"William R. Watt" wrote in message
...
Epoxy is risky to work with because the proportions have to be exact and
the
mix has to be thorough.

Pleeeze guys, can someone explain to me what is so difficult about givin the
resin pump and the hardener pump an equal number of pushes and stirring a
mixture firmly for two minutes????

If one cannot perform such a simple task, I think building a complete boat
is out of the question.......

Meindert

"Meindert Sprang" ) writes:

Pleeeze guys, can someone explain to me what is so difficult about givin the
resin pump and the hardener pump an equal number of pushes and stirring a
mixture firmly for two minutes????

If one cannot perform such a simple task, I think building a complete boat
is out of the question.......

I tried buying a small quantity of epoxy packaged in twin pumps and had
all sorts of difficulty with it. It never worked smoothly. It was messy. A
lot was wasted. For the small jobs I use epoxy for I only buy it in the
twin squeeze tubes now.

I find it a lot easier counting drops of polyester catalyst than trying to
measure out equal volumes of epoxy resin and hardener. Only one container
is used for measuring with polyester. Overall easier to work with in my
opinion.


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"William R. Watt"writes:

I tried buying a small quantity of epoxy packaged in twin pumps and had
all sorts of difficulty with it. It never worked smoothly. It was messy. A
lot was wasted. For the small jobs I use epoxy for I only buy it in the
twin squeeze tubes now.
snip

Stop by your handy dandy restaurant supply house and buy some plastic and/or
paper cups.

I use, 1 oz, 2 oz & 4 oz to mix small quantities of epoxy.

It's simply NBD.



--
Lew

S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
Visit: http://home.earthlink.net/~lewhodgett for Pictures

"William R. Watt" wrote in message
...
I tried buying a small quantity of epoxy packaged in twin pumps and had
all sorts of difficulty with it. It never worked smoothly. It was messy. A
lot was wasted. For the small jobs I use epoxy for I only buy it in the
twin squeeze tubes now.

I use the pump set from West. The easiest way to mix. One push on each pump
and you have a smal dose of the perfect mix.

I find it a lot easier counting drops of polyester catalyst than trying to
measure out equal volumes of epoxy resin and hardener. Only one container
is used for measuring with polyester. Overall easier to work with in my
opinion.

You can also mix by weight. I have used a digital scale for that. You pour,
for instance, 100 grams of epoxy, followed by 20 grams of hardener. Easy.

I would think that counting drops is a very unreliable method. the drop size
would be very dependant on the viscosity of the calalyst, right?

Meindert

A number of years ago WEST printed a small article in their 'How To . . .'
magazine. {subscriptions are free, just call them}. It was on just this
subject and included a couple of dimensioned drawings.

The crux of the story/drawings was a method of employing 'stops' or 'steps'
on the pump shafts. By cutting the shapes from some 1/4inch material and
placing the proper 'end' between the pump 'head' and 'base', you can get a
REPEATABLE '50 percent' or '25percent' pump. I used Hardboard and painted
them each a different color and marked them.

With the a 'full pump' discharging approximately 1 ounce of 'mix', I have
the ability to also get 1/2 ounce and 1/4 ounce {approximately} quantities
for those small projects/uses. I use the 5 to 1 formulation . . . and the
set-up works just as well with my 'standard' RAKA epoxy.

Regards & Good Luck
Ron Magen
Backyard Boatshop

"Meindert Sprang" wrote in message
...
SNIP
I use the pump set from West. The easiest way to mix. One push on each
pump
and you have a smal dose of the perfect mix.
SNIP

"Meindert Sprang" ) writes:

I would think that counting drops is a very unreliable method. the drop size
would be very dependant on the viscosity of the calalyst, right?

not so it's noticeable. one drop of catalyst for every 1/2 teaspoon of
resin. the drop squeezes out of a pinhole in a plastic container with a
bit of thumb pressure. works every time for me. I'd be more suspect of the
size of the pinhole but I've had no problems with it.

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I have mixed both epoxy and polyester for 35 years and have never had a
batch go bad. It ain't brain surgery. All you have to do is follow
exactly the manufactures directions. I have to agree with Meindert, if
you can't do that, you might want to think about whether you need to be
building a boat with two part resins! Only an amateur would
extrapolate to broad use the brushing on of catalyst over polyester
resin already applied to glass as described by Johns for one boat.
There is not a poly resin supplier in the word that would suggest such a
thing because there is no way to predict what the final properties would
be.

As to epoxy, I have mixed batches from 1 gal. down to 6 drops. Yes 6
drops (5:1 West) off of popsicle sticks for RC model aircraft building.
For larger batches I use any container of suitable size thats at hand
and mark off the ratio with a rule. Gee I'm glad I passed 7th grade
math.

Allan, the bottom line is that it is historically well established thru
industry testing, both lab and field, that epoxy is superior to
polyester in most ways except price. No amount of anecdotal evidence or
backyard observations as put forth by the polyester crowd will change
that.

Regards, Ron

PS. Meindert, I learned to measure epoxy in the lab at GE a long time
ago and was doing it on a balance scale until a couple of years ago I
was corrected by Kern of System Three and several other chemist here.
They all said that now the published ratios for the formulated resins
are for volume only as the weight ratio can be different. I never had
any trouble that I could detect but I do by volume ever since to assure
max mech properties.

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

Ron Thornton ) writes:

Allan, the bottom line is that it is historically well established thru
industry testing, both lab and field, that epoxy is superior to
polyester in most ways except price. No amount of anecdotal evidence or
backyard observations as put forth by the polyester crowd will change
that.

no argument there. the question is when do you NEED the superior
qualities of epoxy?

there are other questions about toxicity and so forth but the question
that most interests me is when epoxy is NEEDED. I've used it as an
adhesive in small quantities and to seal seams in some cases. If I used it
instead of polyester and polyurethane on the small boats I've made it
would double the price with no benefit I can imagine. everything has its
place. I don't consider epoxy to be the only product to use. No amount of
anecdotal evidence or backyard observations as put forward by the epoxy crowd
will change that.

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No William, the question is are you qualified to make an informed
decision as to whether poly is good enough. I think not because I like
many others here, none of use having any interest in selling epoxy that
I know of, have worked with this stuff professionally for years at a
technical and engineering level and I doubt that any of us would be
willing to just look at all but the most obvious applications and know
whether epoxy was needed instead of polyester. You can say poly is good
enough all you want but the truth is that you don't really know. All we
are saying is that with todays price difference it is more affordable
than ever to go with epoxy and add an additional margin to a repair or
build.

Regards, Ron

PS for the hovercraft guy. Build one correctly out of epoxy and see how
long its service life is compared to the poly craft.

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

"William R. Watt" wrote in message
...
no argument there. the question is when do you NEED the superior
qualities of epoxy?

Well, that's simple. I once tried to bond two pieces of mahogany together,
using glass mat and polyester. After curing, I could peel the stuff off,
something that I have never been able to do when using epoxy and cloth. So I
guess this is where you NEED epoxy.

Meindert