Can we talk about JB Weld?

[speeder]

I've never used the stuff, it always kind of had a bad inference for me because of a certain unscrupulous Porsche engine builder that we used to discuss here.

It's actually metal epoxy, right? Pretty strong and permanent? Can it be filed or dremeled after it sets? I need to repair a carburetor that is otherwise going to be disposed of and it would be a huge waste. It's not something that would experience any real type of stress once it's fixed, (just air passing through), but it absolutely cannot chunk loose or fail, either.

What say ye?

[GH85Carrera]

I now a lot of folks that swear by the stuff. It is pretty amazing. I would try it before trashing a carb.

[vash]

that stuff saved me. no it actually saved a buddy i was caravaning with. his 928, he had a water fitting that popped out at ButtonWillow.

Jack Olsen actually gave me some JB-Weld..we used it and that fitting is still on there!! i was super skeptical and was telling my buddy to call a tow truck already. but it felt like success the second we plunged that fitting back in.

it'c certainly worth the hail-mary on that carb.

[Bigtoe32067]

Jb weld or metal putty should fix it right up.
If you’re uncomfortable than you can always solder it if it’s just a air passage. Make sure you preheat the surrounding metal before soldering the hole. Make sure it’s disassembled so you don’t damage any rubber seals or gaskets.
Good luck
Tony

[speeder]

Originally Posted by Bigtoe32067

Jb weld or metal putty should fix it right up.
Tony

Thanks, all! Is metal putty something that cures to a hard surface or stays pliable?

[dad911]

As I recall they have some formulas specifically for fuel/tank repair.

[dad911]

Originally Posted by speeder

Thanks, all! Is metal putty something that cures to a hard surface or stays pliable?

A-B types (mix) or the sticks that you knead get hard. I've machined it (filled holes and drilled)

[911 Rod]

Originally Posted by dad911

As I recall they have some formulas specifically for fuel/tank repair.

I think you want seal-all for this.

[Shaun @ Tru6]

surface prep is everything.

[LWJ]

Shaun is correct. Make certain there is some mechanical roughness for the patch to bite to.

If it sticks, it will be fine.

[john walker's workshop]

It doesn't get rock hard. You can bend it. There was a thread a while ago where a guy in france built up a huge blob of JB on his engine case where the right cam oil line fitting broke the case. I wonder how that worked out over time.

[Jims5543]

In 2010 we did an engine rebuild on my RX7. I wanted to go with a very aggressive port job on the intake ports to open them up as much as possible. Rotary engines perform sort of like a 2 stroke engine. Air/Fuel gets pulled in a side port, squeezed, ignited and send out the exhaust in 1 rotation x 3 faces of a rotor x 2 (or 3 in some cases) rotors.

The port job we planned on using would compromise the water jacket that ran near it. That meant we needed to seal back up the water jacket then clean up the repair.

I flat out refused to believe JB weld was the solution. I purchased 2-3 other kinds of epoxies in an effort to find the perfect one, we used them on test pieces, boiled them in water, exposed them to oil and gas and put them through hell. Every one failed.

I contacted 2 very well known engine builders, both said they use JB weld. So we conceded to used it.

10 years later and I would guess 30K miles on that engine now and it still runs strong with no sign of the JB weld failing.

[Shaun @ Tru6]

Originally Posted by LWJ

Shaun is correct. Make certain there is some mechanical roughness for the patch to bite to.

If it sticks, it will be fine.

this and surgically clean. I used acetone.

[speeder]

Originally Posted by Jims5543

In 2010 we did an engine rebuild on my RX7. I wanted to go with a very aggressive port job on the intake ports to open them up as much as possible. Rotary engines perform sort of like a 2 stroke engine. Air/Fuel gets pulled in a side port, squeezed, ignited and send out the exhaust in 1 rotation x 3 faces of a rotor x 2 (or 3 in some cases) rotors.

The port job we planned on using would compromise the water jacket that ran near it. That meant we needed to seal back up the water jacket then clean up the repair.

I flat out refused to believe JB weld was the solution. I purchased 2-3 other kinds of epoxies in an effort to find the perfect one, we used them on test pieces, boiled them in water, exposed them to oil and gas and put them through hell. Every one failed.

I contacted 2 very well known engine builders, both said they use JB weld. So we conceded to used it.

10 years later and I would guess 30K miles on that engine now and it still runs strong with no sign of the JB weld failing.

That’s an amazing story and it’s hard to argue w verified results. I’m sold and going to use it, I’ll post the results. My only concern is how well it can be *dremeled*, I want to match the original surface as closely as possible.

[Shaun @ Tru6]

It sands pretty well. use a pneumatic dremel pen and diamond bit for detail and hard to reach places.

Astro Pneumatic Tool 218 1/8" Pencil Type Die Grinder - 56,000RPM

[speeder]

All I have is a standard Dremel tool, hope it fits in the passage, come to think of it.

[Shaun @ Tru6]

That pneumatic pen is amazing, you can use it with precision that an electric Dremel would never dream of. It's a scalpel compared to a Dremel ax.

[911boost]

And it is not expensive, I am going to order one.

[asphaltgambler]

I used it once back in the day to fill a deeply scratched cylinder on a 250ci chevy 6 in a 1967 van. Short story is the van was smoking, using coolant running on 4 cyls basically. I tore it apart and at some point the head gasket blew between 3/4 and actually grooved the block from the steam / cylinder pressure going back and forth. Also upon closer inspection saw #4 cylinder gouged vertically from a broken ring. Guy didn't have enough money to replace the short block/ engine used or otherwise.

So I removed the pan, removed #4 piston/ rod. Bought 1 new piston- ring set. I cleaned the surface of the block and the cylinder wall, filled in with JB. let it sit for @2 days. I carefully sanded the deck until smooth, checked it with a carpenter's straightedge. I honed #4 until it looked good, put in the new piston/ ring set used Fel-pro gaskets - believe it or not it lasted quite a long time.

[dad911]

Originally Posted by Shaun @ Tru6

That pneumatic pen is amazing, you can use it with precision that an electric Dremel would never dream of. It's a scalpel compared to a Dremel ax.

I don't see a CFM spec. Do you think I can I run that off a small jobsite compressor (occasionally, short duty cycle)