boat owner

T

he crack was to be filled
with a mixture of epoxy,
milled glassfibre (402 filler)
to criss-cross the area and
colloidal silica (406 filler) to
give the mixture the thickness
it needed to ‘stick’ in the hole.
Firstly, the hole was fully cleaned
with acetone, then the inside of
the crack was abraded with 80-grit
paper just to be sure there was a
really good key in there to which
the epoxy could adhere. I placed
a rectangle of polyester release
film on the inside of the boat,
taped it down and then weighed
it down with a couple of out-of-
date Reeds Nautical Almanacs
(one of their many uses!) to stop
the filler mixture escaping into
the inside of the boat.
The hole was wetted out with
unthickened epoxy to give the
thickened mix a good base for
gripping. We were now ready to

3: Filling the crack

Copious amounts of epoxy

were used in the repair

mix up the filler and would use a

plastic spreader to work it into the

crack, ensuring it made contact

with all sides of the crack and left

no voids.

PRACTICAL

THE CRACK IS FILLED! If I’d had my head screwed on at this point, I
would have put peel ply over the top of the crack fill – which is something
Wessex Resins suggested after I had completed this stage of the process.
Peel ply would have meant no amine blush (a waxy coating that needs to
be washed off with water before the next stage of the process) would be
produced and it would not have needed to be sanded.

The template placed over the keel

4: Glass-up the bevel

A

s a rule of thumb

(a useful tip from

the chaps at East Coast

Fibreglass Supplies), for

every 1mm of finished

thickness you will need

approximately two layers

of 300g biaxial cloth.

We needed to build up

7mm, so now we needed to

employ some simple maths.

7mm was 14 layers of our

light 300gm cloth, so we

needed to divide that by the

diameter of our bevel and cut

out the cloth accordingly. I

used another cardboard

template and counted on

being able to stretch my cloth

around the awkward three-

dimensional shape of the

front of the keel. This is the

reason I always use light cloth:

it may require more layers,

but it is more forgiving on

these complex shapes. I then

marked each of my 14 layers

on the cardboard template,

and used this to cut out my

glassfibre with my shears.

The cardboard template,

appropriately marked up

Layers of glass were cut

to the template

The whole area of the repair

was washed with water and a

scourer to remove the amine

blush from the previous fill: this

is important, as amine blush

can affect the bond of the

glassfibre to the substrate. It

was then cleaned with acetone

before a final rub-down with

80-grit paper. (Note: wash the

surface first, and rub down

second. This is to avoid

sanding any contaminant

into the GRP.) We were now

in a position to start glassing

in the hole!

First, we thickened a small

amount of epoxy with colloidal

silica to use as the ‘base’ for

the first layer of GRP. This

ensured any small voids in the

existing polyester were filled

and gave a good base for our

first layer of glassfibre. (You

should always start with the

largest layer of glass.)

If doing this job yourself,

apply each layer, wetting it

out fully by ‘stippling’ with the

brush (do not try and ‘paint’

with the brush as you will just

pull the glassfibre around), and

use the consolidation roller

between every other layer.

Work fast and only mix up as

much epoxy as you can apply

within around 10 minutes

before it ‘gels’. Don’t try to

apply more than 14 or 15

layers of light glass in one go