How to Use Glues and Cement for building and detailing plastic model aircraft

by Lance Roden

Plastic models will not just snap together (well there are snap-together kits too, but those are really mainly just toys). You must use some kind of glue to keep it all in one place. The glue you should use in the first place is called “modelling cement” or “polystyrene glue”. This glue contains a welding agent that actually melts the plastic and fuses the two parts together to form a strong bond.

Since model cement works by melting the plastic parts, you cannot glue together painted parts: the paint will isolate the plastic from the glue. Either you will have to remove the paint from the mating surfaces, or you will have to use another kind of glue.

Be careful – you will not be able to separate the two parts once the glue has cured! To avoid trouble, always rehearse putting together the parts first, without glue. Check the join for imperfections or bad fit before you reach for the glue. This is called “dry fitting” and can save you a lot of headaches later.

Cement application

Model cement can be applied in many ways – like directly from the nozzle or with a disposable brush. The method I find most useful is to use a needle applicator.

This is basically a syringe (a thin needle) attached to the nozzle of the glue tube, as shown on the picture to the right.

This kind of needle applicator makes it very easy to control the amount of glue from tiny droplets to a more continuous flow of glue.
Watch out – if you should get glue on a part, which is not to be glued, the glue will melt the plastic and destroy the surface of the part. If you see a small amount of glue being forced out in the join between the glued parts, resist the urge to wipe it off, or you will just smear it all over the surface and render the parts useless. Instead, wait until the glue has dried completely (it takes a day or two) and then just sand it off. It may even help to disguise the join.

While the glue cures, you should press the parts together to form a strong bond. This is most easily done by using rubber bands, clothespins, or even self-adhesive tape (masking, scotch or magic tape). Be sure to let the parts dry at least one day before doing anything more with it at this point.

By the way, the only way to make a good and pretty model is by having patience – tons of it! Often there is a lot of waiting time between two modelling steps. If you think it’s boring having to wait two days after a major glue-job, why don’t you work on more than one model at a time? Then you can always have something to do if you feel like it, even if one model is in “the drying phase”. Lack of patience will only result in a sloppy job and an ugly model.

Superglue and white glue

Advanced modellers often use superglue or cyanoacrylic glue. This is more useful when you want to glue together painted parts, need extremely strong glue joins, or when you want to fill a small gap between the mating surfaces. Superglue is also your only choice if the model you’re building feature metal parts (quite common for more advanced models).

But don’t use superglue on clear parts, because the fumes released as the glue cures will fog up and ruin the clear plastic parts before you know what’s happening.

Superglue cures very quickly and can be sanded smooth when dry. But it’s just all too easy to glue together your fingers by accident. It may sound hilarious, but is quite a frightening experience. And painful too, because superglue is very, very strong. Should you accidentally glue together your fingers, don’t try to separate them, or you will lose the skin on them. Instead put your fingers under the running tap, as hot as you can stand and carefully and slowly pull your fingers apart. Using disposable gloves is not such a bad idea and never ever touch your face and eyelashes while using superglue.

Other types of glue that can be used in modelling is white glue, which dries clear and is easier to work with. Most often white glue is useful for cementing clear parts, such as canopies and windscreens, but they will not form a strong bond and cannot be used to glue together large parts or parts that need strength.

The first building steps

If you can, always assemble and paint the whole cockpit section before inserting it into the fuselage, as it will be nearly impossible to do later. Leave the ejection seat to be the last item you glue in place because you really should make this piece as pretty as you can and it’s a lot easier to work with if it’s not glued in place.

If there is a pilot figure provided, try to do something with it to make it look more like a human than a showroom dummy. Try sawing off the arms and the head and reposition them to make the figure look like saluting, working the radar panel or making notes on the kneeboard.

You can also add custom made seat belts made of strips of masking tape. An ugly moulded on oxygen hose can be replaced by a bit of thin electric wire (with the isolation part still in place). All these are very simple conversions and will make the model more impressing. Nearly all kits from the same model company contain the same pilot figure, so if you don’t want the crew of your model fleet to look like an army of clones you will have to do something with them anyway.

With the cockpit section assembled and painted, it’s usually best to start working on the wheels, landing gears and weapons. Even if the description tells you differently, you might as well start on this task right away, because cleaning up drop tanks, missiles and bombs can be quite time-consuming. This is even more true for aircraft such as the F-14 Tomcat, carrying a ton of missiles. I like to file down the fins of the missiles as much as I can so that they won’t look like they are made of two inches thick armour plate.

Before joining the fuselage halves, there are a few things to take care of. I recommend that you spray the entire inside of the model black or dark grey. Discovering that you can see naked unpainted plastic through air scoops and other small apertures is not something you want to do. Also, don’t forget to check if there will be some areas where you can see through the model. On some jet fighter models, sometimes you can actually peek through the jet intakes and see the light at the end of the jet pipe. To prevent this awful effect, either glue sheets of styrene cards or at least put some stuffing material inside the fuselage.

It is also important to check the weight centre of the model. Especially for tricycle landing gears, it is important that the weight centre is ahead of the main landing gears, or the model will not sit correctly on the main gears and the nosewheel, but instead on the main gears and the model’s tail. A few bolts or lead weights in the nose cone takes care of this. Just make sure that the weights are firmly attached, or they might shake loose during the consecutive building steps and rattle inside the model – very annoying!

If you can, try to place the cockpit tub in position at the same time as you join the fuselage halves. If you first glue the cockpit tub onto one half of the fuselage (as it is often described in the instructions), you risk ending up with a very nasty and hard-to-conceal gap appearing on the other side.

Assembling the fuselage halves, the wing halves and the wings to the fuselage is a very pleasant step – it is the first time that you can apprehend the size and the shapes of the model. But it can also be a tricky step as you will have to glue quite large pieces of plastic together, and it is just all too easy to mess up! Also, make sure that the fit is as close to perfect as it’s possible. Practice dry-fitting the parts at least two or three times before start squeezing the glue.

Once the parts are joined but before the glue has cured, check all the mating lines, so that the parts are not offset a little bit. It’s best to examine the mating lines in a strong light source coming from the side. If you miss this part, you will later have to perform some very hard filling, sanding and panel line rescribing sessions to remedy the problem.
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Building Plastic Model Aircraft Kits