resin is polymer based and uses a Catalyst – Methyl Ethel
Ketone Peroxide or MEKP to create an exothermic reaction
(heat) when the resin hardens. The rate of catalysation is
controlled by the percentage amount of catalyst used, product
temperature and ambient air temperature.
Resins come in varying grades, which
influence their cost. The lowest grade is “Ortho” which
uses orthophthalic acid in its creation. It is used where
superior weathering and resistance to water or other chemicals
are not required.
“ISO” (isophthalic acid) resin imparts
better toughness and chemical resistance and better exposures
properties. It is better suited to boats and shower stall
“NPG” (neopentyl glycol), in the proper ratio
can provide even better chemical resistance and weather
characteristics. It is used when the greatest quality and
performance is needed such as quality swimming pools, spas and
Epoxy Resin comes in
two (2) parts- the resin itself, and the hardener. Epoxy
cures clear and can be used on table covers, boat deck, and/or
floors and such. There are a number of mix ratios for Epoxy
resins and they relate to the amount of hardener used to the
The proportions must never be changed,
as this will have an adverse effect on the end result.
The only way to change the cure time of the resin mix is by
using a different hardener. Some epoxy hardeners have a cure
times embedded in their product code for example:
510, 520 or 530; these refer to the
hardening time of the Epoxy hardener; 510= Series
500 epoxy, 10 minute hardening time; 520=
Series 500, 20 minute
Series 500, 30 minute
Surfboard resin is
polyester based laminating resin, which cures clear. As with
all polyester based resin, it will change colour when a
suitable catalyst has been added – indicating a chemical
reaction between the two.
This initial change may be
yellow or blue, but the end result is a clear hard
surface. It has UV resistant properties and can be
hardened by using a MEKP based catalyst or more recently an
Ultra violet light activated product called Sunbake.
Clear casting resin is
from the same family as the surfboard resin, but with a few
recipe changes. Casting resin has been used for the
manufacture of jewellery and is prevalent in casting insects,
butterflies and other creepy crawlies, which may have been
cast as paperweights or school biology specimens.
must be taken with casting resin. Low catalysation ratios are
recommended to help prevent heat and oxygen bubbles forming
due to exothermic reaction.
The most commonly used catalyst
is called Methyl Ethyl Ketone Peroxide or MEKP. It is referred
to as a “Room temperature” catalyst, making it the most
commonly used. MEKP is used in various percentage rates to
control the catalysing rates of polyester resins.
Warning: Catalyst is extremely dangerous and can cause
blindness. Uses Safety equipment at all times. Ask for,
read and understand the Material Safety Data Sheet on this
If too much
catalyst is used in a polyester based product then the
associated product becomes weak. In the event of an extreme
exothermic reaction spontaneous combustion may occur. This
reaction usually transpires in the container the catalysed
resin is being stored. Signs of extreme exothermic reaction
include: heat making the container uncomfortable to hold,
cracking or popping sounds and smoke emanating from the cured
resin. It is advisable to remove the container from
the work area and isolate it in a bucket of
Tooling Gel is a
polyester coating specifically designed to be used as the
mirror finish surface of a mould. It generally comes in
Black, Orange, Green and Grey. Some moulds use different
layer colours to indicate if the mould surface has been rubbed
Gel-coat is a specially
formulated polyester coating that is applied to the mold
surface and becomes an integral part of the finished product.
Its function is to protect the fibreglass from the
In so doing, it produces cosmetically
appealing surfaces that are durable and long lasting. When used as a
repair patch, gel coat when cured will retain a sticky or grab
Flow-coat is a specially
formulated polyester based resin with thixotropic agents
(increased viscosity and non sag properties), fillers for flow
properties, pigments to give the desired colour and additives
for specific qualities such as gel time and cure.
Flow-coat usually pigmented, provides a
weather and wear resistant surface and is applied over the top
of glass-reinforced product or over Gel-coat. When used as a
repair patch, flow coat will provide a smooth high lustre
finish with no sticky or grab like properties.
Pigment is used to
influence the colour you see and how that colour will look
next year or ten years from now, over a wide range of
The selected pigment is added to a neutral
gel-coat or flow-coat at a specific percentage ratio mix.