The bicycle thread

[zank]

I silver braze the small parts for a couple of reasons. First, I can braze a bunch of stops and fittings pretty quickly. Second, they can be replaced very easily if damaged, corroded, or if the customer wants to change routing.

Brazing vs welding a frame is another matter entirely. That generally comes down to the customer's aesthetic preferences and what their budget is. I say generally because you can weld a bike in any geometry and tube spec you want. Lug brazing, on the other hand, has some limitations due to the pre-cast lugs.

Regarding fit and design, there are some programs that offer sizing suggestions. But most experienced builders and designers have developed their own methods. The best guys know there is a certain window to stay in. When you "need" to go outside of the window and the bike starts to look weird, chances are good that it will ride weird too.

[zank]

Dry Fit.


Adam H by Zanconato Custom Cycles, on Flickr

Fluxed.


Adam H by Zanconato Custom Cycles, on Flickr

Tacked.


Adam H by Zanconato Custom Cycles, on Flickr

Brazed.


Adam H by Zanconato Custom Cycles, on Flickr

Soaked followed by a little elbow grease, emery cloth, and scotchbrite.


Adam H by Zanconato Custom Cycles, on Flickr

[Ciclista]

Do you braze in the jig or just tack?

[zank]

Just tack. Same as when welding.

[zank]

Kicking off the new year.


Derek G by Zanconato Custom Cycles, on Flickr


Derek G by Zanconato Custom Cycles, on Flickr


Derek G by Zanconato Custom Cycles, on Flickr


Derek G by Zanconato Custom Cycles, on Flickr

[npg170]

Zank relatively new to welding web but bikes are what got me interested welding/metal work in the first place. I remember you and your work from Vsalon and MTBR but I haven't been on either in years. Are you using Weldmold 880 or other stainless filler or just standard er70-s2/6 with a combo of good heat management/gas coverage (and just being really good at it in general)?

I can never get any of my practices pieces to come out nice and shinny like that, granted they are substantially thicker that frame tubing. Mind if I ask what your perfered set up is? I know you run a Lincoln 175 what about torches electrode size ect. This thread really re sparked my interest in building a frame.

[zank]

Sorry for the slow response! Happy to help.

For filler, I'm generally running 880, but I do run ER70S-2 on certain things. When I weld bridges and canti studs, I usually use the ER70 because I have a hard time getting a really good back purge on those pieces. I run 0.035" rod for pretty much everything. In the areas that require a bigger fillet, I just push more wire. It's not a dab; it's more of a push. I like having that control. In terms of nice and shiny though, I think that is more a function of coverage, prep, and speed. The BB cluster below was done with ER70S-2. The bead itself is not as silver as the 880 beads, but ER70S-2 beads don't need to be gray either. I actually think prep and cleaning is something that is often overlooked. Start with bright shiny steel, clean with acetone, clean the filler with acetone. And another thing I see fairly often is guys pulling the torch away very quickly and not protecting the bead with the postflow.


Lonny G by Zanconato Custom Cycles, on Flickr

For my torch, I run a CK Flex Loc. I use the FL130, which uses the 2-series consumables (9/20 style). I use a gas lens and a #7 cup at about 12-15 CFH. I use 1/16" or 3/32" 2% lanthanated tungsten ground to a sharp point. I always use a 1/16" on the seat stays. I find that just that little bit smaller diameter tungsten allows me to get in between the stays without accidentally arcing off one of the stays. Tons of stickout to get down in there means there is a lot of exposed tungsten to bump into tubes if you're not paying attention.


Rep yer torch by Zanconato Custom Cycles, on Flickr

Hope that helps. Hit me up with any other questions. Have fun!

[npg170]

Thanks for the detailed reply. I think I have just been over cooking the welds by not moving quick enough. I guess what it boils down to is I really need to a lot of practice.

[zank]

I think that same thing every time. Attempted continuous improvement and continuous frustration are what welding is all about for me.

[forhire]

Zank, I really like this thread. You are a craftsman.

I happened across an old movie about a bike factory that may be of interest. It shows many of the fixtures and machines used to make the parts of a bike. I liked the spoke machine.

[zank]

That is a great video. There are a couple of other old ones about other bike companies in Britain. I'll have to look around for them.

[gordon stephenson]

Just thought some of our members might like to see this old video of "Jack Taylor Cycles" 3 brothers that lived and worked in Stockton in the north east of England, Wonderful bike building craftsmen and cycling competitors of years gone by, Hope you enjoy it,

[lighttekku]

Dry Fit.


Adam H by Zanconato Custom Cycles, on Flickr

Fluxed.


Adam H by Zanconato Custom Cycles, on Flickr

Tacked.


Adam H by Zanconato Custom Cycles, on Flickr

Brazed.


Adam H by Zanconato Custom Cycles, on Flickr

Soaked followed by a little elbow grease, emery cloth, and scotchbrite.


Adam H by Zanconato Custom Cycles, on Flickr

Ok so I'm really curious about this process here. Its brazing? I've never seen anything like this. Can you give me a quick word walk through of what you're doing? And what's that goop that you've put on the lugs? (I think that's what those are?) Some kind if bonding agent I'm guessing? This bike frame building business is really cool. You're making me want to try and make myself a new DH bike frame.

Edit: I also see that it's been asked a few times but I didn't see the answer, are those lugs made in house or do you order them from somewhere?

Thanks in advance. You do really great work.

[Kavall]

Brazed lugged frames like that is basically the same idea as soldering, just different metal and flux. The paste is a flux that allows the filler to flow into the joint. You take a torch and heat the joint, rub a rod of filler against the edge and the heat sucks the filler into the joint. Done well and it's silly strong and quite nice looking. Zank's work is a terrific example of about as good as you can do, period. I've seen a ton of welded and lugged frame bikes. I can't say I've ever seen better execution.

[lighttekku]

Brazed lugged frames like that is basically the same idea as soldering, just different metal and flux. The paste is a flux that allows the filler to flow into the joint. You take a torch and heat the joint, rub a rod of filler against the edge and the heat sucks the filler into the joint. Done well and it's silly strong and quite nice looking. Zank's work is a terrific example of about as good as you can do, period. I've seen a ton of welded and lugged frame bikes. I can't say I've ever seen better execution.

Oh ok. Good to know. I didn't see the brazing lines so I assumed that heating the paste was what sealed it. I just zoomed way in on the picture and now I see the filler metal.

My dad showed me a small brazing kit that he had from years ago and suggested that I give it a try. I think I'll have to do that. Thanks for answering my question.

[zank]

Thanks for the kind words, Kavall!

Not much to add after your explanation of the brazing process. The lugs are cast over in Taiwan. The company that makes them makes the best lugs in the world. Beautifully cast and help to very tight tolerances for socket dimensions.

I use a silver brazing rod that is 48% silver. Flows very nicely.

[Kavall]

It flows so nice because of the 1/4 lb of flux on your joints and incredible fit up. lol!! I really have never seen so much flux. But hey it seems to work and the cleanup comment has me considering it for some of my work.

[Murphy's law]

Zank you do amazing work!!!!

[zank]

Thanks!

[sparkness]

question , how much distortion do you get in the crank threaded spindle tube? do you need to heat straighten for the bearings to thread in smoothly?

[zank]

I use an expanding bronze heatsink on the id, so I can usually thread the cups in by hand after welding. But I still chase the threads and face the sides parallel.

[sparkness]

thanks, great idea

[Larry K]

I welded bicycle frames for 10 years for a company that sounds like wreck. That is what the frames are now that they are made overseas, big difference between what we were putting out and the current frames. I now weld for a BMX company welding frames and cranks. I also am in the process of making my own custom BMX frames.

[engineer1984]

Zank,

Does your shop offer classes on how-to that allow you take home a bike?

I've found a lot of welding bike frame classes. I don't see any braze bike frame classes.

[zank]

Thanks for the question (and bringing the thread back ). I've never hosted a class before, but it would be an interesting idea. Is it something you would want to do over the winter?