Adhesives

I'm building the Astrobee D and I'm just wondering what adhesive/mix of adhesives they use for the rocket.

On the instructions,

https://www.allrocketengines.ca/docs/astrobee-aerotech.pdf

it says to use medium viscosity cyanoacrylate cement, but I think something else might make a better bond.

Any ideas?

I'm a huge fan of epoxy. Bill Smith Industries makes epoxy for most every application. I'd look as material compatibility there and make my choice.

I helped build a Leviathan with my club, and we used epoxy for the fins. Came out a bit wobbly, but I guess it might work good.

So you think the best epoxy is the Bob Smith brand?

Edit: You mean Bob Smith?

Bill is Bob's older brother; taught him everything he knows, and eventually sold the business to him after losing his shirt in a poker game outside of Spokane.

Bob Smith epoxies work, and are easy to come by, as they're likely in the local hobby shop. As far as GOOD.... eh. West System is better, and I really like the Aeropoxy, but that starts to get pricey. I've built plenty with Bob Smith's stuff, and it's still flying.



Later!

--Coop

Thanks, I'll find some epoxy in the garage to use.

Or my favorite epoxy US Composites 635 with 3:1 hardner, I use it for everything (I haven't and probably won't build a L3 anytime soon) rocketry related when an epoxy is called for. At 35 dollars a half gallon kit (thats the resin portion is a half gallon, the hardener is included). I also ordered cabosil, microballoons and 1/32" chopped fiber from them to modify the normally near water thin 635, and still came out with shipping for less than $70.

And all of those epoxies are overkill for a midpowered rocket. Granted CA (superglue) isn't the strongest thing in the world, but it's also not the liquid lead that epoxy is. Can CA work on a aerotech kit? I built a mustang 8 years ago with CA. I still fly it. Gonna have to retire it sometime soon as the ejection charges have eaten away most of the wall of the tube. Guess it will give me a reason to build another with CA.
Other then fiberglass rockets, epoxy isn't the adhesive of choice. It's overkill. Research your adhesives and understand what they can do for you..there's different applications for Titebond II vs Titebond III......both of which are in the wood glue family.

That is what I was worrying about, but a stronger epoxy won't hurt my rocket, right? It would help.

Well, it will make it significantly heavy. Gob on enough epoxy for super huge fillets and you can significantly change the CP-CG relationship. If you feel the need for epoxy, use it sparingly. Thicker isn't stronger.

I built my G-Force with CA as recommended in the instructions. That is the only rocket I've ever built with CA and it worked out fine. I've flown it quite a bit now, and I haven't noticed any problems.

ThirstyBarbarian said:

I built my G-Force with CA as recommended in the instructions. That is the only rocket I've ever built with CA and it worked out fine. I've flown it quite a bit now, and I haven't noticed any problems.

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I agree, the AT kits build great with CA. I have 8 flights on my G-force now on everything from an F50 to an H170 and the CA holds together fine.

RocketryBill said:

So you think the best epoxy is the Bob Smith brand?

Edit: You mean Bob Smith?

Click to expand...

Yes Bob Smith. Autocorrect strikes again. I hate the keyboard on this phone.

I haven't found the epoxy to add that significant of a weight to my mid power stuff. But I also don't glob it on. CA has just always been too brittle to last in my experience. I've only ever had good luck if the surfaces match nearly perfectly. But again, that's just my experience with it.

I'll probably use some epoxy on the fins, and leave the rest to CA. Like Barbarian said I don't want to add too much weight.

Epoxy applied thinly - in the joint and for small fillets - doesn't have to add noticeably more weight than wood glue used the same way. It has much longer working life that any CA I've ever encountered, and won't grab like wood glues can. This isn't to say it's always the best choice, but imo is very frequently is.