There are many different types of soldering boards, blocks, and surfaces. How do you know which one to start out with, and which one to use for each soldering task? Each type has its own purpose and function while soldering. There are two main categories of soldering board: ones that reflect heat back into your metal, and ones that draw heat out of your metal. The boards that reflect heat are often softer, more crumbly, and good for soldering medium to larger pieces like bezels, hollow construction rings, and sculptural pieces. Reflecting-type boards include charcoal, Magnesium, and Calcium silicate. Boards that draw heat out of your metal are more durable and dense, and good for annealing all sizes of work, and for soldering small elements that will melt if they get too hot. These boards include ceramic, firebrick, honey comb, and pumice stones.
Charcoal Blocks are a very traditional soldering surface for silver and gold. They are the most heat reflective of soldering boards, meaning they produce a cleaner soldering environment than other boards. They also reduce atmosphere, which means less oxidation and your flux won’t stick to them as easily. Charcoal is quite soft (but does come in different densities) so it’s really good for carving groves to position small elements into, or sticking pins and binding wire into. For example, if you want to create a perfect ball, create a depression in the charcoal, fill it with scrap, and heat it until it balls. The ball should be a perfect sphere. The downside of charcoal is that it is very crumbly and will crack when heated. To make a charcoal block last longer, anneal the entire thing before use, and wrap the edges with binding wire.
Magnesium oxide soldering blocks work similarly to charcoal, but they won’t fracture like charcoal. They are also very heat reflective, and the same material is actually used in fire-resistant wall board in construction. Magnesium is very soft like charcoal, so it is also good for sticking pins into, carving into, or positioning pieces into. It can withstand heat up to 2,000°F (1,093°C), which is above the melting temperatures of copper, silver, and gold. Magnesium blocks are asbestos-free, but they do produce slightly toxic fumes when they are heated, so make sure to work in a well ventilated space, and wear a mask.
Calcium silicate (Solderite®)
Calcium silicate (Solderite®) boards are cleaner to work on than either charcoal or magnesium. They are also very heat reflective and are useful for heating larger pieces of metal quickly. They are denser than the previously mentioned boards, won’t crumble or flake as quickly, and have a quick cool-down time. The same material is used for fire-resistant insulation in construction. This material is asbestos free and non-toxic. However, the maximum temperature is 1,700°F (927°C), which is quite a bit lower than charcoal and magnesium.
Firebricks are generally used in ceramic kilns, but can also be used as a surface to solder, weld, or anneal on. They’re made out of dense ceramic material and are very hard. They’re best for annealing or soldering large pieces of metal with a large torch, as they dissipate and distribute heat well. They can also be used for soldering small elements because they will draw heat out so your work doesn’t melt. There are many different types and brands of firebrick, some can be cut with a jewelers saw and some cannot.
Ceramic soldering boards are an ideal surface to do all types of soldering and annealing on. Ceramic is a really good material for distributing heat, as the surface both reflects and absorbs heat. These boards are great for beginners, because they’re so versatile, and also quite durable. They’re denser than charcoal and magnesium, so they cannot be carved or have pins stuck in them, but they’re also easy to clean and resurface with sandpaper. Most ceramic boards can handle temperatures up to 2,000°F (1,093°C), which makes them ideal for copper, silver and gold.
Ceramic Honey Comb
Ceramic Honey Comb soldering boards are the same material as solid ceramic soldering boards, but they’re much more heat-absorbent than reflective. The small holes make this board much more lightweight, and quickly dissipate heat from your metal. This means that there will be slightly more oxidation and residue from soldering, but the soldering itself will go very smoothly. This board is ideal for soldering medium and bigger soldering tasks like rings, brooches, and pendants. It’s not great for soldering tiny things, as your metal or pieces of solder could fall through or get stuck in the holes. This board heats very evenly, but doesn’t retain heat, and cools down very quickly. It can withstand temperatures up to 2,000°F (1,093°C). However, because of the holes, it is much more brittle than solid ceramic, so it will break if dropped.
Platinum Rated Soldering Board
Platinum Rated soldering boards are similar to solid ceramic boards, except that they are made of a special kind of silica material that can withstand heat up to 3000°F (1649° C) and won’t contaminate platinum. Since platinum has an extremely high melting temperature, it’s necessary to buy a different soldering board for it.
Pumice stones are a lot like firebricks, but they’re a naturally forming volcanic rock. They’re very heat absorbent, because they’re loose porous stones. It’s easy to cover or bury part of a larger sculptural piece in the stones for protection if you want to solder something without heating the entire piece. Pumice stones are great for annealing medium to large pieces on, as they will distribute heat well, and you can also position items in them. They also work well for positioning your soldering board into, as a surface for protecting your bench or table from heat. They’re not good for soldering or annealing small pieces, as they’re not a stable surface to put things on.
There are quite a few different types of soldering boards out there, but don’t feel overwhelmed! Start with a Magnesium block or a Ceramic Honey Comb block to learn how to solder, and you’ll get a lot of mileage out of your first board. When you’ve mastered the basics, experiment with other types of soldering surfaces for different tasks.