JB Weld

Been awhile since I've used JB weld. How long does it take for it to totally cure? Had to make an emergency repair to the driver side exhaust manifold front bolt ear on my GTS. I've held off torquing the nut until I know that stuff has totally cured.

There are two types of JB weld. One is fast setting and gets hard in like 6 minutes and cures in like 5-6 hours. The other takes much longer to set like 4-6 hours and like 24 hours for full cure. I would be surprised if if holds.

Just a temp fix until I can get the manifold off. Being a Bigblock the steering column needs to come out.

I'm sure you know this.
If you run it and doesn't hold, you run the risk of burning a valve.

Oh yes, that I know. If it doesn't leak I'm good to go in the short term

Success


Actually Moparpollack told me he had done a couple of manifolds and didn't have a problem

clean the area with brake kleen/let it set up 24 hrs/cross your fingers/get the "regular" type not the fast setting.

What I did was use the slow acting. I cleaned the area with brake clean, let it set then applied the JB to the tab. Placed it into position, put the stud back in, tightened the nut, let it set for about ten minutes. I then backed the nut off so no pressure on the tab. This morning I removed the nut and stud, placed some sealant on the stud and installed it. Ran the nut on and torqued to spec. I'll let it set for another 24 hours to allow the sealant to set before I fill the rad and burp the motor before I fire it up.

I have a buddy up in WA State that's a retired pipefitter who is expert at welding cast iron. This summer, I'll pull the manifold and get it up to him.


Probably in the future when using old cast iron manifolds and other parts is to have them magged to insure there's no cracks. As clean as that break was I'm sure there was a hairline crack.

Your welder buddy is going to hate you. You just packed the crack with contamination that can't be removed without further destruction.

Yeah, but I had to do it. It was either that or let the car sit for 9 months

If the piece that was broken off the manifold has a load on it, the JB weld will not last. It has no resistance to vibration and no inherent strength and will fail shortly. If it survives a week, I'll be surprised.

To weld the manifold, the JB weld will have to be completely removed. Shouldn't be a big deal anyway. You don't just lay a bead on top of a crack, the casting on both sides of the crack will have to be V'ed out so the weld rod can penetrate with both sides of the casting and the weld bead can be built up to fill the void if the outer surface needs to be ground back down. Any machined surface involved in the weld effected area will need to be re-machined flat. Gene

Yes, I know. I've welded cast iron before. Clean parts is a must. We will see how long this lasts. The JB weld which is darker than the cast iron shouldn't be difficult to grind off.

I have seen cast iron successfully welded, but the chances for success are much better if you have a large heat treat oven for both pre-heat and after welding slow cool down. High nickel rods are needed, but the exact best rod depends on what grade of cast iron it is, and cast irons differ quite a bit.

Brazing broken cast iron parts often works better,
and the repair has more "give" under tensile stress
when bolted back in place so re-cracking is less likely.

My original block for my 383 GTS had cracked by the lifter galleys inside. The block was brazed after being heated up then pressure tested afterwards, no issues! This was back in 1979.

You could look into Belzona super metal 1001. VERY expensive, but is the best epoxy out there. $290 a kilo. They repair shaft keyways with it. I used it to seal hole in intake port. Stands up the best to alchol in pump gas

At that price it would be less expensive to replace the manifold unless they are BB A-body.

^^^ what is the smallest quantity of it available! 2.2 lbs would last forever.

They sell it in kits and the 1 kilogram package is as small as it gets.

I've been using Belzona in an industrial setting since 1982. It is an industrial product for industrial use. With the material you can usually get an in-plant demonstration by a tech rep, and training for the people who will be applying it.. The early '80s price, IIRC, was $165 per kit.

Belzona is not intended for hobbyist use.

R.

PS: That old wives' tale about "warping the valves" is just that, a tale. It's not true. It probably came from someone overthinking the situation. I have heard it since I began to be interested in cars in the '60s.
As a youth I helped haul grain from the field and augur it into bins. Our grain augur had a Wisconsin AGND single cylinder gas engine. After a couple of years of use the muffler burnt off. I remember many a dark night as I unloaded the last truck of the day, standing directly behind the exhaust port and looking at the exhaust valve at yellow heat. There was about an inch between the edge of the block and the exhaust valve. Year after year the muffler didn't get replaced and I can attest that the engine compression was as strong as ever. No warped valve for this engine!

Well fellas, went out and fired up the car, big time exhaust leak. Snugged the nut and the JB gave way. Ended up taking the manifold off. It appeared the JB never set up. It was soft. Not sure if it was old or I didn't mix properly. Wire wheeled the tab and manifold. All the JB came off. The tab still fits. Needs some more cleaning with brake clean. Anyway, have to find someone that can do the repair.

Find someone that can do cast iron the "right" way,that is an easy fix.

Found a place here in Phoenix, that is the only place in Phoenix that does castiron welding. Cold fusion

JB Weld sux for something like this. A big waste of time. Fix it right the first time, it's not a Yugo.

[quote=FurryStump]You could look into Belzona super metal 1001. VERY expensive, but is the best epoxy out there. $290 a kilo. They repair shaft keyways with it. I used it to seal hole in intake port. Stands up the best to alchol in pump gas [/quote


Crown Metals Royal 44-30 Mig wire is not cheap either, ($85 for 2 lbs) but might be something that would work well in a DIY situation. Gets good reviews. just wait 'till the wife goes to the store and borrow her oven for the pre/post heat.

http://www.millerwelds.com/resources/com...e-for-cast-iron

Cold Fusion is the way it would get welded at my shop as well. For something like that, be sure the head surface is ground flat again (have the entire head surface milled flat) before you try to bolt it up, or it will break again. If you get it welded and it breaks again, get a new manifold. Cast iron that has been through several heating cycles sometimes won't weld good regardless of the method used.

The JB Weld fix lasted bout as long as I expected. It simply doesn't work anyplace there is a tension. Gene

Yep. Heading over to the facility tomorrow.

Got the manifold back. They ended up not using the old tab. Instead they formed a block of weld at the end of the manifold. Reason was the weld would be too weak. Had to grind away an inch of weld.

So now I have to grind away the excess weld enough so that the mating surface can be trued. After that drill a new hole. Once that's done then I can grind in the contours and get it as close as I can to stock. I'll use a Dremel tool for that.

I gotta say, I too, had little hope of JB Weld doing the trick.
I don't believe in chemical cures for mechanical problems.

I wish you better luck with this effort.
Sure looks like the right way to go forward.

If your not keeping that one section of the manifold on the same flat plane as the other flat sections, you will have a leak and it will break again. You can't just make that one section flat without regard to the rest of the manifold.

Is that all weld build up, or did they weld on a section of cast iron?

Im not that lucky so id eat it now and toss it in the dumpster and find a good manifold. But its not that easy with that one it looks like.

No, had to get it down so the machine shop can get everything true. After that I'll drill the hole then I can try and reshape everything. Keep in mind that this is a temporary fix until I can find another manifold.

you may want to consider the header trick i stole from mr. pbody over on the race forum years ago. that trick was to enlarge one of the attaching holes on each separate tube segment[s]. this allows the attaching points to expand and contract under use and cool down. this may take some strain out of your newly formed ear. this trick works great to seal up even thin flange headers, so i would presume the idea may have some merit for your repair as well. it couldn't hurt [in my opinion], unless the bolt holes from the factory are a bunch bigger than the retaining fasteners, which would then make this idea moot.

^^^ that sounds like an excellent idea, I had to enlarge the holes on my manifolds just from normal warpage.

I've done that. In addition I'll be using Rimflex gaskets.

Well, here's an update. On Saturday I talked with a guy that had an M code Cuda at one of the local shows. I was telling him about my delima with the broken manifold. He speaks up and says he has a pair he's not going to use.

Went over and picked them up today. He had a pair and was willing to split them up. I went ahead and bought the pair. Just got home and checked the numbers. The driver side manifold which has the heat riser intact is 67-69 (900). However, the driver side is a 9002 which is a 67 manifold.

The 67 manifold would be somewhat correct for my car but I'd like to get a 68-69 manifold so I might see if someone wants to trade. In the meantime it goes to the machine shop where I'll have it mag'd and the surface trued.