Canvas Fillers (was C.Canoe Rest.)
Dan Miller
Kurt Bouman wrote:
> I've seen a canoe builder Cuprinol the hull as well as the canvas.
> But--important to point out--there's no way a linseed oil/cuprinol solution could
> fill the weave of the canvas. That takes a filler material (historically, white
> lead; then silica; now, for some anyway--including Rollin Thurlow, last I knew--
> water-based). The liquid alone would not provide a nice finish--nor would it
> waterproof the canvas.
This last bit is interesting, seeing how Rollin markets the linseed
based
filler. If he is switching to water based fillers, I'd like to know why
and
which one.
>
> > > Canvas is traditionally filled with a silica/ boiled linseed oil compound.
> > > Some folks are now using a water-based airplane dope filler that is lighter
> > > and dries quickly. Long term performance seems to be up in the air still.
>
> I'd like to hear from people who've used both current fillers--the oil-based
> silica that one rubs in, and the water-based compound one paints on. Can anyone
> provide a comparison? IE, time, cost, durability, finish, ease of application,
> toxicity--that sort of thing?
From what I understand, the main reason for using water-based filler is
its
fast drying time - you can paint almost immediately (I think waiting
till the
next day is recommended), whereas linseed based fillers require a curing
time
of at least a month, and even then may *possibily* have future problems
with
paint blisters (see discussion on WCHA bulletin board about this). I
have heard
(secondhand from someone that worked for him) that Tom Mackenzie of the
Loon
Works might be having trouble with paint adhesion over water based
fillers
over time - I have not spoken with Tom directly about this. Tom
supplies
several folks around here with the water based filler, which I don't
know the
exact product, but is something out of the airplane industry. Cost is
about the same for Rollin's and the airplane dope - about $40 to fill a
16' canoe with #10 canvas.
I recently visited Jim Suffield of Old Squaw Canoes, and he uses Old
Towns'
filler recipe - a linseed/silica based formula. He states definitively
that it *will* crack over time. Several folks are again going back to
white
lead in their filler. I spoke with Gil Cramer of the Wooden Canoe Shop
on my
way to assembly this summer and asked him why. Aside from the obvious
benefit
of acting as a preservative, he says it fills the weave better, sands
out nicer,
and requires significantly less sanding. I find it interesting that
Bill Clemens,
who is a dealer for "environmentally friendly" fininishes, is a an
advocate
(and supplier) of lead-based filler.
A friend experimented with filling with alkyd paint, and has two
problems. First,
the canvas, which started nicely stretched, now is loose and sagging in
places.
(we canvassed my boat the same time, which I've filled with Rollin's
filler,
and it remains beautifully tight). Also, the paint was thin enough to
saok through
the canvas, and it looks as though it may be adhering to the hull
somewhat -
we'll know more when he starts using it in spring.
I've been researching somewhat Penn Yan's historic filling method. Penn
Yan
was heavy into the aircraft industry as well as building boats, and
their
canoes were filled with airplane dopes. Basically, a real light canvas
(tablecloth
weight) was filled with successive coats of butyrate dope, nitrate dope,
and
dope with aluminum in it for UV protection. I tried to find info about
durability and such from the aircraft homebuilders, and recieved lots of
good info, though much of it is conflicting. Cost is prohibitive
though,
roughly 2 - 3 times more expensive than other methods.
Cheers,
Dan
--
Daniel Miller
dmi...@gcg.com
Independent Boatbuilder and Small Craft History Enthusiast
So many boats, so little time....