Fixing a Damaged Wood Carving
Fixing a Damaged Wood Carving
It's often said that carving is an art form that requires multiple skills. Most carvers will readily acknowledge the obvious disciplines: sculpting, painting, engineering, designing the list goes on and on. One skill that should be definitely included in the list of a carver's talents is that of repairman. Damage and repairs are topics carvers usually don't like to think about because they represent a setback or at the very least, an interruption in the forward movement toward a finished piece.There are many types of damage and subsequent repair that occur on carvings. The few basic types of repairs I will address here deal with a carving in progress. The most important thing to remember about a repair is also the most challenging: the repair must be permanent and invisible. The best repair should never be seen. Poorly executed repairs can be a detriment to the appearance of a carving, so it's important to exercise as much care in their execution as you do in any other phase of carving.
The most difficult type of repair for me involves matching the existing texture on the carving to the texture in the repaired area so there is no interruption in the barb lines. Different types of damage require different treatments based on the type of texture or damage. For most basic repairs, I use epoxies as fillers or build-up material, and sometimes inserts to replace badly damaged wood. Some epoxies machine very well and some don't. Almost all epoxies don't accept burned texture very well because heat from a burning pen causes the epoxy to melt and crumble. Most epoxies that work well as bonding agents don't work very well for replacing stoned or burned texture. Knowing which epoxy material to use for a specific repair helps alleviate the frustration and sense of lost time associated with making repairs.
Whatever approach chosen to take on an individual repair should be viewed as a part of the carving process. Do not try to waste time worrying that the carving is actually damaged or broken. Instead, try to think of the most effective (remember, invisible) way to make the repair. Some repairs are simple and easy, some are more complicated and require more innovative solutions. Remember that the time and effort put into the repair will pay off later when the carving is completed and there is no visible sign to remind you that the damage ever happened at all.
The three types of epoxy generally used for repairs: Quick-Cure Epoxy, Kulis Karvit and Quikwood.
Usually one of three types of epoxy for most basic repairs, the type of repair to be made determines which type of epoxy to use. For repairs, epoxies are usually used as either a filler or build-up material, or as a bonding material. Although all three of these epoxies can perform all three of these tasks, each one has characteristics that steer it to a more specific use.
All three of these products are "two-part" epoxies, that is, they consist of a resin and a hardener. The tube labeled Quikwood comes in a stick form with the resin surrounding a core of hardener. The desired amount of material is simply cut off the end of the stick with a knife and kneaded together until the two parts are thoroughly mixed to a putty-like consistency. Often Quikwood is used to repair areas that will be, or have already been, textured with a stone. Since this material machines very well after it hardens, the stoned texture on a bird can be replaced or duplicated with this material. This material begins to set up in about 15 minutes, and is water soluble until it hardens. Some carvers believe that they can burn this material with a burning pen, but I have not attempted to do so.
Kulis Karvit comes in two plastic containers, one containing the resin and one the hardener. Equal amounts of resin and hardener are kneaded together to form a very sticky, putty-like mixture. This material is excellent for making repairs to areas that have already been textured with a burning pen. It is formed and shaped while it is still soft, and details are pressedinto the surface before it hardens. This material is also excellent for setting eyes (and forming eyelids) and making feet. It is also water soluble until it hardens.
The Quick-Cure Epoxy in the taller bottles on the left is a five-minute type epoxy. Equal parts of the resin and hardener are stirred, or mixed, together on a flat surface to form a thick liquid with about three to five minutes of open time. This clear epoxy is used as a bonding material and works well on both wood and non-wood materials.
A grinder can be used to shape or remove any of the three types of epoxy as long as the correct bit and tool speed is used. All of the epoxies respond poorly to higher grinding speeds because of the heat generated by the friction of the bit against the epoxy. Almost any type of bit will load up and become clogged as the epoxy becomes softened by the heat. Slower grinding speeds don't generate as much heat and the bits cut or abrade more effectively.
- A carbide cutter works well for bulk removal. Since the grinding speed is slow, an aggressive bit like a carbide cutter helps speed up material removal. A "toothed" bit (such as a carbide cutter or stump cutter) can be easily cleaned with a sharp, pointed tool.
- A bud-shaped stump cutter also works well for bulk removal and cleans as easily as the carbide cutter.
- Two flame-shaped diamond bits have a medium grit and work well for shaping the cured putty-like epoxies. A slower grinding speed is especially important with diamond bits since their gritty surface can quickly load with epoxy. Light strokes, low rpm and patience will produce excellent results. If these bits do load up, they can be cleaned with acetone or a foam-type oven cleaner (with proper ventilation).
- A ceramic stone rod is a solid 3/32" diameter rod with the end dressed to an inverted cone with a diamond lap stone. This bit is a very effective texturing tool for grinding (stoning) in barb lines. It's very easy to control, and this shape is easily modified. The effectiveness and control of the ceramic stone rod can be enhanced by grinding small grooves in the side of the inverted cone. A safe-end, fine-grit diamond is used to grind in the grooves. The grooves exit the outer end of the cone, leaving very small teeth in the edge. These teeth make the bit slightly more aggressive and easier to control as it is stroked from wood to epoxy. I usually place four equally spaced grooves around the perimeter of the cone.
- Another effective texturing tool is a synthetic stone dressed to a slightly inverted cone shape. Both the ceramic stone rod and synthetic stone bit work well for texturing over the Quikwood epoxy.