Most
Precious Metals West - Fine Gold alloys made for the torch caster contain
a special deox additive which, when used correctly, allows the castings to
breakout of the investment bright and shiny. Just light pickling is required
to remove investment. No stripping or bombing is necessary. Alloys for induction
closed chamber casting are made differently. Grain refiners and reduced silicon
becomes the best blend for those high production machines. Fabrication alloys
are still another set of additives or lack thereof. Tell us what your processes
are like when you are trying any of our alloys for the first time.
We do have alloys for every kind of technology available for
casting or fabricating.
Metal
You must use
at least a 40% new to old rejuvenation for our alloys to perform as stated
above. We cannot guarantee our metal's properties if this formula is not
followed. Any metal will discolor if proper amounts of new metal are not
added; keep this in mind..... Metal temps should be slightly higher with
the deox alloys. If temp control is not available, inspect your crucible
after each cast to insure all metal leaves the crucible, with no beads or
flashing of gold remaining. Never cast straight from alloying-- alloying
temps are considerably higher than casting temp. Allow metal to cool first,
or pour karated gold into water first. Then proceed with casting.
Flasks
We
suggest a 50°F. To 100°F. flask raise for our alloys. This, of course,
if your oven is accurate. If you're not sure of your oven, consult an industrial
burner technician (yellow pages) to calibrate your oven to temp gauge. This
should be done yearly, to assure accuracy.
Dowse
We suggest you
wait until all color leaves the button in dim light. This varies with flask
temp, from 8 to 15 full minutes. If running full production, cast 5 - dowse
1. *(NOTE: Always dowse flasks completely underwater, to avoid silica powder
poisoning).
Melting
If torch melting,
use cleanest and hottest gas available. We highly recommend Hydrogen/Oxygen
with 40-60 lb. settings, utilizing a medium-sized rosebud torch. Natural
gas fluctuates in pressure and lines are consistently dirty. Propane is very
weak, heat-wise but acceptable. Acetylene is totally unacceptable due to
large amounts of soot. Electric melting over oxidizes metal, and high frequencies
are uncontrollable as well as unpredictable. Blow furnace casting utilizes
desirable reducing atmospheres and treats metal well. Whatever you now use
to melt with, we will help you incorporate our alloys to your system. Our
metallurgist has used every form of casting now on the market. We encourage
you to call him any time you need help.
Flux
We
recommend "Mother
Robinson's Merry Mix" which is 75% Borax and 25% Boric Acid.
This flux is good for gold, silver, white gold, and bronze.
Speech
Fine
Gold operates a Busch vacuum & Memco induction casting labs for profit and to help
our refining, &
alloy customers solve their problems. We cast with these alloys everyday, and
you should feel free to call Keith or Daniel when things don't go right for
you. We will attempt to duplicate your problem(s) and then adjust to solve
them. And when you do call, you will speak to the person who actually manufactures
the alloy, and who casts with them daily. Daniel is always available to talk
to, whether the problem is mechanical, materials, or methodology. We invite
you to call and talk turkey with us, as service is one of our strong points.
Karating
For weight conversion charts and general karating instructions, look to our "Technical
Reference Page" below. All the charts you need to raise or lower
your karat are here. Also, you can use these charts to convert common weights
and measures to and from each other. Also check out Daniel's article on in
house karating. Just click on the "Daniel's articles" here
or in the frame at left.
| Karat |
Gold
% by weight |
Alloy
% by weight |
10k |
.4166 |
.5834 |
14k |
.5833 |
.4167 |
18k |
.75 |
.25 |
Examples: If
you wish to obtain 80 dwt of 14K alloy, multiply 80 times the percentage
of gold in the alloy. This will tell you the amount of gold you need. Take
that number and subtract it from 80. This will give you the amount of alloy
you need. The U.S. government allows a 7/1000 variance on soldered jewelry,
and 3/1000 on un- soldered jewelry.
80 x .5833 =
46.66 DWT 24K gold
80 - 46.66 =
33.34 DWT Alloy
80.00 DWT 14K
gold
If you want
to make 20 dwt of gold all into 10K, just divide the 2O dwt by the percentage
of gold in 10K. Subtract the pennyweights of gold from this number. The number
you get will be the amount of alloy you need.
20 ÷ .4166
= 48
48 - 20 = 28,
the amount of alloy needed
Things
to watch for &
avoid
1.
Crucibles with white gold should never be used with yellow gold & vice
versa.
2.
For those of you who use "city gas". Sometimes a gas company will change
the content of their supply. (Usually on cold winter days). Try to use hydrogen & oxygen
for best results with all precious metals.
3. Vacuum machines
should be kept clean and tested regularly. Adequate vacuum is essential.
4. When you
invest, weigh powder and measure water with care. The investment must not
be overly cold, or it will not react with the water properly.
Karat Raising factors
| Karat
Wanted |
10kt |
14kt |
18kt |
Karat
on Hand |
|
|
|
0k |
.714282 |
1.399998 |
3.00000 |
10kt |
|
.400000 |
1.333336 |
14kt |
|
|
.666667 |
To
raise karat: Find raising factor at intersection of "Karat on Hand" and "Karat
Wanted". Multiply the weight of your karat gold on hand by the raising
factor. This will give you the weight of 24kt you must add to reach the correct
karat.
| Karat
Wanted |
10kt |
14kt |
18kt |
Karat
on Hand |
|
|
|
24kt |
1.40000 |
.7143836 |
.333333 |
18kt |
.80000 |
.285715 |
|
14kt |
.4000 |
|
|
Karat Reducing factors
To
reduce karat: Find reducing factor at intersection of Karat on Hand & "Karat
Wanted". Multiply the weight of your Karat gold on hand by the reducing
factor. This gives you the weight of alloy you must add to reach the correct
lower karat.
Daniel@preciousmetalswest.com
©2007
Keith Weinstein Inc.
