"Armond Perretta" wrote in message
...
Wilbur Hubbard wrote:
"Armond Perretta" wrote in message

... I took a new gallon of Trinidad, split it in half, ... added ...
about one half quart of last year's paint, and then [brought]
the volume to about three quarts in each ... can. This means
the paint was thinned about 25 to 27 percent ...

.... But what you did is an illusion. You
added volume by adding thinner. This will not harm the paint but it
will reduce the thickness of each coat as the excess thinner will
evaporated of sublimate resulting in a thinner coating than if the
paint had not been thinned. What it amounts to is you fooled yourself
into thinking you had more paint while all you really accomplished is
making extra work for yourself in that you have to add at least one
more coat to acquire the thickness you would have had with fewer
coats using paint that was not thinned ...

I'm not sure "illusion" is a good description of my thinking. I am aware
that I am covering the same surface area with less active material (in
this
case somewhere between 72 and 75% of the cuprous oxide active ingredient I
have applied in the past). The question is: "Will this attempt to cut
expenses result in satisfactory single season performance for my
particular
application, when compared with standard application methods?"

Can you comment based on your own experience?

Like I said, it's not the thickness of a particular coat but the overall
thickness of the combined coats that counts. When the extra solvent
evaporates the thickness of each coat will be less but the concentrate of
the biocide will not change. The total thickness will end up the same as if
you'd not added the extra thinner.

I used two gallons of Trinidad about five years ago when I last painted my
22-ft LWL vessel which has remained in the water since. I did not thin it
but rolled on the first coats with a short nap roller. I brushed on the last
two coats with a fore and aft stroke for a smoother surface. The two gallons
resulted in eight coats from the boot stripe around the turn of the bilge
and four coats everywhere else except on the rudder and leading edge of the
bows which got about 10 coats each. I also added four small bottles of
tributyl tin biocide to the paint - two to a gallon. Each small bottle is
2.5 ounces. Five years later the paint is still there except for a couple of
small areas where it is wearing thin from scrubbing. But no corals and few
barnacles are adhering to date - just a lot of slime and other plant
material but it scrubs off easily enough and takes a month or two to grow
back.

Wilbur Hubbard