I'm a bit reluctant to hammer my step wedges in with too much gusto as I know I'll need to remove them whenever I unstep the mast, and the type of step I've built doesn't allow for tapping the wedges upwards from beneath. I've glued and screwed small rectangles of 6mm solid GRP just below the top of each step wedge so hopefully I'll be able to lever the wedges upwards when the time comes to remove them.
Also I spent 2 days of shoulder wrecking work, cutting out, then tapering, beveling and profiling with a block plane, then sanding my set of 44 wedges, so I'm keen to avoid destroying them if possible :-) I can now see why people use Spartite!
As the mast is aluminium I'm not too keen on using screws to secure the wooden wedges in position so I'll probably just clamp a strip of neoprene or suchlike under a long hose clamp around the mast to prevent the step wedges working loose. The mast will be held down in the normal way with a pin passing through the mast held down by brackets attached to the step. Rather than using pieces of angle for the brackets I've epoxy bonded lengths of 8mm threaded stainless rod deeply into the plywood step and used 60mm x 28mm saddles of 15mm thick Tufnol to bridge each pair of rods. These saddles are clamped down with nyloc nuts and allow a small amount of upward adjustment whilst preventing the mast from rotating.
In my haste I'd dipped my set of wedges in clear wood preservative prior to reading David Webb's warning about incompatibility with aluminium. After some rather concerned reading up on the subject I'm reasonably sure the type of preservative I've used is safe as it contains no metals like copper, and the data sheet says the only active ingredients are fungicides like Permethrin. To be on the safe side though I've liberally coated the wedges with the same wax (Autoglym Liquid Hard Wax) I used to coat my bare aluminium mast. So they now have a decent barrier coat plus a little extra lubrication.