Aluminium frames an...
 

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[Closed] Aluminium frames and braze-ons

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I am vaguely aware that re-welding Aluminium frames is not very practical, as they need to be heat treated after welding. Is the same the case for getting braze-ons added to an Aluminium frame? I am not familiar enough with the processes involved to know.

I'm thinking of getting my Chameleon resprayed by Argos and if it's practical it'd be nice if I got some cable guides for its uppy-downy seatpost while it's with them.


 
Posted : 12/04/2011 7:51 pm
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Bump, in case the lunchtime crowd are more knowledgeable on this subject.


 
Posted : 13/04/2011 11:54 am
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you can't braze aluminium.


 
Posted : 13/04/2011 12:01 pm
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So presumably things like cable guides and the like are welded onto Alu frames so will be impractical to add later?


 
Posted : 13/04/2011 12:08 pm
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What does brazing mean and how is it different to welding then?


 
Posted : 13/04/2011 5:04 pm
 jimw
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Brazing is a form of hard soldering, where a filler rod of a different, lower melting point metal alloy, commonly copper/zinc, is added to the components when well below the melting point of the parts to be joined. The filler rod combines with the surface of the component material, commonly steels, to form a microscopically thin compound that holds the parts together. Welding involves heating the components and a filler rod of the same material till all reach melting temperature, forming a join that is all one material. It is possible to produce a kind of aluminium soldering with some aggressive fluxes and a lower melting point alloy rod, but in my (limited) experience is very difficult to achieve good joins as the difference in the melting points of the alloy component an the filler rod is very small!
edit: I should have said that the melting point of all of the common brazing alloys are above the melting point of aluminium,and also aluminium is so reactive it requires special fluxes to keep clean


 
Posted : 13/04/2011 5:13 pm
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I don't think it's possible as the frame is heat treated.

Brazing is akin to soldering and uses lower temperatures.


 
Posted : 13/04/2011 5:14 pm
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You could use glue on guides or some alu frames rivet them on


 
Posted : 13/04/2011 5:14 pm