Hi I had some more Purple Gold Buttons made by Mintek in S.A when I
was there in July 99 -at the SA Jewellery Fair (purple gold
=75%Au-25%Al ) The buttons are about 20mmx7mm thick and weighed
10grams each The buttons are melted in controlled enviroment and at
correct temperature in an induction oven
When you drill it with HSS drills then it seems that they become
blunt-- but that is only the appearance,- 'cause the stuff doesn’t
form little pig tails like normal metal, but powder–and that makes
the drill look blunt – so,- correction to an easier post - files,
drills and burrs feel like you are scratching very hard chalk but I
have used them later in normal goldsmithing applications,- and have
found them to be as comfortable in use as before. Still,- it is a
facinating substance- and sort of nice, from a gemcutting angle. How
ever, it cannot be bent ,rolled, or changed in any mannner in a
mechanically orientated workshop ( I would like to ask this list-
Does the plasticity of an inter metallic compound increase with
heat? My last post produced some very interesting returned ideas -
-namely- (for me-) Is it possible to build up 'claws "around a stone
that (say) has been recessed into the “mother piece” of purple gold
with electro- deposition? Is a combination of AG/Al platable on
another metallic surface ? Is it possible to cast inter metallic
compounds? Ok,- - so this is fwiw stuff,- I took a piece of this
material and heated it higher and higher, with a med/ reducing
flame.- (I use a Little Torch)- As it heats to dullish red (in dark)
it goes a slightly darker purple( in the light) and then it oozes
little bubbles of aluminium. (like granulation) If you sand those off
with your buffstick, and heat it up again the same happens again.(as
in the little granulation ali bubs form again. I assume the Ali is
boiling? So if that is causing a depletion of Al in the outer surface,
then why does it stay the same purple colour? When you grind it
with, ( say), a Mizzy Heatless wheel, then it acts Quartz-ish, with
little chips coming off the cornersThat is not so bad, 'cause the
finer the grit the smaller the chips till 1200 when it get to pre
polish. . Diamond (hanging motor ) wheels give a sharper finish. When
you inlay the stuff it also acts like quartz,in the sense of that
when you try to remove the piece you stand the highest chance of
chipping it. If you heat it up to an easy soldering temp you get ali
bubbles- sure, but it takes heat as good as any of it 's parent
materials-under those temps What I mean is that it does haveany heat
sensitivity like stones I thought that since this stuff contains
aluminium, it may can be soldered with an industrial Alim solder I
used Afrox Aluminium Brazing Flux and matching solder rod. But no
Kudos… Not even those little (supossedly) Ali bubs took to the
braze. So far all of my setting techniques have lent to the
mechanical . I dumped hot PG into a mild concentration of sulphuric
acid -it did not attack the material as such( a very short time in
the acid) , but made the colour of purple more intense. If you use a
1200 grit buffstick (on that acid quenched piece), then it becomes
apparent that the sanded down area is lighter in colour, but where
the gold has been polished it gives a gentle Haematite Purple
colour) Quenched, it’s got a bit of an anodized look-.(my vision)- It
takes an easy polish with pretty much any polish working (Titanium
polish, Platinum and any of the standard polishes) The most intense
colour that I can get is the acid manner , but the most intense
colour is in the broken pieces-- by that I mean that if you take a
hammer and hit this stuff then it looks lots like newly broken rock .
Ok,- this is seriously for what it’s worth–I had an of cut off PG .
So - I inlayed it into a wax model (Purple wax) and cast it in a
spin casting machine with silver and standard investment. I use a
anti oxy type of Sil alloy at 95% purity.It has some Zn in it.
Aluminium melt temp is not of Silver- so – I figured that there
would be a eutectic(sp) solution of sorts. There was,- I think - it
ate into the silver in a pretty rough way-- but not all of the PG
was turned utectic Therenwas a central “core” that I drilled out that
was pure purple dust. . The “excess” of that eutechtic solution was
as unmalleble as the parent metal The mixture looked like a white
metal.I have pictures of all this stuff and I will upload these for
any one-- if some one could guide me through the protocol. My summary
It’s a Gem. It acts like a petulant type of stone with easy polishing
qualities i.e Quartz and Opal–. It’s saturation of colour is less
than a good quality 18kt yellow Having said that it has a (to me ) a
distinctly different colours in three light situations/ 1 Incandescent
light-- warm amethyistish. 2 Neon: cold grey purple 3 Dayligh:t
leaning to the yellow of 18k- with a difficulty to photograph in
daylight so that you get a nice contrast-It sort of looks yellow (to
me ) It is unforgiving Still --it is the latest colour of 18kt to come
out on a saleable scale(I have not sold yet – I have only 4 pieces
of this material, ) Now I am going to do the unforgivable- -Linkie- my
comp/crash- email me- Sala sent , people. Hans
SEROL-WANA Designer African Jewellery P.O Box 266 Kasane BOTSWANA
Tel:(+267)651011 Tel:(+267)650555 Fax:(+267)651168