Titanium Braze on with Chromoly frame
 

Hello all: cursory search did not reveal definitive answer. Of course AI says it is doable but I know better.

I have a 2 years experience with simple brazing tasks such as botte bosses, front derailleur hangers, and cable stops with stainless steel to chromoly, I think I am still a beginner because I don't do it everyday.

When I restore my bikes, sometimes I delete the downtube shift bosses and braze barrel adjusters onto the head tube to handle the STI cables-- some old heads (myself included) know them as Ergo bosses.

I have found them in titanium and want to know what the experts think about brazing them onto a vintage SLX frame (brand withheld to prevent any purist uproar). I like the corrosion resistant properties of titanium and I haven't been able to find them in stainless.

As a reference, I included a picture of a set of steel ones that I brazed onto a vintage De Bernardi I restored (what a great bike).

https://framebuildersupply.com/produ...52232338407734

https://cimg3.ibsrv.net/gimg/bikefor...89e07aa859.jpg
https://cimg5.ibsrv.net/gimg/bikefor...3d2de77f5d.jpg

Cecil Behringer developed a lugged-brazed titanium frame. I don't know what filler alloy he used, but the brazing was done in a vacuum furnace, which I doubt you have access to. Sadly Cecil is no longer with us, so we can't ask him. Here's an article about the Behringer frame, which maybe has details on the filler alloy (dunno, I haven't read it in years).

Titanium will burn in air at some elevated temperature, so I doubt brazing it with a torch is going to work. But if the braze-ons aren't too expensive, maybe buy two pairs and try it on a scrap of steel before committing to braze it on a frame you like.

I was told by a well known builder that one could chrome plate the TI and then silver braze to that surface. The discussion was specifically about the Teledyne frames. Andy

You could try TIG silicon bronze I guess. The internet seems to think it ought to work in theory (even the parts of the internet that aren't AI slop yet).

Why not just get them in steel? I know that Ceeway has them in stock, just bought some. Seems safer and easier.

Mark: Ceeway are fantastic and where I got mine a couple years ago. They are the only supplier I could find at the time who had them (shown on my De Bernardi above). I still have some on hand. The idea behind the post was to find something that is more corrosion resistant and also to see if I could apply titanium bits it to other areas. I also like that the titanium ones are indexed-- the Silvas are not. Do you know anyone who has stainless available? Stateside is best as long as the tariffs are in place. Ugh

I think I will have to abandon the idea based on the information provided by the others. Thanks for the help! Good community here

Lever bosses are a fairly simple bit to make if one has the tools. In my area there are a few small/hobby guys (sorry ladies, all I know of are males) who offer small machining jobs. I've fallen back on a few for projects I couldn't handle. Then there's the on line machine shop services, I've used E Machine Shop dot Com for SS head badges and M5 binder bosses and have been happy with how things went. Andy

I took UBI's very first titanium welding class taught by Gary Helfrich in 1992. He was one of the founders of Merlin. After that class I explored brazing ti brazing ons (ti to ti) because that would have a much clearer look. When I was at a welding show I asked around if this could be done. Everyone said yes but they hadn't done it themselves. They even had a seminar about how to do this so of course I attended. There were about 2 dozen attendees and they all seemed to know each other (I think they were in the aerospace industry) and looked at me suspiciously. Anyway the guy giving the seminar didn't show up so I left none the wiser.

At another welding show the Superior Flux Manufacturing company displayed various fluxes including one for brazing titanium. They had a sample I still have. When I called later to ask about use suggestions, they were much more interested in finding out any information from me. I experimented with one braze but I quickly understood it would take more trials to see if it would work. I just lost interest. I prefer the ride of steel over titanium by a lot so I saw no future in learning more about ti brazing.

https://cimg9.ibsrv.net/gimg/bikefor...4d614bb52.jpeg
here is my sample of flux for ti brazing. It is in a dry powder form. It is not a paste.

Try this and tell us what you found out: https://superiorflux.com/products/br...-brazing-flux/

I make small bits fairly regularly for guys restoring old bikes (I seem to have found a bit of a niche making brass ferrules for 1980 - not 1979 - Ritchey MTBs). I have literally made 100 of them! Anyway, I think having someone make some from SS would be much easier. If you wanted a couple dozen, Paragon might even do a batch for you.

2 comments, I have had STI bike using both the adapters you put on the break bosses (Miyata 1400 and DeRosa pro) and one with the adjusters on the head tube (Kirk)

I found no functionality difference only difference was cable length.

I would suggest looking into brass adjustors instead of aluminum, as corrosion is a concern. I have those on my Kirk and the have worked well so far

The ones on the head-tube are a nice design because they also stop the cable outers rubbing there and chowdering up your paint. Otherwise putting a bit of "helitape" (very expensive sellotape they use on helicopters for some reason apparently) there is a good idea.