Model Kit Building Glues And Uses

New model kits today are marketed as "Hi Tech" or "Multimedia" scale model kits. These kits usually come with some number of fine detail components made out of metal or resin besides the standard     polystyrene (plastic) parts. These kits will require using different types of glues and cements.




Glues come in two types, water based and chemical. The water based glues are usually nontoxic and act as a "tacky" layer that holds the bond between the parts. Chemical glues, however, must be handled smartly in a well ventilated work area as they emit potentially harmful vapors. The chemical glues bond the parts through a chemical reaction with the surfaces, thus fusing the parts together in the way specific to the glue’s chemical properties.



White Glue:



The most common water soluble glue is white glue or carpenter's glue. This glue was originally developed to bond wood and other porous material together. It has found its niche in the plastic kit building world because it dries clear and will not craze clear plastic parts or damage enamel paint. Since it is water soluble any overuse can be quickly cleaned up. The bond however is not very strong so its use is confined to bonding small metal detail parts to clear plastic and not for cementing major plastic components.



Plastic Model Cement:



The common polystyrene glue comes in two viscosities, thick and thin plastic cement. Both melt the plastic parts at the join and fuse the bond as they dry. The thick variety is the well known "tube" cement that is sold in squeezable tubes and comes out very thick and often messy. Decades ago it was the only glue to use and any dime store had it. Its major use in today’s modeling is to cement large structural polystyrene pieces requiring a strong permanent bond. Large aircraft fuselages, ship hulls and rocket halves would be perfect for the thick model glue. The bond will take some time to set up and dry completely. Clamping the pieces together with rubber bands, tape, clothespins, or "C" clamps will be necessary to keep the pieces from shifting as the cement dries.



The thin plastic model cement is of a watery consistency and very fluid. It is used only on the plastic pieces of the kit. It will bond a lot faster than tube glue and is normally applied with a pin or glue brush to allow the glue to flow into the seam or joint being glued. The thin glue dries very quickly so it is used for most of the ordinary construction of the kit. Avoid using model cement with clear pieces as the heat from the bonding process will craze or fog the clear piece making it useless.



Super Glue:



Cyanoacrylate glue, commonly called super glue or CA, is the glue used most to bond differing materials. This is the glue to use to cement your metal parts together or to the plastic pieces. It is also used to glue resin parts together or to the plastic pieces. Some modelers will use it for most kit construction, except for clear parts which this glue will also craze. Super glue comes in both thin and thick viscosities. Just remember the thicker the glue the longer it takes to dry or set. There are very few materials that cannot be bonded with super glue and since CA is water resistant, the bond will also be waterproof when set. Oh yes, if it gets on skin it will bond flesh together, but nail polish remover will dissolve it.



Epoxy:



Epoxy is a two part bonding product that bonds metal, resin and plastic parts. Epoxy adhesives come in both liquid and putty form and in both a fast and slow cure. Use epoxy when structural strength in the joint being cementing is needed or to hold heavy pieces in place. Epoxy, as well, is not recommended for use on clear parts.



Epoxy comes in two parts, resin and hardener, requiring mixing just before application. It comes as two liquids with an applicator or as a two part putty to roll or knead together. The fast curing epoxies will normally set in less than five minutes with full bond in 30 minutes. The slow cures can take up to an hour to set, eight hours before the piece can be handled, and a day to cure fully. Clamps will be necessary for the slow cure bonded pieces. Most modelers will use the epoxy putty to fill gaps in joints and to reshape a part. The putty can be smoothed in position with a wet cloth and sanded easily after it dries to disguise the join.



Knowing the basics on model kit glues and cements serves the modeler well in advanced kit construction. Just remember, as with all model kit building, work in a well lighted and well ventilated area for safety and enjoy the hobby.