Screw through the plywood into the wood chine. Screws should go about 3/4
of their length into the wood chine. I use 3/4" screws through 1/4"
plywood into 3/4" chines. I've also used 1/2" chines and my chines are
never cut exact. Where a screw comes though I either grind off the tip
with a small grining wheel on my drill (noisy) or just extract the screw
and fill in the hole with resin. I've found joints stay together with glue
alone after the screws are removed but it's less work to leave them in. If
you're really cheap you can extract the screws and use them again on
another project. I the space screws 4" apart on my small 1/4" plywood
boats. On soft plywood you sometimes don't need to counterskink. Stewart
recommends not counterskinking because there's less chance the screw head
will pull though the surface ply. I've not had much success because it
takes too much torque to pull the head into the plywood. The drill heats
up too much. So I counterskink in plywood unless I'm going to extract all
the screws once the adhesive cures.


--
------------------------------------------------------------------------------
William R Watt National Capital FreeNet Ottawa's free community network
homepage: www.ncf.ca/~ag384/top.htm
warning: non-FreeNet email must have "notspam" in subject or it's returned