What is Epoxy Resin?
Two-part epoxy is a thermosetting polymer that cures to a hard plastic solid after the resin component is combined with and reacts with the hardener component. This reaction produces heat, which allows the material to cure. Epoxies are used in a diverse range of applications in a number of industries such as boatbuilding, aerospace, construction, electronics, woodworking, and crafting.
Benefits include superb tensile, flexural and compressive strength, impact resistance, chemical resistance, abrasion resistance, corrosion resistance, high-strength bonding to a number of different substrates, minimal shrinkage, and it makes a great electrical insulator to shield against electrical problems.
Different Types of Epoxy
The three kinds of epoxies typically used for boat building, home repair, woodworking, craft projects, and resin art are casting products, coating products, and adhesives.
Casting epoxies can be shaped by pouring into a prepared mold. Examples include resin jewelry, coasters, turning blanks, tables with embedded objects, and the channels in river tables. Casting epoxies such as TotalBoat ThickSet Fathom can be poured in deeper layers than coating epoxies because they generate less heat per thickness/mass.
Coating epoxies are applied in thin layers to provide a protective, glossy surface coat. Their low viscosity is also ideal for laminating and wetting out fiberglass fabric. Examples include composite fabrication, waterproofing plywood, layups, and restaurant-style, high-gloss table tops.
Adhesives create high-strength bonds on a wide range of surfaces. They can be either liquid, such as TotalBoat FlexEpox, or thixotropric (thickened), such as TotalBoat Thixo adhesives. Some coating resins, such as TotalBoat High Performance & Traditional systems can be used as adhesives, fairing compounds, and filleting materials by adding epoxy fillers.
What is Marine Epoxy?
Marine environments offer special challenges from exposure to salt, water, sand, sunlight, oil, gasoline, solvents, and other chemicals. Marine-grade products, such as TotalBoat Traditional 5:1 and TotalBoat High Performance 2:1, are used in boat building and restoration to withstand damage from these sources. While 5:1 has greater strength, 2:1 has greater flexibility when cured, and it cures extremely clear, making it ideal for wooden boat or canoe projects.
Marine epoxies are applied in thin coats (as opposed to deep pour epoxies), can have a range of cure times (depending on the hardener speed used), and can be used for structural components or structural repairs. They can be specified by their use: waterproofing, strong bonding, coating, filling, fiber-reinforced plastics, gluing, laminating and sealing. You can also fillers likes colloidal silica, micro balloons, or milled glass fiber to thicken it for filleting or fairing applications.
Other products intended for marine applications include pre-thickened epoxy adhesives for filleting and fairing, primers for waterproofing and blister prevention, fast-setting glues, and epoxies that go beneath the surface to penetrate deeply and stop rot.
Typical non-marine uses include bonding, casting, coating, embedding, and general-purpose adhesives. TotalBoat products such as MakerPoxy Artist’s Resin, ThickSet and ThickSet Fathom are popular for their cosmetic qualities, good clarity, ability to be tinted, and dimensional stability. Some of these non-marine epoxies can be poured much deeper per layer.
Uses for Epoxy Resin
Applications include bonding, casting, coating, creating composites, fairing, fiberglass repair, filleting, filling, glassing (wetting out fiberglass for layups), gluing, laminating, rot repair, sealing, tabbing, waterproofing, and even creating works of art.
What Surfaces Does Epoxy Stick To?
Epoxy bonds to many different substrates (surfaces), such as wood, fiberglass, metal, concrete, ceramics, glass, and some plastics. For a strong bond, be sure to clean the surface to remove any dirt, dust, grease, oil, water, or other contaminants before applying. Note: epoxies are not compatible with all substrates, and there are some materials epoxy will not adhere to, such as polyethylene, polypropylene, and Teflon.
What’s the Best Method for Mixing Epoxy Resin and Hardener?
For best results, use the two-cup (also called double-cup) mixing method to ensure the product is mixed thoroughly, for best results. To start, add the required amounts of resin and hardener to a clean plastic mixing cup and stirring slowly for 2-3 minutes, scraping the sides and the bottom edges. Then pour the material into a second clean mixing cup and stir for another 2-3 minutes. Stir slowly so you don’t make it too cloudy or introduce a lot of extra bubbles.
What Type of Epoxy Should I Use on Wood?
The best epoxy for wood depends on your goal because it’s so versatile, comes in many forms, and has so many uses.
For building, repairing, and restoring wooden boats, TotalBoat 2:1 and 5:1 epoxies can be used to create high-strength bonds, fillets, fairing material, glue-ups, layups, laminated surfaces, and composite parts. The clarity of the 2:1 system also makes it ideal for clear coating wooden boats, kayaks and canoes. It’s also cures more flexible than the 5:1 product. To fix rotted wood, use TotalBoat Penetrating Epoxy to seal and stop rot, the apply TotalBoat FixWood putty to reshape and smooth the surface.
Woodworkers and makers use TotalBoat TableTop for a beautful, high-gloss, scratch-resistant finish coating on wood tables, bars, countertops, and live edge slabs. For deeper casting applications, tables with embedded objects, epoxy river tables and other ‘river’ pours between thick slabs of wood, TotalBoat ThickSet and ThickSet Fathom deep pour epoxies are ideal.
Do I Need to Seal Wood Before Applying Epoxy?
Bare, porous wood can have cracks, holes, knots and voids that trap air, so it’s important to seal the pores and wood grain with a thin coat of epoxy to fill any air pockets. This will reduce the formation of bubbles that can ruin your project. To help the seal coat flow into the grain, warm the wood surface first. After applying the seal coat, let it cure until the surface is slightly tacky, then apply either a thin coating or a flood coat, depending on your project. Other than penetrating or deep pour epoxies, you can generally use the same resin for the seal coat and subsequent coats.
How do I Make Epoxy Cure Faster?
Epoxy cures faster in warmer conditions, so try raising the ambient temperature using space heaters. Since it’s the hardener that dictates the cure speed, you can also try using a fast-speed hardener, if one is available for the particular system you’re using. Never add more hardener thinking it’ll make the product cure faster – it’ll just change the mix ratio and result in an improper cure.
Is Epoxy Affected by Temperature and Humidity?
Yes, and controlling these two factors when storing, using, and curing can make all the difference. Temperature and humidity affect working times, cure times, and achieving the ideal physical characteristics of the product, such as strength and color. So, take care to monitor temperature and humidity while working and during the entire cure cycle.
If you’re using epoxy in warmer conditions, the working time will be shorter and the cure time will be much faster. If humidity levels are too high, the finish can cure cloudy, which you won’t know until it’s too late.
When working with epoxy in cold temperatures, the cure time will be much longer. The viscosity will be greater, making the product harder to dispense, and making it easier for bubbles to get trapped beneath the surface. Cold temperatures can also make the components crystallize.