Masking Tape for Silver Solder

What can I use as masking tape for silver solder? Reading through a number of threads and references there are a number of options:

  • Pencil Lead
  • Tippex
  • China White
  • Yellow Ochre
  • Jewellers Rouge
  • Rubber
  • Soapstone
  • Anti-flux Commercial Products

There are lots of options and I will try them and report back over time. The one most readily available in the workshop is a graphite pencil. I wanted to try this on copper and brass.

silver solder mask

I marked a square with a solid circle in the middle.

The part was then flux with flux powder mixed with water. Two pieces of 1.5mm diameter easy flow silver solder were placed on each part.

Each part was heated in turn with them raised off the hearth slightly so that the heat could be applied from underneath. I was a bit nervous about blowing the silver solder strips off the sheet.

Both for the copper and the brass the graphite mask worked rather well. There are carbon deposits where the pencil was used and I assume some of this is the binder used in the pencil.

silver solder masking tape
vinegar and salt pickling of silver soldered parts

Both parts were then pickled in a solution of white vinegar and salt.

I think a separate report is needed on pickling fluid options. Vinegar and salt work quite well in the home workshop.

After cleaning in pickling fluid and a wash with soap and water. The results show that the graphite pencil masking has worked. Not quite a masking tape for silver solder, but not bad.

masked silver solder brass and copper
silver solder mask
Apologies for the left to right swap around.

Silver solder coupon tests

Coupon Testing Silver Solder

Understanding how silver solder flows through a joint is really important. Some simple tests on coupons were conducted to build knowledge for a boiler.

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