Berryessa

The following applications instructions should be noted for using any grade of Repel. For specific advice on each product go to Applications & Safety.

Coverage

Everyone tends to start by putting on too much. This gives failures  as bad as too little, and finding the right coverage often needs patience. The payoff is that time spent fine tuning the application rate has always resulted in customers using less, often far less, than they would have believed at the start.

Some important factors affect coverage rates:

• Too much will give poor release because the outer layer of concrete will remain permanently undercured, leaving residues on moulds and spoiling mould profiles. That means cleaning after each moulding. Repel, applied at the correct rate, should entirely remove the need to clean moulds.
• Too little will also give poor release or, worse, inconsistent release.
• For a starting guide, Repel 72 is generally applied to steel moulds at a thickness of 40-50µm = 20-25m²/litre. Repel 64 is generally applied to pipe socket moulds at a thickness of 250-330µm = 3-4m²/litre.
• When properly applied, Repel works well with all types of mould.

Cleaning

New trials of Repel tend to give inconsistent results unless the moulds are well cleaned beforehand. Although well used moulds look as though they have nothing absorbed, there is always some buildup of any mould release agent within the material, even steel, and that tends to interfere with any new mould release agent. Hidden residues of vegetable oils, especially soybean, tends to give false impressions in Repel trials. Thus, trials of at least three cycles using Repel need to be made with intermediate cleaning before a consistent pattern of behaviour can be reliably assessed.

Application

Spraying is the only recommended  method of application. Other methods have been tried and proven, but they are not recommended for good reasons:

• Brushing leaves streak marks which are really lines where the mould release is too thin. Heavy applications by brush to avoid thin areas tend to have areas too thickly spread which tends to cause undercured concrete. Careful spraying avoids these inconsistencies in coating thickness.
• Sponging can result in active ingredients in the Repel being absorbed into the sponge, greatly reducing the mould release capacity of the applied layer. Spraying spreads the whole product without selective absorption.
• In general, Repel can be used either dry or wet, but see Applications & Safety and Downloads for specific advice.

Dilution

Repel stored in original containers seems to be stable indefinitely. Repel 52, 64 and 72 have a proven record of reliable performance as delivered. Other users may find that different strengths – stronger or, more likely, weaker – work better for them. We strongly recommend that dilution be made in clean containers with water low in salts. Dilution should be done shortly before application, and excess diluted product should be discarded.

Repel 54 and 62 are more concentrated versions of Repel 64 and 72 respectively. These stronger products are supplied to both users and distributors, all of whom are under instructions from Berryessa on how to dilute these products. In their diluted forms, they tend to have lower stability and will curtain more than the factory made products, but this is offset by considerable savings on packaging and freight. Please contact Berryessa for specific advice.