Jay,
I'd say the epoxy has finally reached the 'green stage' . . . about 10 days
late, but better then never. True, you really can't *properly* sand it yet -
but it proves that the chemical reaction IS progressing. What a lot of
people don't realize is that because the epoxy 'curing' is an 'internal
conversion' chemical process {as opposed to the 'catalyst additive' of
polyester}, a actual 'FULL CURE' can take several months. It's a geometric
progression so that after about 72-hours {if everything is done 'per
instruction'} it doesn't matter to the typical user. Additionally, because
the reaction is rather temperature dependent it can be somewhat controlled.
That is sped up or slowed down to almost a 'hibernation' point . . . I've
used it as low as the mid 30's, which supposedly you can't do.

If time is NOT a problem, and the surface is horizontal {so there is no
slippage or 'curtaining'} I'd just wait. Especially as the weather is
warming up. When it gets to the point you can't dent it with a finger nail,
give it a couple of swipes with some sandpaper. If it still gums up, wait a
bit longer and use a 'regular nail' for scratch testing. Use the time to
make some small 'test batches' so you get comfortable with mixing {BE
THROUGH - this is the MOST prevalent cause of problems}and application.

When physically possible, sand and proceed, or sand and 'paint on' a thin
cover coat of unthickened fresh epoxy and continue the project.

If not this . . . then get yourself a stack of filter masks, a Tyvek suit, a
couple of Surform tools & extra blades, belt sander & 'Planer' belts, a
4-1/2in surface grinder, and have at it.!!

Regards & Good Luck,
Ron Magen
Backyard Boatshop
{PS - I understand that MAS is quite a bit over-priced for what you get . .
.. and it's formulated relatively close to where I live}
..
wrote in message
oups.com...
I would like to get some opinions on whether I should remove partially
cured epoxy in one large area of my deck.

Due to my failure to follow instruction in mixing epoxy and failure to
do a test batch before using a new type of hardener, I had not
thoroughly mixed the epoxy long enough when I installed the core
material onto the deck. The result is that the epoxy cures very very
slowly:

- After one day, I felt that the epoxy was still wet.

- After three days, I still could use my thumb to dent the epoxy.

- After ten days (today), it is solid enough that I cannot use my
thumb to dent it; but I still can use my finger nail to dent its
surface. And I definitely cannot sand it yet.

What should I do?

Should I wait another week or so to see if it may completely cure? I
can afford to wait because I can do something else while I wait; but I
am not sure if the epoxy will be strong enough even if it is seemingly
cured.

Should I remove everything and start this over? Unfortunately, this
will be very labor intensive to remove the partially cured epoxy.

The epoxy is from MAS and the hardener is MAS slow hardener. The brand
name may or may not matter.

Jay Chan

When I mix a pot of epoxy, and maybe this goes back to my painting days, I
generally mix it really well (scraping sides and bottom with square-tipped
mixing stick) then set it on the bench for a couple of minutes to 'kick'.
While I do that, I get rollers or brushed together, or wipe down the
'project', etcetera. Then I stir up the epoxy real well (again) and go
ahead with using it. I prefer that to just standing there and mixing for 3
minutes and I've never had a failed batch, even with mustard-pump measured
5:1 ratio epoxies (yikes!)

Brian


"Ron Magen" wrote in message
news:uo0kg.26606$X02.20217@trnddc02...
Jay,
I'd say the epoxy has finally reached the 'green stage' . . . about 10
days
late, but better then never. True, you really can't *properly* sand it
yet -
but it proves that the chemical reaction IS progressing. What a lot of
people don't realize is that because the epoxy 'curing' is an 'internal
conversion' chemical process {as opposed to the 'catalyst additive' of
polyester}, a actual 'FULL CURE' can take several months. It's a geometric
progression so that after about 72-hours {if everything is done 'per
instruction'} it doesn't matter to the typical user. Additionally, because
the reaction is rather temperature dependent it can be somewhat
controlled.
That is sped up or slowed down to almost a 'hibernation' point . . . I've
used it as low as the mid 30's, which supposedly you can't do.

If time is NOT a problem, and the surface is horizontal {so there is no
slippage or 'curtaining'} I'd just wait. Especially as the weather is
warming up. When it gets to the point you can't dent it with a finger
nail,
give it a couple of swipes with some sandpaper. If it still gums up, wait
a
bit longer and use a 'regular nail' for scratch testing. Use the time to
make some small 'test batches' so you get comfortable with mixing {BE
THROUGH - this is the MOST prevalent cause of problems}and application.

When physically possible, sand and proceed, or sand and 'paint on' a thin
cover coat of unthickened fresh epoxy and continue the project.

If not this . . . then get yourself a stack of filter masks, a Tyvek suit,
a
couple of Surform tools & extra blades, belt sander & 'Planer' belts, a
4-1/2in surface grinder, and have at it.!!

Regards & Good Luck,
Ron Magen
Backyard Boatshop
{PS - I understand that MAS is quite a bit over-priced for what you get .
.
. and it's formulated relatively close to where I live}
.
wrote in message
oups.com...
I would like to get some opinions on whether I should remove partially
cured epoxy in one large area of my deck.

Due to my failure to follow instruction in mixing epoxy and failure to
do a test batch before using a new type of hardener, I had not
thoroughly mixed the epoxy long enough when I installed the core
material onto the deck. The result is that the epoxy cures very very
slowly:

- After one day, I felt that the epoxy was still wet.

- After three days, I still could use my thumb to dent the epoxy.

- After ten days (today), it is solid enough that I cannot use my
thumb to dent it; but I still can use my finger nail to dent its
surface. And I definitely cannot sand it yet.

What should I do?

Should I wait another week or so to see if it may completely cure? I
can afford to wait because I can do something else while I wait; but I
am not sure if the epoxy will be strong enough even if it is seemingly
cured.

Should I remove everything and start this over? Unfortunately, this
will be very labor intensive to remove the partially cured epoxy.

The epoxy is from MAS and the hardener is MAS slow hardener. The brand
name may or may not matter.

Jay Chan

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.

Also thanks for the suggestion of using a surface grinder. I will look
for it in home center.

Jay Chan


Ron Magen wrote:
Jay,
I'd say the epoxy has finally reached the 'green stage' . . . about 10 days
late, but better then never. True, you really can't *properly* sand it yet -
but it proves that the chemical reaction IS progressing. What a lot of
people don't realize is that because the epoxy 'curing' is an 'internal
conversion' chemical process {as opposed to the 'catalyst additive' of
polyester}, a actual 'FULL CURE' can take several months. It's a geometric
progression so that after about 72-hours {if everything is done 'per
instruction'} it doesn't matter to the typical user. Additionally, because
the reaction is rather temperature dependent it can be somewhat controlled.
That is sped up or slowed down to almost a 'hibernation' point . . . I've
used it as low as the mid 30's, which supposedly you can't do.

If time is NOT a problem, and the surface is horizontal {so there is no
slippage or 'curtaining'} I'd just wait. Especially as the weather is
warming up. When it gets to the point you can't dent it with a finger nail,
give it a couple of swipes with some sandpaper. If it still gums up, wait a
bit longer and use a 'regular nail' for scratch testing. Use the time to
make some small 'test batches' so you get comfortable with mixing {BE
THROUGH - this is the MOST prevalent cause of problems}and application.

When physically possible, sand and proceed, or sand and 'paint on' a thin
cover coat of unthickened fresh epoxy and continue the project.

If not this . . . then get yourself a stack of filter masks, a Tyvek suit, a
couple of Surform tools & extra blades, belt sander & 'Planer' belts, a
4-1/2in surface grinder, and have at it.!!

Regards & Good Luck,
Ron Magen
Backyard Boatshop
{PS - I understand that MAS is quite a bit over-priced for what you get . .
. and it's formulated relatively close to where I live}
.
wrote in message
oups.com...
I would like to get some opinions on whether I should remove partially
cured epoxy in one large area of my deck.

Due to my failure to follow instruction in mixing epoxy and failure to
do a test batch before using a new type of hardener, I had not
thoroughly mixed the epoxy long enough when I installed the core
material onto the deck. The result is that the epoxy cures very very
slowly:

- After one day, I felt that the epoxy was still wet.

- After three days, I still could use my thumb to dent the epoxy.

- After ten days (today), it is solid enough that I cannot use my
thumb to dent it; but I still can use my finger nail to dent its
surface. And I definitely cannot sand it yet.

What should I do?

Should I wait another week or so to see if it may completely cure? I
can afford to wait because I can do something else while I wait; but I
am not sure if the epoxy will be strong enough even if it is seemingly
cured.

Should I remove everything and start this over? Unfortunately, this
will be very labor intensive to remove the partially cured epoxy.

The epoxy is from MAS and the hardener is MAS slow hardener. The brand
name may or may not matter.

Jay Chan

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.

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.

wrote:

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


The only times I've had problems like this have been on very humid days.

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.

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.

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.

If I was you, I'd wait a couple of weeks til it seems to harden as much
as possible. Then, I'd start scraping. Sicne it hasn't cured properly,
you can try a heat gun to soften up the epoxy before scraping. Paint
scrapers, window scrapers, utility knives, 40 grit sandpaper. Try
everything, except a garden rake....

Seriously. Especially since this is structural, I'd be removing all of
the epoxy, down to bare wood, and starting over. cured epoxy is
fantastic, but partially cured is a disaster waiting to happen. Why
ruin a good boat over some bad epoxy??

Mike
Saskatoon, SK

wrote:
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
groups.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.