Stainless steel dropout joint failure

[Mark Kelly]

Once the oxide layer is gone you have a good surface with some keyed surface, then it is just like a normal brazing operation.

This.

It's "stainless" for a reason.

[EricKeller]

My observation is that the drop out was kept too hot for too long and the silver started flowing back out of the joint. The blob on the outside makes me think that anyway.

Filler doesn't flow out of a joint unless the heat is in the wrong place. While I have seen it done by no-talent hacks, drawing filler out of a joint is not an easy thing to do. My motto is "no file," but blobs happen. However, in this case I suspect the blob never made it into the joint. When I saw the blob, my thought was that the builder overcooked or under-cleaned the joint, and tried force more filler in with no success. While you can finesse more filler into a (very slightly) overcooked joint in regular steels, with stainless it's hopeless. There is a tendency to add more heat when things don't go quite right, but it's almost never the answer

[devlin]

That's what I meant in that he got the metal way to hot away from the joint. You're explanation of not being hot enough makes sense as well. Then it would not have properly flowed into the joint at all.

[William Chitham]

The Framebuilders' Collective | Llewellyn – The Limpet

Questions?

In the Limpet series of photos, what are we seeing in the last "process" shot where it looks as if you've pulled the limpet off the tube?
Thanks,
William Chitham.

[progetto]

Perfect penetration.

In the Limpet series of photos, what are we seeing in the last "process" shot where it looks as if you've pulled the limpet off the tube?
Thanks,
William Chitham.

[nspace]

Love that filler rod slot in the Limpet!

[Dazza]

Love that filler rod slot in the Limpet!

They are nice. The slot is not my idea, it has been done on many parts before, the first braze on I saw with a slot was in the late 1980's, some Japanese made parts. Cannot recall the part. Might have been a Suntour front derailleur boss ??

[dinucci]

I am kinda with Richard on this. Skip the stainless (until you know what you are doing). I mostly just skip the stainless. Show me an F1 crankshaft made of stainless (you can't, so why use it).
Dazza is correct, the joint was not clean enough. I use rust remover, after the processes Dazza outlined, when I have any doubt about the cleanliness of the stainless. I also use the Cycle Design products and recommend them. I think the builder knew while brazing that the joint was not going to work. He should have stopped, cleaned the joint, and started over.
mark dinucci

[Nipper]

Am Grateful for all answers above, thanks.
I appreciate your advice on starting small, Darell and I know you are absolutely right, of course. It is one of my many failings that I try to sprint before I can crawl. So far, my first two efforts - with guidance from the framebuilder who built the failed dropout - touch wood are still good (1st - 853 frame and forks, st/st front lugs and dropouts, bespoke fillet brazed seat lug. 2nd - 953 lugged frame only). I put my heart and soul into them so of course will be devastated should they fail but knew at the time I was pushing the boundaries (a complete novice, I have never before done any metalwork, even at school). The manufacturer making the repair has offered to check the integrity of the 953. Photo’s of both below, of which I am, of course, very proud ;-) Next effort will be more “small” and won’t include stainless I promise!
John, the spacing was certainly spot on and I’m pretty sure the alignment was also good (I didn’t specifically check this but I would have noticed if not) The shape of the failure is through the silver braze of the hinge joint - the dropout is in two pieces.
Re comments of getting things too hot, below are photo’s of the st/st front lug and stem of the failed frame post brazing and do not have the experience to know if these are good or show over heating? As mentioned earlier I have many photo’s on https://www.facebook.com/nipper.varney of my own efforts which I am now concerned about over heating etc. if anyone wishes to advise?DSC_0439.jpg5.jpgDSCN2602.jpg
DSCN2603.jpg
Stephen Varney