General Tips on using CA adhesives.
Heat and moisture will decrease the shelf life of CAs. Unopened
bottles can be stored in a freezer or refrigerator, but allow them
to reach room temperature before using. Keep your bottles in a
cool place that won’t be exposed to direct sunlight and store away
from bottles of accelerators. Due to the freshness of our CAs,
their shelf life is guaranteed for 24 months.
For the initial opening of the top, loosen and retighten the top
first to relieve internal pressure, then hold the bottle against
a near vertical surface and cut off the top 1/32" with a knife
or razor blade without squeezing the bottle. To prevent clogging,
do not let the tip of the nozzle touch a surface that has been
sprayed with INSTA-SET™. Before replacing the coloured cap, set
the bottle down hard to knock the remaining CA back into the bottle
before squeezing it in an upright position to blow air through
the nozzle, then wipe the tip clean.
With all CAs, the closer the parts fit together, the stronger
the bond. Always hold the bonding surfaces together as tightly
as possible. Any rough spots on the mating surfaces should be smoothed
out. Although CAs will hold objects together with considerable
strength within seconds, the full strength of the bond is not reached
for several hours. Allow for this before subjecting parts to maximum
stress. Also, CAs are generally a little less brittle and have
higher strength when they are allowed to cure on their own. |
Common FAQ’s |
1. |
My epoxy doesn’t seem to be completely cured. It
still feels tacky on the surface. Is it defective? |
2. |
My 30 Minute epoxy started to cure in only 10-20
minutes. Did I get mis-marked bottles? |
3. |
My cyanoacrylate has been working great but today
I can’t get it to stick two pieces of wood together. Did the CA suddenly
go bad? |
4. |
Can anything be used to thin CA (decrease its viscosity)? |
5. |
What can I use to bond clear plastics without getting
the frosting effect that occurs with regular CAs? |
6. |
Is cyanoacrylate toxic, and does odorless CA just
cover up what will still be toxic effects? |
7. |
Can SUPER-GOLD™ odorless CA be used on white foam? |
8. |
How come SUPER-GOLD™ is so expensive and has a
shorter shelf life? |
9. |
My colored cap sometimes can be difficult to take
off. What can I do? |
10. |
After applying FINISH-CURE™ and sanding it down
to a smooth surface, I accidentally went down to the bare balsa.
Do I have to apply more epoxy to seal this area? |
11. |
You may be interested to know.......... |
Q: My epoxy doesn’t
seem to be completely cured. It still feels tacky on the surface.
Is it defective?
A: Several factors can affect the curing of epoxies. Not mixing equal
parts is usually the first suspected cause of problems, but since
the 50-50 ratio has a plus or minus tolerance of about 10%, this
is rarely a problem. Sometimes modelers will intentionally mix in
extra hardener. This is not recommended! The improper ratio can result
in brittleness and/or loss of strength in the cured epoxy. Incomplete
mixing of the two parts will also cause problems. Spend at least
one minute to thoroughly mix the two components.
The vast majority of problems with epoxies are temperature related.
Most epoxies need an environment that exceeds 70 degrees F. while
they are curing. Heating the epoxy hours after mixing will not
solve the problem of improper curing. The temperature must be correct
during the initial curing time. Maintaining proper temperature
control in your workshop will solve most epoxy problems; however,
since the majority of workshops are garages where work is mostly
done at night when temperatures are low, temperature control can
be impractical. In this case there are two options. First, the
two epoxy components can be pre-heated before mixing. We have found
heating epoxy bottles without their tops in a microwave oven to
be the quickest method. The bottles should be heated to where they
are only slightly warm to the touch, which usually only takes 10
to 20 seconds, with the resin (black top) taking less time. Do
not mix components that have been overheated, as the cure time
will be greatly reduced.
The second option is to heat the epoxy after is has been mixed
with a heat gun.
This should be done both before and after applying
the mixed epoxy. If your workshop is particularly cold, run the
heat gun over the epoxy again about 15-30 minutes after applying.
If you are bonding metal, pre-heat it for best results. Of course,
during summer none of these precautions usually need to be taken. |
Q: My 30 Minute epoxy
started to cure in only 10-20 minutes. Did I get mis-marked bottles?
A: The minute designations on our epoxies are the amount of time
one has before the components start to cure to a taffy-like consistency
when mixed on a flat surface (such as the flexible plastic top to
a coffee can). Higher temperatures will reduce the working time.
As epoxies cure, heat is created. If a larger amount of epoxy (1
oz. or more) is mixed in a cup, a mini-reactor is created which concentrates
the heat of curing which causes the epoxy components to kick-off
faster which creates more heat which further speeds the curing, creating
more heat, so on and so on. On warm days, you can end up with a smoking
blob. Lay down parallel, equal lengths of each component before mixing
them together to get consistent results. The 20 minute designation
of our Finish-Cure™ takes into account its being mixed in larger
quantities in a cup. |
Q: My cyanoacrylate
has been working great but today I can’t get it to stick two pieces
of wood together. Did the CA suddenly go bad?
A: Not usually. CAs cure (polymerize) when pressed into a thin film
in the presence of an alkali environment. In general, ambient humidity
in the air and on the bonding surface provide the proper pH to initiate
cure in a few seconds. The best bonds are achieved when relative
humidity is 40 to 60 percent at room temperature. If the surfaces
to be bonded are excessively dry or are acidic, the curing can be
much slower or not occur at all. In such cases, Insta-Set™ accelerator
should be sprayed on one surface and CA on the other. Insta-Set™
is formulated with a high pH that initiates curing in less than 8
seconds.
The CA can lose its potency if exposed to higher temperatures
for an extended period. A bottle of CA in a tool box that is left
to sit in the summer sun or a bottle that is exposed to direct
sunlight will greatly increase the aging process. The CA tends
to thicken and turn darker as it ages. Kept in cooler surroundings,
Bob Smith Industries will maintain its potency for two years or
more. A good test for thin CA is to shake the bottle and notice
how long it takes for all the bubbles to disappear. If it takes
longer than 3 seconds, the CA is on its way downhill. It will still
form strong bonds, but they will be slower and with less penetration.
Using the wrong consistency of adhesive on a joint will also lead
to problems. Thin CA should not be used on end grain balsa wood.
The CA can be "sucked" up the fibres of the wood for
an inch or more, i.e. the CA is drawn away from the bonding surface.
Thicker CA should be applied sparingly to only one surface. The
best bonds are achieved if only enough adhesive is applied to fill
a gap. |
Q: Can anything be used
to thin CA (decrease its viscosity)?
A: The only substance that can be added to thicker CA to reduce its
viscosity is thin cyanoacrylate. Any other additive will quickly
harden the adhesive. |
Q: What can I use to bond
clear plastics without getting the frosting effect that occurs with
regular CAs?
A: When CAs cure they volatise, creating the appearance of a white
haze around the bondline. This phenomenon occurs when the cyanoacrylate
monomer reacts with moisture in the air, and settles on the part.
On areas where this may be a problem, Super-Gold+™ is ideal, especially
for clear plastics. You will want to use the minimum amount of CA,
so a regulate or extra-fine extender tip should be used to apply
to theSuper-Gold+™. It works best to apply the CA to the area on
the clear plastic to be bonded. This way if you make an error in
the placement of the two parts adhesive does not get on areas you
want to remain clear. Super-Gold+™ sometimes has a tendency to “string”
as the glue tip is pulled away from a surface. The "string" that
may be created can be drawn to the clear plastic by static electricity,
which can ruin your whole day. It is best to wash the clear plastic
with plain water and wipe it dry before bonding. Insta-Set accelerator
can be used to immediately cure the Super-Gold+™ since it will not
affect clear plastic. (Insta-Set actually works as a great surface
clearer. Use it to remove the residue adhesive from adhesive backed
labels.) |
Q: Is cyanoacrylate toxic,
and does odorless CA just cover up what will still be toxic effects?
A: Cyanoacrylate is not toxic! The fumes from CA are a vaporized
form of the cyanoacrylate monomer that irritate sensitive membranes
in the eyes, nose and throat. They immediately are polymerized
by the moisture in the membranes and become inert. They do not
penetrate into human internal systems. In fact, CA that is used
to suture wounds avert some of the infections that occur in stitched
wounds. It also eliminates the need for stitch removal because
it sloughs off along with the outer layer of skin after a couple
of weeks. Cyanoacrylates have been successful in grafting skin,
bone and cartilage; repairing eyes; closing dangerously ballooned
blood vessels in the abdomen; and stopping spinal fluid leaks.
About 5% of the population can become sensitised to CA fumes after
repeated exposure. Just a small exposure can result in flu-like
symptoms. Our odorless Super-Gold+ CAs eliminate any adverse reactions.
The most common misnomer about CA is that they contain cyanide
and that the fumes will poison you. Not True! Period. Case closed. |
Q: Can SUPER-GOLD™ odorless
CA be used on white foam?
A: Super-Gold and Super-Gold+ are completely white foam compatible.
Insta-Set accelerator is also white foam compatible, but it must
be used correctly. While Insta-Set will not attack the foam, the
heat generated during the curing of the Super-Gold may melt the foam!
The minimum amount of Insta-Set should be used. Since there is usually
little or not moisture present in white foam, when bonding two pieces
of foam one piece should be lightly misted with Insta-Set and left
for 2-3 minutes before applying Super-Gold+ to the opposite part
and bringing them together. |
Q: Why is SUPER-GOLD™
so expensive, and why does it have a shorter shelf life?
A: It’s the nature of the beast. The raw materials for odorless CAs
are universally extremely expensive and limited in supply. Their
shorter shelf life is an unavoidable result of their chemical makeup
and adds to its marketing costs. The Super-Golds’s have a maximum
shelf life of 1 1/2 years under ideal conditions. |
Q: My colored cap sometimes
can be difficult to take off. What can I do?
A: The different rates or shrinkage in the various colors of plastic
we use for our caps and tolerance variations in molds can sometimes
result in caps that fit too tight. A twisting motion as you pull
up on the cap is usually all that is needed to remove it. If you
find the cap too difficult to grip, take a spare 1/4 - 20 or 1/4
- 28 metal nut and self-thread it onto the top of the cap, which
will give you a better grip. When using Insta-Cure™ super thin CA,
we recommend using teflon tubing or an extra-fine extender tip. They
can remain part of the top and the blue cap can be set aside without
having a significant affect on the shelf-life. The finer tips allow
more precise control of the thin CA and greatly resist clogging. |
Q: After applying FINISH-CURE™
and sanding it down to a smooth surface, I accidentally went down
to the bare balsa. Do I have to apply more epoxy to seal this area?
A: The objective of most modelers who use FINISH-CURE™ is to achieve
a durable and smooth surface while adding the minimum amount of weight.
If you haven’t sanded down through the epoxy in a couple of spots,
you haven’t sanded the surface enough and are adding extra weight!
Since it is usually very inconvenient and time consuming to mix a
small batch of epoxy for such small areas, IInsta-Cure™ super thin
CA is the best alternative. Apply a few drops to the balsa and use
the fine tubing on the tip as a brush to spread it around. Wipe off
the CA with a paper towel and then apply more CA, followed again
by a quick swipe of the paper towel. A light spray of Insta-Set accelerator
to insure a full cure allows the area to be sanded within 10 seconds.
A hard-backed sanding block will blend the area into the epoxy finish.
Older CA that has lost some of its potency can actually be easier
to use for this application. Entire surfaces can be finished smooth
using just thin CA. The fumes that result from the application of
such large quantities of CA can be overwhelming so extra precaution
must be taken to provide sufficient ventilation. Thin CA can also
be used to apply light weight fibreglass cloth. Substituting Super-Gold
odorless thin eliminates the problem with fumes. |
You may be interested
to know.....
Insta-Cure works very well with 3/4 oz. to 6 oz. fiberglass cloth
for reinforcing joints. Lay the cloth on the surface and apply
drops of the thin CA until capillary action saturates the fiberglass.
Hobby paints that are alcohol based (acrylic) can be used to
add color to epoxies with little effect on the epoxy’s characteristics.
Cured CA is actually acrylic plastic. Thick CA with an accelerator
can be used to quickly build up layers to replace or modify plastic
parts. Unfortunately, neither CA or epoxy works well on most polyethylene
or polypropylene, i.e., the flexible, waxy plastics.
Quik-Cure epoxy works for bonding clear plastics. It will not fog
the plastic and if the epoxy gets on the wrong spot, it can be
carefully removed with a razor blade without leaving a mark.
Small bits and shavings of plastics can be mixed with INSTA-CURE+™
to repair nicks and other damage to large plastic parts. Once cured,
it can be sanded smooth to create a surface indistinguishable from
the main part. This technique is used for the repair of vinyl automotive
bumpers and allows the recycling of existing parts.
Quik-Cure, like all other fast setting epoxies, is not resistant
to long term exposure of raw model aircraft fuel. It can be used
to tack glue firewalls into place but should be coated over with
SLOW-CURE™ 30 MINUTE EPOXY for permanent installation.
For the application of very small amounts of INSTA-SET™ accelerator,
use our fine tip CA applicator for dispensing one drop at a time.
Loosen and retighten the top to the CA bottle before cutting off
the tip. This relieves any internal pressure from inside the bottle,
which prevents CA from being forced out unintentionally.
It should be noted that while the curing process takes place regular
CA’s give off a mildly unpleasant vapour that can be irritating
to the nose and eyes so always work in a well ventilated area. |
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