/w8rvcJ-6YYg

Doug Fattic 

I have a number of smaller "aircraft" style of torch handles for frame building class students to try including the Meco Midget. While the Midget is okay I'm not a fan because it takes more hand action (well mostly wrist action) to flick away the flame from the work. I can roll the round handled ones with my fingers. It is also the least likely torch handle for students to like after trying them all out. However those that like it really love it. Here are a couple of tips for improving the use of the Midget. John Clay suggested to me to turn the elbow so it is parallel to the torch body instead of being at a right angle. I found it easier to flick the flame (meaning less hand motion) when the elbow is at that location. My second suggestion is to increase the body length by putting flashback arrestors on the body. The Meco is pretty small and the addition of the arrestors (instead of the smaller check valves which otherwise should go there) made it easier for me to handle and keep my fingers away from the control knobs.

It should be noted that the best place for flashback arrestors is on the regulators in case the flame cuts a hose so the resulting flame can't reach the tanks. This should be obvious if one thinks about it but arrestors are made specifically to either attach to the regulars or torch handle, One made to attach to the handle can not be used on the regulator or vise versa.

I'll second Mark's suggestion of using TM Technologies light hoses. The less experienced one is, the more important light hoses are in helping with good torch control. No student has ever wanted to go back to standard rubber hoses after trying out light hoses. They make a difference.

GiovanniLiCalsi

Everything ordered. Here is a photo of my MiniFlam micro jewelry torch and other jewelry tools I have. Jewelry working bench and lamp are circa 1906.