Best Adhesive to Buy in Bulk for HPR?

[wyattjohnson35]

I need to buy a large amount of adhesives for my 12 person rocketry team. We figured out we'd need to buy 24 JB Weld packs or Gorilla epoxies at the Home Depot which can get pricey, so I was wondering what's the best adhesive to use with HPR that you can buy bulk on the cheap?

 

[Zeus-cat]

How much epoxy are using on a rocket? 24 packs of JB Weld seems like a lot to me. I only use the high temp JB Weld for attaching motor retainers. I just use regular two part epoxy for all other applications.

How many rockets are you building? I assume they will be L1 rockets. Is there a local club you could have mentor you? Finally, where are you so we can steer you to a club or person to help mentor you.

 

[Andrew_ASC]

I would contact Madcow or Wildman rocketry vendors. They could give you an educational discount on whatever you need in bulk. The adhesive depends on what materials you are using and what application in rocketry. Like how fast or thermally hot the rockets get. You will get tons of epoxy opinions on this forum.

 

[wyattjohnson35]

How much epoxy are using on a rocket? 24 packs of JB Weld seems like a lot to me. I only use the high temp JB Weld for attaching motor retainers. I just use regular two part epoxy for all other applications.

How many rockets are you building? Is there a local club you could have mentor you? So, where are you?

We'll be building 12-15 rockets this year. New members start with mid-power, experienced can go ahead and start on high-power. I got the 2-JB weld-per-rocket metric from my friend who just finished a 4" LOC Goblin and used that much, he said he was pretty liberal with the glue. We're based in Atlanta, and I'm also a member of Southern Area Rocketry. I'm trying to be more involved with their club to see if we can get some mentors, but I'd have to find people in Atlanta rather than where the club is located which is Alpharetta, GA (about 1hr with no traffic from ATL)

 

[rharshberger]

Cheap and Easy to use are usually two different things. The easy to use, quick setting epoxies usually are more money per ounce than the stronger, long cure time epoxies. US Composites 150 (sold in several pot life durations) is one of the better structural or bonding epoxies but it requires adding fillers like milled fiberglass fibre to thicken enough to be easily workable and it requires a long cure time ( at least 12 hours), they upside is its reasonably inexpensive per ounce. Bob Smith Industries aka BSI which is usually sold at most hobby shops in the 5-15-20-30 minute varieties in bottles from just a couple of ounces to like 8oz is more expensive but easier to work with due to the reduced fixture time and quicker set times (full cure time is still 24hrs though). The 20 minute BSI aka Finishing Resin is for fiberglass laminating though it can be used for part to part bonding with care. Rocketpoxy might be a good choice as it already has fillers in it and is the proper consistency, however the cure and set time is longer than the BSI, but shorter (I think) than the US Composites. Most epoxies need fillers like cabosil, phenolic microballoons, or milled fiber (carbon or FG) to thicken the epoxy for filleting, some like JB Weld, and Rocketpoxy already have fillers added, and they are recommended not to be modified.

Edit: if the rocket is cardboard and wood very little epoxy is needed as Titebond is stronger than the materials being joined, Titebond Quick and Thick can be used to build fillets.

 

[Andrew_ASC]

I think he could bulk buy Rocketpoxy G5000 cheaply from a rocketry vendor. It has a datasheet. There is a moderate tensile strength. It takes low supersonic flight fine. It works on fiberglass and Carbon fiber builds. You can add some heat to it and reduce the cure time slightly. It has consistency of peanut butter and is easy to mix.

I’ve used Cotronics and Rocketpoxy on university projects and an L-1 build. I chose mainly Rocketpoxy for my L-1 by economic reasons. Our materials were fiberglass and CF. BSI slow cure also works on oddball plastics to shock cord that Rocketpoxy won’t bond well.
I would not recommend Cotronics for your application because it’s so expensive but it’s higher performing for higher temperatures at high Mach numbers. The other people here know more than I do.

 

[boatgeek]

You're not going super high or fast, so you don't need the most expensive epoxies. I would buy the following:

A couple of smallish sets (~8 oz total) of 5-minute epoxy (helpful for touchup or tacking stuff in place
A medium size set (1-1.5 quarts total) of a medium speed (~40 minutes) West Systems or another marine laminating epoxy plus some fillers (fillets and general gluing)
One or two small tube sets of JB Weld if you're going to use Aeropack retainers

JB Weld is kind of expensive per ounce and is hard to sand smooth. For fillers, I'd use mostly structural fillet material (wood flour, West's structural filler, etc.). That gives you a thick structural epoxy that won't sag. Use that for fillets and maybe gluing in centering rings. Structural material is harder to sand smooth, so I like to get them smooth-ish and then go over with a thinner mix of microballons for final sanding.

There are lots of other good options as well; other people will tell you about them.

 

[daveyfire]

I use this for my general-purpose adhesive:

https://www.ptm-w.com/aeropoxy/AEROPOXY Product Bulletins/AEROPOXY ES6279 Bulletin.pdf

It's almond-butter consistency, perfect for general bonding and fillets, and it's lower modulus than a filled laminating resin, so fillets won't crack on hard landings. A quart-size kit (= 2 quarts, mixed) lasts me a couple of years, and I build a lot of rockets. I get it from Aircraft Spruce:

https://www.aircraftspruce.com/catalog/wppages/es6279adh.php

 

[Andrew_ASC]

Masking tape also works for friction fitting motor casings to airframes old school way. Just roll the tape around the casing end near nozzle until you can’t pull the motor out. It’ll require a stick, hammer, or broom to bash out the old motor post flight. You’ll want masking or 3M tape to make fillets cleaner anyways. There are many forms of motor retention. If Aeropac retainers aren’t in budget, good old masking tape works, but only when real snug.

If the friction fit isn’t snug enough there’s a chance you lose a casing and an L-1 attempt fails.

 

[DavidMcCann]

Rocketpoxy, Aeropoxy ES6209, West Systems are all good sets. West should be available locally if you have any know of body of water nearby you. Being able to run out and grab more in a pinch is a nice benefit.

Personally, I use Aeropoxy ES6209 for most building, and proline 4500 for fillets. Rocketpoxy I've used for both, so if you want a single use solution, thats the way to go.

 

[markkoelsch]

I use this for my general-purpose adhesive:

https://www.ptm-w.com/aeropoxy/AEROPOXY Product Bulletins/AEROPOXY ES6279 Bulletin.pdf

It's almond-butter consistency, perfect for general bonding and fillets, and it's lower modulus than a filled laminating resin, so fillets won't crack on hard landings. A quart-size kit (= 2 quarts, mixed) lasts me a couple of years, and I build a lot of rockets. I get it from Aircraft Spruce:

https://www.aircraftspruce.com/catalog/wppages/es6279adh.php

I very strongly agree with this recommendation. This stuff is great.

 

[LOC]

As stated above. I don't think you'll need any obnoxious bonding agents. US composites 150 is an excellent choice for what you're doing. It may take a bit longer to cure, but it will be much stronger than any "quick cure" alternative. It's our primary adhesive in house, and we've dropped 50# rockets in form 800' + with zero damage.... Not that we're proud of that! =) It should handle anything you're going to throw at it... for a fraction of the cost. But please DO USE a gram scale for accurate measuring.

 

[Eric]

I like BSI 30 minute for tacking. Rocketpoxy for fillets, but recently tried some System Three T-88. It was very affordable on Amazon. It did have a very slow cure time iirc 6-8 hours? But its very strong.

https://www.amazon.com/gp/product/B005H1PLOM/?tag=skimlinks_replacement-20

I bought the Quart set and did all the 9 rockets MMT's, fin tacking and internal fillets. And still had 20% of the kit left. So for the price, it built a lot.

 

[Andrew_ASC]

As far as fall tests go, not proud of it, had one flight with rocketpoxy G5000 survive approx fall 5,400ft into two yard depth grass, 2.34 lb body tube, no damage to fiberglass airframe or fins after cord snap. Nosecone chillingly stuck eight inches into mud with a thud from a pound counterweight in it for stability. Another was roughly 2,500ft body tube fall to hard clay with only two of eight fins slightly lose from fins directly hitting clay which were repaired that day in a hotel room with same epoxy and flown next day from using too short of shock cord. Any of these epoxies these guys and gals list are excellent choices. I was having certification issues recovery issues with a nose heavy scale rocket snapping shock cords and shearing mount points from bad techniques.

You can use a hairdryer on rocketpoxy to about 120F and shorten it’s cure time if needed. So I fall tested rocketpoxy for yah with my craptastic L-1 attempts.

 

[Flyfalcons]

You can build a lot of rockets with a 9oz set of Bob Smith epoxy.

https://www.hobbytown.com/slowcure-30-minute-epoxy-9oz-by-bob-smith-industries-bsi206/p37086

The 30-minute epoxy is good for bonding and fillets, odor is very light, and a simple mix at 1:1 ratio. All of my mid and high power rockets except for my Drago 4XL were constructed with this epoxy. I have found the 30-minute mix to be much less brittle than the 15-minute mix.

 

[Andrew_ASC]

I’ve found BSI 30 minute slow cure to be tacky for up to 24 hours, even after the eight hour cure time. I don’t know if anyone else has had that happen? Maybe it’s a southern humidity thing. It’s good stuff once it’s hard though.

Hobbylobby generally carries it.

 

[OverTheTop]

I like West Systems 105/206. If you want something a bit quicker you could go for a medium or fast hardener.

 

[Andrew_ASC]

Do you have to add anything to the West Systems 105/206?

 

[Eric]

Do you have to add anything to the West Systems 105/206?

I also use West sometimes. The 105/206 works good in my climate. I have the colloidal silica 406 if I need to thicken it up.

But I think it was over $140 for a gallon size with pumps.

 

[OverTheTop]

Forego the pumps and just mix by mass.

 

[rharshberger]

Here is an epoxy comparisons thread I did a while back, included are all the listed products and their data sheets. For most rocketry applications all the normally used epoxies have pretty similar properties, it just comes down to cost really. Some like Aeropoxy, some like West, some US Composites, Rocketpoxy, Proline, etc, they all do the job. The real difference is when you start talking projects that push the limits now you really have to start picking and choosing epoxy adhesives carefully, and the cost of them goes up, that includes Cotronics and Hysol products (great products but expensive, and have special handling/curing requirements).

I need to fix the table as the new forum software seems to have broken its but the data sheets are there.

https://www.rocketryforum.com/threa...nd-technical-data-sheets.138953/#post-1668062

 

[SteveThatcher]

I need to buy a large amount of adhesives for my 12 person rocketry team. We figured out we'd need to buy 24 JB Weld packs or Gorilla epoxies at the Home Depot which can get pricey, so I was wondering what's the best adhesive to use with HPR that you can buy bulk on the cheap?

JB Weld does come in a 10oz package. Amazon has them for a bit under $15, but do a search. I found a paint place online (www.thehardwarecity.com - I have no experience with them though) that had them for $10.39. Besides the JB Weld that I used for motor retainers, my epoxy of choice is West Systems and additives they make.

 

[OverTheTop]

Do you have to add anything to the West Systems 105/206?

The only time I add anything to the mix is when I am doing fillets and I add microballoons (Q-Cell) to the mix to thicken it up. It also makes it easier to sand .

Remember though that the microballoons will reduce the performance of the cured epoxy.

 

[SteveThatcher]

The only time I add anything to the mix is when I am doing fillets and I add microballoons (Q-Cell) to the mix to thicken it up. It also makes it easier to sand .

Remember though that the microballoons will reduce the performance of the cured epoxy.

I use the colloidal silica adhesive with West Systems. I add just enough to thicken for whatever purpose that batch is for. Without a little something added, I find it too runny and easier to crack. I also use micro balloons for dressing up of fillets because, as you said, it makes it more sandable.

 

[markkoelsch]

I use the colloidal silica adhesive with West Systems. I add just enough to thicken for whatever purpose that batch is for. Without a little something added, I find it too runny and easier to crack. I also use micro balloons for dressing up of fillets because, as you said, it makes it more sandable.

You should try chopped carbon fiber or fiberglass. Maybe 1/8” or 1/4” long. Toughens the epoxy up nicely.

 

[cerving]

BSI epoxy really isn't that good for HPR, it doesn't have the strength of the more expensive ones like RocketPoxy or West Systems. If you need a lot of it, West comes in gallon pump bottles. All epoxys have a shelf life, so you don't want to buy much more than you're actually going to use, or you'll end up throwing a lot away. Hobby/hardware store epoxys are rarely marked with an expiration date, but the structural ones always are.

 

[SteveThatcher]

BSI epoxy really isn't that good for HPR, it doesn't have the strength of the more expensive ones like RocketPoxy or West Systems. If you need a lot of it, West comes in gallon pump bottles. All epoxys have a shelf life, so you don't want to buy much more than you're actually going to use, or you'll end up throwing a lot away. Hobby/hardware store epoxys are rarely marked with an expiration date, but the structural ones always are.

I am not a fan of BSI. As for not being good for HPR, that is relative depending on what type of projects you are building. I would not use anything but West Systems for a L3 for example because of weight. It also depends on what stress you intend to fly the rocket under (aka - mach fever for example ). I haven't used RocketPoxy, but the price was a turnoff for me. I can make my own with the West Systems that works for me, so I didn't see a need for another epoxy.

 

[Bat-mite]

BSI is fine for cardboard and various phenolics, but I would not use it on fiberglass or carbon fiber.

 

[smugglervt]

I like BSI for attaching CRs in cardboard MMT and tubes because it doesn't grab as quickly as tightbond and gives me time to adjust if needed. I've used it on fiberglass rockets but found that I had a couple of rockets where the fin fillets cracked or separated on some energetic landings. I now use Rocketpoxy for my fiberglass builds and haven't had any further issues with cracked fillets.

 

[prfesser]

Most epoxies are adequate for HPR as they are stronger than the items to be glued, when the surfaces are properly prepared. Some brands appear to be more tolerant of less-than-excellent surface prep. With that being said, I purchased a gallon of el-cheapo US Composites epoxy and enough slow hardener and fast hardener to cure a half-gallon each. For a thicker mixture, fumed silica is most effective but others such as microballoons, alumina (aluminum oxide) or even talc (real talcum powder, not the cornstarch variety) work. With these materials at hand I can laminate, assemble, fill, fillet, work slowly or quickly, whatever.

I'll also admit to buying a clear epoxy kit from eBay. A gallon of rather thick resin and a half-gallon of hardener ran about $70. No good for lamination, but it's fine for building stuff that isn't going mach, and the wife can use it for embedding her polymer-clay objects.

I've used epoxy that's at least five years old with no issues. Keep it tightly capped. And gloves are never a bad idea. I plan to live forever or die in the attempt.

Best -- Terry
PS: if you don't want to wear an entire glove for a small job, cut the fingers off of a glove and put these "finger cots" on the fingers to be protected.