All About Epoxy
An adhesive and a finish, epoxy finds a variety of uses in woodworking and boatbuilding
Epoxy resin is a versatile material that finds uses as diverse as boatbuilding and fine furniture making. It can be used in finishing, as an adhesive, or for a variety of specialty applications such as inlay. Epoxy comes in two parts, a resin and a hardener, and is available in a variety of types, each with varying properties. There are fast-curing and slow-curing epoxies, and they can be thick or thin; It all depends on the application.
– The boat builders choice: Water resistant and gap filling, epoxy keeps boats afloat.
– A sturdy finish: Great for protecting outdoor furniture from the elements.
– An adhesive: A variety of open times makes epoxy a versatile adhesive.
– Gap filing: Fill dents, glue imperfect joints, and create decorative inlay.
The boat builder’s choice
Epoxy-resin adhesive is used in several capacities in boat building. Unthickened it’s used to bond fiberglass tape (along the exterior seam of the hull) and as a strengthening and waterproofing agent in a process known as epoxy saturation. This process involves coating the hull with the epoxy resin, usually both inside and out, rendering the boat absolutely watertight. This prevents rot and delamination of the plywood body and adds strength to the hull by filling the grain that’s opened from the plywood’s being contorted into shape. The epoxy also soaks deep into porous woods leaving a tough, protective exterior skin and a smooth base for a varnish finish.
A sturdy finish
As a wood finish, epoxy holds its own with outdoor furniture. Taking a queue from boatbuilding, furniture makers have embraced the virtues of epoxy for its protective qualities against water and sunlight. When used as a primer coat, epoxy penetrates deep into the wood hardening to create a protective exterior. A varnish can then be applied for an attractive top coat.
When used as an adhesive, epoxy resin is thickened with chopped cotton or silica fibers to slow the epoxy’s flow and to increase its strength. It is a good choice for tasks, such as making curved panels out of several layers of veneers or bending plywood, because it will undergo very little spring back. Epoxy is not always the best choice for gluing up standard woodworking joinery, unless you require a longer open time than a PVA will allow.
One of the most popular characteristics of epoxy is its ability to fill gaps when gluing up imperfect joinery, filing dings and cracks in wood, and even specialty applications such as inlay. When mixed with dyes, epoxy can mimic the look of wood inlay without any of the hassles of cutting and mitering small pieces of wood.