BLOCKS and SURFACES

There are quite a few choices when it comes to choosing a soldering block. Different types of blocks have characteristics that would make them suited for a soldering job, or less-than-ideal. Almost any heat resistant surface will work, but some have proven better than others. You may still encounter some old asbestos soldering blocks, but they are best avoided due to potential health risks. Most often, an asbestos strip was tightly coiled in a metal pan which made a great surface, and work could be pinned to it. A suitable non-asbestos material is now being used in this manner.

Charcoal blocks are great, since they create a "reducing" atmosphere, and can also be pinned and carved. A reducing atmosphere means that the charcoal is actually absorbing oxygen from the air, reducing the amount available to oxidize with the metal. That's almost always an advantage when working with metals alloyed with copper. Charcoal blocks are surprisingly expensive and will deteriorate with time. They will deteriorate rapidly if allowed to continue smoldering after a soldering job. The longevity of a charcoal block can be extended by wrapping it with a strip of metal followed by a band, or two, of binding wire. This will hold it together as a block when it might otherwise crumble into a number of smaller blocks.

Blocks made from garnet, ceramic, magnesia and other materials are also available, each exhibiting its own characteristics. Some are hard, durable, and very heat resistant. These will last for years. Others are soft, so that you can press pieces into them or pin work down. These tend to be more consumable. Some blocks are considered to be heat reflective, and others heat absorbing, which may also have an impact on your decision of which block to use.