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tg08

tg08

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Hey, for a little information, I'm working on a level 1/hopefully level 2 rocket, and wanted to learn a little more about adhesives on the high powered rockets. I know I should use JB weld for high temperatures like the motor retainer ring, but what would you recommend for general construction like couplers and centering rings? My biggest question, what about for the fin fillets? I was thinking Aeropoxy ES6209, or should I use a laminating epoxy instead? Finally, what do you use to create fillets. I currently use tongue depressors, but they don't give very much depth to the fillet if you understand what I'm saying. Thanks a lot.
 
For most builds - a cheap 5-min will work. I only use high-grade epoxies on laminating fiberglass or motor retainers.
 
You will get a lot of opinions... I used to use a wide range depending on the specific application, ProLine, RocketPoxy, JB weld, West System, 30 min, and 5 min, etc and certainly bought into the "must have the right tool for the job" approach. Over the years, I stopped worrying about using a "specific epoxy" have moved to using a single epoxy plus additives, namely West System 105 Resin and adding high density filler, colloidal silica, and/or milled carbon fiber to alter the properties for the given application. This cut down on cost, dealing with supply shortages, and confusion. I do still use JB Weld for motor retainers (necessary? probably not as the outside of the motor case really doesn't get that hot).

After learning about thixotropic epoxies and practicing, that's all I'll use for fillets now. You can either buy a thixotropic epoxy or create one with laminating epoxy plus colloidal silica (and high density filler if needed). For fillet shaping, cheap fondant shaping tools from Amazon work great. I also 3d print specific radius tools for larger builds. Definitely practice on scrap materials until you figure out how to mix a consistency that works for you. Many talk about "ketchup, manyaise, and peanut butter" consistency and I find that doesn't actually help me.

Having said all of this, you can certainly build an L1 and L2 cardboard/plywood kit using wood glue and 5 min and it will work. 5 min does turn brittle over time though.
 
Glue threads are always such fun!

For the wood/cardboard rockets that much of the hobby flies, wood glue, epoxy of whatever flavor - they're all fine, provided you follow instructions.

As you start pushing things harder, that can shift.

Just understand the limits of the adhesives you're using, and know if/when you need to change.

-Kevin
 
Well... because you know these are fun.

Ignore everything that has a high price and either go with some good wood glue, or some cheap Bob Smith or equivalent 15 minute epoxy. JB weld if you really want with the fin root and motor retainer. :)

Otherwise go build.
 
SkyFire said:
Hysol 9462 - it's thixotropic (doesn't flow) and super strong.
It's all I use.
Have been using it on giant scale RC airplane firewalls for years, due to it's strength.
View attachment 611767
Click to expand...
I use this as well. Expensive but strong and worth it. With the precision mixing tip there's not a lot of waste or mess so it goes farther. It's used nearly everywhere for higher performance rockets, and on fillets for most (because it's just so easy to use being thixotropic).

Aeropoxy for other things, and I use the fondant tools (almost exclusively the biggest one) referenced earlier. Wipe them down with isopropyl before each pull and they stay clean.

JB on high heat parts, and BSI stuff here and there when I need a quick solution for something not critical (or for low power).
 
Has anyone found an epoxy they would not actually recommend?

I've been using Total Boat High Performance/Slow Hardener for coupler tubes, centering rings, and on the motor tube because it flows well and doesn't go up in smoke when using a lot of it.
JB weld for the aeropack retainers
BSI for eye bolts, u-bolts, 1010 button screws
 
Stay away from:

Don't bother with any vinylester glues. They are intended for high volume production over molds. Difficult to get the ratios right, finicky about temperature.

Also, I never use anything that cures in less than 5 minutes. It's just brittle.
 
Bob Smith Industries 30 minute epoxy is my go-to epoxy. It's relatively cheap and holds up well. I mix it with microbaloons to make exterior fillets. I will likely change to Rocket Epoxy when I build a bird I plan to fly on a K motors or larger, and it becomes available again.

I also use JB Weld for fastening Aeropack retainers, securing rail button weld nuts in the airframe, and as a locking mechanism for the retaining nuts on eye bolts.
 
Rob Campbell said:
Bob Smith Industries 30 minute epoxy is my go-to epoxy. It's relatively cheap and holds up well. I mix it with microbaloons to make exterior fillets. I will likely change to Rocket Epoxy when I build a bird I plan to fly on a K motors or larger, and it becomes available again.

I also use JB Weld for fastening Aeropack retainers, securing rail button weld nuts in the airframe, and as a locking mechanism for the retaining nuts on eye bolts.
Click to expand...
Bob Smith is a great option.. I love the stuff.
 
I'm personally a System 3 man, and try to use the right tool for the job. I like the way their products work, so I stick with them. Like a few other people have said, unless you're running extreme flights (say >Mach 2) it probably doesn't matter much. The only epoxy I don't recommend is stuff that isn't suited to the task. Like use a thin, longer-curing epoxy for laminating carbon or glass instead of a thick resin. FWIW, here's my choices, all System 3 unless otherwise noted:

Laminating: Silvertip (it sheds bubbles off the surface better than anything else I've used)
Structural gluing: T-88 or Silvertip filled with wood flour
Tacking fins in place: Any 5-minute epoxy
Fillets: Silvertip filled with wood flour for strength, external fillets get a thin skim of Silvertip filled with microballoons to make sanding easier. My next rocket will use GelMagic since I've just gotten a tube of that.
 
-Slick-Ice said:
Has anyone found an epoxy they would not actually recommend?
Click to expand...
Yes ---- BSI.

It's way too brittle. It's the only epoxy that I've had fail.

I had a fin break off of a rocket that was attached with BSI 15 minute. The epoxy was still adhered to the fin and body, but it was the epoxy itself that broke. Field repair: As the 2 pieces fit together precisely, I just ran some thin CA into the crack.

JB 5 minute cures very flexible. The left-overs on my mixing pad flex like vinyl when cured.

I've done very un-scientific tests on left over bits of epoxy about 1/8" thick. BSI breaks easily with just a light snap. Rocketpoxy is very hard, much more difficult to break. T-88 is also very hard. And JB 5 minute you can fold it in half without it breaking.

When bonding something like a coupler, all this is moot. But for fin fillets, I don't want something that gives with just a light snap - or a sub-optimal landing!

Hans.
 
I've only used the slow cure BSI. It cures pretty well but I have never used it on fiberglass.
 
Glenmarc have unfortunately been MIA for a little bit but I've only every used Rocketpoxy. How does it stack up in the glue hierarchy? It has always felt like the perfect viscosity and curing characteristics to make beautiful fin fillets. I'm interested in West Systems 105/206. How do you utilize it in your builds?
 
I have decades-old rockets built with BSI 20 and 30 minute that are still holding up well. This one was built in 1996.

eIMG_8799.jpg

It's presently undergoing airframe repairs and repaint. Using a palm sander, I gave up sanding these fillets any further.

BSI 30 minute survived a core sample on a fiberglass rocket of mine, too. Most of the SMT devices sheared off the altimeter PCB and the chute melted together in spots from the extreme impact. The BSI joints held up fine and the rocket flew again with no repairs.
 
Find someone whose rocket is everything you aspire to and become their friend.

For fillets....
Rule 1 : put masking tape anywhere you do not want epoxy.
Rule 2 : Don't forget rule 1
Rule 3 : Don't forget rule 2
Rule 3a : Only do 2 fillets as below at a time until all are done. When this has set do the next 2. This photo is from jcrocket.com as part of the tip-to-tip fin can method. @JohnCoker here's no masking tape because John is expert level :) and will be sanding this all down before covering it all in expensive carbon fiber......
Rule 4 : Watch the John Coker videos.

1698901061337.png
 
OzHybrid said:
Find someone whose rocket is everything you aspire to and become their friend.

For fillets....
Rule 1 : put masking tape anywhere you do not want epoxy.
Rule 2 : Don't forget rule 1
Rule 3 : Don't forget rule 2
Rule 3a : Only do 2 fillets as below at a time until all are done. When this has set do the next 2. This photo is from jcrocket.com as part of the tip-to-tip fin can method. @JohnCoker here's no masking tape because John is expert level :) and will be sanding this all down before covering it all in expensive carbon fiber......
Rule 4 : Watch the John Coker videos.

View attachment 613121
Click to expand...

One other point. Have gloves on and a roll of paper towels or a pile of rags and some Brakleen/acetone available to touch up mistakes, drips, or runs.

My epoxy hygiene improved dramatically when I realized sometimes you have to just wipe it off.

Not talking about smoothing when it is close to cured, just for drips and issues.
 
Where do you purchase Aeropack Epoxy cannot find it anywhere in PA.? or online?

PR 2032/3660

Thanks,

Sterk03
 

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