1) Use my 30 Ounce Kerr Electromelt, with graphite sleeve, and use
your formula to convert a troy ounce of Sunshine Mine fine silver
into a proportonately larger amount of 925. From what I
understand, I need to add copper filings, silver chunks, and a
pinch of borax. In that order?
Yes, but I’d recommend that you do not use copper filings. The
reasons are that for one, filings have much more surface area, so any
oxidation will more quickly affect a larger amount of the copper.
Also, when you file metal, you are also often breaking off a few file
teeth bits. You can run a magnet through the filings to get rid of
most of the extraneous bits of steel, but you never quite get it all,
and iron that might alloy with your silver will tend to make your
metal more brittle. Instead of filings, take scrap electrical wire,
and clip pieces off onto a scale to weigh out the right amount.
They’re larger pieces, so the melted metal will need to sit there a
bit longer to be sure all the copper dissolves, but that’s not a
problem with the electromelt, since it’s covered.
2) I recently chatted with a Dine' master, Lyndon Tsosie, who I
knew back in Gallup. We had walked me through a vertical casting
three years ago at his studio back when I was living in Sanders. He
reassured me via echat that my silver should suffer no ill effects
if were to simply use the CNC to carve a thin horizontal line (.05
inch wide line by.1 inch down?) into a tufa slab, heat the slab
lightly, and pour the silver into it: capillary action would do the
rest.
If your mold is too narrow, you may have some trouble getting it to
fill, and the tufa, as I recall, has a distinct texture which might
impede metal flow, but I’m sort of guessing here, as it’s been a
VVEERRYY long time since I last did anything with tufa.
I've never done jewelry soldering before, just electronics
soldering. If all I have is the borax powder, should I just make it
into a slurry paste with a little bit of water?
yes, but you’ll have even better luck if you mix it up with boric
acid too, half and half should work. Add sodium phosphate (mono, di,
or tri phosphates all work. TSP is the cheapest) in a mix of 3 parts
boric acid to two parts of the other two, and you’ve got Prips flux,
useful when sprayed or brushed on to prevent fire scale and fire
stain on sterling, and also a reasonable though not especially active
soldering flux. Better than borax alone. Check Orchid archives more
more extensive discussion of Prips flux. If you can afford a small
container of Handy flux or Dandix flux or similar, these much more
active silver soldering fluxes (any welding supply shop should have
them, usually cheaper than at jewelry supply shops) will make your
soldering experience a lot easier. But you can, if you need, get by
with just the boric acid and borax mix. Borax alone, if you must, but
it might not work as well with easy grades of silver solder.
4) I have dry Sparex for pickle, but I'm very seriously
considering buying citric acid instead at the drug store, because I
don't want Sparex fumes rusting all of my tools. I remember citric
acid being very important as a canning preservative, and I have a
crock pot I can use for the citric acid.
Citric acid is safer, but if you keep the pickle pot (crock pot)
covered and only warm, not boiling, you shouldn’t have a problem with
Sparex. However, next time you need to get pickle, do yourself a
favor and don’t buy the Sparex product. It’s crap, with some sort of
brown waxy contaminant in it. For less money, you can get sodium
bisulphate products sold in hardware stores or pool supply shops, as
the agent used to lower ph in pool and spa and hot tub water. Less
expensive than Sparex, works just as well as pickle, and without the
nasty gunk messing up your pickle pot.
While the Orchid community has many people who’ve opted to use
Citric acid as pickle instead of sodium bisulphate, in truth, if
you’ve got any sort of reasonable ventilation / air flow in your shop
area, and you keep the pot covered as above, you really don’t have a
safety problem with Sparex. If you’ve already got it, I’d suggest
using it.
Refinements to my self-study lesson plan, anyone?
I’m not completely sure what type of chain you’re planning to make.
Have you got a link to a photo? That would make suggestions easier.
Also, it occurs to me that if this is among your first attempts at
jewelry making, a chain isn’t exactly starting at square one. If I
were teaching a beginner, I’d start not with actually making a
serious object, but with making sure the student had some exercises
in the proper use of files, jewelers saw, and basic soldering and
annealing on scrap pieces. Maybe a little basic forging practice too.
But on the other hand, you’re probably not starting with a project
thats intrinsically beyond the basic levels of craftsmanship, so if
this is how you’d like to proceed, go for it.
In beginner level classes I’ve seen, though, the usual first
products start with usually commercially produced sheet metal
(usually brass or bronze, not yet silver) with some cold work methods
such as sawing, filing, and exploring means to texture metal, put
various types of tool marks on the metal for decorative purposes and
how the marks made when working the metal can thus also be part of
the design. Then one explores joining metal by cold joints, ie
rivets, wrapping, etc, before introducing soldering and a torch. The
idea is that one starts with basic processes and the fewest basic
tools, sees what they can do, and then adds tools and methods. if you
start all the way up with pouring ingots or bars to make into wire,
you’ve jumped more than a few of the basic steps. But then you’re
also not starting at square one with working materials so perhaps
much of that basic material may be info you already have in some
form, and if you’re comfortable starting with that chain, then do so.
Keep us posted, and ask questions when something isn’t behaving as
you expected.
Peter