Reynolds 631

General cycling advice ( NOT technical ! )
peetee
Posts: 1800
Joined: 4 May 2010, 10:20pm
Location: Cornwall

Re: Reynolds 631

Postby peetee » 3 Feb 2020, 10:46pm

LollyKat wrote:
David9694 wrote:When you say welded, do you mean fillet brazed?


Not being an engineer I'm not too sure of the difference :oops: . I meant lugless.


Put simply brazing is used as a glue that runs in to a tiny gap between adjacent surfaces. Welding is a join that melts the adjacent faces together.

531 could be built with lugs or lugless brazed. If the latter it was important that the tubes were cut and finished to produce a perfect mating surface and a strong joint. This can involve a lot of time filing by hand.
631 can be welded so the builder can save time and expense on the tube interfaces by just cutting to shape and letting the weld bridge the imperfections.
Last edited by peetee on 3 Feb 2020, 11:00pm, edited 2 times in total.
Current status report:
Back on two wheels in deepest Pastyland and loving every minute. Mission: to enjoy big, bad hills again.

LollyKat
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Location: Scotland

Re: Reynolds 631

Postby LollyKat » 3 Feb 2020, 10:53pm

Thanks. With either of those methods can a tube be replaced if necessary?

PH
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Re: Reynolds 631

Postby PH » 4 Feb 2020, 7:22am

David9694 wrote:When you say welded, do you mean fillet brazed?

I don’t know who you’re asking, when I say welded that’s what I mean.

mercalia
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Re: Reynolds 631

Postby mercalia » 4 Feb 2020, 10:40am

David9694 wrote:When you say welded, do you mean fillet brazed?



https://www.kaempfandharris.com/industry-news/difference-between-brazing-and-welding

As the article says welding means melting the metal so the bits become one piece

i would think that a frame that has tubes where you can see some join metal then its brazed - seems like my 1-Down is brazed not welded and dont have lugs.

tatanab
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Joined: 8 Feb 2007, 12:37pm

Re: Reynolds 631

Postby tatanab » 4 Feb 2020, 10:49am

Back in the mists of time, say 1960s/70s, fillet brazing was also known as bronze welding.

I have several frames from 1956 to 2012 which are filet brazed, and several lugged frames. No welded frames.

pwa
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Joined: 2 Oct 2011, 8:55pm

Re: Reynolds 631

Postby pwa » 4 Feb 2020, 10:54am

Brazing is joining two steel parts (eg tubes) using another metal with a lower melting point, possibly in conjunction with lugs. Welding involves melting the steel itself and is a much higher temperature procedure.

peetee
Posts: 1800
Joined: 4 May 2010, 10:20pm
Location: Cornwall

Re: Reynolds 631

Postby peetee » 4 Feb 2020, 11:20am

LollyKat wrote:Thanks. With either of those methods can a tube be replaced if necessary?


Yes, in theory. Replacing a brazed tube is a case of reheating the joints and sliding the tube out whilst it’s hot. When properly done the new joint and the tube strength is not compromised and should be straight and as strong as the original joint.
With a welded joint the situation is a bit more complex as the heat applied is far more intense and the material strength, tube proportions and frame geometry can be adversely affected.
Current status report:
Back on two wheels in deepest Pastyland and loving every minute. Mission: to enjoy big, bad hills again.

mig
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Joined: 19 Oct 2011, 9:39pm

Re: Reynolds 631

Postby mig » 4 Feb 2020, 11:26am

wasn't there also an oversized tubset in 631?

Brucey
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Re: Reynolds 631

Postby Brucey » 4 Feb 2020, 1:43pm

Dawes one-down

Image

appears to be tig welded in the main triangle, with brazed joints to the dropouts, BO fittings and to secure the seat collar.

'Bronze-welding' (AKA fillet brazing) is most like high temperature brazing, and (unlike filler for brazing of lugs) the bronze welding filler stays mushier for longer but (under a microscope) there is noticeable dissolution of the steel tubes into the filler material. Brompton frames are Bronze-welded.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

David9694
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Joined: 10 Feb 2018, 8:42am

Re: Reynolds 631

Postby David9694 » 5 Feb 2020, 9:42am

peetee wrote:
LollyKat wrote:
David9694 wrote:When you say welded, do you mean fillet brazed?


Not being an engineer I'm not too sure of the difference :oops: . I meant lugless.


Put simply brazing is used as a glue that runs in to a tiny gap between adjacent surfaces. Welding is a join that melts the adjacent faces together.

531 could be built with lugs or lugless brazed. If the latter it was important that the tubes were cut and finished to produce a perfect mating surface and a strong joint. This can involve a lot of time filing by hand.
631 can be welded so the builder can save time and expense on the tube interfaces by just cutting to shape and letting the weld bridge the imperfections.


I’m not an engineer either, but my understanding is that you braze (bronze, silver) at a much lower temperature than you would weld - I don’t think you would want to weld any Reynolds tubing.

PH
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Re: Reynolds 631

Postby PH » 5 Feb 2020, 10:46am

David9694 wrote: I don’t think you would want to weld any Reynolds tubing.

Some, if not all, modern Reynolds tubes are specifically intended to be suitable for welding. As already said my 631, 725 and 853 frames are welded.

peetee
Posts: 1800
Joined: 4 May 2010, 10:20pm
Location: Cornwall

Re: Reynolds 631

Postby peetee » 5 Feb 2020, 11:18am

PH wrote:
David9694 wrote: I don’t think you would want to weld any Reynolds tubing.

Some, if not all, modern Reynolds tubes are specifically intended to be suitable for welding. As already said my 631, 725 and 853 frames are welded.


Very true. Putting two and two together I would surmise that Reynolds had no choice but to market steel tubing that allowed this. The market for costly hand built frames was diminishing and the only option was to offer a steel that would cater for the volume builder with a eye on the cost book.
Current status report:
Back on two wheels in deepest Pastyland and loving every minute. Mission: to enjoy big, bad hills again.