Improper mixing of the two parts could be the problem, but 98% of the time your situation is caused by the epoxy curing in an environment below 70°F. It must be above this temperature for the entire 8 hour cure time of the Slow-Cure for the epoxy to have maximum strength. BSI’s Quik-Cure is less sensitive to temperature since it creates a significant amount of its own heat when curing. Finish-Cure, however, must be kept at above 75°F during curing for it to have the properties that modelers are looking for.

Exposure to heat and moisture are the two main factors in decreasing the shelf life of CA. If kept at normal room temperature (74°F) and humidity levels, BSI’s regular CAs will have a shelf life of over two years. Unopened bottles can be stored in a freezer, but this offers little or no advantage over storage in a refrigerator. CA bottles can be stored in a sealed container inside the refrigerator to isolate them from moisture. Adding a desiccant (silica gel) to the container can extend the life of the CA to over four years. Opened bottles that are frequently used should not be put into into the fridge since condensation can occur inside the bottle. Accelerator should never be stored with CA.

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When the two components of epoxy are mixed together, they create an exothermic reaction. If the resulting heat is not allowed to dissipate it can cause the cure time of the epoxy to accelerate drastically. This will happen when larger quantities (more than an ounce) are mixed in a cup. The container traps the heat, which speeds the cure, which creates more heat, etc, etc. If the mixture is stirred every minute, it will allow some of this heat to be released. Pouring the epoxy onto a flat surface also allows the heat to disperse and is the best way to get the full working time of the epoxy.

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The first important step is to make a clean cut with a razor blade or hobby knife when you first cut off the tip of the nozzle. When you are done using the bottle, sit it down hard and then squeeze the bottle. Wipe the nozzle clean of any excess CA, then squeeze the bottle again to verify you can hear air blowing through it. If you look straight down at the tip (not while squeezing it!) you should see a black dot. That means the nozzle is clear and you can put the colored cap back on. If a buildup of CA occurs at the tip, many times you can clear it just by using your fingernails to remove the cured CA.

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Heating epoxy will make it thinner, but this also lowers your working time. BSI’s Finish-Cure is thin enough naturally to be brushed on. 91%-99% isopropyl alcohol is the best solvent to add to epoxy for thinning and it is available at most drug stores. Usually adding no more than 10% is enough to sufficiently lower the viscosity of the epoxy. Do not use rubbing alcohol. While it can be used for the cleanup of uncured epoxy, it contains 30% water and has an adverse affect on the curing process. Acetone can be used but is more likely to change the cured properties of the epoxy. Acrylic paint can be used to color epoxy, but some paint stores have tubes of concentrated tints in paste form for acrylic/latex paints that come in many colors. These work best for coloring epoxy.

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BSI’s Super-Gold+, along with all our epoxies, is compatible with all foams. With ELAPOR® and other EPP and EPO foams, however, it is not necessary to use foam safe CA. BSI’s Insta-Cure+ gap filling CA is used by many modelers for these foams with great results. For maximum durability, tests have shown that BSI’s Insta-Flex+ clear rubber toughened gap filling CA creates superior bonds on these foams. For all foam-to-foam bonding, BSI’s Insta-Set accelerator must be used in conjunction with the CA since foams do not have the moisture content that normally initiates the curing of CA. The Insta-Set can be sprayed on one part and the CA applied to the other before bonding, or Insta-Set can be sprayed on a joint after the parts are assembled. Epoxies can be used but they are heavier and produce generally weaker bonds on EPP type foams.

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The resins (the black bottles) of BSI’s epoxies are heavier than the hardeners by a 1.1 to 1 ratio. As long as the epoxies are mixed in equal amounts within a 10% margin of error, there will be no distinguishable difference in the cured characteristics if done at the proper temperature. Since the 1.1 to 1 difference in weight falls within this 10% margin, the epoxies can be mixed with equal volume or equal weight with the same results. Additional hardener should never be intentionally added to “improve” the curing of epoxy. As a general rule, each molecule of resin needs to have a matching molecule of hardener for optimum results. If all the resin molecules already are attached their “partner,” any excess hardener molecules will be left floating in the mix, which will degrade the cured properties of the epoxy.

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For the precise application of Insta-Cure, Insta-Flex and Super-Gold, BSI makes accessories that can be very helpful. Our Extra-Fine Extender Tips #302 slip over the bottle’s nozzle so that thin CA can be applied a drop at a time. BSI’s Teflon® Tubing #305, however, is the best solution for applying thin CA. By cutting back the nozzle a little under a 1/16” to get to a slightly bigger I.D. and cutting the end of the tubing at a 45° angle, it can be inserted into the nozzle about 1/8” and kept there. The CA will always flow back into the bottle, ready for the next application. CA that may build up on the tubing can be easily pulled off. Worst case, 1/8” can be cut off the end of the tubing.

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You can contact BSI directly. Eventually, BSI’s MSDSs will be on our web site, but for now we like the boost to our ego that we get at least every other day when organizations and companies like NASA, Northrop-Grumman, BAE Systems, Wright-Paterson AFB, Sandia Labs, Max Planck Institute, AAI, Siemens, Raytheon and many others contact us about MSDS information. They have all found BSI’s quality and performance matches or surpasses that of the leaders in industrial adhesives. The consistent freshness of BSI’s products is a large factor in this. BSI’s network of hobby shops reports that a least 35% of their adhesives sales go outside of hobby. Word has gotten out that hobby shops have the best adhesives available for many industrial applications at a fraction of the cost.

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BSI’s Super-Gold thin and Super-Gold+ gap filling have developed an international reputation as being the best foam safe CAs. They are also odorless and are the best alternative for modelers who have developed a sensitivity to the fumes that are an irritant emitted by regular CAs (these fumes do not contain anything related to cyanide like some have claimed). Unlike many other foam safe CAs, modelers do not have to sacrifice any significant performance characteristics when they use the Super-Golds on other materials like wood and plastic. Super-Gold thin is not quite as thin as Insta-Cure super thin, but is a direct substitute. Super-Gold+ can be used on clear plastic, like canopies, without producing the fogging that occurs when regular CA fumes settle on a surface. The only disadvantage is their price.

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Yes, Finish-Cure™ is your best choice. It will be the easiest to apply since it is formulated to have a thin consistency so that you can brush it on. Finish-Cure™, along with BSI’s Slow-Cure™, is 100% fuel proof, which makes it ideal for sealing engine and fuel compartments. It penetrates balsa better than other hobby epoxies, making Finish-Cure™ the best choice for applying fiberglass cloth over wood. It is also easy to sand to a smooth finish.

Since it is thin, Finish-Cure™ works very well for laminations and for sheeting foam wings. Once it is applied into a thin layer, it has a working time up to 40 minutes, with full cure in 6-8 hours. Temperatures need to be above 75°F during Finish-Cure’s entire curing time to assure it has the specified characteristics.

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Being located in earthquake country, BSI’s Glue Pros have become experts at this. CA is always the best choice for these types of fixes. If a precious object is broken into two or three pieces, any of our thicker CAs (except IC-2000) can be sparingly applied to one part and then the pieces can be aligned and held tightly together for 15 seconds.

If there are more than three pieces, the object needs to be reassembled without using any adhesive, using small pieces of masking tape to hold everything in place. Once every part is perfectly aligned, any of BSI’s thin CAs can be applied along all the joints. After about 30 seconds, all the joints can be sprayed with Insta-Set and the tape can be removed. A paper towel soaked in Un-Cure will then remove any excess CA from the outside.

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The epoxies that are formulated for hobby use are thermosetting polymers that have varying glass transition temperatures. This is the temperature at which the epoxies will begin to soften, but not necessarily fail. The result of this softening can be seen in our models, and many full size composite aircraft, when an epoxy and cloth finished surface is set out in the sun. The higher heat levels can cause the weave of the cloth to become visible in what was once a perfectly smooth finish.

BSI’s epoxies and CAs are all rated down to -40°F. The upper limit for Quik-Cure epoxy is 140°F, Mid-Cure 165°, Finish-Cure 175° and Slow-Cure 190°. Cyanoacrylates can be used when higher temperature resistance is needed. Regular CAs are good up to 220°F, while BSI’s black IC-2000 is rated at 250°F. One aerospace firm tested Super-Gold+ and found it was stronger after being heated to 270°.

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BSI adhesives are consistently the freshest that consumers can buy. BSI starts with the finest raw materials available, then blends and bottles them here in Atascadero, CA. The adhesives are then sold direct to hobby shops and industrial users. They never sit in warehouses where they can be exposed to adverse storage conditions. It is not uncommon for a California modeler to purchase a bottle of CA from their local hobby retailer that was bottled just the day before. BSI’s specially made bottles and labels help preserve this freshness so that modelers can experience to the full extent the high performance that CAs have to offer.

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Yes, the Finish-Cure can be used to harden the surface of the balsa without the cloth. One advantage of using 3/4 oz. cloth, however, is that you can squeegee away any excess epoxy and end up with a layer of epoxy with a uniform thickness, thereby producing a lighter structure. By just using epoxy over the balsa, you never really know how thick the epoxy is until you sand through it. If you sand through the Finish-Cure down to the balsa, use thin CA to provide the finish for these smaller areas so that I don't have to mix up more epoxy. As long as you sand the CA within 15 minutes, it’s not difficult. Thin CA can also be used to provide a hard, smooth finish on just about any wood surface.

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Thank you. You just did.

About 5% of the population can become sensitized to the fumes created by CA. The fumes are the evaporated form of the CA and can irritate some membranes in the body. The Super-Golds have a higher molecular weight and don’t emit these fumes. The makers of the new movie ‘The Hobbit’ are only allowing the Super-Golds to be used on the film’s set in New Zealand.

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In all our experience, we have never seen a CA failure due to water in model construction. BSI’s Maxi-Cure and IC-Gel are used extensively for bonding fragments of coral to underwater rocks in the aquarium industry. We have a tile roof that had a large tile break in half 12 years ago and Maxi-Cure is still holding it together. Thousands of model boats have been built with CA without failure.

Drug store CAs are a factor in the bad rap that CA has received. They just don’t hold up as well as the industrial grade CA that companies like BSI provide for modelers.

As a general rule for maximum results, CA should not have constant exposure to water until it has cured for 12 hours, although this time period is not always necessary.

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Cool the work pieces that are being joined. I broke a small metal hollow tube and needed to splice it back together by inserting a small steel wire into each piece about 1”. It was in a cramped working space and I knew thin CA would do the job but I needed at least one minute of working time. I put the steel wire and tubing into the freezer. It was really cold when I took it out to assemble. The wire went together perfectly and several minutes later the CA set up.

(CA in bottles that have been kept in a freezer will also bond very slowly until they get to room temperature. Using accelerator on very cold CA can cause the cured adhesive to become much more brittle. Do not use these techniques with epoxies. They will not cure correctly.)

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BSI’s Insta-Set has become the favorite CA accelerator for many dental labs, industries and modelers. It is not flammable, it is foam safe and, since we add a strawberry scent, it smells a little better. Insta-Set takes a few more seconds to cure the CA compared to many others, but that results in one of its primary strengths. Many accelerators create excessive heat that may cause the CA to become very brittle. Insta-Set has the least affect on the strength of CA, and its longer evaporation time (which some feel is its only drawback) actually helps cool the CA during the curing process.

Insta-Set is compatible with all surfaces, even clear plastic. It is also a great cleaner of adhesive tape residue and tree sap on automobiles.

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To give CA the best chance at a long shelf life, the virgin plastic that the bottle are made from must be made as thick as possible so that it provides a good barrier against moisture that can actually creep through plastic. When CA was introduced to the hobby by Satellite City, their bottles were too thin, which contributed to their very short shelf life. If BSI used round bottles with a wall thickness as large as we use for our oval bottles, you could barely squeeze them. We felt it was better to get complaints about the bottles falling over than complaints about the CA not coming out of the bottles or having a shorter shelf life.

Oval bottles also give us the room to add the information in a readable form that is required by constantly increasing worldwide government regulations.

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BSI is signing up more than a dealer a day as hobby shop owners and manufacturers are discovering there can be a major difference between brands of adhesives. BSI makes a larger variety of CAs, ranging from high performance to rubber toughened to odorless, than any other hobby adhesive manufacturer.

Bob Smith adhesives are usually found in your LHS with the shop’s name imprinted on every bottle. As long as you see the BSI code on the back of the bottles, you’ll know you’re purchasing the highest quality adhesives available to modelers.

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If you are good at soldering, it is the best method to use. We have seen, however, many reports of BSI’s IC-2000 being successfully used for applications like this without any failures. IC-2000 is a carbon reinforced and rubber toughened black CA that many have said is the strongest cyanoacrylate on the planet. As a testament to IC-2000’s durability, it is used by golf pro shops to bond the heads onto golf clubs.

BSI’s standard CAs and accelerator, along with IC-2000, are used by Boeing’s Insitu division in the manufacture of their ScanEagle and Integrator, the most numerous small UAVs. Lockheed-Martin and Aerovironment use IC-2000 and Super-Gold+ in their lines of micro-UAVs that are operated by America’s foot soldiers. The U.S. military settles for nothing but the best.

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It sounds like the foam was reacting to the excess heat from the curing process. This is much more likely to occur with the thin Super-Gold when Insta-Set is used on it, so a minimal amount of the spray mist should be applied. Some foams, especially the fine grain blue and white foams, have much lower tolerance to heat, so only the Super-Gold+ should be used on these. Thin can be used on the fine grain foams when it is applied to the surfaces that have been cut with a hot wire. But if you were to sand an edge of that same foam, the thin seems to react with the foam dust and quickly cures, creating excess heat that can melt a lot of foam.

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Be sure to thoroughly clean and dry the canopy, or clear plastic sheet, first. Super-Gold+ works perfect for this application. You can also use Insta-Set to speed the bonding with no affect on the clear plastic.

Insta-Flex flexible thin CA works great on opaque plastic, especially when it’s thin. It is a version of a medical grade CA that produces less heat when curing. Rumor has it that it is also ideal for cuts on fingers. It cures to a flexible consistency, even when accelerated, which also makes Insta-Flex ideal for use with CA hinges since the hinge line will not become brittle. It also has a different, less irritating odor compared to regular CAs.

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With the normal shedding of the outer layers of the skin, cured CA will be gone after 24 hours and a shower. Our Un-Cure or acetone will soften the glue so that it can be removed, but this can be messy and spread it over more areas of the skin. We usually have the glue picked off with our fingernails within three hours.

Our Un-Cure will soften CA so parts can be separated, but we have found just using a razor saw to cut the pieces apart is usually the fastest way to undo a joint. This is also your only option if any of the material is foam, since anything that will soften the CA will also dissolve the foam.

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