Hi Maria;
You can use silver or gold solders on steel and iron. But you will
have the best results if you sand or grind away the grey scale from
the surface of the steel and use a paste type flux. You can also
grind borax very fine and make a paste with water and use that as
flux. Don’t put the article in acid after the gold or silver is
attached, as the copper in the silver or gold alloy will get plated
onto everything, making everything pink. This will always happen when
steel is put in acid that has been used to clean copper bearing
allows. You can use dilute muriatic acid to clean the steel (before
you’ve attached other metals to it). Use mild steel (commony used to
make auto bodies, appliances housings, etc.) If you use tool steel,
as is used to make tools, knives, springs, etc., you will be using a
very tough and hard metal which is difficult to work with. Pure iron
is very nice to work with, but not easy to find. Most steel has at
least some carbon in it, which is there to harden it, so it will be
best to anneal it by heating to a red color and letting it cool
slowly in the air. This will leave a grey coating called "scale"
which will need to be abraided away by sanding, grinding, sand
blasting, or soaking for a while in acid. It’s not likely you’ll be
able to harden mild steel very much by heating and quenching in water
or oil, but you can get a nice dark color on the steel by cleaning it
and then heating it to achieve colors from faint yellow to dark blue
to black. But these colors will be replaced by rust if you don’t seal
the surface with something like wax or laquer. You can also
deliberately let it rust, or speed up the rusting by leaving it in a
closed container with a little bit of acid, or spray with ferric
chloride and water then leaving it for a few days. Ask your
blacksmith fried for scraps of mild steel, and especially if he
knows of any old wagon wheel rims. Those are often “wrought iron”.
It’s an old form of nearly pure iron that, when it weathers, shows a
grain like old driftwood. That is due to it’s fibrous structure. That
aspect can be exploited by eposing the material to acid for
prolonged time periods, which brings out that wood grain effect,
creating a very interesting artifact.
Hope you enjoy working with iron and steel. Long before I was a
jeweler, I was a blacksmith, and made some of my first jewelry
articles of iron and steel.
David L. Huffman