Fibreglass boats
Practical Action
the ground on a steel cradle (see figure) with a removable brass tap screwed into the drum
lid. There should be a drip tray beneath the tap. Between the tap and the tray will be enough
room to place a 5–10 L plastic bucket, which can be filled with resin for use by a laminator.
Every two days, the drum should be rotated by 1800 and the tap removed and cleaned with
acetone, to prevent blockage. Outside the resin room should be a two separate store
cupboards for catalyst and for accelerator.
Accelerator can be added during the preparation stage and mix well with a clean, disposable
wooden stick. The amount of accelerator added will be determined based on the weather
conditions (humidity). Catalyst is only added at the very last moment before laminating
begins, when everything else is ready. Both these additives are supplied in 20 or 5 L plastic
drums (not in steel containers because resin reacts with rust) and are used to refill 1 L plastic
bottles fitted with a graduated pourer for final mixing.
In the case of gel coat, a colour pigment will have been added to uncoloured gel coat
according to supplier's mixing ratios. Standard white pre-pigmented resin is widely available
as it is the most popular hull and superstructure colour.
Preparing the mat
The task of storing and cutting the
mat may be allocated to one
labourer who then becomes skilled
at this task. For preparation, a
cutting table is needed (see picture)
with a vertical rack for the rolls of
different types of reinforcement
from which appropriate lengths can
be drawn and cut and then re-rolled
and labelled with a felt tip pen to
indicate to the laminators what it is
for.
It is good practise to use a plywood
template for each section of mat
needed. Lengths up to 10 m can be
prepared on a shorter cutting table
by folding the reinforcement. The
Credit: Practical Action South Asia
table edge should have graduations
at 10 cm intervals to ensure precise
measurement. A sharp knife is needed for cutting and since glass reinforcement blunts steel
blades very quickly, they should be sharpened often. A straight edge is needed to cut the
glass to length. An aluminium strip is best as it is light to handle and does not contaminate
the cloth.
For cutting curves, a felt tip pen or chalked line can be drawn for guidance and the cut made
freehand whilst allowing a 10 cm margin. Industrial quality scissors may also be of use.
The building process
Preparing the plug
To begin, place the plug (or existing hull being used to create to mould) upside down on a
level floor, and make sure the plug is absolutely level using a spirit level or transparent
flexible tube filled with water. At the deck edge, which is in this case near the floor, attach a
plywood flange so that later during the moulding process, gelled Fibreglass can be trimmed
back to leave a solid laminate with a clean cut edge. If the plug is wooden, cover the plug
with a Fibreglass skin. This layer can then be filled where necessary with resin putty to
remove the shallow indentations, which will show up once the fibreglass skin is consolidated.
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