If you've spent any time in a hobby shop or scrolling through DIY repair forums, you've almost certainly seen those distinctive bottles of BSI cyanoacrylate sitting on the workbench. Most of us just call it "super glue," but once you move past the tiny tubes you find at the grocery store checkout, you realize there's a whole world of specialized adhesives designed for specific tasks. Bob Smith Industries (the "BSI" in the name) has basically become the gold standard for hobbyists, woodworkers, and even surgeons because they've figured out how to make CA glue that actually behaves the way you want it to.
I remember the first time I moved away from the generic stuff and tried a bottle of BSI. The difference wasn't just in how well it stuck things together—it was about the control. Whether you're trying to fix a chipped ceramic mug or assembling a high-performance RC plane, knowing which bottle to grab makes a huge difference in whether your project looks professional or like a sticky mess.
Why the Color-Coded Bottles Matter
One of the best things about the BSI lineup is that they don't expect you to read the fine print every time you're in the middle of a project. They use a color-coded system that tells you exactly what the viscosity of the glue is. If you're working fast, you just look for the label color.
It sounds like a small detail, but when you have glue drying on your fingers or a delicate part held in place, you don't want to be squinting at a label. Each color represents a different thickness, or "viscosity," and using the wrong one is usually why people end up frustrated with CA glue.
Insta-Cure (The Blue Label)
The blue label is the "Thin" version of BSI cyanoacrylate. This stuff is literally as thin as water. If you aren't careful, it'll run right off your workpiece and onto your lap before you even realize it's out of the bottle.
But that's also its superpower. Because it's so thin, it works through capillary action. You can press two pieces of balsa wood or plastic together, drop a tiny bit of Insta-Cure on the seam, and it will "wick" deep into the joint instantly. It's perfect for tight-fitting parts where there's no gap to fill.
Insta-Cure+ (The Purple Label)
This is the "Medium" viscosity and probably the one people use the most. It's about the thickness of syrup. It doesn't run as fast as the thin stuff, which gives you a few seconds to wiggle a part into the exact right position before it sets.
I find the purple label is the best all-rounder. It fills small gaps, works well on most plastics, and doesn't soak into porous surfaces (like wood) quite as fast as the blue label does. If you're only going to buy one bottle to keep in your junk drawer, this is usually the one.
Maxi-Cure (The Pink Label)
When you have a "whoops" moment and end up with a big gap between two parts, you need the pink label. This is the "Extra Thick" version. It stays exactly where you put it. You can even use it to build up a structural fillet or fill a hole. Because it's so thick, it takes a bit longer to dry on its own, which is actually a blessing if you're trying to align a complex assembly.
The Secret Sauce: Using Accelerators
If you're using BSI cyanoacrylate, you really should be using their "Insta-Set" accelerator too. It's a pump spray that makes the glue cure almost instantly.
Normally, CA glue relies on moisture in the air or on the surface of the material to cure. That's why it sticks your fingers together so fast—your skin is moist. But on a dry piece of plastic, it might take a minute or two to harden. With the accelerator, you can apply the glue, join the parts, and then give it a quick spritz. Boom. It's hard.
A little tip though: don't overdo it. If you soak the joint in accelerator, it can sometimes cause the glue to "bloom," which leaves a white, chalky residue around the joint. Also, if you're using a lot of thick glue, the chemical reaction happens so fast that it actually gets hot. I've seen people get minor burns or melt thin plastic because they sprayed too much accelerator on a big glob of glue. Just a light mist is all you need.
Dealing with Foam and Delicate Plastics
One of the biggest heartbreaks in the RC world is spending forty hours building a foam-core wing and then watching it melt because you used regular super glue. Standard BSI cyanoacrylate is "hot," meaning the solvents in it will eat right through expanded polystyrene (EPS) or Depron foam.
For those situations, BSI makes a "Super-Gold" line. These are foam-safe and don't have that "kick" that melts sensitive materials. They also don't have that strong, eye-stinging odor that regular CA glue has. If you're working in a basement with bad ventilation, or if you're gluing clear plastic parts (like the canopy of a model airplane), the Super-Gold is the way to go because it won't "fog" the clear plastic.
Some Pro-Tips for Better Bonding
I've glued a lot of things to a lot of other things over the years, and I've learned a few tricks to make BSI cyanoacrylate work even better:
- Prep the surface: I know it's tempting to just squeeze the glue on and hope for the best, but a quick wipe with isopropyl alcohol makes a world of difference. Oils from your fingers can prevent the glue from grabbing properly.
- Rough it up: If you're gluing smooth plastic or metal, hit the mating surfaces with a bit of 220-grit sandpaper. That extra "tooth" gives the glue something to bite into.
- The "Baking Soda" Trick: If you're out of thick glue and need to fill a hole, you can drop some thin CA glue in and then sprinkle a little baking soda on it. It turns into a hard, plastic-like filler instantly. It's an old-school hobbyist hack that still works perfectly.
- Don't over-glue: More glue doesn't mean a stronger bond. In fact, CA glue is strongest when the layer is as thin as possible. If you use too much, it just takes forever to dry and ends up being more brittle.
Keeping Your Glue Fresh Longer
There's nothing more annoying than reaching for your bottle of BSI cyanoacrylate only to find the tip is clogged solid or the whole bottle has turned into a hockey puck.
Since CA glue reacts to moisture, the worst place to store it is in a humid environment. Some people swear by keeping their glue in the refrigerator. If you do this, just make sure the cap is on tight and let it come up to room temperature before you open it—otherwise, moisture from the air will condense inside the bottle the second you open it, and you'll ruin the whole batch.
Personally, I just make sure to wipe the nozzle clean with a paper towel before I put the cap back on. BSI bottles are actually pretty good about not clogging compared to the cheap tubes, but if you do get a clog, don't try to poke it with a needle while squeezing the bottle. That's a one-way ticket to getting a face full of glue. Just soak the tip in some acetone or replace it with a fresh one.
Is It Worth the Extra Couple of Dollars?
Honestly, yeah. While you can get a tube of generic super glue for a buck at the dollar store, it's usually hit or miss. BSI cyanoacrylate is consistent. You know exactly how it's going to flow, how fast it's going to set, and how it's going to react to the accelerator.
Whether you're a serious maker or just someone who wants to fix a broken high heel or a loose piece of trim, having the right viscosity for the job saves so much frustration. It turns a "repair" from a stressful event into something that just works. Just remember to keep some debonder (or at least some acetone) nearby, because no matter how careful you are, you're eventually going to glue your fingers together. It's practically a rite of passage.