On 09/15/2010 04:27 PM, Paul Hovnanian P.E. wrote:
Tim Wescott wrote:

On 09/14/2010 09:03 PM, Paul Hovnanian P.E. wrote:
Tim Wescott wrote:

On 09/14/2010 06:08 PM, Artemus wrote:
"Tim wrote in message
...


Update: the local welding shop has an aluminum soldering kit and
aluminum brazing flux, but was out of aluminum brazing rod. They had
some zinc-alloy rod that may or may not have worked with the aluminum
brazing flux, in a size way bigger than my job.

So I got the soldering kit.

I'm going to see how well the soldering process works -- if it seems
almost but not quite strong enough then I'll try brazing, if it works a
charm I won't change.

--

Tim Wescott

As you have an OA torch it seems to me that if you use a reducing
flame the aluminum will have less of an opportunity to form an oxide
coating and may solder easier. Expert opinion anyone?

AFAIK that would only slow things down. Keep in mind that aluminum is
so electronegative that it'll reduce rust back to iron, and produce
enough heat in the process to melt the iron to steel (think "thermite
welding"). I don't know if it can reduce CO or CO2, but I wouldn't be
surprised.

Aluminum can be gas welded. Its tricky. You have to get the right kind
of flux nd the correct filer rod for the alloy you're working with.
Preparation is important, as is adjusting the flame correctly. But it is
do-able.

If I were going out and buying new material for this project I'd
probably do just that. But cost _is_ an object, and I have boxes full
of surplus parts from a former employer that are all nicely machinable
aluminum in unknown alloys (well, probably 6061 and some 2xxx alloy or
another). Since I have no clue about the weldability if the various
bits, and I'm not interested in spending money on a bunch of new bits,
soldering or brazing is the process of choice.

That makes sense. The strength welding will get you probably isn't
needed in your application. You might want to check on the max temp.
your assembly will see and compare that to the soldering or brazing
process you are using.

Having burnt myself numerous times on glow engines I can attest that
they often get to 'Ouch', but rarely do they get to '@#$%ing Ouch'.
Mufflers will go up to 'shiny spot'.

This is silver solder, which if I'm not mistaken melts way up there
around 'browned spot' if not 'burnt black'. So I think I'm OK.

At any rate, we'll test it when we get it on the engine :-).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

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