brazing aluminium

[BrokenBiker]

need to join some aluminium square bar and have been asked to braze it.

what brazing rod do i need and will my normal flux be ok?

 

[voipio]

This might help.

http://www.aluminiumrepair.co.uk/index.php?option=com_content&view=article&id=70&Itemid=97

 

[brightspark]

This might help.

http://www.aluminiumrepair.co.uk/index.php?option=com_content&view=article&id=70&Itemid=97

yep the same as tecnoweld or durafix easyweld rods

 

[BrokenBiker]

cheers will give that a read when the missus puts something crap on telly

 

[brightspark]

cheers will give that a read when the missus puts something crap on telly

might as well start looking now then why do i think im on here a lot dancing on ice anyone

 

[gordon stephenson]

There are quite a few makes of aluminium brazing rod, Techno-weld, Dura fix and HTS2000, i have used a couple of them and found the results very similar.If you have not used these before, I suggest a fair amount of practice first. Used correctly they give excellent results,There are lots of video's on youtube.

 

[Paul G]

I must confess I had to reach for my copy of A C Davis to check the percentages,
but I did manage to remember that aluminium brazing is done with a 10-13% silicon rod.
This rod melts 65 to 100 deg C lower than the parent aluminium and produces a surface sweat
and therefore a straight line bond.

See. I didn't just sit up the back of the class, half asleep.

Paul G

 

[hotrodder]

^^ yeah, 4047 filler with the appropriate flux* The other stuff mentioned is a self fluxing zinc based aluminium solder when bought from a 'proper' welding supplier (cheaper too) and not hyped up to be 'better than' welding or called a brazing rod as done by the snake oil salesmen. Self fluxing aluminium solder is typically ~ 90% zinc with a little ally, traces of copper, mag and sometimes other stuff. If it melts at 370ish C (most do) then it's gonna be near as damn it identical to SIF 555 Al solder. The shills that hype it up are right when they claim it's stronger than many flavours of aluminium but stronger = harder which = more brittle most of the time. Bodging a casting back together this is less of a deal as castings are brittle anyway but compared to the softer wrought Al alloys the stuff is glass brittle which may or may not matter depending on the application of the part- if brazing was specced for a reason (and they meant 'real' brazing not the snake oil variety) it might...

* different to 'regular' brazing stuff as fluxes are fairly application specific, melting point of the brazing (or welding) rod for one thing

ETA square bar probably means a 6xxx aluminium, joined with 4047 be looking at % elongation in the 8 - 12% range. The monkey metal solder is 3%