Dave - I helped my father do some glass work back in '60s.
after I joined the Navy, I was stationed in Key West, FL for 6 years
and worked part time at a boat yard - where I learned sooooooo much
about wood and fiberglass work on boats.
So I have layed many, many yards of glass cloth and mat. During my younger years,
I have had several wood and fiberglass boats that I did a lot of work on.
to answer your question:
the glass seam that you see in the photo is one layer of 2oz biaxial chopped strand mat.
twice as thick as cloth. and the mat holds twice as much resin.
once both sides of the wood panels are coated with copius amounts of resin, place the
mat in place and saturate it - removing all white spots, which is actually air trapped in the glass.
all air must be removed prior to laminating.
the clamps are only used to squeeze the wood down tight while you put in the screws.
the screws will hold it all together while you move it around.
Remove all the screws once you have all the weight in place.
if you leave the screws in place, they will prevent even compression of the panels.
which "could" result in less than favorable results.
I applied about 400 pounds of weight on the panel over night and it turned out quite nice.
the heavy weight will squeeze out the "excess" resin and leave that nice even glass seam in the middle
which is VERY strong and rigid.
SAFETY WARNING: once the resin has cured, the protruding glass edges are extemely SHARP.
handle with caution. leather gloves strongly suggested while trimming the wood to shape.
do not let children play with any of the cut-off edges.
if you do not use enough newspaper around the edges while the weight is applied, you will literally
glue your panel to the floor and can only be removed with crowbars - destroying the panel in the process.
I use a medium hardner in epoxy and polyester resin because I know their working limits.
ambient temperature plays a big part in the setting time: hot weather=faster set up.
cold weather=slower set up. I do not suggest putting the epoxy in a cold ice bath. Once you spread it
out on the wood panels, it quickly reaches the ambient temperature and will cure accordingly.
sorry to make this into a science project - but that is the nature of the product.
for the novice, I would recommend the slow hardner to give you more time to get it all together.
if you don't dilly dally around, you can do your project easily in 15 minutes for two panels. not 3.
apply the 3rd panel the next day and you will be golden.
If you measure the 3 layers of your 1/2" plywood and 1/8" glass core and it is way
less than 1.5", you can add a layer of 1/4" plywood with the same specs as your 1/2".
oh - precut the fiberglass to fit the panel
before you start. Then you won't be fumbling
around trying to lay resin and cut glass at the same time.
(the panel I just made is 14"x53" and it weighs 24 pounds).
I just looked at the sticker on your plywood and it is only 15/32" thick.
depending on the total thickness you want your transom panel to be,
you may have to make some adjustments somewhere along the way.
does that help ??
again - this is just my way of doing things...... other folks have their methods, I have mine.
.
