Repairing cracks in wood
Small cracks in wood are not dangerous and are natural. It’s bad when the defect reaches a width of 3-5 mm and spreads in length over the entire surface. Moisture that gets into the crack leads to wood rotting. The bark beetles that have settled there will undermine it from the inside.
Cracks form when wood dries unevenly. Outside the process goes faster, inside – slower. Therefore, the inner layers are compressed, and the outer ones are stretched, the fibers break and cracks appear.
Now let's look at a way to repair a crack and use the wooden material for its intended purpose. What do we need for this?
Required materials and accessories:
- polyester resin included in the set;
- small plastic container;
- construction tape;
- plastic film and plastic bags;
- stirring stick or spatula;
- protective gloves and glasses.
Polyester resin is traditionally used for such restoration repairs. It easily penetrates the fibers and forms a strong physical and chemical bond with them. When hardened, the resin becomes very strong, but at the same time retains some residual flexibility, which is very important since wood can contract or expand depending on air humidity.
The process of repairing a crack in wood
Even a schoolchild can do this job. Only ordinary care is required.
1. Seal the cracks at the ends of the wooden part and at the bottom with tape so that the binder does not leak out through them. If the end area is large, you can put a plastic bag over it and secure it with tape.
2. Prepare the working composition by adding a dosed amount of catalyst to the resin, vigorously mixing the ingredients for 1-2 minutes. The resin can be given the color of the restored material by adding an appropriate pigment to it.
3. Pour the resulting composition into the cracks until it completely fills their volume and begins to spread over the surface.
4. Wrap the treated wooden part in plastic film, secure it in several places along the transverse perimeter with tape and leave it alone for 1-3 hours. This time is necessary for the complete completion of the polymerization reaction, that is, the final hardening of the polyester resin under the action of a catalyst.
5. Unfold the restored wooden part and remove the tape from the ends and bottom. We mechanically remove excess hardened polyester resin from the surface. The reclaimed wood element is ready for use, both for decorative and structural purposes.
In custody

A wooden part containing polymerized polyester resin can be processed without restrictions with any tools: saw, plane, sander, drill, etc. But when processing with a chisel or chisel, you need to be careful and wear safety glasses, since resin particles will fly apart like fragments glass

One final warning.The polymerization reaction of polyester resin and catalyst releases heat and the substance styrene, which is harmful to humans. Therefore, it is better to perform all restoration operations on wood outdoors or in a workshop with reliable ventilation.
Original article in English
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