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JB Weld #2398793
11/05/17 01:19 PM
11/05/17 01:19 PM
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Mesa, Arizona
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dart4forte Offline OP
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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.


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Re: JB Weld [Re: dart4forte] #2398836
11/05/17 02:21 PM
11/05/17 02:21 PM
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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.

Re: JB Weld [Re: mopars4ever] #2398838
11/05/17 02:25 PM
11/05/17 02:25 PM
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dart4forte Offline OP
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Originally Posted By mopars4ever
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.


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Re: JB Weld [Re: dart4forte] #2398879
11/05/17 03:26 PM
11/05/17 03:26 PM
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I'm sure you know this.
If you run it and doesn't hold, you run the risk of burning a valve.


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Re: JB Weld [Re: bboogieart] #2398891
11/05/17 03:49 PM
11/05/17 03:49 PM
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dart4forte Offline OP
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Oh yes, that I know. If it doesn't leak I'm good to go in the short term


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Re: JB Weld [Re: dart4forte] #2398900
11/05/17 04:07 PM
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Re: JB Weld [Re: bboogieart] #2398919
11/05/17 04:52 PM
11/05/17 04:52 PM
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dart4forte Offline OP
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Success luck


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

Last edited by dart4forte; 11/05/17 04:53 PM.

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Re: JB Weld [Re: dart4forte] #2398922
11/05/17 04:55 PM
11/05/17 04:55 PM
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RapidRobert Offline
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clean the area with brake kleen/let it set up 24 hrs/cross your fingers/get the "regular" type not the fast setting.


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Re: JB Weld [Re: RapidRobert] #2398927
11/05/17 05:08 PM
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dart4forte Offline OP
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Originally Posted By RapidRobert
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.


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Re: JB Weld [Re: dart4forte] #2399038
11/05/17 08:53 PM
11/05/17 08:53 PM
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Your welder buddy is going to hate you. You just packed the crack with contamination that can't be removed without further destruction.


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Re: JB Weld [Re: ruderunner] #2399083
11/05/17 10:14 PM
11/05/17 10:14 PM
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Originally Posted By ruderunner
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


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Re: JB Weld [Re: dart4forte] #2399147
11/06/17 12:56 AM
11/06/17 12:56 AM
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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

Re: JB Weld [Re: poorboy] #2399170
11/06/17 02:23 AM
11/06/17 02:23 AM
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dart4forte Offline OP
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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.


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Re: JB Weld [Re: dart4forte] #2399218
11/06/17 09:09 AM
11/06/17 09:09 AM
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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.

Re: JB Weld [Re: 360view] #2399242
11/06/17 10:47 AM
11/06/17 10:47 AM
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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! up This was back in 1979.


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Re: JB Weld [Re: dart4forte] #2399292
11/06/17 12:27 PM
11/06/17 12:27 PM
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FurryStump Offline
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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


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Re: JB Weld [Re: FurryStump] #2399309
11/06/17 01:08 PM
11/06/17 01:08 PM
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62maxwgn Offline
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Originally Posted By 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


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

Re: JB Weld [Re: 62maxwgn] #2399344
11/06/17 02:01 PM
11/06/17 02:01 PM
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RapidRobert Offline
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^^^ what is the smallest quantity of it available! 2.2 lbs would last forever.


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Re: JB Weld [Re: RapidRobert] #2399407
11/06/17 03:42 PM
11/06/17 03:42 PM
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dogdays Offline
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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!

Last edited by dogdays; 11/06/17 04:10 PM.
Re: JB Weld [Re: dogdays] #2399443
11/06/17 05:10 PM
11/06/17 05:10 PM
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Mesa, Arizona
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dart4forte Offline OP
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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.

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