let’s say you’re building a canoe. it’s ugly, too, but sound and light. and you’re not concerned about looks, etc. but a painted hull would look better than varnish, which would show damaged wood strips that have been filled. here’s my question: is there any weight difference between a quart of marine paint and a quart of varnish? either more durable on a wood boat, ounce for ounce? thanks
Not much difference
It’s not the weight of the liquid in the can that matters, it’s the weight of the solids that remain after the the solvent evaporates. You could figure it out from the info on the representative technical data sheets if you really wanted to, but there is not enough difference to matter.
A good paint will be more durable than varnish.
Th UV protection
from two coats of paint will be better and last longer than many more coats of varnish.
Spar varnish has UV proectants, but I
like paint. If you can find a Dulux paint store , they carry an industrial paint made for exterior use on exposed surfaces. It really stinks but looks good.
Use exterior latex paint. Works well,
is that what you’re talking about?
thanks for all the posts. if paint will protect better with fewer coats, then paint it is. for example, if two coats of paint protect as well as four coats of varnish, the paint would have to weigh the same or less. i’m talking about one-part paints.
now, question 2: i’ve read that white paint is lighter than other colors because all paint is made from white, ie black is really white paint with pigment added. is that true, too?
Yes, house paint, as recommended by
Dynamite Payson, one of the guys who kicked off the stitch and glue boat building revolution. Hell of a lot less messy and difficult to deal with than an oil base paint.
Go to a paint store and ask them to
weigh the pigment. Doubt if the difference is substantial. Won’t matter much once the boat is in the water.
You would be surprised
It depends on the colour but pigmented paint will aways weigh more than varnish. This could be up to 50% higher.
Whoever wrote that one knows
Nothing about the subject.
Its easy to determine. Take a can of
white paint and a can of the preferred color and weigh.
so 32 ounces of varnish will weigh less than 32 ounces of paint?
How to calculate
Get the technical data sheets for whatever products you are considering. They should list the density of the liquid as lbs/gallon and the percent solids.
Multiply the two together. This will be the weight of the film left after the paint or varnish dries.
Or just paint the damn thing and live
with the few extra ounces.
The ounces of varnish or paint are fluid ounces, not ounces by weight.
Except most of the low density
constituents will evaporate during the film formation leaving the highe density constituents behind.
You will never notice the weight
Let’s say you weigh 180 lbs and the boat is 50, or 230 lbs. total.
Add 2 lbs and you are now paddling 232 lbs.
You’ve added less than 1% overall to the amount you are propelling.
Impossible to notice.