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Q: I have used polyester
resin and only part of it has hardened. What’s
happened?
A: The problem is caused by not thoroughly
mixing the resin and the catalyst.
When mixing make sure
you use a rectangular shape stirrer – like a ruler.
Ensure
you scrape the sides of the container and mix the solution
from the bottom up and back down again.
To ensure a
thorough mix, we suggest you also pour the resin from one
clean mixing container to another.
Q: Can I fix the problem and how?
A: Yes
you can. Remove us much of the uncured resin as possible
without disturbing the layers of glass underneath, thoroughly
mix up a new batch of resin of sufficient quantity to cover
the uncured area and reapply. Thoroughly roll the affected
area with a bristle or disc roller.
Q: My resin is taking a
long time to go off, why?
A: There are several factors
that can cause this problem.
1: You may have used
too little catalyst. This will create a slow cure, but a
strong laminate. Check our Catalyst usage guide.
It
is based on an ambient air temperature of 25 C and note that
the product to be used is measured in weight and the catalyst
in millilitres.
2: Your catalyst may be old. Time
affects the ability and stability of the catalyst. Use a new
supply of Catalyst
3: Resin uses a product called
“Cobalt” to promote the resin. The more cobalt, the faster the
reaction time to the catalyst.
You may have purchased
resin that was created for use in the summer months and you
are using it in the cooler Autumn / Winter months. Use a
resin promoted for the time of the year
4: Your
product may be below the manufacturers recommended usage
temperature. The product should never be used if its
temperature is 15 C or below.
The ambient air temperature
will also effect the cure time. Increase the amount of
catalyst used, but do not work greater than 2%
5: The
resin or the glass reinforcing may be contaminated
Q: I have hot spots
over my finished lay up. Why ?
A: This can be caused
by a poor resin / catalyst mixing technique. Ensure you mix
your product thoroughly.
Resin pooling or resin rich areas
can also cause this problem. Reduce your resin usage over the
area.
Q: My resin is going off
very rapidly, Why?
A: There are several factors that
can cause this problem.
1: You may have used too much
catalyst. This will create a rapid cure, produce a vast amount
of exothermic heat and create a weak laminate. Check our
Catalyst usage guide.
It is based on an ambient air
temperature of 25 C and note that the product to be used is
measured in weight and the catalyst in
millilitres.
2: Resin uses a product called “Cobalt”
to promote the resin. The more cobalt, the faster the reaction
time to the catalyst.
You may have purchased resin that
was created for use in the cooler Autumn / Winter months and
you are using it in the summer months. Use a resin promoted
for the time of the year
3: The ambient air
temperature will also effect the cure time. Keep the product
and the project you are working on out of direct sunlight
4: The polymerisation or hardening reaction of resin
gives off heat., it is important that this reaction be
controlled. This is done by keeping the concentration of
catalyst to a minimum. It is important not to laminate too
many layers at one time. Allow the lower layers to cool to
room temperature before continuing with additional
layers.
5: The resin or the glass reinforcing may be
contaminated.
Q: Why does the resin
drain from the sides of my mold and pool in the
bottom?
A: Again there are a number of
causes:
1. You may have applied too much resin and it
is slumping to the bottom of the mold.
2. You may have
over agitated the resin. Agitation reduces gel and increases
flow causing the resin to drain to the lower level of the
mould.
3. You may have purchased a “Cheap” resin to do
the job.
Just like “Oil’s ain’t Oil’s” – “Resins ain’t
Resins” either. You get what you pay for. To put it
bluntly, there has to been a reason why resins are different
prices, generally; the higher the price, the better the
quality. The lower the price the less you get in it,
let’s face it, the only what they can get things cheaper, is
to leave things out. The things they leave out effects the
thixotropic properties of the resin. You can over come this
problem by using a better quality resin, or by the addition of
a thixotropic additive like cab-o-sil®
Q: Why do I have voids –
bubble like gaps in my finished product?
A: This is
generally caused by poor rollout. Rolling of the
laminate is very important to release entrapped air. A bristle
or ring roller is generally preferred over the paddle type
roller or brush.
Q: Why does the glass pick
up on my roller?
A: Again several factors can cause
this problem.
1. The resin is nearing gel time. To
give a more efficient lay-up time, reduce the area the resin
is applied to.
2. Styrene has evaporated from the
resin. Use fresh catalysed resin.
3. Rolling too
fast.
4. Too high a percentage of glass – apply more
resin
5. Dirty rollers. Clean in fresh
solvent.
Q: Why does the tooling
gelcoat pull away from my plug?
A: Catalysation of
tooling gelcoat is critical. Use 1.8% Norac MEKP-9 as per the
gel coat data sheet. Do not use more than 2.4% in the tooling
gel coat as more can cause excessive shrinkage. Do NOT allow
tooling gel coat to cure completely as it can shrink and pull
away. This means you should never leave tooling gel coat over
night or over a weekend without laminating
first.
Never reduce tooling gel coat with any
thing.
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