There are many different kinds of adhesives used in model making. Here we go through each type.
Polystyrene Cement
(Plastic Glue)
Polystyrene cement is an adhesive designed to be used with plastic model kits, which are made of a dense polystyrene plastic. There are several types of applicators available.
Tubes: These are the classic style of glue for plastic models, such as the Humbrol Poly Cement. The poly cement that comes in tubes is the thickest and so gives you the longest to work with, making them a good choice if you need to move pieces around to make sure they fit.
Precision Bottles: These are bottles of liquid cement in a bottle with a fine needle-like nozzle applicator, such as the Humbrol Precision Poly and the Revell Contacta Pro. These are ideal for small parts as you can be very precise with the application of glue. One thing to be aware of with these glues is that eventually glue will dry in the needle and will need to be cleared out. There are two ways of clearing the blockage. You can clear it out by pushing a fine length of strong wire down the needle to push out the dried glue. The other option, for adults only, is to run a flame along the needle for a few seconds. This will quickly dissolve the dried glue and clear the blockage, but as the glue is flammable you may get a small burst of flames if you catch the open end of the needle. Also be careful not to melt the plastic where the needle fits into the bottle.
Liquid Cement: Liquid cement comes in bottles with a brush applicator. These are suitable for applying glue to larger surfaces before putting them together. Humbrol Liquid Poly and Tamiya Liquid Cement are popular brush-on plastic glues. For gluing much larger parts I would recommend an extra-thin liquid cement.
Extra-Thin Liquid Cement: When using an extra-thin liquid cement you put the parts together first then brush the glue along the join. The glue will be pulled between the parts by capillary action. This is particularly useful for large sections such as the sides of an aeroplane fuselage or the deck and hull of a ship. With a normal glue it will start to try before you can get all the way round, so will not stick well unless you put a large amount of glue on an risk making a mess. The most popular of these amongst modellers is Tamiya Extra-Thin Cement, while Plastic Weld has been used by architects for a very long time.
Glue for Clear Parts
The fumes from normal poly cement will cloud up clear parts, and as it works by melting the plastic if you accidentally get any on the surface it will damage it. There are several adhesives available designed specifically for clear parts, such as Revell Contacta Clear, Humbrol Clearfix, and Microscale Kristal Kleer.
Glue for Chromed Parts
Chromed parts can be a little tough for most plastic glues, especially getting through the chrome. I recommend grabbing the Revell Contacta Liquid Special adhesive as it is specifically designed for use with chromed parts. This glue can also be used to stick polystyrene plastic parts to paper and cardboard.
Super Glue - For Metal & Resin
Cyanoacrylate, more commonly known as super glue, is mostly used by modellers as a glue for metal and resin parts. Super glue comes in different consistencies that are suited to different applications.
Thin: A thin super glue runs like water and is used when you need it to soak through something. When using liquid gravity to add weight to an aircraft nose cone to give the model balance, or for weighing down model railway wagons for greater stability. You pour the tiny metal balls where you want to add weight, then carefully drop thin super glue so that it soaks through and sticks it in place. You can also use this method to fix scatter materials such as sand to a model's base, or loose loads in railway wagons.
Medium: Super glue of a medium consistency is the most commonly used. It is ideal for use with metal and resin parts and is is thick enough to stay whre you put it, but flows easy enough to squeeze into recesses when you press the parts together. It also works well if you are using a super glue applicator with photo-etched parts.
Thick: Thick super glue is ideal if you are working with a porous material, such as wood, where the thinner super glues would just soak in before the glue had a chance to bind the parts together. Thick super glue will also work with metal and resin parts. If you are working with photo-etched parts and don't want to use an applicator, squeeze a small amount of glue onto a tile then gently touch the point of the part you want to glue to the blob of glue and it will only pick up a small bit of glue.
Gel: Lastly we have an extra thick gel-type super glue. These come in tubes with fine appllicator nozzles and are ideal when working with very small parts.
UV Set Super Glue: For when you need super glue but need time to get parts into position, such as photo-etched parts with several contact points, you can get a UV set super glue. As the name suggests this type is set using UV light - get the parts into position then shine the light to set the glue.
Super Glue Applicators: There are two different kinds of applicators for super glue. The first is a metal tube like those that come with precision poly cements, which fit our 20g bottles. These Precision Applicator Tips allow for more precise applications than using the nozzle of the glue bottle, but they are likely to clog quickly. The other type of cyanoacrylate applicator has two small prongs at the end of a needle . To use this applicator you touch it to a blob of super glue and a small amount is pulled up between the prongs. When you then touch this to where you want to put the glue it is released from the prongs. Make sure to clean this regularly as there will always be some glue left on the applicator.
Super Glue Activator: In case super glue doesn't set as fast as you like, you can get a super glue activator to spray on that will set the glue instantly.
Wood Glue/White Glue/PVA Glue
These adhesives are perfect for use with wooden and paper models. Wood glues set best under pressure so using clamps is advised where possible.
PVA: Polyvinyl acetate (PVA), is a colourless and odourless glue. PVA glue is ideal for working with porous materials such as wood and paper, and is even used as an adhesive for porous stone. Thin applications of PVA glue will dry clear, making it a suitable adhesive for clear parts such as aircraft canopies. We stock the Javis Velo Set Quick Setting Wood Glue.
Aliphatic Resin: Aliphatic resin works in the same way as PVA, and looks very similar, but has a thicker consistency and a slight yellowish hint to it. Aliphatic Resin is more resistant to heat and water than PVA, and forms a stronger bond.
Epoxy Resin
Epoxy resin is an extremely strong two-part glue that sets clear. Epoxy resin cures under a wider range of temperatures and moistures than other glues, does not require pressure, and is better at gap filling. In fact, near-perfect joins with very little space for the glue will actually have a weaker bond than joins with larger gaps. Care must be taken not to get the glue on your skin as it has been known to trigger allergic reactions.
All Purpose Glue
As the name suggests, all-purpose glue is the typical 'jack of all trades, master of none'. An all-purpose glue such as the popular UHU All-purpose Glue, with its clear, stringy consistency, will form a bond between all common materials including fabric, ceramics, wood, plastic, stone, and metal.
Expanded Polystyrene Glue
Most other glues contain chemicals and solvents that melt polystyrene. With hard polystyrene such as in plastic models this is desired as the parts are welded together. This is not desired with expanded polystyrene foam. While a wood glue would work as it is solvent-free, a dedicated adhesive for expanded polystyrene, such as UHU Por, will form a stronger bond.
Hot Glue
Hot glue is a thermoplastic adhesive that comes in solid sticks and applied using a hot glue gun, which melts the glue. Care must be taken as the glue is hot enough to burn your skin. The melted glue is very sticky and dries dries after a few seconds. Hot glue is great for quick craft projects when precise application of glue isn't important. Hot glue is also becoming a popular casting material, as it can be easily injected into a mould with the glue gun and sets quickly.