JB weld

Has anyone built a rocket using only JB weld? How did it turn out? Was it a pain to use? How did your fillets turn out? Does it hold together with high thrust motors? Pros/cons? I'm thinking about using JB weld on my next build and would like to get your advice on it before I start. Thanks :grin:

Kehoes23 said:

Has anyone built a rocket using only JB weld? How did it turn out? Was it a pain to use? How did your fillets turn out? Does it hold together with high thrust motors? Pros/cons? I'm thinking about using JB weld on my next build and would like to get your advice on it before I start. Thanks :grin:

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My D-Region Tomahawk scratch build is all JB Weld. It features TTW Fins and instead of Fillets, their are Gussets that are JB Welded in place.
The chute shelf was assembled with JB Weld, and epoxied into the tube with JB Weld.



Also used it to reinforce my threaded rod for the Sled, which goes up into the Cone and is anchored with PC Steel Epoxy Putty.

I have, but honestly, unless I need the properties of JB Weld I'd rather use something that sets and cures faster.

When this has come up in the past usually the number one reason against is cost. So if you have a good supply, let us know!

At first I only used it on motor retainers, but I have been expanding to some other parts recently. Especially between wood and steel, it seems like it may be the best option.

I use JB Weld only occasionally in rocketry...attaching Aeropack retainers and that's about all I can think of.

I once used JB Weld to repair an automotive heater core for which a replacement was no longer available. The repair never failed. Since that time, I've never doubted JB Weld's ability to make a permanent joint.

As others noted above, there are however faster epoxies that cost less and do just as good a job in rocketry.

If I remember correctly (not a great assumption) it sets in 3 to 4 hours and cures in about 15 hours. I only use it where I really need it because of these long times.

If I did'nt get it at a discount from the store I once worked at, I would likely not use it so liberally.

This topic surfaces over and over and I don't understand why you would want to. JB Weld is a specialty adhesive. It is a basic epoxy with calcium carbonate and iron powder as fillers. The lime is a thickener, and the iron acts as a heat transfer agent. Look into the specs for it and you will find JB Weld is actually noticeably weaker than other epoxies. It was invented for automotive cooling system repairs.

But, it's a hobby and whatever floats your boat.

H_Rocket said:

It was invented for automotive cooling system repairs.

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Well that explains why it worked so well on my heater core.

H_Rocket said:

This topic surfaces over and over and I don't understand why you would want to. JB Weld is a specialty adhesive. It is a basic epoxy with calcium carbonate and iron powder as fillers. The lime is a thickener, and the iron acts as a heat transfer agent. Look into the specs for it and you will find JB Weld is actually noticeably weaker than other epoxies. It was invented for automotive cooling system repairs.

But, it's a hobby and whatever floats your boat.

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+1 Exactly

o1d_dude said:

Well that explains why it worked so well on my heater core.

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I fixed a broken distributor with it once. Never failed.

I do it all the time using JB Quik, when I want to throw something together, well... quick. You can build a small fiberglass rocket in a day, easily. I wouldn't use it for anything big, though... that's what Rocketpoxy is for.

It's why I asked first, to get your opinion on it first before I did the build, I'll just used it for the retainers and filling in spiral on the tubes. Thank you everyone who posted on this thread and share your experience and advice.😄

It is really way overkill for spiral filling. If you don't want to buy the big fillers, just use Carpenters wood putty as written about all over the forum. Or use hobby epoxy and mix it with talc. On the other hand a cheap can of Bondo makes for some serious spiral fills.

Yes JB weld may be over kill but it's the only thing that works for me, I've tried everything else with poor results, no matter how many times I've filled in the spirals I can still see them after a coat of primer

On my 24mm MD Alpha, The Fins go on with JB since there will be heat, but when I Tip to Tip them there should be no chance of them shaking off.
The JB Weld is also nice to rub into the edges of the fins, as it allows me to sand the edges nice and perfect.
Have I mentioned how nicely JB Weld sands?

Kehoes23 said:

Has anyone built a rocket using only JB weld? How did it turn out? Was it a pain to use? How did your fillets turn out? Does it hold together with high thrust motors? Pros/cons? I'm thinking about using JB weld on my next build and would like to get your advice on it before I start. Thanks :grin:

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It's suggested for use in high temperature areas to avoid adhesive softening. For instance, it's specified by Aero Pack for the attachment of their motor retainers. I've also known someone to use it to attach HPR motor centering rings since he claimed he once discovered that the regular epoxy he used was very soft after the rocket's recovery. However, I suspect it was the result of a long period of heat conduction during descent and probably not much was conducted prior to burnout and ejection, the critical interval where you don't want any softening of your adhesive.