Working with Minerva
Mitre Guillotine: Take more bites through the moulding, as you would with a harder wood.
Powered Mitre Saw: Ensure the blade moves quickly through the moulding to minimalise heat build up. Blades should have fewer teeth and negative rake. Contact our technical service department for advice: Jack@lionpic.co.uk.
PVA adhesives are not effective as the water cannot soak into the polymer, which is impervious to moisture. A cyanoacrylate adhesive is often used. These instant adhesives deliver the best join, but take practise to use as there is little margin for error with alignment.
Slow drying adhesives are easier to use but do not always add the same mechanical strength to the join.
Rebate Clamp: If the fences are not set exactly for the moulding, the powerful rebate clamp on an air-operated underpinner can open the join as it pushes the moulding into the fences. If the underpinner does not have a separate pressure adjustment for the rebate clamp, experiment with adjusting the fences or working without the rebate clamp.
V-nail positions: Polymer mouldings behave much like harder woods - when the v-nail is inserted the core material is displaced rather than compacted. This can have the effect of pushing the mitre apart if the v-nails are not properly positioned. V-nails can be placed quite near the front of the moulding, but avoid the back edge and do not stack v-nails. Inserting too many v-nails or placing them too close to the back edge can make the back of the mitre open up.
Recommended V-nail positions for Minerva:
V-nails closer to inner edge give neat, tight joins.
Do not stack V-nails towards the back of the moulding.
V-nails too close to back edge displaces core material and can open the join.