# JB Weld wins hands down!



## BrokeCurmudgeon (Feb 8, 2016)

Many of us use JB Weld as we refurbish and repair our 60 to 70 years old American Flyers. I was interested in how it stood up to other adhesives. I came accros this video that reconfirmed my opinion. https://www.youtube.com/watch?v=H4xX7VecgzA:thumbsup:


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## mopac (Feb 24, 2011)

Thanks for posting the video Broke. A very unusual video, but I liked it. I figured Flex Glue would do better than it did, it didn't. JB Weld the clear winner for most cases. I
bought a set of O scale passenger cars from a member here on the forum. They made it 
fine in the mail except one side rail broke off the truck. It didn't really break, it just came off. I wish I had used JB Weld to repair it. I used an epoxy I got from Harbor Freight. The problem with what I used was it did not dry hard, it is still somewhat flexible. Not good for a side rail. I am going to have to try and remove the epoxy I used and redo with JB Weld. I have the trusty 2 tubes for JB Weld.


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## tjcruiser (Jan 10, 2010)

Interesting experimental comparison. Great results for JB!


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## Shdwdrgn (Dec 23, 2014)

I built a terrarium years ago and forgot to drill the glass for hinges. Ended up using JB Weld to stick the hinges in place. They only came off once due to getting hit, and they took a thin layer of glass with them. I just used another application of JB Weld to stick it all back together again, and haven't had any further problems. I've heard that stuff is strong enough to hold a V8 engine block together.


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## tjcruiser (Jan 10, 2010)

These are the critical JB numbers, from the manufacturer's tests. Not quite steel, but not bad, for a glue/adhesive ...


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## flyboy2610 (Jan 20, 2010)

mopac said:


> I am going to have to try and remove the epoxy I used and redo with JB Weld. I have the trusty 2 tubes for JB Weld.


Acetone will soften epoxy, just be careful what else it touches.


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## mopac (Feb 24, 2011)

Thanks flyboy, I will try that.


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## Fire21 (Mar 9, 2014)

Fascinating video, amazing results. Thanks, Broke.


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## mesenteria (Oct 29, 2015)

mopac said:


> ... I wish I had used JB Weld to repair it. I used an epoxy I got from Harbor Freight...


I could be wrong, but I think JB must be an epoxy. He seemed to mix two gels or liquids, and usually that means an epoxy made out of resin and hardener/catalyst measured in equal quantities and they have to be mixed very thoroughly.



mopac said:


> ...
> 
> The problem with what I used was it did not dry hard, it is still somewhat flexible. Not good for a side rail. I am going to have to try and remove the epoxy I used and redo with JB Weld. I have the trusty 2 tubes for JB Weld.



When an epoxy fails to harden, or remains somewhat 'sticky' on its surface, it is usually for one of two reasons: improper measuring or improper mixing. Again, epoxies comprising hardener and resin must...MUST...be carefully measured, and then they MUST be mixed over three or four minutes. You must occasionally scrape the bottom and the sides of the mixing vessel. You must also change up the way you are stirring, going from a figure eight to a reverse figure eight, and then going in concentric circles left and then right. Then scraping, then back to figure eight, etc. Every instruction I have seen even goes so far to say that after two minutes of mixing you should pour the mix into a fresh disposable container and then continue mixing for yet another two minutes. This is for pourable epoxies such as the kind you want over a nice wooden table. Four the gel glues that we're talking about, no need to change mixing surfaces, but you do have to be very certain to get the right quantities and then mix it for several minutes.


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## BrokeCurmudgeon (Feb 8, 2016)

"I could be wrong, but I think JB must be an epoxy. He seemed to mix two gels or liquids, and usually that means an epoxy made out of resin and hardener/catalyst measured in equal quantities and they have to be mixed very thoroughly."

It is epoxy based with additions, but outperforms most others!


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## teledoc (Oct 22, 2014)

I don’t care what you call JB Weld, but I swear by it, both the quick cure or the long cure. Plain and simple, I love JB Weld.


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## gunrunnerjohn (Nov 10, 2010)

I knew I made the right choice years ago when I started using this stuff. I was really impressed by a couple of the tests, I like when he ran out of weights on the one. Apparently, it's still not good enough for engine repairs.


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## tjcruiser (Jan 10, 2010)

Yes, JB Weld is a true epoxy. Hardener and resin ... chemical reaction when mixed.

TJ


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## Fire21 (Mar 9, 2014)

gunrunnerjohn said:


> I knew I made the right choice years ago when I started using this stuff. I was really impressed by a couple of the tests, I like when he ran out of weights on the one. Apparently, it's still not good enough for engine repairs.


Think you'd ever blow a head gasket if you used JB Weld AND the head bolts?! :laugh:


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## Nikola (Jun 11, 2012)

JB Weld is pretty good but there is something even better. MarineTex. Available in black or white.

MarineTex is to JBWeld as JBWeld is to Elmer's Glue. It can and is used to repair engine blocks and drive units, particularly in the marine industry. It is a two-part epoxy also.

Then there are industrial epoxy products that make MarineTex look like dried snot. I saw one used to attach a very heavy solid hunk of cast iron to the ancient cast iron of a very historic stationary engine. The component in question was part of the original casting from the 19th century, and had been hacked off and lost over a hundred years ago. A clever machinist fairly recently made a replacement out of a cast iron billet and GLUED it on with one of these special epoxies - and it holds - the engine runs; no problem!

Technology is awesome.


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## BrokeCurmudgeon (Feb 8, 2016)

*Followup on JB Weld Original on Plastic*


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## MichaelE (Mar 7, 2018)

Very few adhesives will actually bond to what appears to be nylon or Delrin bolts he is using for these tests. Anything with a polypropylene or polyuerethane base is going to be very difficult to bond even to itself without special bonding agents.

It may hold it in position, but it will not 'weld' it to whatever surface it is mated to.

For simple modeling chores just about anything could used, but I would choose the JB Weld from past experience.


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## gunrunnerjohn (Nov 10, 2010)

Nikola said:


> JB Weld is pretty good but there is something even better. MarineTex. Available in black or white.
> 
> MarineTex is to JBWeld as JBWeld is to Elmer's Glue. It can and is used to repair engine blocks and drive units, particularly in the marine industry. It is a two-part epoxy also.


You forgot IMO.  I did a search and read a few reviews. 

In truth, they look very similar, hardly the vastly different speculative comparison you indicate. The shear strength of JB-Weld is actually better, one of the most important properties in many applications.


JB-Weld









Marine Tex


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## Genetk44 (Feb 26, 2016)

I used JB Weld to repair the split in the diesel fuel injector line on a Cat. 3208 engine...thats the high-pressure line that runs from the fuel pump to the injector...it held for over just over 28 hours until a new replacement line arrived on the island. I kept that line as an emergency back-up....been sold on JB Weld ever since


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## tjcruiser (Jan 10, 2010)

John, I saw that same JB mechanical properties data link that you posted above. I'm not quite sure I believe it: each type of mechanical strength (flex, shear, etc.) listed at exactly 3960 psi. That's too coincidental for me.

See the other JB spec sheet that I found online, in my prior post above.

Regards,

TJ


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## doneuald (Jan 2, 2016)

I've seen devcon used to repair oil coolers that were damaged on ice racing cars with great results!!
And on stuff in the pulp mill I work at devcon is used on large vacuum boxes


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## gunrunnerjohn (Nov 10, 2010)

TJ, I just confess, I did wonder about all those similar numbers.  I missed your chart, probably more to the point. 

In any case, I've never been disappointed in JB-Weld, and for anything I encounter with model trains, it's been more than up to the task.


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## Matt_GNo27 (Feb 7, 2016)

MichaelE said:


> Very few adhesives will actually bond to what appears to be nylon or Delrin bolts he is using for these tests. Anything with a polypropylene or polyuerethane base is going to be very difficult to bond even to itself without special bonding agents.
> 
> It may hold it in position, but it will not 'weld' it to whatever surface it is mated to.


Thread drift:
Epoxies also do not bond well to untreated polyethylene. The trick is to oxidize the surface by passing a torch over it, and not touching the surface with your skin afterwards. (This trick is used repair polyethylene canoes and kayaks, where West System's G/flex 650 is the epoxy of choice.)

I wonder if the torch trick would work for polypropylene?


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## Luke 221 (Feb 12, 2013)

I use my local GOLF store's golf club epoxy. 3M DP810 is what PGA tour vans use to build the pros' clubs. Shear strength is around 3500 psi. The local golf store sells it for 10 bucks for a package.


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