14 April 2020
Modellers are always getting themselves into sticky situations, but do you have the right glue for each?
If there is any glue we all need in large quantities, it is Polyvinyl acetate, better known as PVA.
You will probably stick your ballast down with a 50:50 mix of PVA and water. Add a couple of drops of washing up liquid to reduce surface tension, then dribble it on the stones using a pipette. If you can spray the ballast with a small amount of water, the glue will flow even more freely.
Straight from the bottle, paint PVA over the scenery to hold down scatter materials or static grass. In tiny amounts, stick cardboard and wooden kits together or use more when building your baseboards. It's not much use for sticking plastics, but for porous materials, it's the first choice.
PVA is sold in many forms and you can buy if from art shops to builders merchants.
2) All-purpose clear glue
There are many brands to choose from but all work the same way - a thick clear glue that will stick many different materials to each other.
Applied straight from a new tube, the results are likely to be messy, so try holding it with the nozzle upright. While it might sound odd, we normally squirt glue down, this way gravity helps slow the flow. Less glue usually equals less mess. As long as there is a thin coverage on the surface to be stuck, then that's normally enough and your modelling will look tidier for it.
While the drying time will allow for plenty of adjustment, you'll need to work out how to hold the parts in place before taking the top off the tube. Once dry, there is often a tiny amount of movement in the joint, most of the time this doesn't matter and sometimes, it can even be an advantage.
3) Plastic glues
We're talking about two types of glue here.
Plastic cement is very like all-purpose glue, but isn't any use sticking wood or cardboard to anything. If you remember building plastic aircraft kits as a youngster, you'll know how easy it is to get too much glue in the joins and that results in it oozing out everywhere. Worse, the stuff will fog clear plastic, as many canopies on Airfix Spitfires will attest.
Nowadays, plastic cement can be bought in bottles with fine needles as a spout. These allow controlled application of tiny amounts of glue - perfect for neat kit assembly. This spout can become blocked, but a piece of thin wire pushed down it usually sorts this out.
It's also worth having some plastic solvent to hand. Looking like water, this glue attacks the plastic, melting it slightly. If the melting takes place within a join, then the parts harden, they will bond together as one piece. The results can be incredibly neat which is why solvents are popular with modellers.
The easiest way to apply a solvent is to hold the parts together and apply the glue with a brush to the join. Being very thin, it will be pulled in by capillary action, setting almost instantly. Be careful not to touch the solvent until it has dried or you'll leave a fingerprint in the soft plastic!
Both glues should only be used in a well-ventilated area as they will give off fumes.
Cyanoacrylates, or superglues, are a more recent addition to our toolbox, although they have been around for over 70 years. You'll find them sold as a general fix-all glue capable of all manner of household repairs.
Capable of sticking most materials to each other, they are set by moisture. The tiny amounts found on all surfaces are usually enough to do the job, although if a joint takes too long to set, blowing gently on it can speed things up.
Dispensers come in many different forms from tubes to fine droppers and even brushable forms. You'll also find different consistencies. Very runny versions will pull themselves into joints but can be difficult to control. Gel versions are bulkier but stay where you put them. The joints aren't always that strong, but sometimes this is an advantage. Locomotive chimneys and other vulnerable details can be stuck in place safe in the knowledge that if they are broken off, the break will be clean and often easily repairable without even touching up paintwork.
One hazard with the glue is that it's especially effective on skin. A bottle of superglue remover is a useful addition to the workbench, just keep it within easy reach.
5) Epoxy resin
When you need a strong joint, then for many, epoxy resin is the only way to go. Modellers have been sticking whitemetal kits together with it since the 1950s and for many, it's the preferred alternative to soldering.
Epoxy is usually supplied as a two-part glue, the user has to mix up the glue and harder before use. Do this on some scrap plastic with a coffee stirrer or matchstick. Once mixed, the glue starts to set and you may only have a few minutes to make use of it, so have the joint to be made ready. A useful rule of thumb is that the longer a glue takes to set, the stronger the joint will be. For most of use, a five-minute glue is fine, but there will be engineers out there who have jobs for which only the 24-hour versions will do.
Strength comes at a price - epoxy glues tend to be quite bulky and it's hard to produce an invisible join. Mind you, this can be useful where the parts aren't a perfect fit as the glue will happily fill any void and once dry, can be sanded and then painted.
A reliable layout is a fun one to operate. With time on your hands, we've put together a few ideas to help you fettle your model to make it run like a Swiss watch.
If you’d like some more advice, take a look at the BRM Techniques page for all our latest guides and advice articles.