When using a jigsaw to cut thin sheet material such as aluminium. First place a sheet of 2 inch thick polystyrene on the work bench or garage floor then lay the aluminium sheet on top. This will give you a firm base to work on, you can now happily jig away without damaging the aluminium. The polystyrene is quite inexpensive and is easily available in handy packs from Wickes D.I.Y. stores, it is used for wall insulation by the building trade. If you use a short fine blade in the jigsaw the polystyrene will live to fight another day. The same method can be used for cutting perspex or thin ply etc. Good luck and mind your fingers!

Ray Clark