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Soldering Aluminum


#1

Does anyone know why you can’t solder aluminum? I know the
melting point is 1220 degrees F, but what would happen if you
use tin solder (or any low fire solder)? I’m doing a project
out of aluminum and silver, and the connections are driving me
NUTS!

Thanks,
Daryn


#2

Daryn,

Have you tried using cold connections such as rivets instead.

Charlene
Charden Designs


#3

do yourself a big favor and attach it with a form of mechanical
lock unless you use a heli arc rig.

Frank


#4

Does anyone know why you can’t solder aluminum?

Daryn, get the proper aluminium solder and the proper flux. It
stinks, and you may have a few falures, but that’s the way to
go.

Brian
B r i a n A d a m

j e w e l l e r

a n d e y e w e a r m a k e r

s i n c e 1 9 8 1

http://crash.ihug.co.nz/~adam/


#5

I understand that surface oxidation is the problem. Maybw a non
answer that sounds good. Go to a welding supply and ask for Welco
alloy and aluminum soldering flux.

Bruce D. Holmgrain
e-mail: @Bruce_Holmgrain
http:\www.knight-hub.com\manmtndense\bhh3.htm
snail mail: 311 Sugarland Run Drive, Sterling, VA 20164
phone:: 703-593-4652


#6
Does anyone know why you can't solder aluminum?  I know the
melting point is 1220 degrees F, but what would happen if you
use tin solder (or any low fire solder)?  I'm doing a project
out of aluminum and silver, and the connections are driving me
NUTS! 

Daryn-
Actually you can solder aluminum, it just takes a special solder
and procedure to do so. I personally haven’t done it, but I have
seen it done. Maybe you could check with a welding supply or a
A/C supply dealer and they could put you on the right path to do
this. Regards-RL


#7

You need to have a heli-arc to solder aluminum. The oxides build
up so fast when trying to solder it that you have no chance to
actually make a joint. Without a heli-arc, it IS impossible.

Penny


#8

Hi Daryn:

You can solder aluminum, but you need a special paste solder to
do it. I don’t know what the mixture is, so I don’t know what
would happen to your silver. Check with your local hobby or
model train shop to see it they carry it. (I’m hoping this info
is not out-dated as I once carried this product in my own shop;
however, it was kind of expensive and not in high demand so I’m
only assuming it’s still available.)

Elaine (MoonStones)


#9

Dear Daryn, Aluminium has a very thick oxide coating which makes
it extemely difficult to solder. You can get an active aluminium
flux which does help to prevent oxygen from getting near the
aluminium. You must also solder with aluminium solder. The best
way to solder or braze aluminium is with an Argon torch which
will create an oxygen free atmosphere around the metal. I don’t
think that you will be able to solder aluminium to silver because
of the oxidisation problems. Richard W UK


#10

Hi Daryn,

I think you’ll have to go to cold connections (rivets, most
likely). I think the reason you can’t solder aluminum is that it
oxidizes immediately, and you can’t solder it in time to get
solder to flow.

Tin solder may hold it together for a short period, but unless
it’s going to sit on a shelf, it will need repair eventually.
Low temperature solders don’t penetrate the metal’s molecular
structure (metal doesn’t get hot enough), so it’s not a true
bond. You might as well glue with Elmer’s.

If the metal were to get hot enough, the solder would turn
corrosive and start eating up your silver. Been there, done
that! That was in the days before we had such a wonderful
resource as Orchid!

Good luck,

Dave Sebaste
Sebaste Studio
Charlotte, NC (USA)
dave@sebaste.com
http://www.sebaste.com


#11

From the way I understand it, the O2 oxidizes the metal, so they
use an inert gas (Argon) to displace the O2. I have not heard
of any sucsessful ways around this. Any time I have played with
aluminum it gets brittle and colapses.

Rick


#12

unless you’ve an expensive welding rig & special gasses, can’t
be done. Tried. can’t do it. Use rivets, fastners, etc. There
are tech reasons, like alum sucks, but can’t remember the other
tech terms. Give up, you’re too young to go grey - trust me,
been there, done that, tried again, still won’t work.


#13

Charleen,

My problem is that I am attaching aluminum tubing of various
sizes to sterling silver. I can try tube rivets, but I think I
may have to use tabs (I think that is what they’d be
called)-wire that is slightly bigger than the tubing, but
tapered to fit and you’d fit them together. Is that a pop
rivet? Any way thanks for your suggestion. Daryn


#14

Daryn,

as far as i know, you have to weld aluminum with an arc machine,
or cold commections.

best regards,

geo fox


#15

Dave, I think I have decided to use presure fit wire and tube
rivets. Soldering aluminum just seems so complicated and a hit
and miss situation. (I also wanted to solder aluminum to
aluminum) I’ve soldered silver to mild steel with the tin
solder and if the silver got too hot, the solder would eat right
through it. However, if I was careful, the bond would hold
without damaging my silver. This has held up the “wear and
tear” of several rings. Thanks for the advice. Daryn


#16

unless you’ve an expensive welding rig & special gasses, can’t
be done. Tried. can’t do it

I went to a welding supply. They suggested Welco alloy and a
special flux. Worked fine. It’s an aluminum version of soft
solder. Sorry. I’m getting real tired of experts saying it can’t
be done.

Bruce D. Holmgrain
e-mail: @Bruce_Holmgrain
http:\www.knight-hub.com\manmtndense\bhh3.htm
snail mail: 311 Sugarland Run Drive, Sterling, VA 20164
phone:: 703-593-4652


#17
  I went to a welding supply. They suggested Welco alloy and a
special flux. Worked fine. It's an aluminum version of soft
solder. Sorry. I'm getting real tired of experts saying it can't
be done. 

Hello Bruce & Group

I will stand corrected; after I wrote it I realised I was
thinking more of alum that would have to stand up to wear &
pressure - like a radiator, or fittings - than something which
would be purely ornamental. I was going by what I was taught by
welders, many of whom do off shore & even under water welding
where pressure is critical. Didn’t ask if it was for ring,
statue, etc. Could you be more specific as to what torch you
used, and the thickness of metals?


#18

Wondering why you don’t just use silver tubing instead of the
alum.???


#19

They suggested Welco alloy and a
special flux. Worked fine. It’s an aluminum version of soft
solder.

Could you be more specific as to what torch you
used, and the thickness of metals?

I think that any torch will work. I used natural gas and oxygen.
It’s not a real strong bond, but it is a solder.

Bruce D. Holmgrain
e-mail: @Bruce_Holmgrain
http:\www.knight-hub.com\manmtndense\bhh3.htm
snail mail: 311 Sugarland Run Drive, Sterling, VA 20164
phone:: 703-593-4652


#20

Hi Kat, Bruce, and gang,

I don’t recall anyone here claiming to be an “expert”… even if
some of them are. We’re all just trying to help each other.
For all practical purposes, you can’t solder aluminum for use
with jewelry. It won’t stand up to the use/abuse, even if you do
get it soldered using the proper solder and flux.

I assume, based on the nature of this forum, that he is talking
about jewelry… he didn’t state otherwise. Soft solder is not
generally acceptable for jewelry use. You also did not
address whether this magical flux and solder would allow the
joining of aluminum and silver, which was the problem as
presented. Soldering aluminum gutters or radiators is one
thing… making jewelry, I find, is something much different.

NOT an expert nor a professional,

Dave Sebaste
Sebaste Studio
Charlotte, NC (USA)
dave@sebaste.com
http://www.sebaste.com