Epoxy or TB3?

[WiredGoat]

I'm about to start on a LOC Precision IV and was wondering what to use? I have used BS 30min epoxy on a few builds and
Titebond 3 on a couple. Longevity wise what would be the pick? I have no issue using either, just wondering what the
consensus would be. Thanks!

 

[Steve Shannon]

Both would be stronger than the wood and cardboard tubes. Titebond 3 would match the materials better. Pick whichever you enjoy working with better.

 

[mccordmw]

Aliphatic resin glues like Titebond III would be strong enough. I go with those if I can since they're cheaper than epoxy, less toxic, and easier to clean up. That being said, I did use Rocketpoxy on my last scratch built 3" rocket.

 

[heada]

Woodglues like TB3 have some give to them but still retain the bond strength. Epoxy has no give (without additives). Since wood (solid, plywood, paper, etc) does move with humidity and possibly with launches/landings, I'd use wood glue.

-Aaron

 

[Incongruent]

I wanted to post this earlier, but I couldn't find the reference, I have it now.
It's in NAR member guidebook #11, Estes Modeling Secrets by Mike Dorffler.

"Now you can attach the fins. Here we do Titebond. Do not use epoxy. The Titebond will make a better bond because here you want the water of the glue to pull the resin into the wood of the fin and the paper of the tube. Sorry, but epoxies won't do this do this and contrary to popular belief among rocketeers, epoxy is the poorer of choices for attaching [wood] fins [to paper tubes]."

 

[WiredGoat]

I posted this question before tearing open the package and reading the instructions on the LOC IV. One of the very first lines on the instructions is to use epoxy!
However, I think I'll use some Titebond 3 on this one and see how it goes. It does seem logical that there would be better penetration with wood glue vs epoxy.

 

[dhbarr]

I would think it very much depends on which WG & which epoxy? It's essentially just down to viscosity unless I'm missing something.

 

[Incongruent]

I posted this question before tearing open the package and reading the instructions on the LOC IV. One of the very first lines on the instructions is to use epoxy!
However, I think I'll use some Titebond 3 on this one and see how it goes. It does seem logical that there would be better penetration with wood glue vs epoxy.

There's probably advantages to epoxy in high power rocketry that I don't know of. Also, John Coker made a video on building a LOC IV where he uses epoxy, so if you do the same, that'll help.

 

[DavidMcCann]

If you dig around, you can find photos on here of a guy's L3 attempt (which failed). He built a LOC magnum with wood glue and then stuck a long burn M in it. It blew the fins to shreds. The interesting point, is that the glue joints did not fail.

I built a LOC Onyx with cheap 5 minute epoxy. failed ejection on the 6th flight and it drilled itself into the dirt at around 400 MPH. folded in half, but all the fins stayed put.

Epoxy, Wood glue, both are going to work on wood and paper. Don't think about it too much. Personally, I use wood glue now to keep the weight down and because its much, much easier to work with.

 

[billdz]

Wish I had seen this thread earlier. Two days ago I started building an LOC Expediter for my level 1 test. The instructions say use only epoxy so I'm doing so. It's the first time I've ever used epoxy and I don't like it, was just thinking I may not continue with HPR if I have to use this stuff for every build. Glad to hear there is a viable, or perhaps even better, alternative.

 

[Incongruent]

I would think it very much depends on which WG & which epoxy? It's essentially just down to viscosity unless I'm missing something.

My understanding is that the weak points in terms of stress are where the materials attach (the glue to substrate(is that the right word?) joints) and the top layer of whatever the substrate is. (Especially if the layers are more weakly connected, like the layers of paper on a paper tube.) So if you can have the adhesive be stronger than the base material, then the adhesive won't break from stress, but the bonds might if the adhesive isn't compatible with the base materials. (Think wood glue on plastic.) If the materials are bonded well and the adhesive is of sufficient strength, then the base material is stressed much more on the bonded surface layer to underlying layer bonds, which can also break, which is why in paper and wood rocket, non TTW accidents, there's the fin and the fillet and a fuzzy layer of paper underneath that snaps off. So the glue soaked far enough to get the top layer of wood but not through the entire tube. Except maybe CA or really low viscosity glues (I assume this is what you mean), the chances of soaking very deep are really low unless you have a physics violator. Unfortunately, low viscosity glues don't have much bulk and that leaves the adhesive bond as the weak point, and if you want to make a fillet you have to bond a glue to the other glue. This Wikipedia page has some info of the different ways failure can happen: https://en.m.wikipedia.org/wiki/Adhesive#Failure

TTW fins spread out the stress so that the adherends don't break as easily, as do fillets.

As for shock breaking, if the adhesive is too brittle and can't absorb enough of the shock, it'll break, as with the other materials. If the material is strong enough not to break, it'll transfer the shock to the rest of the rocket.

As usual, I try to explain something I thought I understood and end up more confused than ever. Here's to some one else will come along and enlightening us...

 

[T-Rex]

I only use epoxy when fiberglass is involved. Everything else gets wood glue. The current bottle says Gorilla, but I have used a lot of Titebond II.

 

[Nytrunner]

Wish I had seen this thread earlier. Two days ago I started building an LOC Expediter for my level 1 test. The instructions say use only epoxy so I'm doing so. It's the first time I've ever used epoxy and I don't like it, was just thinking I may not continue with HPR if I have to use this stuff for every build. Glad to hear there is a viable, or perhaps even better, alternative.

What epoxy are you using? Some can be easier for beginners than others.

I had the advantage of using epoxy for ~3 years before my L1 so I was quite comfortable with how to use it.

 

[Flyfalcons]

The NAR high power certification checklist says that epoxy is preferred for bonding fins.

 

[billdz]

"What epoxy are you using? Some can be easier for beginners than others."
I have Great Planes 30 Minute Pro epoxy. I can see how someone could get used to it with some practice. It was a bit scary at the start, all the warnings -- wear gloves, wear a respirator, wear long sleeves, don't let the glue touch you, watch out for allergies, etc. I've been working outside, biggest problem so far has been spills, getting epoxy on things that shouldn't have any. Not much fun but I'll at least get this rocket built. There's no pre-mixed version with an easy applicator?

 

[Nytrunner]

"What epoxy are you using? Some can be easier for beginners than others."
I have Great Planes 30 Minute Pro epoxy. I can see how someone could get used to it with some practice. It was a bit scary at the start, all the warnings -- wear gloves, wear a respirator, wear long sleeves, don't let the glue touch you, watch out for allergies, etc. I've been working outside, biggest problem so far has been spills, getting epoxy on things that shouldn't have any. Not much fun but I'll at least get this rocket built. There's no pre-mixed version with an easy applicator?

The longer cure stuff (30 min and +) may need some preparation beforehand to contain the mess. Like Tape dams. You'll definitely want to keep the rocket still while working on it. If its stable and in the right position, you can either pour directly on the adhesion site or hold your pot real close and use an "applicator" (usually a balsa scrap for me).

I got away with using the 5 minute Loctite Heavy-duty for my L1 on a Madcow cardboard rocket. Just means I mix smaller amounts and apply it precisely where I need it. I'm fond of the 2-part syringes for 1-1 mix ratios. That way a squeeze portions out exactly how much you need. There are small syringes with mixing nozzles, but after you use them once they're shot, and there's always wastage left in them. (that being said, some people really like the mixing nozzles)

I kind of chuckled when you said "pre-mixed". Pre mixed epoxy is usually a plastic brick .

 

[WiredGoat]

I don't get too concerned about all the PPE equipment, gloves or respirator. If I get it on my hands I just wash it off asap and continue on with what I'm doing.
I do use foam disposable dinner plates to mix on, and then use bamboo skewers (already had 200 in the kitchen) to apply with. The skewers are about 14" long, so it helps
applying epoxy deep into a body tube if needed. I typically use Bob Smith 30 minute epoxy as the hobby store in town carries it already.

 

[Flyfalcons]

You can get epoxy in a tube that dispenses both parts. I have one and have never used it. I just use a mixing cup and craft stick. After the epoxy cures, it can usually be removed from the mixing cup. Epoxy is more work than wood glue or CA but it's an essential ingredient to high power rocketry.

 

[DavidMcCann]

The NAR high power certification checklist says that epoxy is preferred for bonding fins.

protip: don't believe everything you read..... oh no, you're reading this... don't believe! don't believe!!!!!!!!!

 

[Incongruent]

I wonder if you put the two parts of the epoxy (preferrably a thicker kind) in plastic bag and squeezed it to mix then cut a hole (like icing cakes) whether that could be used as a dispenser. Just a thought.

 

[rharshberger]

I will concur with your statement on this David, most anytime a wood to paper/wood bond is being made wood glue is more than sufficient and is stronger than the materials being bonded. One of the advantages of wood glue for wood and paper rockets is weight, epoxy is heavier by volume than wood glue. Depending on how I am feeling is whether or not I use epoxy for fillets on a paper and wood rocket. It also can come down to using what an individual prefers epoxy or TBI/II/II etc, use the one best suited to the materials you are working with OR the effect you hope to achieve (Epoxy will build bigger fillets faster than TB TMTG for example).

And yes,Incongruent it will work (bag mixing and dispensing), but with a bit of practice really isn't necessary.

 

[DavidMcCann]

I don't get too concerned about all the PPE equipment, gloves or respirator. If I get it on my hands I just wash it off asap and continue on with what I'm doing.

just gonna toss it out there that this is the worst advice I've read on this forum. Especially with the commonly available 1:1 epoxy syringes down at wal mart and autozone.

At least walk walk over to the painting section and get a pack of nitrile gloves for $5.

 

[samb]

I don't get too concerned about all the PPE equipment, gloves or respirator. If I get it on my hands I just wash it off asap and continue on with what I'm doing.
...

just gonna toss it out there that this is the worst advice I've read on this forum. Especially with the commonly available 1:1 epoxy syringes down at wal mart and autozone.

At least walk walk over to the painting section and get a pack of nitrile gloves for $5.

A big plus one on David's comment. Maybe exposure wont affect you now. Maybe it wont affect you 10 years from now. That's what I thought 10 years ago. I don't use it often anymore. Sometimes the odor doesn't close me up. Sometimes. Sometimes I don't get the skin crawling heeby geebies. Sometimes.


One thing about wood glue vs. epoxy. Every wood glue instruction I've seen mentions two things: Clamping pressure for best adhesion and no gaps in the pieces to be joined. This becomes more important for high power builds.

 

[Incongruent]

I was reading about epoxy and came across this:

"Don’t use barrier creams with epoxies.Barrier creams, or “invisible gloves,”are not recommended for many kindsof epoxy work. Contact with abrasivematerials can break the seal of thebarrier cream. Also, reapplying thecream in the work area may seal thechemicals to the skin."

It seems to be about only relying on barrier creams rather than using it as a second line of defense, though.

 

[WiredGoat]

just gonna toss it out there that this is the worst advice I've read on this forum. Especially with the commonly available 1:1 epoxy syringes down at wal mart and autozone.

At least walk walk over to the painting section and get a pack of nitrile gloves for $5.

What I said wasn't advice. I've used epoxy for a few years now, and I seldom get it on me. Some people may feel the need for PPE and that's fine. But I'm not going to panic if I come in contact with a little.

 

[Incongruent]

What I said wasn't advice. I've used epoxy for a few years now, and I seldom get it on me. Some people may feel the need for PPE and that's fine. But I'm not going to panic if I come in contact with a little.

To each their own, I suppose. But didn't everyone say that until they became hypersensitive?

Now what if I told you that epoxy is actually Miley Cyrus music? Do you recant?

 

[markkoelsch]

What I said wasn't advice. I've used epoxy for a few years now, and I seldom get it on me. Some people may feel the need for PPE and that's fine. But I'm not going to panic if I come in contact with a little.

You forgot one thing- you can also become sensitized to the fumes.

Wearing nitrile gloves makes sense. If doing epoxy work that will expose you to fumes can largely be mitigated by a respirator with cartridges rated for organic vapors.

 

[billdz]

What about doing the epoxy work outside? Does that limit the fumes to a safe level?

And how much epoxy is used to build a typical HPR level 1 rocket? I'm about finished with the gluing and I've used about half of the 9 oz bottles on my LOC Expediter and the MMA-3 adapter.

 

[Flyfalcons]

I've found the fumes on Bob Smith 30-minute to be nearly nonexistant.

 

[Steve Shannon]

Everyone who works with any adhesive should request and read the MSDS for the adhesive. Some epoxies do not require any kind of respirator and the MSDS will say so. All that I have read recommend nitrile or poly gloves. Also, the MSDS will tell you how to clean it off your skin without making things far worse. For instance, wiping epoxy from your skin with a volatile solvent, such as acetone or alcohol will drive epoxy into your system. That's bad. Soap and water is usually recommended.


Steve Shannon