To estimate the quantity of materials needed for a specific laminating project,you will need to know the surface area of the mould you will be using. From this, the required quantity of Resin B (Gelcoat) can

be calculated - allow 500gm of Gelcoat for every square metre. The surface area of the mould, in square metres, also gives the amount of glassfibre needed. Multiply the area by the number of layers you

intend to lay down (ie, the required thickness of the finished laminate), and the result is the total glassfibre quantity. Use this quantity to ascertain, from the table below, the amount of lay-up resin

required:

RESIN TO GLASSFIBRE RATIOS

For an effective laminate, it is essential that each layer of the glassfibre material is thoroughly "wetted-out" with Lay-up Resin (Resin A). The amount of resin needed to do this varies, depending on the type of glassfibre material:

MIXING QUANTITIES: POLYESTER RESINS & CATALYST

The proportion of catalyst to resin is normally 2ml of liquid catalyst, or 16cm of paste catalyst, per 100gm of resin. The catalyst should be stirred thoroughly into the resin.

Resin                     Liquid                    Paste

Catalyst (ml) Catalyst (cm)

50gm                        1                              8

100gm                      2                           16

250gm                      5                           40

500gm                    10                          80

1 kg                         20                          160

1.5 kg                     30                            -

2kg                          40                            -

5kg                         100                           -

10kg                       200ml                      -

25 kg                      500ml                      -

With lay-up resin (but NOT gelcoat), the rate of cure can be slowed down, by using 1ml liquid catalyst or 8cm paste per 100gm resin - ie, halve the quantities shown above. This can be useful in very hot weather, when the resin might otherwise cure too quickly.

Chopped Strand Mat, 300gsm         Requires 650gm Resin A per square metre

Chopped Strand Mat, 450gsm         Requires      1 kg Resin A per square metre

Chopped Strand Mat, 600gsm         Requires 1.35 kg Resin A per square metre

Plain Weave Fabric, 127 gsm           Requires 150gm Resin A per square metre

Plain Weave Fabric, 200gsm            Requires 250gm Resin A per square metre

Satin Weave Fabric, 500gsm           Requires 350gm Resin A per square metre

Woven Roving, 290gsm                   Requires 500gm Resin A per square metre

Woven Roving, 600gsm                   Requires 600gm Resin A per square metre

Woven Roving, 780gsm                   Requires 780gm Resin A per square metre

Surface Tissue                                 Requires 200gm Resin A per square metre

The pigment quantity can be varied to reach the required depth of colour.

The table shows the MAXIMUM amounts which can be used - do not exceed these,

as too much pigment will impair the curing process.