Polyester or Epoxy?
 

"Richard Lamb" wrote in message
...
David Bosworth wrote:

I guess what I should have said was, there should not have been any
blush
to cause the failure in the first place, of course if it is left on the
work
there will be little or no bond at all with what ever is applied on top.
This is not a failure of the product, but in the application.

--

Im curious if using peel ply is a common technique in boat building?

Fairly common, I think. Saves one from a helluvalot of sanding on a larger
hull.

Meindert

Polyester or Epoxy?
 

"William R. Watt" wrote in message
...
"Meindert Sprang" ) writes:

Exactly! I have at least three sizes of teaspoons in my kitchen
drawer.....
Which one is right? :-)

are they metric or British teaspoons?
hint: turn over and look for country of manufacture.
if Japan, China, Tiwan, or Korea don't use. :)

Nah, no luck. They're completely blank.... cheap sh*t. :-)

Meindert

Polyester or Epoxy?
 

I have never tried it myself but I have heard people use it when vacuum
bagging.
I would be skeptical of claims that no further prep work would be needed by
using peel ply, too much to lose, but hey I said I never used it before, I
have also heard people laying a second coat or layer down before the first
has fully cured, not right away but many hours later, this again I would not
try on a bet, I am really just a dabbler in this stuff but I try and get it
right.
I wish this group had been around when I restored my 30' Chris Craft back
in the 80's, could have used the help, took alot of those lumps of life that
made me so pretty, heheh
--
From the rocky shores of the Skykomish river
David Bosworth
http://www.premier1.net/~daveb/
Richard Lamb wrote in message
...
David Bosworth wrote:

I guess what I should have said was, there should not have been any
blush
to cause the failure in the first place, of course if it is left on the
work
there will be little or no bond at all with what ever is applied on top.
This is not a failure of the product, but in the application.

--

Im curious if using peel ply is a common technique in boat building?

This is a light layer of dacron or cheap polyester fabric placed over
the wet layup. When cured, the peel ply is "peeled" off leaving a clean
raw surface ready for the next lamination.

Takes the blush off too.


Richard

Polyester or Epoxy?
 

"William R. Watt" wrote in message
...

I don't think anyone would recommend polyester as an adhesive.

Noone should, but is happens. I once bought plan for a 15 sailing dinghy.
The building method specified was stich and glue, using glass tape and......
polyester.

However I
think you'll find plastic resin or polyurethane cheaper than epoxy and all
that is needed in a good many situtations, from laminating to
screwed-and-glued chine battens. I use the least cost adhesvie for the job
which means I have used epoxy in some situations.

I don't like polyurethane. It needs high clamping force, just like
resorcinol. I tried to laminate a stem once, using PU glue. Didn't work.
It's simply impossible to clamp 10 layers of mahogany around a mould AND
apply a pressure of at least 4 kg/cm2 on ALL layers.

Meindert

Polyester or Epoxy?
 

"Meindert Sprang" ) writes:
"William R. Watt" wrote in message
...

I don't think anyone would recommend polyester as an adhesive.

Noone should, but is happens. I once bought plan for a 15 sailing dinghy.
The building method specified was stich and glue, using glass tape and......
polyester.

I don't recommend it but I've tried but I have used it for taped butts on
a small (virola) plywood boat and its holding up after a couple of
seasons. These butt joins are all above the waterline though, so they
never get wet.

I don't like polyurethane. It needs high clamping force, just like
resorcinol. I tried to laminate a stem once, using PU glue. Didn't work.
It's simply impossible to clamp 10 layers of mahogany around a mould AND
apply a pressure of at least 4 kg/cm2 on ALL layers.

The polyurethane which people use on cheap plywood boats is the thick
construction mastic frequently referred to a "liquid nails". The brand
most often used is Bulldog PL Premuim because its supposed to be stronger.
I've lamainated plywood with PL Premium using weights, and used if for
screwed-and-glued chines, gunwales, and skids. It works fine. There's a
photo on my website under "Boats", "Folding Cabin". I used plastic resin
for my first boat and PL Premium for the other two. Plastic resin requires
a closer fit, more heat (70 deg F vs 50 deg F), and is less tolerant of
repositioning.


--
------------------------------------------------------------------------------
William R Watt National Capital FreeNet Ottawa's free community network
homepage: www.ncf.ca/~ag384/top.htm
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Polyester or Epoxy?
 

On 19 Jan 2004 14:23:32 GMT, (William R.
Watt) wrote:

"Meindert Sprang" ) writes:
"William R. Watt" wrote in message
...

I don't think anyone would recommend polyester as an adhesive.

Noone should, but is happens. I once bought plan for a 15 sailing dinghy.
The building method specified was stich and glue, using glass tape and......
polyester.

I don't recommend it but I've tried but I have used it for taped butts on
a small (virola) plywood boat and its holding up after a couple of
seasons. These butt joins are all above the waterline though, so they
never get wet.

I don't like polyurethane. It needs high clamping force, just like
resorcinol. I tried to laminate a stem once, using PU glue. Didn't work.
It's simply impossible to clamp 10 layers of mahogany around a mould AND
apply a pressure of at least 4 kg/cm2 on ALL layers.

The polyurethane which people use on cheap plywood boats is the thick
construction mastic frequently referred to a "liquid nails". The brand
most often used is Bulldog PL Premuim because its supposed to be stronger.
I've lamainated plywood with PL Premium using weights, and used if for
screwed-and-glued chines, gunwales, and skids. It works fine. There's a
photo on my website under "Boats", "Folding Cabin". I used plastic resin
for my first boat and PL Premium for the other two. Plastic resin requires
a closer fit, more heat (70 deg F vs 50 deg F), and is less tolerant of
repositioning.

.......and is not a marine glue.

Polyester or Epoxy?
 

"Meindert Sprang" wrote in message ...
"William R. Watt" wrote in message
...

I don't think anyone would recommend polyester as an adhesive.

Noone should, but is happens. I once bought plan for a 15 sailing dinghy.
The building method specified was stich and glue, using glass tape and......
polyester.

However I
think you'll find plastic resin or polyurethane cheaper than epoxy and all
that is needed in a good many situtations, from laminating to
screwed-and-glued chine battens. I use the least cost adhesvie for the job
which means I have used epoxy in some situations.

I don't like polyurethane. It needs high clamping force, just like
resorcinol. I tried to laminate a stem once, using PU glue. Didn't work.
It's simply impossible to clamp 10 layers of mahogany around a mould AND
apply a pressure of at least 4 kg/cm2 on ALL layers.

Meindert


Lord knows I am not a chemist, but the two part polyester I have used
"seems" to harden more brittle than the epoxy I have used. I like the
property of a little flexability, especially on smaller boats.
Scotty from SmallBoats.com
Scotty

Polyester or Epoxy?
 

Come on William, I didn't say epoxy is necessary. I said that without
an informed opinion (in part the application testing you speak of, which
I did at GE for 10 years) you had a better bet (guess) with epoxy. Your
right, I don't know. That's why at todays prices I chose to go with
epoxy and increase my odds.

You are the only one I'm hearing that says epoxy doubles the cost of a
small boat. In fact, so far the other builders seem to disagree. You
sure of that?

I agree that epoxy has been overpromoted especially in the area of
encapsulating wood but we're not talking about that here. Allans
question was what to use to repair a boat of poly glass construction.
For that amount of material I believe epoxy wins hands down.

Regards, Ron

I don't recieve e-mail at this address because of spam. E-mail me
at crtsrATmsnDOTcom.

Polyester or Epoxy?
 

Meindert and William,

Please note that a proper drop is dispensed from a pipette or in my case
for building models, a popsicle stick.

Regards, Ron

I don't recieve e-mail at this address because of spam. E-mail me
at crtsrATmsnDOTcom.

Polyester or Epoxy?
 

On 19 Jan 2004 14:23:32 GMT, (William R.
Watt) wrote:


I don't recommend it but I've tried but I have used it for taped butts on
a small (virola) plywood boat and its holding up after a couple of
seasons. These butt joins are all above the waterline though, so they
never get wet.



Your boat never gets wet above the waterline?



Rodney Myrvaagnes NYC J36 Gjo/a

"Religious wisdom is to wisdom as military music is to music."