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Fabricating aluminum jewelry


#1

Hi,

I am interested in creating a collection in aluminum, but am not
familiar with its properties. Is it possible to cast in aluminum?

Thanks!
Beth


#2

on our wall we have a really nice 3D picture cast from a polystyrene
blank bedded in sand, that my partner made in school when he was
fifteen.

so yes - definitely possible! I was thinking about this only
yesterday, oddly enough.

sophie


#3

Yes you can cast it. You can machine it. It can be formed. It can be
welded with alternating current TIG welding. It can be anodized. It
can be polished bright.

Kevin Lindsey
@Kevin_Lindsey


#4

Hi Beth,

Sure, it’s possible to cast aluminum.

The colour of bare aluminum can be atractive, but it can give black
marks on your cloth and body.

It all depends on what you want to do after wards with the material.
Do you want to keep it in aluminium finish or do you want do an
anodizing job.

As far as I’m informed, they add silicon to the base material
aluminum to give a better casting.

This silicon is not nice in the anodizing process. When there is too
much silicon it’s hard to receive a fine, bright anodizing colour.
The standard profiles that are for sale in metal shops contain
mostly less silicon. That’s why they are suitable for anodizing.
Those
profiles are not normally cast, but made by extrusion; a complete
different process.

On the other hand; when you look at all those different shapes in
standard profiles; there is a lot possible to use them for
jewellery. You only have to think in a different way then for
standard jewellery.

In our collection we use aluminum for allmost 25 years. It still
keeps me going.

My advice: buy this material (it’s not expensive) and experiment a
lot. There is allways something unexpected and usefull happening.

Good luck!

Jan Matthesius
www.dubbelop.nl


#5
It can be welded with alternating current TIG welding. 

I’ll point out that there are some few people who can solder it -
some on Orchid have talked about doing it well. It’s near impossible
for most mortals…

http://www.donivanandmaggiora.com


#6

Yes you can cast it, but if you do not want to have massive porosity
problems you need to use aluminum alloys designed specifically for
casting. In aluminum casting alloys there is a higher amount of
silicon or other eutectic forming element(s) when compared to the
wrought alloys. This allows the alloy to be fluid longer and to
continue to fill the casting as it cools to deal with the very high
shrinkage rate of the aluminum.

James Binnion
James Binnion Metal Arts


#7

Hi Beth,

Sure, it’s possible to cast aluminum.

The colour of bare aluminum can be atractive, but it can give black
marks on your cloth and body.

It all depends on what you want to do after wards with the material.
Do you want to keep it in aluminium finish or do you want do an
anodizing job.

As far as I’m informed, they add silicon to the base material
aluminum to give a better casting.

This silicon is not nice in the anodizing process. When there is too
much silicon it’s hard to receive a fine, bright anodizing colour.
The standard profiles that are for sale in metal shops contain
mostly less silicon. That’s why they are suitable for anodizing.
Those
profiles are not normally cast, but made by extrusion; a complete
different process.

On the other hand; when you look at all those different shapes in
standard profiles; there is a lot possible to use them for
jewellery. You only have to think in a different way then for
standard jewellery.

In our collection we use aluminum for allmost 25 years. It still
keeps me going.

My advice: buy this material (it’s not expensive) and experiment a
lot. There is allways something unexpected and usefull happening.

Good luck!

Jan Matthesius
www.dubbelop.nl


#8
I'll point out that there are some few people who can solder it -
some on Orchid have talked about doing it well. It's near
impossible for most mortals..... 

Soldering aluminum is not difficult, though doing it “well”, for a
jeweler, may be another thing entirely.

You need special flux to get through the oxide layer, and you need
to be careful about the components of the solder, because of galvanic
action. Tin is a no-no, iirc.

I have heard of, but never seen, special soldering tools which break
up the oxide layer using ultrasonics.

Al Balmer
Sun City, AZ


#9
I'll point out that there are some few people who can solder it -
some on Orchid have talked about doing it well. It's near
impossible for most mortals..... 

I suspect it’s mostly a matter of what you’re attempting to solder
it with. Ordinary gold or silver solders and the like, as well as
normal brazing fluxes for gold or silver work, won’t work with
aluminum. But back when I was in grad school, one of the other grads,
as a research project, did a bunch of inquiry into just this. What he
found were industrially available brazing rods made for aluminum,
that then worked just fine. Flux coated rods of a special aluminum
based alloy, they worked like solder without other flux, with a
torch. Color match, as I recall was acceptable. Now that was 20 years
ago, but I assume such materials are still available.

Welding, both TIG and a few other methods, work fine, with suitable
gas shielding.

And capacative disharge fusion welders, like the Sparkie family of
welders, can put all sorts of findings in other metals (gold, silver,
stainless, etc) onto aluminum.

Back in that same school studio, the students often worked with
casting aluminum, as well as anodizing the results. To do that, they
used a specific alloy designed to be compatible with both casting,
and anodizing. As others have noted, most aluminum alloys designed
for anodizing, don’t cast well, and vice versa. But there are
exceptions specifically made to allow both. There are also casting
investments made that are better suited to aluminum casting than
standard gold/silver investments. The main difference is that they
were much easier to remove after casting. We were using a pretty
standard vacuum casting machine, melting the aluminum on a gas
melting furnace. Mostly we did big flasks, 4 x 6 and larger, so it
was usually a fair volume of metal, which seemed to help the quality
of the castings.

In general, aluminum is pretty easy to work in many of the same ways
as silver. The main differences are the light weight, the wonderful
color possibilities available with anodizing, the low cost of the
material, and the limitations on joining. You can use any manner of
cold joints (rivets, screws, etc), as well as a number of methods of
welding and even brazing with the right materials. But it’s not a
simple matter of just ordering different flux and solder and
proceeding to fabricate things the same as you would with silver.
You may have to do some experimenting to work out methods and design
ideas that work with this different and interesting material, and for
welding or brazing, you may need different equipment too. If you
stick with “cold” joints, the learning curve will be simple.
Anodizing too, can be simpler than it may seem. You do need some
equipment, but it does not need to be extremely complex. You can
even send work out to be anodized, which merely builds up a porous
oxide film on the surface that can accept a dye. You’d then do your
own coloring if you wish, and the sealing step afterwards (easy, you
boil it in salt water) which seals in the color and makes that oxide
layer pretty impervious. Doing it this way avoids the whole anodizing
sequence, with coustic chemicals, power supplies, and the like, so
then it’s really simple. Dyes used are usually made expecially for
the purpose, but even things like colored marker ink will penetrate
the unsealed anodic coating, and after sealing, it’s pretty permanent
(especially if the dye you use is light fast so it doesn’t fade. Not
all markers fit that requiremet).

Hope that helps.
Peter Rowe
Peter


#10
But back when I was in grad school, one of the other grads, as a
research project, did a bunch of inquiry into just this. What he
found were industrially available brazing rods made for aluminum,
that then worked just fine. Flux coated rods of a special aluminum
based alloy, they worked like solder without other flux, with a
torch. 

Peter is correct of course, except that soldering (as opposed to TIG
or MIG) aluminum is a real art, still. Three main reasons: The oxide
layer is really something to deal with, soldering temperature for
aluminum is not hot enough for it to change color, and it tends to
just collapse when it gets to melting temperature. Yes, it can be
done, and people do it, but it behaves pretty much unlike other
metals in soldering. All I really mean to say is to expect a learning
curve… I can solder anything to anything with my eyes closed, but
the times I’ve tried aluminum (with aluminum rods) I felt like a
little boy…

http://www.donivanandmaggiora.com


#11

Your aluminum thread (pun intended) brought up memories of my
experiences casting aluminum as a young teenager. I was in an
industrial arts class in the 7th grade ( imagine that now?? no way!!)
that cast aluminum daily. We would make the classic split mold out of
a sand/dirt mixture complete with sprues. The furnace was a natural
gas fired unit that had combustion air, i believe. It was considered
a mark of honor / responsibility to be allowed to do the actual pour.
The class as a whole collected all kinds of aluminum. Everything from
old automotive pistons to aluminum “mag” wheels were melted and
re-cast. It wasnt jewelry, but it was FUN!

steve


#12

Beth,

I was trained to keep aluminum out of my studio. I was taught to have
a separate set of tools, one for silver and another for aluminum if I
did bring aluminum into the studio. If you also work in silver you
might want to check this out.

Good luck.
Mary A