Silver Soldered Bottle Bosses - Stainless or Non-Stainless?
 

EDIT: Title was supposed to be "Stainless or Non-Stainless". Sorry for the confusion.

I can't seem to find the answer to this using the search function, so sorry if this is question has been asked before.

I'm building up a single speed frame with some Reynolds 631 and wanted to try silver soldering in the water bottle bosses. Should I get stainless or non-stainless bosses?

Additionally, at what wall thickness do people use those bottle boss reinforcement stars like the ones offered at BFS?

Thanks

I almost always use the reinforcements. I always use stainless braze ons of any kind. I don't like rust, and it seems like braze-ons are the first thing to rust.

You can use either steel or stainless steel. I prefer stainless closed bottom bosses to prevent rust in the threads and keep water out. I never use reinforcements on my frames.

Rusted braze ons are a reflection of the bike's maintenance (lack of) IMO.

I rarely use a SS braze on (went through that phase a while ago) but nearly always use silver to install them (the exception are drop out and SS rack eyes, ask me why...). Main frame (or fork blade) reinforcements as aesthetics dictate (I don't build with really this walled tubes). Andy

Guilty. Still rather not have rust.

"...but nearly always use silver to install them (the exception are drop out and SS rack eyes, ask me why...). "

I gotta do this...why? I use silver on everything and have no issues whatsoever.

One of my frame failures was a rear drop out eye that I added to a touring frame. The commercially sourced machined eye was brass brazed to the end of a 1/8"x1/2" stand off of steel strip which was then silvered to the drop out just rearward of the forged in eye. On a bike tour that used UPS to ship the bikes one of these eyes on a stand off was broken off by something that penetrated the cardboard bike box side. Had the stand off's brazing been done with brass i think the stand off would have bent, instead of the filler's cracking mode. I think brass to be a better steel joint filler when the contact surfaces don't mate perfectly well.

Here's a shot of the type of eyelet I have made. This one isn't the failed one, note the brass at the dropout/stand off joint:) Andy.

https://cimg3.ibsrv.net/gimg/bikefor...24c0918644.jpg

One of my frame failures was a rear drop out eye that I added to a touring frame. The commercially sourced machined eye was brass brazed to the end of a 1/8"x1/2" stand off of steel strip which was then silvered to the drop out just rearward of the forged in eye. On a bike tour that used UPS to ship the bikes one of these eyes on a stand off was broken off by something that penetrated the cardboard bike box side. Had the stand off's brazing been done with brass i think the stand off would have bent, instead of the filler's cracking mode. I think brass to be a better steel joint filler when the contact surfaces don't mate perfectly well.

Here's a shot of the type of eyelet I have made. This one isn't the failed one, note the brass at the dropout/stand off joint:) Andy.

https://cimg3.ibsrv.net/gimg/bikefor...24c0918644.jpg

I did an experiment where I brazed some eyelets onto a dropout and hit them with a hammer. The results weren't good. I decided I wasn't going to braze eyelets on dropouts any more. Usually when I want to do that, the little hourglass fittings will work just as well.

Q: did you miter the dropout to fit the boss so there was a decent amount of surface area in contact?

I've seen lots of frames where the roughly-cylindrical boss was just placed on the compound curve of the back of the DO such that contact was just a mathematical point, zero area.

When I file a divot into the DO with a round file the same diameter as the boss, deep enough that almost half the circle of the boss is "buried" in the DO, I think that's strong enough for even a rack. Though I generally only use brazed-on bosses for fenders, using the forged-in boss for the rack.

I never* braze a boss on the top of the front DO, because those are only for racks, and the stakes are high if the BO lets go. A rack strut going into the front spokes, though unlikely, can really ruin your day. I am a little more sanguine about rear wheel lockups, not great but more survivable.

*um, well maybe I have done it, like back in the '80s when I had less confidence in my ability to say No to a customer... or to my boss. But I did on several occasions talk customers out of it, by pointing out that there were (back then) no commercially-available racks made to bolt on there. I made myself a custom Cr-Mo front rack, Herse/Singer 'campeur' style, in the '70s, but never got a single customer to order one, after they heard the price, until decades later. In the '70s and '80s, people thought Blackburns were good enough, even for a custom bike. Or if they were fancy, a Gordon — which also connects to the lower fender eye. Front racks to use the eye above the axle were rare-to-nonexistent on American custom bikes that I saw.

Even so, some people just want every single possible BO on a touring bike, whether there's anything that can bolt on there or not. Like "be the first kid on your block to collect 'em all!"

Mark B

Mark's comments about the surface area of a braze on's joint being important is a good one, especially if using silver. The rear stand off eyelet that broke off on one of my bikes was not well mitered to fit the curves of the drop out. Silver (56% especially so) loses much of its strength after the gap opens up beyond single digit thousandths of an inch. These eyes are for the rear fender braces and not the first ones I did thus way. Aftyer this experience I now do a better job on the miter and use brass filler. My experiment with a hammer and the current method had the stand off part bend and the joint to the drop out intact, as it should be.

I admit to being a "kitchen sinker" when it comes to braze ons. My moto is "one bolt one job". So no doubling up placing fender braces on the same bolt the rack is using. Andy

I tested all three obvious configurations. Well-mitered, a flat filed into the eyelet, and the point contact. I thought I had a pretty decent fillet on all three. The point contact one came off with one blow, the flat might have taken more than one, and the mitered one took some number of blows I forget, but it still came off easier than I wanted. I think the mitered one would work fine for fenders, but you know someone is going to put a fully loaded rack on it someday. I'm pretty sure I bent the eyelet in the process of knocking off the mitered eyelet.
A hammer blow is worse than a rack, but it's going to take a beating over the lifetime of a bicycle. If I really wanted an eyelet added, I would get someone to TIG it for me.
Even though I have been brazing since the mid-70s, it started me wondering if I knew what I was doing. Imposter syndrome is a powerful evil.

Okay, I read Mark's post again. The miter I did was certainly not half the diameter of the eyelet. Maybe not even 1/8", I don't really remember. I wonder if I can find the piece of steel that I used to take the place of a dropout.

If you're adding a second set of eyelet to a dropout that already has an eyelet as part of the forging, use the added eyelet for something that won't carry much load, e.g. mudguards, and use the forged eyelet for mounting a cargo rack.

As someone that sweats A LOT, stainless cable stops and bottle bosses is a great mitigation against rust. It's amazing how much salt can collect inside a braze-on, even if you are diligent about cleaning.

That’s beautiful work.

Andrew, if you need any more of those standoff things, I had 50 or so made to test out the Cut Send Cut service. They would be perfect if you continue to do as you've done here. The ones I have are stainless and take a 6mm boss insert. Happy to send you a dozen or two. (Sorry for the big pictures)
https://cimg9.ibsrv.net/gimg/bikefor...97e919e15d.jpg
https://cimg0.ibsrv.net/gimg/bikefor...f64b23232d.jpg
https://cimg1.ibsrv.net/gimg/bikefor...840039332b.jpg

Duane- Thank you for the offer and if the eyes were steel (and not SS) I would take you up on it. But I have been gun shy (will the auto sensor strike out g u n ?) to attach eyes with silver since my touring bike's broke off. I hope some others here might want some. Andy