United
Precious Metal Refining, Inc.
Type "88" Sheet and Wire
Covered under one or more of the following #‘s. U.S. Patent #
4,973,446, # 5,039,479
Sterling Silver # 88 is a proprietary deoxidized Sterling Silver
formulation designed to eliminate fire scale, porosity and greatly
improve tarnish resistance. Sterling Silver # 88 sheet & wire
products will be slightly softer than traditional Sterling Silver
sheet & wire stock. Working characteristics of Sterling Silver # 88
sheet & wire stock will be the same as traditional Sterling Silver.
FABRICATION
Use the same methods and procedures as those used for traditional
Sterling Silver. A minimum 50 % reduction should be taken on stock
before annealing to avoid excessive grain growth.
ANNEALING
The best method for annealing Sterling Silver # 88 stock is in a
controlled atmosphere furnace. In belt feed, controlled atmosphere
furnaces the anneal times and temperatures will be determined by
experience. In open furnace annealing, a 1200 degree F/ 648 degree C
temperature should be used. Anneal times will be 10 to 20 minutes,
depending on thickness of material. A fire coat flux should be used
in open ovens to protect the metal from oxidation. Avoid over
annealing the Sterling Silver # 88 as this can cause orange peel
surfaces from excessive grain growth.
PICKLING
If pickling is needed use hot "Sparex" (Sodium Bisulfate) solution
or a 10% Sulfuric Acid solution.
HARDENING
Soft annealed stock may be order hardened by a heat treatment in a
preheated oven set at 575 degrees F / 300 degrees C for 1 hour
followed by air cooling. A fast pickle may be needed after heat
treatment to remove the light surface oxidation.
OXIDIZING
The regular "Liver of Sulfur" solutions do not blacken Sterling
Silver # 88 well. Two chemicals are effective for blackening this
product, "Silver Black" from Griffith Chemical available from Grobet
(201) 939-6700 and "Black Max" from Rio Grande (505) 839-3000.
CYANIDE
Cyanide treatments are not recommended for Sterling Silver # 88
stock.
NOTE
We welcome your comments on this product.
TECHNICAL ASSISTANCE
Always available…
Call 1-800-999-3463 / 1-800-999-FINE
E-mail / doc@unitedpmr.com
Web-Site / www.unitedpmr.com |