Jay,
I just thought of something ...is there any chance that the core material
that you are using is incompatible with epoxy? Was it designed to be a core
for polyester fiberglass structures? Is it polystyrene? If so, be aware
that sometimes epoxy won't cure when in contact with certain other
materials. Any chance you can do a test with properly mixed epoxy to see if
the stuff will cure? System Three has an epoxy that's designed for
surfboards that will cure on a variety of substrates that others won't. If
you run into problems, then something like that may be your answer ...with
more testing that is.
And when you say the tent is 'hot', I'd ask "for how many hours a day". For
example, I've got a small repair going on a boat outside the shop right now
(Oregon), but the weather has been cool and damp. Sure, it gets up to 70
during the day, but only for a couple of hours and then it cools off all
night and morning long. After several days, the medium-speed epoxy is still
'green'. I know it'll cure and if I get room in the shop today then I'll
pull the boat in, but epoxy is like growing corn. For a cure, you need to
count how many hours ABOVE a critical temperature you get. Your slow
hardener will be even worse unless the temperature is even higher... like
80+.
Keep us updated ...this is interesting stuff.
Brian
wrote in message
oups.com...
I am sure I will give the partly cured epoxy a bit more time to cure.
I am not particularly enthusiastic about removing it. But I will only
give it until the end of this month. You see. The temperature inside
the tent (where the boat is) is high. I don't believe cold temperature
has anything to do with this problem. Therefore, the chance is high
that the epoxy may never cure completely. I can afford to wait because
I have something else to do anyway. But at the end, I have a feeling
that I will have to remove it.
I don't quite understand why I should use Dynel instead of regular
fiberglass cloth. Is there any particular reason why Dynel is better
suit for this situation? Thanks in advance for any follow-up info.
Glad to learn that I can use a belt sander instead of a surface
grinder. I already has a belt sander with coarse sanding belt. This
means I am all set if I need to use a power tool to remove the partly
cured epoxy.
Jay Chan
Ron Magen wrote:
Jay,
It's kind of like hypothermic death in the cold climates . . . 'Your not
dead until you are WARM and dead . . .'.
Absolutely - there IS a chemical structure difference between Poly and
Epoxy. However if time is no problem I wouldn't limit the 'wait time' to
a
week. In addition I would 'add energy to the reaction' by applying heat.
There are a couple of simple ways to do this, depending on the area in
question. a}Throw a tarp over the area, then an electric blanket set on
'LOW' or 'Medium'. b} set up a 'long board' or 'panel' with several
simple
sockets for light bulbs. Place it SAFELY & CAREFULLY in the compartment
below the deck area. Use 100w or less bulbs. {I use arrangements like
this
when building in the colder months - with the hull upside down and a tarp
thrown over & hanging down to trap the heat, and with a 'drop cord' in a
Styrofoam 'cooler' to keep the epoxy components warm}.
Once there is NO MORE apparent hardening {after a total of about 30-days
or
by 'scratch test'}, then I'd make my decision. If it IS 'sandable' {even
if
you have to do it gently with course paper to prevent 'gumming'} I'd
apply a
thin coat of CORRECTLY mixed epoxy, then lay in a layer of Dynel. This is
NOT like f'glass. It WON'T become clear, but will still look somewhat
white.
Also without several more coats of epoxy it won't be perfectly smooth.
However these are NOT BAD points for a white deck - it won't show and
will
add traction. PLUS the stuff is VERY abrasion resistant.
On the remark about the 'surface grinder' . . . Yes, this is a very
useful
tool - I have three of them. In your case I would not choose this first -
look at the smaller, 'straight-line' BELT SANDERS with adjustable speed.
MUCH more controllable, much more sanding material in contact with the
surface, less tiring in use, and an all-around more multi-functional
tool.
Regards & Good Luck,
Ron Magen
Backyard Boatshop
wrote in message
ups.com...
Thanks for pointing this out. Sound like I have a hopeless case on my
hand. OK, I just have to treat it as a learning experience.
Jay Chan
derbyrm wrote:
I think there's some confusion between polyester resin and epoxy.
As someone else pointed out, with polyester, the hardener is a
catalyst/accelerator and the resin will eventually cure.
As I understand epoxy, it is the combination of the chemicals in the
resin
and those in the hardener. Too few of the hardener molecules and
you'll
never end up with actual epoxy, only with a slurry of cured epoxy and
uncured resin molecules looking for their mates. It will not be very
strong.
I'd suggest you start scraping.
Roger (sorry)
http://home.insightbb.com/~derbyrm
wrote in message
oups.com...
Glad to hear that there is some hope. OK, I will wait a week or
two
to
give it a chance. Meanwhile, I can always work on something else
or
go
fishing on a rental boat. If after two weeks my finger nail still
can
make a dent on the epoxy, I will remove it.