Beginners’ Workshop 2: Gluing and joining

Welcome to the Beginners’ Workshop. Some of you experienced modellers might prefer to skip this post, but I hope some newcomers to the hobby will pick up a few tips here.

Gluing parts together: that is the essence of model making for many people and to be fair, it is the central process for any build, but there are a few misconceptions. People who have never built a model often assume that they are stuck together with ‘superglue’. When I was a young modeller, I learned to NEVER use superglue. And as for PVA wood glue, surely it has nothing to do with assembling a plastic kit? Here, I will try to clear up a few misunderstandings and hopefully offer some useful advice.

POLYSTYRENE CEMENT

So, what do you stick kits together with? The preferred glue for assembling a conventional plastic model kit (the ‘plastic’ is a form of polystyrene, or styrene for short) is polystyrene cement, which is sold in model shops and hobby stores under various brand names and is specially formulated for kit building. Despite the ‘cement’ name, it has nothing to do with building cement! It actually does a different job to most other adhesives: it melts (very slightly) the surfaces of the plastic parts being joined, and forms a bond as the melted areas fix to each other. Because it is the glue most people first attempt to build models with, it is also the glue that people associate with poorly-built models from their junior years. It can make clear parts cloudy, and it doesn’t stick chromed or painted parts very well because the plastic underneath the coating cannot melt. This type of glue is available in tubes, jars and precision applicators from most model shops.  

Upsides:

It is the best adhesive for general kit building

Used properly, it forms a strong bond for years

Readily and cheaply available, can be kept for years

Downsides:

It clouds clear plastic on contact, spoiling windows and lights

Does not stick chromed or painted parts reliably

SUPERGLUE

Cyanoacrylate, or superglue as it is usually known, is great stuff but has its drawbacks. Unlike polystyrene cement, it works by simply forming a solid coating on the surfaces it is joining, bonding them together. It dries in contact with air, so a thinner coating dries quicker. People sometimes joke about sticking their fingers together with superglue and joining your fingers to each other – or to other things – is all too easy. Superglue is not ideal for joining kit parts together because it can warp or dissolve styrene, and it is almost too good at its job, bonding your kit parts, your tools and your fingers to each other at any opportunity. However, it does a couple of important jobs very well: chrome-plated parts and painted parts, often impossible to join with polystyrene cement, are easily joined with superglue. Resin and white metal parts can also be assembled with superglue.

Upsides:

Sticks practically any materials together – chromed parts, metal, resin

Cheap and easy to get hold of

Bonds quickly

Downsides:

Can ruin kit parts

You WILL glue your fingers to something unexpected at some point

PVA (WOOD GLUE)

What good is PVA wood glue for modelling? PVA is great for lots of jobs, especially if you are creating display bases or dioramas. PVA (polyvinyl acetate) is formulated for joining wooden parts together, which it does well. PVA works by soaking into the parts and setting hard, so it is best at joining together porous materials like wood and card. PVA can be diluted with tap water, which is excellent for creating gravel tracks and grass fields for your models: you can sprinkle your miniature gravel or grass onto your display base, then drip diluted PVA over it which will set hard overnight, fixing your scenic material in place.

PVA is what I always use for installing glazing or light lenses in models, whether it is a car, truck, aircraft or whatever. Though in theory PVA should not be able to do this job, it does it brilliantly – it dries clear, it does not cloud the clear plastic, and it sticks well enough to hold the parts in place thanks to its rubbery polymer form. Best of all, it does not create nasty fumes and does not irritate your skin.

Upsides:

Cheap and easy to buy

Harmless to your kit parts and to your skin (the glue you used to get all over your hands and enjoy peeling off at school was PVA)

Can be diluted for various uses

Downsides:

Not suitable for general kit assembly

When diluted, takes hours to set

HOT GLUE GUN

Glue guns work by heating up sticks of solid glue and releasing a stream of melted glue from a nozzle which, when cool and hardened, bonds almost any surfaces together. This kind of bonding ability is essential for heavy jobs like carpentry but not necessary for assembling kits, and in any case hot glue is not ideal for easily-melted plastic parts.

Upsides:

Creates very strong bonds

Downsides:

Too hot to use with plastic parts

Not designed for fine work, so too clumsy for kit building

Glue sets when it cools, so you need to fix parts together quickly

Not recommended for modelling at all



OTHER OPTIONS

There are other types of adhesive out there, and a few other materials which can be used as adhesives. Epoxy glues and contact adhesives are very strong but often damaging to kit parts. Various kinds of varnish can be used as adhesives, though beware the solvent properties of many of them. Some household products like Johnson’s Klear floor polish (sold in the US as Future) are also used by some modellers, though apparently Klear is only suitable for gluing small parts as it does not form a strong bond. I understand it is also good for fixing clear parts though I have never tried it as an adhesive myself.

Do you have more suggestions for useful modelling adhesives? If so, please comment below.