HOBEN International: Care

Master models must always be clean and dry prior to use. Rhodium electroplating is recommended for models to improve the quality of the mould, especially when the models are made of brass. The plastic liner supplied as a backing material to formula 8 rubber must be removed completely prior to vulcanisation. The technique for packing and filling the mould frame is according to the preference of the mould maker. Best results will be obtained using a vulcanising temperature of 152ºC (307ºF). Recommended vulcanisation time is 7½ minutes for every layer of mould rubber (3.2mm or 1/8"). Minimum vulcanising time should be 30 minutes, maximum vulcanising time 75 minutes.

Recommended vulcanisation times at 152ºC

Mould thickness	Time to vulcanise
13 mm (½ inch)	30 minutes
16 mm (⅝ inch)	37 minutes
19 mm (¾ inch)	45 minutes
25 mm (1 inch)	60 minutes
32 mm (1¼ inch)	75 minutes
38 mm (1½ inch)	75 minutes

Care of uncured rubber

Care of cured rubber moulds

If uncured rubber is stored at temperatures below 21ºC and out of direct sunlight, it will retain its properties for up to 1 year. Rubber kept in a cold or refrigerated store will always last longer but will need warming to at least room temperature to soften it prior to use. On delivery it is recommended that boxes of rubber are marked with the delivery date and the stock should be rotated. Always keep the rubber in a clean dust free area and avoid handling the rubber

Rubber moulds made from Formula 8 should last for may years provided they are stored away from heat and direct sunlight which will cause the moulds to discolour and become brittle. If it is necessary to clean the moulds after storage then use the mildest cleaning process available. Formula 8 moulds can be used without a mould release agent or if preferred with a light coating of silicone spray or a dusting of fine talc.