Previous to arriving at Bengel, I hadn’t really worked with aluminum. In a goldsmith’s studio, you don’t really work with ferrous metals or metals with a low melting point that will create pits and holes when they come into contact with your gold or silver through soldering, etc.
Aluminum is often worked in a metal shop or machine shop, (or garage, etc….), but these are places goldsmiths don’t usually like to work as the tools are rough, and not accurate. Bengel presented an interesting situation as all their jewellery and chain wares in recent years had been made from aluminum, and the jeweller’s workbench area I had to work in was clearly filled with aluminum and steel dust and scrap everywhere.
I decided t keep my own hand tools free of aluminum and store them at the school. After a two-day “tidy-up” of my Bengel working space, I was ready to start experimenting to see if aluminum could be a compelling contemporary material for jewellery.
Many jewellers have a distaste for the way it feels- kind of crackly and airy, but I found two things compelling. The material is free at the factory, and because it is strong but lightweight I could optionally make larger forms. I love making big, bold earrings, but as soon as they get too heavy, they are not working and it’s a delicate balance to not cross this line.
No one at the factory could tell me much about fabricating with aluminum, and it was also not being used too much at the school. (No one really wants aluminum in their workspace.)
I did what anyone would- turned to Youtube to watch some tutorials. Silver is ‘Soldered”. When you put two pieces of silver (or gold, copper, nickel, brass) together, clean them, paint on flux, you then melt a lower-melting-point alloy of silver between the two and the metal is strongly connected.
The process for connecting aluminum is sometimes called “soldered” and sometimes ‘welded”. At a larger scale, there are rods made of aluminum, tin (maybe lead) that are heated and drawn into seams. At a larger scale, a welder is also used to braze or weld the metal together. (Simply melt the two sides of metal together and hope they connect in a strong way.)
I was also keen to try the Puk Welder at the school. Puk and Orion make very small welding machines, where you look through a microscope at a tiny needle, hold your metal job up to the welding needle, and when contact is made, an incredible charge of heat is sent to one tiny spot. More and more of these micro welders can be found in jewellers studios, as they are very handy for tacking components together before soldering, for adding new material onto prongs near stones, and other fabrication processes where a huge soldering flame would ruin a work.
NSCAD has an Orion welder that is a few years old and I’ve had limited success using it. (Likely due to limited experience.) The Hochschule here has two Puk4’s. They have a setting for aluminum, so I decided to try.
I made aluminum samples with different challenging connecting- a butt joint, T joint, bent connection, jump ring, ear post into a hole, etc. I read online that aluminum needs to be really clean for success, so I scraped it, and also put it in the ultrasonic.
Looking into the welding microscope is so amazingly fun, I could do this all day. It’s hard not to get distracted by the terrible condition of one’s fingernails up close when trying to weld.
I started to weld without adding any additional material. (called “speed wire”). It was working pretty well, but if every side of a piece is not thoroughly welded, the connection is brittle and can be snapped apart. Unlike silver solder, the merging of the two sides of metal is happening right at surface contact, there is no strong pool of liquid metal making its way inside the joint.
One of the MFA students who had previous experience working with aluminum at a larger scale told me he would share his “beautiful setting” for aluminum welding with me. On the welder, you can set the amount of power, and the milliseconds it fires for. There are pre-sets for different materials and types of joints, but most people experiment and keep a log of what setting worked for them.
The “beautiful setting” for aluminum is:
The icon of the point welding a 90 degree corner,
Thanks, Oliver- this setting produced a strong, clean weld.
I had also purchased some thin ALMG3 welding wire from Horbach to see if it made for a stronger weld. After my experience welding with and without extra wire, I would say it is not needed unless a hole/pit forms that you need to start building material back up on.
It’s also important to know which alloy of a aluminum you are using. There are many, and its best to keep it consistent if you want to have the same results every time. Frau Hartenburger told be they order the same alloy of aluminum for all the stock they have at Benegl- sheet, tubing, wire. I can’t confirm this is true, but she did show me the invoice of their last order of Aluminium wire from Guttman. The alloy specified is: AW1090
After fabrication, the aluminum pieces can be “Eloxiert”, (Anodized) with bright permanent colours on their surface. You can also do a clear anodizing so the surface is strong/hard/protected, but the aluminum colour does not change or oxidize. I’ll be trying this later, as there is a local firm here that specializes in this.
Apparently, certain alloys can also be hardened with heat. I’ll have do more research to find out if this alloy can.
“Soft” soldering aluminum with some low- solder and “soldering-fat” I found laying around on the workbench did not work at all. The aluminum crumbled into a ball before any of the solder spread out onto it.
I have not tried aluminum brazing/welding rods from the hardware store…
Now, can I make anything interesting with this material?
Some updates after more work with Alumnium~
I thought my first completed Bengel earring (above) was pretty clever. I had found all the parts needed to puff/press a shape and then cut it out, and I could use pre-stamped off-cuts of material in a new way. I then created an integrated earwire, and Puk-welded the form closed. It never needed to go in the pickle (acid) to clean which was great, and I believed I could make many of these earrings, drop them off at the Anodizers, and come back later to pick up some wildly colourful fully complete earrings.
I took my earrings and some aluminum samples with different finishes (tumbled with stones, sandblasted, glass-brushed, shiny and pre-plated) to the local annodizer, Jakob Wild. He was not happy to see me and my small job. He said he had all the colours of anodize, but no samples. He told me things could not be shiny, just matt, (at his firm), and he also said any wires that were already in my aluminum pieces (brass, silver, steel) would just dissolve in the caustic anodizing baths. He really did not want to do my sample job, but I wanted to see how the electroplating would actually look so he told me I could pick 1 colour and for 30€ I could put in any number of pieces I wished.
The finished sample pieces did not look that great. The matt finish loses much of the interesting faceting effects of the stamping process. The chain looked the best- I had used a chain that was already anodized clear and shiny from another firm. The red coating feels very superficial- some bits of a silver show through in places. I read on the internet that you could buff gently on a wheel after anodizing, which I tried, but it does not have that rich satiny finish you see on water tumblers from the 60’s. Mr. Wild said if I had a black anodized piece, and graved into it, it would not be possible to put a clear coat on top, the electrolytic process just gets rid of the colour underneath.
I had hoped to make a group of pieces and have them fully completed here, but I am sensing I may need to find an anodizer back in North America.
I got in touch with professor Frankie Flood from Boone State to ask a few questions (gratefully in English!). Frankie gave me lots of good information and also suggested if I switched my ear wires to a Titaium wire, they could withstand the electroplating bath. This was a great tip, although it did send me down another path of trying to find some Titanium wire locally and having exhausted every firm, buying wire from Ebay. Having never worked with Titanium before, I have since learned it is very hard to work with. It is grey matt in colour, very springy, can’t be drawn down, but wow-it welds beautifully with the PUK! We will see if I can tame a bit of this material in my quest to get a single pair of earrings strongly made, and done.
I also found some solder/weld rods at the local Building supply store Globus Baumarkt. They say “hard-solder” and have integrated flux. Soldering with these rods is tricky, and it leaves a lot of solder in the area which is not desirable for a goldsmith. Mr. Wild also told me that any aluminum soldered pieces will fall apart in the anodizing bath, so I am ruling out this way of working for the moment. Frankie suggested I try some weld wire sold by Kent White in America so I will try this when I return home.