ASCAS Association of Small Collectors of Antique Silver
ASSOCIATION OF SMALL COLLECTORS OF ANTIQUE SILVER
ASCAS
article # 157
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by Jeffrey Herman
 
(click on photos to enlarge image)

A GORHAM STERLING MATCH SAFE RESTORED USING PULSE ARC WELDER

As any silversmith knows, silver solder is the ideal material to use when joining sterling pieces by the traditional method of brazing. Sometimes I will receive an object which has been lead-soldered in the area in need of repair (or re-repair).
Sometimes the joined area is not visually accessible, and I don't know if lead has been used.
In either case, I cannot use silver solder because the high temperature required will melt any lead in the joint and allow it to form its own alloy with the silver. Not pretty! And, using a low temperature tin/silver solder won't give me a sound joint or good silver color.
For this reason, I use the German-made Lampert PUK 3s Professional Plus pulse arc welder. Pulse arc welding allows me to use solid sterling wire for a perfect color match (silver solders contain less fine silver than sterling).
Argon gas is pumped through the handpiece and engulfs the welding area with a protective atmosphere to eliminate firestain. The heat is so localized that I can handle the object without getting burned.

 
Jeffrey Herman using pulse arc welder on a sterling match safe



 
Jeffrey Herman restoring a sterling match safe
Restoration on this 19th century Gorham match safe started with this steel burnisher. This isn't a specialized silversmithing tool it's a modified and polished mason's jointer.
Positioned for burnishing.
Jeffrey Herman restoring a sterling match safe
Jeffrey Herman restoring a sterling match safe
I apply pressure on both sides of the safe's body, raising the dent.
Reforming the cover.
Jeffrey Herman restoring a sterling match safe
Jeffrey Herman restoring a sterling match safe
I used a chasing tool to remove a cover dent.
The dent was removed by pushing the cover down on the tool, rubbing it back and forth, raising the metal. Lighting is very important, especially in this area of the workshop. The four-foot florescent tubes overhead give me a perfectly straight reflection, highlighting any imperfections appearing on the object I'm working on.
Jeffrey Herman restoring a sterling match safe
Jeffrey Herman restoring a sterling match safe
The most tedious repair on this safe was closing the seam (or joint). The first order of business was to open the seam to remove any solder. Ultra-fine 0000 steel wool was used inside to remove any grime around the seam, making the surface smooth for burnishing.
This is another modified burnisher. Metal burnishers are generally highly polished to allow their surfaces to glide smoothly along the object. Burnishing is the least invasive technique in removing dents. Virtually any material can be used as a burnisher, including stone, plastic, and wood, providing its surface is smooth. I have even ground down and polished steel files for this purpose!
Jeffrey Herman restoring a sterling match safe
Jeffrey Herman restoring a sterling match safe
I'm wearing a 2.5-power magnifier from this point on in the safe's restoration process. Here I'm raising the seam with the burnisher past its normal state, opening the joint for greater access when I scrape the seam walls.
This modified dental tool has a narrow triangular scraper on its end. It is used to remove all solder in the joint so the filler wire will be welded to the clean sterling. Pulse arc and laser technologies will not fuse successfully to solder that previously melted. The filler metal will combine with the existing solder and produce a grainy alloy with a color that doesn't match the surrounding material.
Jeffrey Herman restoring a sterling match safe
Jeffrey Herman restoring a sterling match safe
The joint is now tapped closed using a rawhide mallet. The left and right side of the seam are aligned to the same height. There still exists a very slight taper from the bottom of the seam to the top, which will enable me to deposit sterling filler wire.
Here, a pulse arc welder is used to close the seam. This technology allowed me to use .005"-.010" diameter sterling wire on this repair as opposed to brazing with hard silver solder. Silver soldering would have taken much longer: fluxing the piece to prevent firestain, clean-up of the solder joint around the chased detail, and extensive repatination. Pulse arc welding localizes the heat and surrounds the weld area with argon gas. This gas totally eliminates oxides from forming in the sterling. As you can see, the heat required to melt sterling (1,640F) is so localized, the safe can be handheld!
Jeffrey Herman restoring a sterling match safe
Jeffrey Herman restoring a sterling match safe
The joint after welding.
A rotary compactor is used to hammer down and compress the sterling wire that was used for the weld.
Jeffrey Herman restoring a sterling match safe
Jeffrey Herman restoring a sterling match safe
A fine rubberized abrasive wheel removes any compactor imperfections.
A polished burnisher is then used to redefine the chased planish marks and refine the restored seam.
Jeffrey Herman restoring a sterling match safe
Jeffrey Herman restoring a sterling match safe
This is the result before repatinating.
A patina that will match the existing patina is applied.
Jeffrey Herman restoring a sterling match safe
Jeffrey Herman restoring a sterling match safe
Wadding is finally used to remove any unwanted patina and to produce a soft antique finish. The match safe is then degreased and wiped with a lint-free Selvyt cloth.
Jeffrey Herman restoring a sterling match safe Jeffrey Herman restoring a sterling match safe
Before
After
Jeffrey Herman restoring a sterling match safe Jeffrey Herman restoring a sterling match safe
Before
After

Jeffrey Herman
- 2012 -
Jeffrey Herman worked at Gorham as designer, sample maker, and technical illustrator. Upon leaving Gorham, he took a position at Pilz Ltd where he learned the fine art of restoration, and fabricated mass-produced ecclesiastical ware. He earned a BFA degree in silversmithing and jewelry making from Maine College of Art in Portland, studying under Harold Schremmer and Ernest Thompson, two outstanding designer/craftsmen. He started his business in 1984 gaining a national reputation of quality craftsmanship repairing and reconstructing everything, from historical pieces to single spoons.
He is the founder of the Society of American Silversmiths.
Further details about Jeffrey Herman and information contact are available in his website at http://www.hermansilver.com