In this episode the Rocket N00b answers some model rocketry questions – some beginner’s questions commonly asked on online forums, as well as a couple questions sent to him through social media.
“What’s the Best Glue?”
Yes, we know. This question gets asked a LOT online, and some rocketeers get tired of seeing it. But it’s a good sign – it means there are new people entering the hobby all the time. That’s good for us, as it means more people to support our vendors of kits and motors, as well as greater awareness of this safe and awesome hobby.
The long answer is on the show (the N00b does tend to ramble). The short answer: for most model rocketry applications, you want to use white or yellow glue. Brand is pretty unimportant – pick one you like. The bond formed between paper and wood with these glues is stronger than the materials themselves. If a fin breaks off, it’s not the glue that failed – it’s probably that the body tube’s paper has ripped off, or a fin has snapped at the root.
Here’s a video sent to the N00b by Kirk G. showing a strength test of various white and yellow glues.
Obviously the construction technique here is quite different from what you’d be doing when building a model rocket, but it does illustrate the point that these glues are plenty strong.
Here’s the link to the Titebond page showing the differences between Titebond I, II, and III.
And here’s a quick video from Titebond comparing the three glues.
We also talk about epoxy, CA or super glue, plastic cement, glue sticks, and finally, hot glue (DO NOT USE HOT GLUE).
The plastic cement the N00b mentioned (but couldn’t remember the name) was Plastruct Plastic Weld.
“Do Engines/Motors Go Bad?”
A lot of times, people will have rocket motors from a decade ago or more. Many people on the forums ask if they’ll still be good.
The fact is that model rocket motors, whether they are black powder or composite motors, do not have an expiration date. The important thing is how they’re stored. If they’ve gone through a lot of hot and cold temperature cycles over the years, the propellant grains can crack, making them more prone to catastrophic motor failures, or CATOs.
But people have flown 30-40 year old motors with no problems.
Some composite propellants, such as White Lightning or White Thunder propellants, can have some surface oxidation on them, making them harder to light, but that’s about it. Again, temp cycling may be a problem, but if properly stored, they don’t really “go bad.”
If you’re not sure, you can always soak old motors in water and dispose of them, and get new ones. Or, heck, fly ’em. That’s what minimum safe distances are for! (Click here to see the Model Rocket Safety Code.)
“How Do You Fill the Seam Between Two Body Tubes?”
Some kits come with two short body tubes, instead of one long one, and you’re supposed to join them together with a tube coupler. A follower on Instagram asked the Rocket N00b, “How do you fill in the seam so it looks like a single tube?”
It can be done easily. But the first thing to ask yourself is if you actually want to do that. There are two good reasons not to fill in that joint.
The first is if the rocket is to be painted two colors, and the color separation coincides with the length of the body tubes.
Here’s one of the N00b’s favorite Estes rockets, the Cosmic Explorer. The top is black and the bottom white.
If you paint the rocket first, with the top black and bottom white, and only glue the tubes together at the very end, you’ll have a perfect color separation – a straight line, no bleed through of the black paint onto the white – and because of the color difference, you won’t see the seam.
The second reason is you might want to convert the rocket into a payload carrying vehicle. Some kits come with a payload section. Instead of a hollow tube coupler, they come with a balsa bulkhead called a nose block.
But even if there’s just a coupler, you can make your own bulkhead from heavy card stock, balsa, or basswood, add a small loop of Kevlar string, and now you have a payload section. Instead of blowing off the nose cone, the rocket will separate at the coupler during parachute ejection. You can fly your payload (such as an altimeter) in the upper section and keep it safe from ejection gasses.
The Estes U.S. Army Patriot is a perfect kit for this conversion. So is any kit with two tubes.
But if you do want to make one seamless tube out of two, you can use Elmer’s Carpenter’s Wood Filler.
Thin it until you can brush it on with a paint brush, and coat an area around the seam about two inches long. Once it’s dry, sand it smooth. Even if the tubes are a little uneven in their thickness, the wood filler can cover that up. The rocket will be slightly thicker in that spot, if you measure it with a digital caliper, but you won’t see it.
“What Kinds of Cameras Can You Put On a Model Rocket?”
A number of small video cameras can be attached to a model rocket to record the flight. A very popular kind is called an 808 keychain camera. This little “spy camera” looks like a key fob. They’re cheap and compact, and can simply be taped to the side of a rocket with electrical tape.
These little cameras range from very cheap (less than $10) to not so cheap (some cost between $70-90). Quality varies a lot, but even the cheap ones may be good for fun.
Little cameras like this can simply be attached to the side of a rocket with electrical tape.
MateCam seems to be a popular brand among rocketeers. Aside from video quality being on the better end, MateCams have a larger lens assembly. You can take one apart and arrange its guts to fit a special project.
The little cameras the N00b mentioned are called flash drive cameras.
There are a number of kinds of so-called “flash drive cameras,” but the ones referred to here can be found on eBay for less than $9.
Here’s video of the hidden camera payload rocket, the Ceres B booster with ICU2 payload, the design of which came from Mike Westerfield’s book, Make: Rockets: Down-to-Earth Rocket Science.