CHEMISTRY

70%, which is a relevant decrease of the overall

usability of the product. It follows that the ideal

storage environment is dry, cool and dark. You

have a refrigerator or a freezer, as does every

household, and this is ideal for storing CA. To the

contrary, these recommendations do not apply

after opening the glue container and exposing

the contents to the local environment. Storing

opened adhesives in the refrigerator or freezer

in order to extend their life is a pure myth. The

aforementioned locations provide high levels

of moisture, relatively speaking, which within the

conditions of the way the glues work, impact the

shelf life of the material negatively. On opening,

the container with the glue loses its protective gas

layer, and the moisture can now directly activate

the chemical reaction of the adhesive. One way

to combat this might be to store the containers

in plastic Tupperware with sealable lids that will

restrict the amount of moisture getting to the

glue, and combine this with storage in a cool,

dry dark place. But in the case of storing the

container in a sealable containers, it is necessary

to consider the unavoidable rise in the glues

temperature to that of the local environment.

The shelf life of the glue can be extended, but the

gradual thickening of the liquid is unstoppable.

With this in mind, it makes sense that the size

of the package and quantity of glue that it

contains, are a factor corresponding to shelf life.

The modeller should acquire bottles of CA that

they can use in the course of a couple of months

after first opening it. It is also important to store

the glue away from other materials, especially

those that act as activators. The glues are

generally compatible with one another, so that if

one bottle of CA becomes thick, it can be thinned

with thinner stuff to achieve a compromised

viscosity that is acceptable to the user.

After opening the adhesive, its lifespan in the

above-mentioned storage in the freezer or

refrigerator will be quite variable, depending on

the quality of the seal and exposure to moisture.

However, if after opening, the glue is stored in

a typical modelling room at a temperature

between 18 and 20 degrees Celsius and always

closed tight after use, a shelf life of about three

months can be expected.

CYANOACRYLATE GLUE VAPORS

After the application of cyanoacrylate adhesives

and their subsequent hardening, effects of the

inevitable vapors can often be seen, which

resemble frost. Such evaporation has negative

effects when it is released into difficult to reach

places on the model, such as the inner parts of

the canopy, especially when they are displayed

closed. Why does this phenomenon arise and can

it be eliminated or reduced? During the hardening

of the glue, the natural and gradual evaporation of

ethyl cyanoacrylate and its reaction with humidity

occur. These vapors thus harden as a result of

April 2023

Storage Medium

Temperature

Resulting Shelf Life

Freezer -18 °C 2 Years

Fridge 4 °C 1 Year

Indoors 18–20 °C 6 months

the reaction, which results in the formation

of micro particles of hardened instant glue.

A larger amount of these hardened micro particles

settle in the vicinity of the applied glue and the

frosting effect becomes obvious. There are some

options to minimize or optically eliminate this

phenomenon. It is easiest to use only a small

amount of glue to minimize the fumes. Another

option is the use of special alkoxycyanoacrylates,

which have a reduced evaporation rate.

In general, it is good to avoid closing the area

where we apply the CA adhesives early, so that

there is room for evaporation. When drying, it is

a good idea to rotate the parts resulting with the

glue at the top, to allow vapors to escape into

space and prevent them from spreading over

the surface of the model, which would happen

when they are turned over and the fumes have

access to them as they escape. Since the release

of vapors can occur even after some time, the

entire glued joint can be sealed against vapor

release by applying an overcoat, which ensures

coverage of the release adhesive even after

it has hardened and thus minimizes negative

effects on the model. Despite all our efforts,

however, a situation may arise when unwanted

vapor escape occurs and we are forced to remove

these negative consequences of CA use. In most

cases, it is sufficient to clean the affected areas

with a dry brush or cotton swab (on clear parts).

Alternatively, you can use the thinner embedded

in the surface, which, however, must not dilute

the base color of the given parts.

BASIC TIPS FOR CYANOACRYLATE

GLUES AND THEIR USE ACCORDING TO

COMPOSITION AND VISCOSITY

A large number of cyanoacrylate adhesives

from various manufacturers are available on the

market today. As was mentioned at the beginning

of today‘s chemistry class, for the sake of clarity

between the basic types, we will focus on Bolt

brand products. At the same time, the described

properties and use can be freely applied to

various products of other manufacturers with the

same or similar consistency and composition.

BOLT! CA BOLT THIN

The classic representative among cyanoacrylate

adhesives are the thin variety, which are the most

accessible type of CA in terms of their consistency.

Their use is very universal and they represent

the ideal ‘entry’ type for working with instant

glues. They can be applied in the usual way, i.e.

by applying them to one or both glued parts,

which are then pressed together. Alternatively,

the procedure where the parts are pressed

together and the glue is applied along the joint

can also be used. Here, however, it is necessary

to maintain a gap between the parts to provide

the glue someplace to wick into. The minimum

size of such a gap depends on the viscosity of

the thin instant glue, but in general it needs to

be at least around 0.03 mm, which in modelling

practice is quite small. Thin instant adhesives

are especially suitable for gluing non-porous

materials, and wood and paper should generally

be avoided, where the glue will quickly soak

into the material, causing insufficient amounts

of CA in the joint its subsequent instability and

fragility. The reaction time of thin second glues

is generally very short and varies between

1-3 seconds, which restricts the possibility

moving and manipulating glued parts.

CA HOT BOLT ULTRA THIN

The follow-up type to thin instant

adhesives is the so-called ‘super

fast’ adhesives with an accelerated

reaction time. Their application

differs from regular thin glues

in that it becomes impossible to

apply them to the abutting surfaces

of the parts and then pressing

them together, because during the

necessary handling, the glue reacts

with the surrounding environment

and hardens virtually immediately.

So, super fast instant glues need to

be used by applying drops at points

INFO Eduard

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