Reynolds 921 down - crack - help

[www.arkobici.sk]

Regards gentlemen,

Big frustration from this morning.

Last night all seem to be good - I do always little root around the joints (focus on heating) and then the major brazing. Using 54% Ag content. 

I started filing the fillets and in total disappointment found this crack! What a shame. I don't seem to understand what went wrong. No tension while in the fixture tough.

It's #SS6225 921- 31.7* .8/.5/.8 * 635 but I've measured over 0.9mm but I didn't care much about that as I was delayed on this frame. Now, after all the work I've done this. logically I contacted Reynolds this morning and asked for replacement but is it fine to re-do again, to braze again around BB-ST area? I'm using 921 head tube

Many thanks

Marek

 

[www.arkobici.sk]

That entire frame would be in the recycling bin if it was me. Walk away and start over. It is a never ending problem with stainless from them. I gave up on 953 long ago. 921 was suppose to be a variation of 17-4ph and not as hard as 953 and should have better rust prevention properties, but apparently still issues. Often the issues are longitudinal and a result of the tooling used to draw and butt the tubes.

-Drew
.........

Hi Marek,
That to bad and kind of shocking. I would concentrate the heat on the damaged tube and wire brush the rest of the solder off than polish and re-braze.
please keep me informed as to the results.
Anthony
Mezzatesta Custom Cycles
Cranberry Twp. PA. 16066
www.mezzatestacustomcycles.com

............

Hi Marek,

I have a fellow framebuilder (in France) who also had this problem, but on a Reynolds 953 top-tube (31.7mm). Reynolds sent him a replacement tube, and it happened again, exactly at the same place. The 3rd one was OK... He has a very good experience with fillet brazing (I think it was his frame Nr 200 or something), so I'm confident his technique was OK.
I wonder if somebody on the list has a good technical explanation... ;-)

Cheers,
Francois

[Alex Meade]

Marek,

For a technical explanation, consider contacting Keith Noronha (k...@rtl.cc) or Tom Cleverly (t...@rtl.cc) at Reynolds.  These two fellows have been very communicative recently with me, and Reynolds seems to be interested in custom builders.  If you get a technical explanation, please pass it along to us assuming Reynolds is OK with you doing so.  Also, Andy Newlands (an...@strawberrybicycle.com) at Strawberry reps Reynolds, so he may be able to get technical information from Reynolds even though you're not in the US.  Andy is also on this forum.

Sorry to see that crack.  A bunch of work wasted!

Alex

[www.arkobici.sk]

Hi again,

First thing in the morning I went to Reynolds and was in touch with Paul and Tom.
I'm grateful for their approach towards to this and here's what Tom says;

I am very sorry to hear about the issue that you have experienced. Although it does not appear that you have over heated the joints. we do know that austenitic stainless steels such as 921 can be particularly susceptible to heat input whilst brazing. I am aware of builders having experienced problems similar to yours in the past. We believe it to be inter-crystalline cracking caused when braze material enters in a long grain boundaries under high temperatures. I must apologise for you not having been informed of this before you placed your order as this may have affected the tubing chosen. I have attached a copy of our alloys document which outlines this information further.

Just for clarification.

What filler are you using? We recommend a 40% silver for filleting of all of our stainless materials, with a 56% silver if soldering into lugs.

Can you please confirm that the crack did indeed appear in the 921 tube and not the 953.

As Paul has said, we are more than happy to replace the damaged tube for you.

Many thanks and best regards,

Tom Cleverly
Project Engineer
t...@rtl.cc

[M-gineering]

No comment on the tube under investigation, but I just finished my first
921 (silver brazed b&w bilams, but joined with brass as a let's see what
happens experiment). In the process i played with a few offcutts. 'Lets
put a drop of Cuni rod on this' was rather spectacular, it literally
exploded! So yes, the intercristalline cracking is very much around the
corner

--
mvg

Marten Gerritsen
Kiel Windeweer
Netherlands

[Jon Norstog]

The bottom bracket looks great!  Too bad about the crack.  Perhaps you can salvage enough to build a second, smaller frame?

Good luck!

jn

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[www.arkobici.sk]

Hi, 

I guess not for the frame again since it was already heated, then I had to cut that piece out of the frame (actually butts are long enough) and also the inner routing of brake cable comes out on the bottom of BB.

Probably I use it for making custom reinforcement? nice inox shiny reinforcements..

Cheers

Marek

[www.arkobici.sk]

Hi, just to follow on this thread,

Frame is finished, yet I have to clear varnish, make decaleur and assembly the entire unit. For me the most difficult frame work so far, also because Stainless though.

Thanks for support and see you later

Marek..

linnk for album: https://www.flickr.com/photos/jednokolecko/albums/72157679041354185