1/8th inch thick plates will suffice in S/S on your sized vessel. Use a
thick epoxy to "back" the plates onto a curved surface.. slightly tighten
the plate so the uncured epoxy squeezes out and trim the excess. Back-off a
bit on the nuts and allow to cure. Polishing with wax or a light coating of
oil [or some plastic wrap] on the metal will prevent the epoxy from adhering
to it.

CM

"Wally" wrote in message
...
| I'll be making some stanchion base backing plates for my boat sometime
soon,
| and was wondering what size/thickness they should be. The boat is 18',
GRP,
| and there are no backing plates at present (3 stanchions each side). The
| bolts come through into the cabin and the plates would bear against the
GRP
| cabin ceiling.
|
| The plan is to use stainless steel plate, partly for corrosion resistance,
| and partly because of the way the stanchion bases were aligned when they
| were originally fitted - they aren't all set out such that all
through-bolts
| are clear of the internal cabin wall (ie, some of the nuts are very close,
| such that some plates would have a slot in the outer edge, rather than
three
| clear holes). I feel that a softer material, such as wood or brass, might
| give at the edge and not do the intended job.
|
| What thickness of stainless should I use? 3-4mm sounds good from a
| fabrication point of view, but would it be adequate?
|
| The bases are 62mm in diameter (about 2.4") - how wide should the plates
be?
| I was thinking of a rectangular shape with the long side running fore/aft.
| Maybe 3" wide and 6" long.
|
| Given that the cabin ceiling isn't perfectly flat, how should I attain a
| good contact over the area of the plates? Would a layer of thin (1-2mm)
| rubber help? Or should any packing be solid?
|
| What about rotating those bases that are poorly aligned, so that all three
| holes are clear of the inside wall, filling the old holes and drilling new
| ones?
|
| Any other ways to approach this? Comments invited.
|
|
| --
| Wally
| www.makearatherlonglinkthattakesyounowhere.com
| Things are always clearer in the cold, post-upload light.
|
|
|