During the initial stages of decay, fungal growth produces areas of discoloration and intricate patterns of dark lines in some woods called spalting. Many turners prefer spalted wood because it gives another depth to the wood’s form. The process has a disadvantage because it weakens the wood because the wood is decomposing, parts of the wood may become punky. Pieces of spalted wood may be extremely hard, while others are incredibly soft. The lack of consistency makes things more difficult for the turner. Additionally, the wood may be brittle or stringy, making clean cuts difficult.
A soft, rotted area, typically in a tree or log center, is described as punk or punky wood. A fungus usually causes this condition, and it can be hard to detect from the outside. Projects like shaping become challenging, mainly because punky wood is traditionally found in the center and may not appear noticeable until the project is well underway, a common issue in woodturning, as the working process uncovers large amounts of undetected material. Punky wood lacks the ability and structural integrity of the outer layers. Some punky wood is only slightly decomposed and can be left in place when the project does not need structural support. Other punky wood is exceptionally soft and will cause the piece to fall apart. Punky wood can also refer to weak, diseased portions of a tree and hardwood that has become extremely dry as a product of overseasoning.
Spalted wood is a beautiful material that can be used as the focal point of a decorative turning. Woodcraft.com posted, “Spalted wood varies widely from board to board and source to source, so it is hand-selected. Select each piece of wood for usability in regards to the project you have in mind. Watch for voids in the wood that could weaken its structure, depending upon where the void may end up in your project.” Punky wood happens, or the spalting process goes too far, resulting in fibers too soft to cut and finish the project properly. Once this occurs, you have Punky Wood, an excess of spalting, requiring extra work to make it usable. Craftsmen prize spalted wood which creates a beautiful pattern of lines and gives a natural beauty to any wood art. However, there is a fine line before it becomes punky. Three factors must be present for the fungi to grow correctly and produce spalting; temperature, oxygen, and moisture. You will need to keep wood temperatures between 70 and 100 degrees Fahrenheit. Make sure the moisture content stays higher than 25%. Additionally, the wood needs oxygen. Do not submerge it in water because there won’t be oxygen. There isn’t a specific amount of oxygen required, be careful because altering any part of this process will produce punky wood. You might try products that stabilize the wood. Don’t use the piece for anything that requires structural integrity; this can potentially be dangerous.
Wood distorts and deteriorates as a result of temperature and humidity. Wood Turners Catalog posted, “The basic principle of wood stabilizing is to take a piece of soft or punky wood and inject it with resin to create a stable, hardened wood blank that is safe to turn.”The resin displaces air pockets throughout the grain structure, creating a dense blank that is nearly impervious to moisture changes and polished to a high gloss. Before you use a method to fix punky wood, you’ll need to do several things. Create a covered work area. On top of that, place your wood. Gloves, a ventilation mask, and safety glasses are all recommended. Sand the surface and remove as much rotten wood as possible. Additionally, try a hammer and be mindful of the pieces of wood that are still usable. There should be no oil or paint on the region you’re treating, as this will impede absorption.
One solution for fixing punky wood is to apply Cyanoacrylic glue, though it can be expensive on larger projects. Acrylic floor polish is another popular option. Another option is to use chemical treatments to reinforce the wood. Because you’re adding a liquid chemical that will harden the wood, it will gain weight and color. Although there are thousands of ways to stabilize wood, these are the most frequent. The wood can typically be worked in the same way as regular wood once it has cured. On larger pieces with patches of spalting, brush floor polish onto the spalted areas. Maintain the dampness of the decomposing fibers until the piece is fully saturated. You might try Epoxies, available in a wide range of types, a long-term solution that may be used for everything from small holes to completely reconstructing damaged wood. The two parts work together to fill in any gaps and stabilize punky wood.
You can sand, drill, and plane the fixes to get a repair that looks and acts like wood but won’t deteriorate or fall out. Epoxy repairs are one of the most long-lasting and robust methods of fixing wood. The composition is helpful throughout the punky spots, and they are rarely harmed by water, unlike other wood fillers. Allow two to four hours for drying. Before refinishing the product, fill any cavities with wood filler. Allow the blanks to rest for 24 to 48 hours after the resin cures. When turning your stabilized blank, please remember that the resin makes it more fragile, so handle it like an acrylic blank.
Burning punky wood is another option. The ideal situation for a fire to start are when the initial spark or flame can catch in soft, dry material with significant air gaps. When creating a fire, use punky wood that has rotted until it feels spongy, then dried. Willow Haven Outdoor posted a four-minute video showing how to start a flame with punky wood. Although, if you are not in the middle of the woods with nothing else to burn, it may be best to do a smaller project or use a different piece of wood.