jb weld ?

I don't know much about JB weld except one thing. It's heavy. Although I haven't started to work on my first high power rocket, I might use a little JB on the engine mount. The rest is 5 minute epoxy.

Andrew

A couple of months ago a forum member (I don't recall who) mentioned painting an ejection baffle with prepared JB Weld that had been thinned with isopropyl alcohol in order to increase its durability. I thought that was a really cool idea and I have used the same technique to "paint" booster stage parts and the inside surface of a gap-staging coupler on a two-stage rocket that I am building with thinned JB Weld. I used a tin-handled horsehair acid brush to apply it. The thinned epoxy adhered well and soaked a little bit into the surfaces. When it had cured, the components had hard, shiny dark gray coats of heat-tolerant epoxy on them. I haven't finished the build yet, let alone flown it, but my goal with the treatment is to make it easier to clean off the heavy soot that gets deposited on them during staging. So thanks to the member who mentioned using the technique on his baffle for sharing this great idea!

i wonder how hi-temp engine spray paint would work for that app? would be a bit easier to apply - just thinking out loud

SteveF said:

i wonder how hi-temp engine spray paint would work for that app? would be a bit easier to apply - just thinking out loud

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I have thought of that and I do have some engine block paint, but the epoxy coating is a bit thicker than a paint coat, which may help in this situation. The paint is worth a try too, though.

I used the Pro-Line epoxy that came with my Mongoose 54mm.
That correct ratio was more like: 10 g of resin for every 1.6g of hardener by weight. If you go by volume it maybe a bit different.
I never had any trouble with using those numbers.


JD

I have read where people say that thinning the epoxy weakens the final product. The problem with that statement is when the epoxy is used in this manner then it's ultimate strength isn't a factor. What you are trying to do is improve the toughness of what your soaking the epoxy into. So what if it isn't a strong as undiluted epoxy, it's many times better than not at all and the undiluted epoxy doesn't soak in as well.

I like useing Luan door skin plywood for making large rocket fins and centering rings. It's very pourous for a hardwood, Mahogany, and the thinned epoxy soaks almost all the way through.

Guys,

here is a great deal on 10oz of JB Weld (5x more than you get in the blister packs) on Amazon for less than 2x what you would pay for the two 1oz tubes:

https://www.amazon.com/dp/B000ALG8LO/?tag=skimlinks_replacement-20

I stil don't think I would use the stuff in parts of the rocket that were not subjected to IMMEDIATE high heat, but it is a great deal, and of course has many non-rocketry uses..... I know people whose 25 year old cars are 70% JB Weld and Bondo!!!

Kevin.

khill444444 said:

Guys,

here is a great deal on 10oz of JB Weld (5x more than you get in the blister packs) on Amazon for less than 2x what you would pay for the two 1oz tubes:

https://www.amazon.com/dp/B000ALG8LO/?tag=skimlinks_replacement-20

I stil don't think I would use the stuff in parts of the rocket that were not subjected to IMMEDIATE high heat, but it is a great deal, and of course has many non-rocketry uses..... I know people whose 25 year old cars are 70% JB Weld and Bondo!!!

Kevin.

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I have a 7 yr. old car that's still running with the help of liberal amounts of duct tape.

That looks like a great deal. Thanks for the link!

Gorilla brand duct tape. Slap some on a fender, leave it there for three months, and then try to remove it. Go ahead; I double-dog dare you.

MarkII said:

I have a 7 yr. old car that's still running with the help of liberal amounts of duct tape.

That looks like a great deal. Thanks for the link!

Gorilla brand duct tape. Slap some on a fender, leave it there for three months, and then try to remove it. Go ahead; I double-dog dare you.

Click to expand...

He he he. As I tell my college students, 90% of life's problems can be solved with JB Weld, Bondo, WD-40, and Duct Tape. They are on their own for the other 10%.......

Does anybody have any experience in coloring JB weld so its black like Proline? I want to try and mix it with glossy black paint and see what happens.

I wouldn't use paint in epoxy,that can cause problems being water with latex or oil in the paint BUT:

You might try carbon or graphite powder.

I haven't tried it myself, but you could try either black tempera paint powder or toner from a laser printer or a copier (my office has one that stores surplus toner in an overflow bottle that needs to be replaced once in a while).

I personally have just painted the JB Weld after it cured. One ore two coats of primer, and rattlecan paint lays down cleanly.

G.D.

I suppose one could try powdered tempera paint (normal use is add water to make paint).
rex

blackjack2564 said:

I wouldn't use paint in epoxy,that can cause problems being water with latex or oil in the paint BUT:

You might try carbon or graphite powder.

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West Systems info on coloring epoxy: https://www.westsystem.com/ss/adding-pigments-to-epoxy/

Also, from JB Weld FAQ (https://jbweld.net/faq.php#faq009)
Q: Can I thin J-B Weld to make it pour easier?
A: Yes. Add up to 1 tsp. of acetone or lacquer thinner per 2 oz. (1 full package) of mixed product.

BTW, pigments added to epoxy weaken them.

-Kevin

Pigments as well as dyes weaking epoxies regardless of maker.

Many of us old timers have been using epoxy coatings on Baffle and motor mount parts for years to extend the service life of the model.
I personally don't use JB weld as it seems twice as heavy as most other 2 part epoxies without adding any additional strength for the added mass.
Personally I'm rather partical to Devcon 5 minute and 2-ton (30 minute) epoxies for motor mount and fillets. No thinning needed and the come out pertect with a single alcohol moisened Gloved finger sweep.

As for the use of JB weld as the only adhesive used for an entire build. Well even if it's free...I still adhear to the use of Proper Adhesives or glues for the application. JB weld just doesn't fit the bill.

I use jb weld for most of my builds my local autozone sells industro weld which is the big tubes of jb for about 15 bucks. Jb weld is the best epoxy for fillets imo. I use it for at least the fillets on all my builds. It lays in so smooth and doesn't run out very easily. It sands very nicely. Also you have a long time to work with it so I can spend time cleaning up each fillet without rushing. I just built my entire darkstar with jb weld and jb qwik. I love the stuff. I have used loctite 5 min, devcon, west, proline, cotronics, and others and I prefer jb for all around. Proline is a close second but due to availability I use jb.

Micromeister said:

I personally don't use JB weld as it seems twice as heavy as most other 2 part epoxies without adding any additional strength for the added mass.

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Pretty dang close there, Micro. I was curious, so I looked it up on JB Weld's MSDS and Devcon 5 Minute epoxy data sheet. 1.943 gm/cc for mixed JB Weld, and 1.10 gm/cc for the Devcon.

Kevin - thanks for the lead on the Industro packs from Amazon. I use it for some of my other hobbies, and I like that pricing.