Briolette Adhesion Technique
By Steve Green
Rough and Ready Gems, Inc.
Over the years, we at Rough and Ready Gems have specialized in briolettes.
One of the big problems found with briolettes is setting them. Many jewelers
have expressed their desire for a cap to facilitate setting.
In order to set briolettes, we make a series of cone-shaped caps in 12, 20, 30, 40, 50, ~ 60 degree angles. These caps have 1 mm. thick walls, and are 6 mm. deep from their openings to the bottom. Since the angle is continuous for length of the cap, it may be trimmed to any length to fit the particular briolette size. Only the corresponding cap angle to fit the corresponding briolette angle needs to be determined. The original models were precision milled on a milling machine for accuracy and to fit well a range of briolette tapered angles. These were intended as a starting point for the jeweler from which to obtain a good snug fit and create a design of choice. The caps fit all the round briolettes with no modifications needed. The oval briolettes require that the caps be custom fitted while still in their wax stage, to the oval cross section of the particular briolette. This is a considerable time saver and allows for an extremely accurate fit. Caps come with a sprue at their tip to facilitate turning, as well as for holding them during the jewelry making process. By placing a ring or a bail to the caps, they can be used to make some great looking designs.
Caps are available with the sterling silver at $10 each and the 14 Kt. gold at $25 each. Complete sets of sterling caps are available to allow anyone to make their own molds.
To achieve the best bond possible between the adhesive, the briolette, and the metal of the jewelry, it is necessary to observe a few simple procedures. I recommend that the briolette not be drilled or externally notched. Drilling or notching only removes material from the thin end of the briolette. Weakening it by adding a stressed area will render it prone to shear off when impacted.
If drilling is absolutely necessary, then use an ultrasonic drill and
use the following procedure for proper adhesion. Dufault Lapidary in Denver
can ultrasonically drill the briolettes. (303) 595-0302
The method I recommend for briolette attachment is to abrade both the inside of the metal cap and the top portion of the briolette with an air abrasive tool. This method removes very little structural material from the briolette and does little to weaken it or instill any stressed areas. The abraded surface gives a far superior adhesion than compared to one on a smooth surface.
First, both the briolette and the cap should be cleaned and de-greased with isopropyl alcohol. The briolette can then be masked with tape, exposing only the portion to be abraded. I have successfully used a 180-grit aluminum oxide. Silicon carbide should also work.
After air abrasion of the briolette and cap, clean again; de-grease thoroughly with isopropyl alcohol. Acetone or MEK will also work.
There are numerous high quality industrial strength adhesives on the market. I recommend an epoxy for its strength, ability to fill gaps, the 3 to 5 minute working life, shock resistance, and transparency. Epoxies can also be broken down with relatively low heat, between 300-400 F, in case a piece needs to be disassembled. Uncured epoxies can be cleaned with acetone or mineral spirits.
The 3M Company manufactures a full line of epoxies. DP-IOOPLUS CLEAR
and DP -100 CLEAR are both good for the job. They come in 50 ml. tubes
with a finger plunger for dispensing and are listed for under $15. For
longer working times, such as 8 to 10 minutes, DP-110 TRANSLUCENT can be
The Loctite Company makes convenient and inexpensive epoxies under the Permatex brand name. Their product QM-50A comes in an easy to use 29.5 ml. dispenser for the low price of $3. It is available at Checker Auto Parts stores.
The telephone number for the 3M Company is 1-800-362-3550 to locate the dealer closest to you. The telephone number for Loctite Company is 1-800-562-8483.
I hope this information and the suggestions are of help. I hope that I can be of assistance in supplying your briolette needs. I have single and matched briolettes in over 50 gem materials, and I am always on the lookout for new materials to offer my customers. Precision-made blank caps are also available in the metal of your choice.
Rough And Ready Gems, Inc.
P.O. Box 621813
Littleton, Colorado 80162-1813
FAX 303 933-7056
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