Step-by-step guide to using paste solder in your next chain repair
Chain repair is based on fundamental skills and techniques every jeweler should master. When a chain is repaired, the repairs should be undetectable. Often times, this is easier said than done. So here is a step-by-step guide to using paste solder in your next chain repair.
Inspect the chain
Look over the chain to ascertain how the links are put together. In order to re-assemble the chain where it’s broken, you must know how the links are assembled. At this time, look for other areas in the chain that need repairs. Although the sales person taking in the repair should have already done this, it is a good idea to double-check their work.
Remove damaged links
Start by removing any damaged links from the broken ends of the chain. Use a permanent marker to color a few links near the joint for easy location. Use Tronex Cutters (46-0036) to cut open one or more links, and open them slightly to connect to the other section of chain. Make sure you fit the cut ends of the link together as tightly as possible to ensure a good solder joint.
Tronex Cutters (46-0036)
Cut end links
The end link needs to be cut in order to reassemble the chain. Some chains require cutting one or two links on each side. The number depends on how the chain is assembled. You can cut the links with a fine saw blade, small end cutters, or a cut-off wheel in your flex shaft.
Reassemble the chain
Lay the chain on a clean ceramic soldering board. Using your tweezers, fit the two ends of the chain back together. Then squeeze the links closed.
Repair tip: Once assembled, it is often difficult to find the break in the chain. To help you find the break, mark the broken links with a felt tip marker before assembly.
On some chains, like rope chains, you can add the solder to the broken link before assembly. Another method to help you locate the break in the chain is to cut a line down the center of a ceramic soldering board using a cut-off wheel in your flex-shaft or with the edge of a diamond file. Then lay the chain on the soldering board and place the broken link over this line.
With this method, you can lay out several chains about 1″ apart. Then start at one end of the solder board, solder the first chain, and proceed to the next one. With all the chains laid out, you can quickly solder each one, and the line shows you where to solder—with no time wasted trying to find the correct link.
Add the solder
Apply a small amount of paste solder to the joint. Do not coat the chain with boric acid. The flux in the paste solder is all that is needed for the solder to flow. The slight oxidation on the chain from the heat keeps the solder from flowing to the other links.
Repair tip: Choose a steel pick because solder won't adhere properly to titanium or tungsten.
Heat the chain
With a small pointed (oxidizing) flame, heat the ceramic soldering pad next to the joint in the chain. Do not use a bushy (reducing) flame as you will heat too much of the chain. On most chains, you will not need to place the flame directly on the chain. Place the flame on the solder pad and let the reflected heat melt the solder. This will help you from melting the chain.
On larger chains, heat the solder pad on one side of the chain, then quickly move the flame across the chain to the other side. Heat the pad on this side and move back across the chain. Repeat the process if the solder has not completely flowed. However, never direct the flame on the chain for any length of time. Move it quickly across the joint and heat the solder pad, allowing the reflected heat to melt the solder.
Clean the chain
When cool, hold the joint of the chain on your bench pin and clean off all flux and oxidation with a scratch brush. A brass brush or a small satin finish brush in your flex-shaft works well. The new 3M® Radial Bristle Disc (10-9115) kit is excellent for this purpose. I prefer the blue wheels and stack four to six on my mandrel at one time. Pickling the chain before doing this can help, but it’s unnecessary.
3M® Radial Bristle Disc (10-9115)
Polish the chain
Never polish chains on a polishing machine. Polishing machines love chains. They eat them up. Come near a polishing machine with a chain and it’ll snatch it right out of your hand. I don’t know of any other procedure in the shop that has cut and broken more fingers than a chain becoming tangled around a polishing wheel’s wheel and arbor. Not to mention the expense of replacing a customer’s chain. So, keep chains away from polishing wheels.
To polish, lay the chain across your bench pin. Then hold the chain down tight with your thumb and index finger. With a bristle brush in your flex shaft, polish (at medium speed) the area of chain between your thumb and finger. Polish the chain little by little in this manner. It is a safe and efficient means to accomplish the task.
Embrace the chain reaction
If properly repaired, your customer will return with a different chain for you to repair—and then a third. Eventually, they will return to purchase jewelry. And that’s a chain reaction we can all live with.
Do you have any favorite jewelry repair take-in tips you’d like to share? We’d love to hear about them. Please provide them in the comment section below. Or, email us at bench_jeweler@stuller.com.
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