Mixing Catalyst

There are two crucial points to consider when mixing catalyst into resins/gelcoats/topcoats.

The catalyst must be accurately weighed for the amount of resin being used
The catalyst must be very thoroughly mixed into the resin to achieve the desired effect

We advise using some form of dispenser to ensure that the catalyst has been measured as accurately as possible. Our catalyst bottles have a built-in dispenser – simply squeeze gently to dispense the desired amount of catalyst, then pour into your mixing container.

The table below shows the correct ratios of catalyst to resin/gelcoat/topcoat by weight.

As a rule:

1% is considered a slow mix – useful when working in higher temperatures
2% is what we generally advise for ‘normal’ temperatures
3% is considered a fast mix – useful when working in colder temperatures

Used correctly, these ratios will ensure an adequate ‘pot life’. Additions outside of these guidelines are not advised for proper curing – in fact, adding more than 4% catalyst may result in a failure to cure.

As noted above, temperature can affect pot life. The higher the temperature, the faster the cure. As a general guide, 2% catalyst addition at 20˚C will give 15-20 minutes pot life.

TIP: Resin will cure more quickly if left in a mass such as the mixing bucket or in castings.

Catalyst Mixing Ratio for mixing various resin weights:

ADDITION OF CATALYST (ml)	50g	100g	250g	500g	1kg	5kg
1%	0.5	1	2.5	5	10	50
2%	1	2	5	10	20	100
3%	1.5	3	7.5	15	30	150

For measuring, we supply 10ml & 50ml syringes or 15ml & 80ml dispenser bottles.

For measuring tiny amounts, a medical eye-dropper may be used. A plastic teaspoon, not metal, can also be used. 1 tsp = 5ml