How to anneal and form a silver band in controlled stages

What to take away

• Write the process card before you light the torch: alloy, temper, batch, anneal range, cooling method and forming tools.
• Measure the strip at the center and both quarter points, and photograph both faces under raking light, so forming damage is not confused with stock defects.
• Heat the whole working section evenly under local exhaust; thin ends gain heat faster than the center.
• Quenching is a decision, not a default. Follow the alloy supplier's cooling step.
• Stop at any crack, edge split or fold. A crack cannot be formed out.

This guide covers an open practice band formed from documented silver strip. It does not cover a soldered ring, a stone-set piece, plated stock, or a wearable cuff, where opening and fit need their own design review.

Step 1: write the process card

Record the alloy, supplier, batch and temper. Record strip length, width and thickness, the required inside contour, and the opening. Add the minimum section, edge radius, approved annealing range and the indicator you will watch.

List the tooling:

• torch
• fuel
• tip size
• support
• exhaust
• fire controls
• forming mandrel
• hammer or mallet If the supplier publishes no annealing data for the stock, stop and get it. Colour memory from a different alloy is not a procedure.

Step 2: prepare and measure the strip

Square or shape the ends to the drawing. Deburr the edges without reducing the stated width. Mark the centerline and the quarter points, then measure at each one.

Photograph both faces under raking light. Rolling marks, pits and edge defects belong in the starting record. Without that record, a pre-existing pit reads as forming damage and you will chase a fault you did not cause.

Step 3: inspect the tool pair

Check that the mandrel is clean, secure and free of raised damage. Inspect the hammer or mallet face and the handle. The contact has to move the strip, not stamp sharp marks into it.

Historical research on Paul Revere's workshop describes work hardening and annealing as linked stages in shaping silver. That account sets no temperature and no quench method. Your alloy specification controls this exercise.

Step 4: anneal under exhaust

Clear combustibles, verify local exhaust, complete the torch inspection, and set out a marked landing area for hot metal. Wear the eye and body protection your shop's hazard assessment requires.

Heat with the approved flame and keep the torch moving so the section reaches condition evenly. Thin ends run hot before the center does. Do not treat redness, melting flux or elapsed time as a universal indicator unless the qualified procedure names it. Shut the torch down correctly, and treat the strip, support and tweezers as hot.

Step 5: cool, clean, inspect

Use the cooling method written for that alloy and that stage. Quenching is not automatically correct. If the procedure calls for pickle or another cleaner, use labelled compatible tools with ventilation, protective equipment, rinsing and waste controls.

Dry the strip and look for melting, scale, firestain, pits, contamination and distortion. A damaged strip does not go to the mandrel.

Step 6: start the curve at the center

Support the strip at its center against the mandrel. Work outward toward the ends with light, balanced blows or pressure. Keep the strip square to the mandrel unless the drawing calls for taper or twist.

Turn the work often enough to see both faces and both edges. Never put fingers between the work and the mandrel, or inside a curve that is closing.

Step 7: measure after every pass

Lift the band off the mandrel without prying against an edge. Then check:

Feature	Method
Center alignment	Compare the center mark with the deepest curve
Paired quarter points	Measure distance and curvature from the center
Opening	Use the drawing's gauge, not finger fit
Width and thickness	Measure at the named positions
Edge condition	Look for flare, roll, dents and cracks
Surface	Compare against the raking-light photographs

Return only the high or flat areas to the mandrel. Do not thin the opposite side to imitate symmetry.

Step 8: decide on a second anneal

Use the deformation or hardness limit on the process card. Rising springback and resistance suggest work hardening, but they do not replace that limit. Stop at any crack or edge split.

If another anneal is allowed, repeat the full sequence: heat safety, cooling, cleaning, inspection. Log every cycle.

Step 9: release the band

The practice band passes when contour, opening, symmetry, minimum section, edge radius and surface all match the drawing. Clean and store the tools, segregate the filings, and attach the final measurements and images to the job record.

Common questions

Must silver glow before it is annealed?

Glow is not a universal indicator. Follow the alloy supplier's range under lighting bright enough to judge it, and treat any colour chart as specific to one alloy.

Should the band be quenched straight away?

Only when the documented process says so and the construction allows it. For some alloys and stages, air cooling is the correct step.

Why does one end curve more than the other?

Compare anneal uniformity, starting geometry, support, blow order, section thickness and center alignment. The uneven end is usually a symptom, not the fault.

Can the mandrel set the final size?

No. Measure the released work, because springback and any taper change the diameter once the band comes off the mandrel.