Instructions for the Gold Stripping Process
Equipment and supplies required
- Stainless steel pot or tank (Pyrex container and a graphite or steel rod can be substituted)
- Heavy gage copper wire (#10 or larger)
- Stripping solution
- Rectifier or battery charger, 50 amp or larger (a battery charger may be used only if using a Visionware or similar Pyrex container. The amperage will be regulated by the exposed surface area of the steel or graphite rod)
- Hotplate or stove
If using a battery charger, the charger must have a minimum continuous charge of 10 amps and a fast charge of at least 50 amps and must have an ammeter built in. The amperage will be regulated by exposing more or less of the graphite or steel rod.
If using a rectifier, the minimum recommended amperage rating is 50 amps. The amperage will be regulated by means of the variable transformer (the knob) built into the rectifier.
- Take your premixed stripping solution and pour that into the pot or tank that you will be doing your stripping in.
- Fill the container to within a few inches of the top. If using a rectifier, we recommend the use of a stainless steel container. If using a battery charger, a Visionware container is required. If using a Visionware container, place a 12" long graphite or stainless steel rod in the container. The rod must have a plastic tube partially covering the rod like a sleeve. This "sleeve" can be slid up or down to expose more or less of the rod, regulating the amperage.
- Place the container on your hotplate or stove top. If using a stainless container, do not allow any the tank to make direct metal-to-metal contact with the stove. Separate the pot from the stove by ceramic fiber or non-asbestos strips.
- Run a copper wire (preferably #10) from the negative terminal of the rectifier or battery charger.
- Connect that wire to the stripping pot or graphite rod with a battery clamp.
- Connect a heavy copper wire (preferably #10) to the positive terminal of the rectifier or battery charger.
- Bend the other end of this wire into the form of a hook and hang the jewelry from this hook. Step-By-Step Process
- Heat the stripping solution to just below boiling.
- Turn on the battery charger or rectifier. Experiment with voltages between 10V and 15V.
- Agitate the work while in the solution and remove it for inspection every few seconds to see if stripping is complete.
- When the work is immersed in the stripping solution, the amperage drawn (as shown by the movement of the ammeter needle) will increase in proportion to the work area.
- Do not immerse so much work that the ammeter needle moves beyond the end of the dial scale. This will cause the fuse to blow due to an overload of the rectifier. The ammeter needle should not go beyond 3/4 of the capacity of the rectifier. Repeated overloading will damage the rectifier.
- When agitating the work, be careful that the work does not touch any part of the pot.
- Rinse the jewelry, preferably under running water. If running water is not available, use a pot of water, changing the water frequently.
- Some of the gold that is stripped into the cyanide water will plate out onto the sides of the pot or onto the graphite rod. Some will remain in solution. Contact Shor for instructions for recovery of the gold.
How Many Rings You Can Strip At One Time?
Because the amperage rating of the rectifier refers to the capacity of a rectifier a proper question would be, "how many rings can be stripped with a 50 ampere rectifier, or a 100 ampere rectifier or a 200 ampere rectifier?" Unfortunately, this is a question to which you cannot get a precise answer, because of several variables: (A) The specific stripping solution which you use (B) The specific voltage which you use (C) The total surface area of the jewelry to be stripped.
Two people each use 200 amperes (0-18 volt) rectifier with a two gallon stripping pot. Each person has turned the voltage regulator knob until the voltmeter shows 15 volts. They each have 20 identical ladies’ rings. Each hangs their rings on a heavy copper wire, dips and shakes the rings. Because each pot contains a different formula stripping solution, one rectifier shows an ammeter reading of 100 and the other rectifier shows an ammeter reading of 15.
Two people each use a 200 ampere (0 to 18 volt) rectifier with a 2-gallon stripping pot. Each pot contains the same formula stripping solution. You give each person 20 identical ladies rings. But one person had adjusted his rectifier to 10 volts and the other has adjusted his rectifier to 15 volts. The first rectifier will draw 100 amperes when the load of rings is put into the stripping pot. The second rectifier, with the same quantity of identical rings will draw 150 amperes.
Two people each use a 200 ampere (0 to 18 volt) rectifier, each adjusted to 15 volts, each with the identical formula stripping solution in a 2-gallon stripping pot. One person puts 20 ladies’ rings (weighing a total of 60 dwt.) into the stripping pot. The ammeter reading on his rectifier is 100 amperes. The other person puts 20 ladies’ rings (which are different from the other person's rings) weighing a total of 40 dwt.) into his stripping pot. Surprisingly, his rectifier does not show a lower ammeter reading than the first rectifier. It shows a higher ammeter reading. The reason for the higher reading is that his 20 rings are made of fine filigree work so that despite their lesser weight, these rings had 50% more surface than the heavier rings.
To clear up this apparent confusion and to put the matter into a logical sense, we recommend either (A) The purchase of a large rectifier or (B) Make the following test procedure if you have a rectifier available to you: Use a 2-gallon stainless pot with a stripping solution that we recommend or with a stripping solution which has been recommended to you. From a large bunch of identical ladies’ rings, take 4 rings and strip at 10 volts. Then, take 4 unstripped rings and strip these 4 rings at 11 volts. Then, take 4 unstripped rings and strip these 4 rings at 12 volts, etc. at 13 volts, at 14 volts, and at 15 volts. Determine by examining the rings, which voltage gave you the best results. Now with the voltage determined, try different quantities of different type of rings, taking careful note of how high the ammeter needle goes in each case. For example, if a group of 4 rings draws 20 amperes and it is your desire to strip 32 rings of similar dimension at one dip, then the total draw on the rectifier will be 160 amperes. Because the action of shaking the rings in the stripping solution (which is necessary) will cause the ammeter needle to surge upwards, the reading may go back and forth between 160 and 200 amperes. In this example, you need a 250 ampere rectifier. Otherwise the rectifier would be damaged.