A Fiberglass Matting Alternative
by Dale Ruth
I wish to submit a hopefully fresh idea that I experimented with last year that
might interest " economy " minded boatbuilding readers.
I was redoing my house windows last year with Vinyl-Coated ( PVC ) Fiberglass
Window Screen Fabric ( 18 X16 conventional mesh ) when I got the uncanny notion
that since this is afterall fiberglass mesh and exceptionally strong, durable and rot resistant
material at that, I decided to apply a small piece to an old weathered scrap piece of
exterior fir plywood just to see what the results would be. It bonded surprisingly well as
I thought for sure the polyurethane resin would not adhere the mesh's vinyl coating to
the plywood. I gave it only one coat ( when the resin cured I cut a deep slit in the center
as shown in order to allow moisture to penetrate ), a little sanding and left it exposed to
all the harsh elements that our northern climate can throw at it including all winter long.
The plywood piece lifted, rotted and checked in a few unprotected areas near the mesh piece
but amazingly no separation or deterioration occurred whatsoever - it remained in tact as
though it were welded to the plywood - it is permanently affixed !
This was quite promising so I decided that since my small boat
requires the bottom to be sanded, resealed and repainted anyways
I went ahead and draped the entire bottom using this fibreglass window screen
mesh. The mesh went on very well, cutting was simple including no worries of
fray edges, air-born glass particles or annoying itching which is so often the case
when using fibreglass matting. Applying 3 coats of resin was another easy
task as the mesh filled with resin evenly and smoothly.
The biggest concern I had was the fear of multiple cracks occurring when
stepping into the boat with my 185lb weight. To my amazement this did not
happen at all. Repeated stepping in and out of the boat ( with my 14 yr son
on board at times ), the throwing in of all kinds of gear including running the
boat dozen of times up on to and off gravel, rocky and sandy shorelines for the
past 4 months including not covering the boat when stored outside has proven
that this fibreglass screening has stood up very well to normal use.
The pic below shows intentional removal of paint in a small area of the completed
bottom so that the mesh can clearly be seen how it appears embedded in resin - it acts
very much like rebar in cement. I am completely satisfied with the results and it
only cost me next to nothing for the amount of mesh I needed to do the whole bottom and I
still had some left over to boot. Smaller or tighter weaved fibreglass mesh (20 X 20)
is also available.
I'm planning to build a "12 ' - Jonboat" found on the "Free Boat Design Resources"
webpage. Looks like a solid but heavy boat design (1978) so I will incorporate modern building
techniques to reduce weight. I feel confident in using this material to do the transom, stem
and side sections as well. Perhaps I will also do all the seams with this stuff, but I will
definitely test that before doing so.