# jb weld ?

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#### Bxtreme

##### Active Member
i wanted to see some opinions on using jb weld throughout my entire rocket.
i am building a pml x calibur kit to use for level 1 cert.

and i had planned on using jb weld to attach the fins and a aero pack retainer.
i also was going to use it on the centering rings for the mmt and i used it to attach the body tube coupler and the bulkpplate for the piston.
any pros or cons on this ?
i've been reading about all these different epoxies that can be used but in my opinion jb weld would work considering the heat in all areas of the rocket.
is it heavier than most epoxies because i;ve notice most tend only to use it to attach a retainer.
thanks looking forward to your responses

#### MarkII

##### Well-Known Member
Gee, I don't know; I like JB Weld, but I suspect that it would be total overkill to use it as the sole adhesive for a rocket. In rocketry, JB Weld is valued for its tolerance for high heat. The stuff is not easy to mix up, though (it is very stiff) and you don't get all that much from the standard blister pack tubes. Using it throughout the rocket would get awfully expensive. One thing that you have to watch out for is the temptation to overbuild your first high power rocket. H and I motors are classified as high power (appropriately so), but they are not hugely more powerful than mid-power motors. You don't need to build a tank.

MarkII

#### blackjack2564

##### Crazy Jim's Gone Banana's
TRF Supporter
......ditto what Mark said.

It's great for retainers. Hard to work with for general use. Heat should not be an issue on a L-1 rocket other than the retainer.

JB is usually reserved for that and minimum diameter rocket fin fillets and other parts where the airframe IS the motor mount tube. Then heat is an issue.

15 -30 minute hobby epoxy if fine for your build. If you plan on continuing into the rocketry experience then do consider getting a quart system of West, Pro-Line, Mr Fiberglass or other higher quality product. But consider your wallet when deciding it will run you 30-75 bucks for the upgrade vs 10-15 for Hobby types.

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#### Donaldsrockets

##### Well-Known Member
I would also think that using JB Weld for an entire build would be way overkill.

That and the PML Excalibur is a pretty sizable rocket. You would probably need at least 2-3 packages of it and at about $5.00 each from Wal-Mart, it would really add up$ wise.

Not to mention that once mixed, that stuff is very thick and is not that easy to spread either.

Your best bet would be to grab some regular 30 minute epoxy ( I like Pacer 30 minute Z-Poxy) from your local hobby shop. It will cost about \$10 or so but you will get enough to be able to build your rocket and possibly an additional rocket and/or to make repairs if necessary.

But if you plan to use an Aeropack, Slimline, etc type motor retainer, then you will need it for this.

Hope this helps.

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#### Viperfixr

##### Born Again Rocketeer
Attached at the very bottom is a photo of a PML X-caliber flying *FAST* on a Pro38 I285. I did nothing that special to building it, and the only 'modification' was to add a tailcone motor retainer from Giant Leap. I used Aeropoxy ES6209 epoxy, and it stuck to the Quantum Tubing just fine--superb epoxy, but it takes awhile to cure.

Great kit, BTW. Perfect for your L1!

Ready to fly on an H210 two weeks ago...

On an AT H148...

On an H128...

#### Evo666

##### Well-Known Member
I used JB weld on my Estes black brant II and over 10 years later I now think that's overkill
I was young and used whatever I could get my hands on.

#### als57

##### Well-Known Member
Use the slow cure JB on the Aeropack retainer. A 15 min hobby epoxy from your local hobby shop should do fine for the rest of it. Skip the stuff in the syringes - its pretty expensive for what you get.

Or try US Composites 635 series epoxy for a less expensive alternative to West Systems.

Al

#### Rocketeer41

##### Well-Known Member
Is a jb weld a model rocket or some kind of weld?

#### exprditer789

##### Well-Known Member
It is a type of epoxy that is heat tolerant.Alex

#### MarkII

##### Well-Known Member
Is a jb weld a model rocket or some kind of weld?
http://jbweld.net/products/jbweld.php

It is a more-or-less general purpose epoxy with some interesting characteristics. I think that the claim on the website that it "welds" things is a bit exaggerated; what JB Weld does, all epoxies do - it bonds two items together.

MarkII

##### Well-Known Member
Well the cost (mis)management alone may qualify him for NASA if you did use Jb weld all throughout the rocket it would be overkill as even humble epoxy clay would deffinetly hold up; have you thought about about the blue phenix from always ready rocketry? I heard they last forever I acctually know a guy who flew a blue phenix that survived a Cato :jaw: DISCLAMER!!!!: i ha e not flown the blue phenix or any hpr kit yet I'm just usesing secondhard knowladge. And you are so lucky I have to wait SEVEN YEARS Before I can get my HPR cert; markII you know why

#### FlyBack

##### Well-Known Member
Not to mention that once mixed, that stuff is very thick and is not that easy to spread either.
Use a hair dryer or heating pad to warm it up to 85-90 degrees (after it's mixed). It flows pretty well in that range.

I've used JB-weld to plug E-15 motors and for bonding aluminum to aluminum. Other than that... I'm with the right glue for the right job crowd.

Regards,

FlyBack

#### MarkII

##### Well-Known Member
Thanks for the tip, DJ. I don't know why I didn't think of that. You are absolutely right; a little bit of heat would loosen it up.

MarkII

#### dave carver

##### ....what hump?
I use JB Weld a lot for a lot of different things like holding in the freeze plugs and sealing off wet bolts (stock head bolts had a sealant on them) in my race motor among other things.

And despite it's cost and weight I've made the prettiest filets using JB Weld

#### Bxtreme

##### Active Member
Well the cost (mis)management alone may qualify him for NASA
actually i get the stuff for cheap. FREE!thats why i was gonna use it for all applications on the rocket so nasa might not need me as i look for the cheapest way out.

thanks for all the opinions its helped open my mind to other alternatives out there.

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#### MarkII

##### Well-Known Member
If you do decide to use JBW throughout in your X-Calibur build, let us know how it works out. I, for one, would be interested in hearing about it.

MarkII

##### Well-Known Member
If be does use that stuff through the entire build; also let me know what happens, I bet you could build the X-calibur with that stuff; you could probobly use nose-blow recovery and it would survive......

#### MarkII

##### Well-Known Member
If be does use that stuff through the entire build; also let me know what happens, I bet you could build the X-calibur with that stuff; you could probobly use nose-blow recovery and it would survive......
For anyone on the ground, though, it would be a different story. No RSO would allow it to be put on a pad anyway.

We don't joke around here about launch safety.

MarkII

#### 1974_Trident

##### Well-Known Member
Is a jb weld a model rocket or some kind of weld?
Ryan, had you finished dinner more quickly the night I epoxied the Aeropack retainer onto my G-Force you would know the answer. I used JB Weld because it has a high heat resistance.

##### Well-Known Member
For anyone on the ground, though, it would be a different story. No RSO would allow it to be put on a pad anyway.

We don't joke around here about launch safety.

MarkII
I was assuming the bystanders would be tucked away safely in a test bunker :blush:

#### Evo666

##### Well-Known Member
I think I'm going to use jbweld or epoxy on my upscale patriot missile that's going to be flown max with an E9. Unless you guys think thats overkill still?

#### MarkII

##### Well-Known Member
I think I'm going to use jbweld or epoxy on my upscale patriot missile that's going to be flown max with an E9. Unless you guys think thats overkill still?
Watch the overall liftoff weight (with motor) if you are using an E9. It doesn't have enough thrust to get a larger, heavier rocket going fast enough to be stable. Anything that I intend to launch on an E9 I try to build as light as practical. You can build your Patriot with wood glue and it will be more than strong enough for anything you put in it. People have certified for Level 3 with rockets that were assembled with wood glue.

Epoxy and JB Weld have their uses. Epoxy is useful for bonding certain materials together (example: fiberglass to fiberglass) and for creating fillets. JB Weld is useful for bonding motor retainers into tubes. Period. (OK, maybe on occasion for fin fillets, too. But use it sparingly.) Few mid-power rockets need to be built throughout with epoxy and none need to be built throughout with JB Weld. I have never heard of anyone ever doing that.

When you move from building low-power rockets to mid-power, there is a tendency to overestimate how strong you need to build them. Unless you are careful, your first builds will often be overweight, overbuilt tanks that will barely get off the ground with anything smaller than a large G. Using JB Weld on a rocket that is to be flown on an E9 is definitely an example of overbuilding. Your Patriot will never experience any stresses that would come close to requiring such an extreme building technique.

MarkII

#### MarkII

##### Well-Known Member
Let me add that I built my 42.5" tall Eos out of lightweight paper tubing (Semroc ST-13 and ST-16), with a balsa nose cone, a balsa transition and balsa fins. I papered the fins with cardstock for added strength. I used Titebond II wood glue throughout the entire build, but I used epoxy thinned with microballoons for the fin fillets. It is rock solid but light in weight (7.5 oz., I believe). I gave it a 29mm motor mount but I use a homemade 24mm adapter and fly it on Estes E9s. It is rock solid and it flies beautifully to 1200+ feet on that motor. There is no JB Weld anywhere on the rocket, and the only places where I used epoxy were in the fin fillets, the attachment of the screw eye in the bottom of the transition and to bond the blind nuts that I installed for motor retention. It is more than strong enough for an F or G motor, if I am ever crazy enough to launch it on one of them.

MarkII

#### Evo666

##### Well-Known Member
Thanks for your input. I'll stick to regular wood glue then.

#### Bxtreme

##### Active Member

Well i went ahead and used only one pack of jb weld to build my xcalibur rocket. It went quite easily and there was more than enough in the one package to build the whole kit coupler, mmt, centering rings, ejection piston and engine retainer.
all that is left is some sanding and painting and attachment of the chute.
Plan to fly it at the april metra launch.

#### dnl2

##### Well-Known Member
This thread kind of relates to my issue, so I thought add my question here. I used Proline epoxy on a Aeropack retainer with a fiberglass body tube.

I mixed the epoxy to the correct ratio and let it fully cure over a month ago.

The last few days I had the rocket out in my garage day and night while I worked on the paint.

Today I pulled the painters tape off of the retainer and the retainer slid right off.

The temperature has been in the 80's with fairly high humidity. But the temp and humidity in my garage is obviously higher.

Anyone ever have an issue like this? I was told by several rocket folk that Proline epoxy would be more than fine for Aeropack retainers. I am assuming that the high humidity on the rocket for a few days was too much.

I had cleaned the fiberglass tube with acetone prior to the epoxy.

I used epoxy because the rocket is only to be flown on G through I motors.

#### MarkII

##### Well-Known Member
Is it possible that you got the mix ratio wrong? I don't know anything about Pro-line epoxy, but not all epoxies are meant to be mixed in 1:1 ratios.

#### MarkII

##### Well-Known Member
I'm glad that the JB Weld worked out for Bxtreme. I was just thinking about this thread the other day. Since last year's discussion I have come around in my thinking and I'm now a lot more open to the idea of using the product in various situations during general building. I have increased my use of it myself since last year and I find that JB Weld is much more versatile than I had originally thought. So, Bxtreme, you were right.

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