Adhesives 101

Cyanocrylates  •  Epoxies  •  Polystyrene Cement   •  Other Glues

Ask an experienced hobbyist what the most useful tool on their workbench is and they're likely to tell you, "Glue!" From hinging ailerons to assembling a plastic model kit, choosing the right adhesive can be critical to the success of your project. If you're uncertain which glue to use, or just want to learn a little more about them, read on!

Cyanoacrylate (CA) Glues

The most widely used type of hobby adhesive is cyanoacrylate (or 'CA') glue, which is sold for household use under brand names like Super Glue® or Krazy Glue®. Wikipedia describes cyanoacrylate as "an acrylic resin that rapidly polymerises in the presence of water (specifically hydroxide ions), forming long, strong chains, joining the bonded surfaces together." As there are trace amounts of water present on almost every surface, CA will start to set almost immediately upon application, forming bonds that are sometimes stronger than the materials being glued. CA glues are extremely versatile and will adhere to almost any surface, so they are often used when joining two different materials, such as wood and plastic.

CA glues come in different thicknesses. Thin CA, such as Insta-Cure™ from Bob Smith Industries (BSI), has approximately the same viscosity as ordinary water, begins to set almost instantly (1-3 seconds), and will wick into porous materials, such as balsa wood. This makes it a favorite of people building airplane models or scratchbuilding structures for train layouts and gaming terrain. It will not fill gaps, so the two surfaces being joined must be very tight-fitting and held closely together while the glue cures.

Medium CAs, such as BSI's Insta-Cure+™, are thicker, cure more slowly (5-15 seconds), and will fill small gaps. They are a great choice for more loosely fitted balsa joints, and for working with other soft woods.

Thick CAs have a much higher viscosity than other types, allowing them to fill larger gaps. They are slower to cure (as much as 60 seconds, depending on brand), giving the user more time to re-position or align the items being glued; many hobbyists find thick CA the easiest type to work with. Thick CAs, such as BSI's Maxi-Cure™, can bond to almost any material, and are a great choice for repairing ceramics, working with hard plastics (including Lexan), and gluing fiberglass.

There are also special-purpose cyanoacrylate glues, such as foam-safe CAs, which are safe to use on Depron and other white foams. Flexible CAs form a less brittle bond than normal CAs, and work well for CA aileron hinges and applications where vibration is an issue. Rubber-toughened CAs, including BSI's Insta-Flex+™ and IC-2000™, are even more flexible and shock resistant, making them a great choice for gluing R/C car tires. You can buy an accelerator to help CA cure faster, or a debonder, such as BSI's Un-Cure™, to soften or dissolve hardened CA joins.

Epoxies

Epoxies are another popular type of hobby adhesive. Epoxies consist of two parts, a resin adhesive and a hardener that allows the resin to cure. The two parts are usually mixed in a 50/50 ratio, though that may vary depending on brand. Like cyanoacrylate glues, epoxies can be used to join almost any type of materials; they often prove more cost-effective than CAs for projects where a large amount of gluing is required. Epoxies are usually rated by their curing time, which may range from five minutes to twenty-four hours, with slower-setting epoxies forming the strongest bonds.

Hobbyists appreciate epoxies for their strength and versatility. Epoxies, especially slow-curing varieties, form bonds that are more water-resistant than CA glues, making them great choices for building boat kits. When mixed with microballoons, some epoxies can be formed into a sandable putty. Other epoxies, such as BSI's Finish-Cure™, can be used for applying fiberglass cloth to wood or for preparing wood to be primed and painted.

Polystyrene Cement

Polystyrene cement, or "plastic model glue", is specially designed for use with rigid polystyrene, the material most commonly used to manufacture plastic model kits. When applied, polystyrene cement actually dissolves the surface of the plastic; as the plastic re-hardens, items attached to it will adhere. If two pieces of polystyrene are joined in this manner, the cement essentially welds them together, forming an extremely tight bond. Polystyrene cements comes in different types and thicknesses, from thick tube glues like the well-known Testors Plastic Model Cement to fast-curing products with a watery consistency, such as Tamiya Extra-Thin Cement and Tenax 7-R Plastic Welder.

Other Glues

There are many other types of adhesive used by hobbyists. Model boat builders often use silicone glues and caulks to waterproof their creations. Plastic modelers and radio control airplane enthusiasts often use "canopy" glues that won't cloud clear plastic parts, as CA and polystyrene glues sometimes do. Carpenters wood glues have many hobby uses, while model railroaders, gamers, and other scenery builders find clear-drying water-based adhesives such as Woodland Scenics® Scenic Cement™ indispensable. Whatever your project, Hub City Hobby has the perfect adhesive to make it happen!

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