- All About Bob Smith CA
courtesy of Bob Smith Industries
Safe Use of CA Adhesives
Before using any adhesive, adequate ventilation of your work area needs to be addressed. A window or door should be open and/or a small fan placed to circulate the air over your workbench. When using CA, especially super-thin INSTA-CURE, always loosen the top and then retighten it before carefully cutting off the end of the nozzle. This relieves any pressure that may have built-up inside the bottle that could cause the CA to spurt out. This is definitely an issue when CA is used at higher altitudes. Never have the bottle pointing close to your face while opening it.
CA or CyA?
Readers of model magazines have probably noticed that they are split down the middle on how their editors prefer to abbreviate cyanoacrylate. They use CA or CyA. BSI will always use the proper designation, which is CA. One editor says he uses CyA to avoid confusion with the postal designation for the state of California. Since we are talking chemicals and not states, CyA is the symbol for Cyclosporine A. Case closed.
The manufacturing process that produces plywood can sometimes leave a tiny layer on the outside surfaces that inhibits bonding. Plywood should therefore be lightly sanded before bonding to produce the best results. Lite-ply is the most difficult plywood to bond. It soaks up thin CA like a sponge. Thicker CA's such as MAXI-CURE are what achieve the best results with plywood. Strength tests of such bonds usually result in the plywood delaminating before the glue joint gives way.
BSI’s CA Tops are Clog-Free
Bob Smith Industries’ CA tops are acknowledged to be the best available. To achieve the best clog-free results, modelers should follow some basic procedures. Initially, the top should be loosened and then re-tightened to relieve any pressure inside the bottle. Then the most important step is to use a sharp hobby knife of razor blade to cleanly cut off the tip of the top. A rough edge here invites clogging. Squeezing the upright bottle after use will blow air through the top and assures a clear nozzle. If the top is allowed to touch the surface on which accelerator has been applied, a hardening of the glue at the tip will usually occur. Flexing the tip and using your fingernail to remove the hardened CA usually gets the CA flowing again. If a top is abused to the point it cannot be unclogged, soaking it overnight in acetone will return it to as good as new condition. Of course, we also have replacement tips and tops available here at Sirius Rocketry.
What to use?
has a water-thin viscosity that wicks deep into joints by capillary action and cures in a matter of a few seconds. Surfaces to be bonded must be tight fitting and should be held together while you apply the CA around the edges of the seam. At the moment CAs cure, they give off a vapor that can irritate the nose and eyes, so be prepared. Thin CAs work very well on balsa since they penetrate into the wood and form more than just a surface bond.
is a higher viscosity CA for loose fitting joints in which the adhesive must bridge gaps. Normally, the thicker CA is applied to one surface and then the parts are held tightly together for about 5 to 15 seconds. For large surface areas, including those with close fitting joints such as laminations, INSTA-CURE+ ™ should also be used. To prevent premature curing, don’t spread the glue into a thin film. Lay down a serpentine bead with about 1" separations on one surface, then assemble the parts, letting the pressure spread the CA out.
extra thick CA is the best CA for most plastics, including GE’s Lexan MAXI-CURE™ is the best choice for plastic model assembly. When used with INSTA-SET™, it works better than any putty for modifying or filling voids. It can be carved with a knife or razor blade and sanded and feathered to form a finish indistinguishable from plastic.
bonds fiberglass, hardwood, metal and rubber better than any other hobby adhesive. For gluing to the inside, clothtextured surface of fiberglass, scrape the area to be bonded with a razor blade or coarse sandpaper before using MAXI-CURE™ or any other adhesive. It also is best for bonding the tires for R/C cars.
is a catalyst which acts as an accelerator that allows CAs to quickly cure in thick layers by enhancing the alkaline conditions during polymerization. INSTA-SET™ in a spray bottle is normally used to cure the CA that flows from joints when parts are pressed together. Applying an additional bead of thick CA along a seam and then curing it with INSTA-SET™ significantly enhances a joint’s strength. For difficult to bond materials, INSTA-SET™ can be applied to one surface and CA to the opposite surface. When brought together, they will bond instantly. INSTA-SET™ is formulated with a strawberry scent and activates CA in 6 to 8 seconds without any degrading of the CAs strength, which can occur with many other accelerators. It is compatible with all surfaces, even clear plastic and white foam.
debonder will soften cured CA. If parts are bonded incorrectly or your fingers are stuck together, a few drops of UN-CURE™ will dissolve the CA in about a minute. Apply on bonded skin and roll apart fingers. Once stuck, use acetone to clean off softened CA, then wash off with soap and water.