14
Tools
All tools should be mounted on a baseboard. They should not have undercuts and must be produced with
slightly angular sides (‘draft angle’) to aid release. Vent holes are needed to allow the air to be evacuated
from pockets and sharp angles on the tool. Providing these holes are kept small (1mm diameter or less) they
will not leave marks on the surface of the finished moulding.
Tools made from wood or medium density fibreboard (MDF) are easily constructed and can give short runs
of good quality mouldings at a low cost (see notes page 16). The use of close-grained wood will avoid grain
patterns appearing on the mouldings.
Plaster of Paris may be used for one-offs but the plaster must be allowed to properly dry out. (See notes
below)
Aluminium tools have the advantages of carrying fine detail and being more resistant to both distortion and
surface damage. Aluminium tools should be pre-heated before use. A cool metal mould will absorb some of
the heat from the plastic sheet before it can take up the full definition.
Resin tools combine most of the advantages of metal moulds with relative ease of manufacture. Various resi-
nous materials are commercially available especially for vacuum forming tool production.
Repairs to the vacuum circuit can be costly. The use of talc as a release agent is not recommended.
It may clog the vacuum pump, valves and hoses.
MDF Baseboard
Aluminium Baseboard
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