Re: A new boat, now boil test
--- In bolger@y..., "Harry W. James" <welshman@p...> wrote:
and he says the basic issue is to identify what kind of glue is in
use. The right glue is chemically stable, and not heat activateable
(I think it's resorcinol). I have boiled ply samples, and all sorts
of other samples that held to gether. I have yet to find one that
falls apart. But I have also seen a lot that come apart if hand
peeled just after a boil, I think from what he said, that's the wrong
glue. If I can find a small piece of Brunzeel I'm going to give it a
go. But that is probably what you should be looking for, not long
term dishwasher survival (its all good). If there was a chemical
test for dried resorc. that would be very satisfactory.
In other words we aren't so much doing quality control as just
testing for the type of glue. It isn't important what happens to the
ply while being boiled, but what it tells you about the glue. You
could, however, choose to build with the crappy glue, in which case
what happened to samples would mater, as some kind of outcomes
indicator. There is also the issue of whether enough glue was used.
I have heard it said that the difference between some Int, and ext.
or marine was just how glue starved the joint was.
I have to look further into these issues. The boil test tells one
very little. It is supposed to simulate long term testing of a type
that would reveal glue composition. But if it is true that Resorce
isn't heat activate that would be a much simpler test, but that isn't
what is being said.
Interestingly the Gougeons recommend two cycles of boiling followed
by baking. That is a fairly mild test compared to some I have heard
of . So if you want to push the envelope and get there quickly, that
might be the ticket, but keep in mind they are assuming encapsulation.
> I believe it is Vince Chew of this list who puts a square of plywood in
> his dishwasher for a month to test its qualities. I have startedthat
> and think it is a good testing method.I was talking to John Marples (constant camber, and searunner tris),
>
> HJ
and he says the basic issue is to identify what kind of glue is in
use. The right glue is chemically stable, and not heat activateable
(I think it's resorcinol). I have boiled ply samples, and all sorts
of other samples that held to gether. I have yet to find one that
falls apart. But I have also seen a lot that come apart if hand
peeled just after a boil, I think from what he said, that's the wrong
glue. If I can find a small piece of Brunzeel I'm going to give it a
go. But that is probably what you should be looking for, not long
term dishwasher survival (its all good). If there was a chemical
test for dried resorc. that would be very satisfactory.
In other words we aren't so much doing quality control as just
testing for the type of glue. It isn't important what happens to the
ply while being boiled, but what it tells you about the glue. You
could, however, choose to build with the crappy glue, in which case
what happened to samples would mater, as some kind of outcomes
indicator. There is also the issue of whether enough glue was used.
I have heard it said that the difference between some Int, and ext.
or marine was just how glue starved the joint was.
I have to look further into these issues. The boil test tells one
very little. It is supposed to simulate long term testing of a type
that would reveal glue composition. But if it is true that Resorce
isn't heat activate that would be a much simpler test, but that isn't
what is being said.
Interestingly the Gougeons recommend two cycles of boiling followed
by baking. That is a fairly mild test compared to some I have heard
of . So if you want to push the envelope and get there quickly, that
might be the ticket, but keep in mind they are assuming encapsulation.
I believe it is Vince Chew of this list who puts a square of ply wood in
his dishwasher for a month to test its qualities. I have started that
and think it is a good testing method.
HJ
smshatz wrote:
his dishwasher for a month to test its qualities. I have started that
and think it is a good testing method.
HJ
smshatz wrote:
>
> Okay, I get the point about the poly resin. I'm going to have to
> think that one through a little more. I'm just cheap at heart.
>
> I may have to do the boil test on the plywood. I've read a lot of
> good things, even in "Build the New Instant Boats", abou luan, but
> agree the qua;ity may vary. Maybe I should leave a piece out in the
> snow this year, and see what it looks like in the spring. I do want
> to keep the boat light, and the DF plywood in So Cal is heavy.
>
> Thanks for the advice. Keep it coming!!!
>
> Stephen
>
> --