Unfortunate terms ...what would you call a primer that's designed to act as
a chemical barrier between alkyd enamel and amines on epoxy?

As a point of information, I spent quite a bit of time on the phone with a
paint expert (working for Ameron) once and he explained that topsides paints
work by blocking moisture in the short term but were unable to block it in
the long term. If kept in the water, moisture could get underneath it
eventually, but then not be able to get back out quickly enough to prevent
blistering when heated by the sun. Below the waterline paints he explained,
were designed to allow moisture to flow in and out more easily and this
prevented blistering ...but required a waterproof substrate instead. I'm
confused because I would guess that waterproofness was what determined if a
paint was for below the waterline or not. Or maybe he was implying that
there was no truly waterproof paints? Maybe Awlgrip or Sterling? Anyone??

Brian


"Jim Conlin" wrote in message
...
When thinned as directed, 404/414 is very porous and only prevents the
passage of bacteria and up. 404/414 is not a barrier coating in the sense
that it prevents osmotic blistering ('pox'). Not the usual meaning of
'barrier coat', in spite of interlux's labelling. The Interlux product
for
that is Interprotect 2000. . Being epoxy-based, it provides good
mechanical bond for oher finishes.
"Robert or Karen Swarts" wrote in message
...
Just for the record, Jim, the can is labeled Epoxy Barrier-Kote. And the
catalog describes is as suitable for above or below water applications.
The
directions also state that it must be thinned.

Thanks for your thoughts.

BS

"Jim Conlin" wrote in message
...
Interlux 404/414 is not a barrier coat. It's a sandable primer whose
function is to provide a tie coat between sime substrate and an
impervious
finish coat such as an LPU paint. If applied as directed, it's just
loaded
with expensive solvents and is consequently pretty porous. Useless
under
bottom paint. If you are using it as a primer under finish paint and
not
under bottom paint, go for it. I'd try acetone. Let us know your
result.

"Robert or Karen Swarts" wrote in message
...
Can I successfully use acetone to thin epoxy barrier coats? I am
thinking
of
Interlux 404/414 in particular, but the question is also a general
one.

I am aware that there are proprietary products for this application,
but
I
need to paint tomorrow morning, and the nearest dealer is about 60
miles
away.

Bob Swarts