J-B Weld

[kmw1954]

Has anyone here used J-B Weld as a bedding material? I have used others but not this. Looking for feedback on how well it works.

[tangolima]

I did it for smaller jobs, JB weld or epoxy putty of similar kinds. A few drawbacks. It could become expensive if you use a lot of it for a big job. It doesn't flow well. Work time may be a bit short.

-TL

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[kmw1954]

The one I have in front of me states 4-6hr set time. 15-24hr cure time.

[tangolima]

Mine starts to hardened in 15 minutes. I probably have 10 minutes to work it. It doesn't flow and "wet". I need to factor that in my prep work.

My favorite is devcon steel putty. It is just right in all aspects. But its price has gone way up.

-TL

https://a.co/d/fo9slly

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[JohnKSa]

I think I did a really quick and dirty job of bedding the back of the receiver of a 10/22 with JB Weld once. It worked ok. Of course that was a very small area so the speed of curing wasn't an issue.

[guncrank]

Yes I have used JB for bedding of action and liners

[Shadow9mm]

Yes, i have done it with jb weld and devcon. Your much better off buying a bedding kit. You can get them for around $20. https://www.midwayusa.com/product/1023724374

[tangolima]

Originally Posted by Shadow9mm

Yes, i have done it with jb weld and devcon. Your much better off buying a bedding kit. You can get them for around $20. https://www.midwayusa.com/product/1023724374

I did my first bedding job with it some 20 years ago. The price hasn't gone up at all.

It is pretty good stuff. A bit on the soft side to my liking though. That's why I switched to devcon in all bedding jobs afterwards. JB weld is pretty hard too.

-TL

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[kmw1954]

Guess I should try it, worst that can happen is I have to grind it all out and start over.

[Shadow9mm]

Originally Posted by tangolima

I did my first bedding job with it some 20 years ago. The price hasn't gone up at all.

It is pretty good stuff. A bit on the soft side to my liking though. That's why I switched to devcon in all bedding jobs afterwards. JB weld is pretty hard too.

-TL

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That's one of the reason I really like it. In my experiences with epoxies, generally, the harder it is, the more brittle it is, and Brittle is exactly what I do not want in a bedding materiel. Id rather have a little flex, than things shearing off under load. Granted the application is important, material strengths needed for a 22 are vastly different from a 30-06.

I have seen some great stuff used by some profession smiths called acraglas. https://www.amazon.com/Brownells-ACR...2406459&sr=8-2 Their kit can be had for about $32 off amazon and comes with brown and black dies, release agent, as well as mxing cups with markings...

Heres a pretty cool video from a smith doing a stock repair with acraglas. https://www.youtube.com/watch?v=LKeOQVsyRMU I have learned a ton from his channel, really cool stuff.

[tangolima]

If it is pure epoxy glue, I agree with you on brittleness. But it is not. The hardness / strength comes from the metallic particles embedded in the mixture.

Other important parameters is stability. How much it shrinks after curing and due to temperature variations or stress applied. Don't have any data to substantiate, I think devcon is the best, followed by JB.

-TL

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[Unclenick]

The basic slow-set epoxy resins are usually cross-compatible. You could try mixing JB Weld with a portion of West System G-flex 655, which is already thickened with a flex agent and which is designed to bond not only to the usual things, but also to some plastics and to woods, including wet wood. Or you could try the 655 by itself or add some phenolic beads or steel powder as a filler. You would want to experiment with mixes until you got the hardness you wanted.

There was a period about 30 years ago when folks were bedding with the putty form of Devcon Flexane 80, which is a black two-part polyurethane rubber that sets to a Shore A scale durometer hardness of 87 (stiff-ish rubber; the familiar black rubber nitrile O-ring is softer at about 70 on the same scale). The idea was that flexible bedding would compress a little while the bullet was still moving down the tube, and thus, the gun would have a slightly delayed muzzle climb, letting the bullet pass the muzzle without much movement. The 30-06 Browning A-bolt I bought in the mid-'90s had that sort of rubber bedding in the synthetic stock, and it shoots very well. I remember when Champion Shooter Supply used to sell it back then in pouches that would mix to a few ounces for one-time use, but I don't see those smaller dispensing packs available currently.

[Shadow9mm]

Originally Posted by tangolima

If it is pure epoxy glue, I agree with you on brittleness. But it is not. The hardness / strength comes from the metallic particles embedded in the mixture.

Other important parameters is stability. How much it shrinks after curing and due to temperature variations or stress applied. Don't have any data to substantiate, I think devcon is the best, followed by JB.

-TL

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I have used a number of different epoxies along with jb weld over the years. In my experience some epoxies are more brittle than others. Regardless if they are filled or not and it really comes down to the epoxy being used. I hsve found jb weld to be both stronger, but more brittle than others. The purpose made bedding compounds I have used tended to be a bit softer , more flexible, less brittle.

Dont get me wrong, I love jb weld, but based on my personal experience I would not use it as a bedding compound.

[Nathan]

JB Weld should be a good bedding epoxy.

Basically bedding compound has 2 main features that cause the word bedding to appear on the package. First, it needs to have low shrink. That is normally done by adding steel or some other filler to block shrinkage. It has that. Second, it needs to have pretty long working time like 2-4hours so it cures slow enough to allow fitting the action in it and also for scrapping lightly cured epoxy that is still "chewy". It has that too.

It would be better if it were available in black or brown. I think it is solvent resistent, but that is important too.

[totaldla]

Originally Posted by Nathan

JB Weld should be a good bedding epoxy.

Basically bedding compound has 2 main features that cause the word bedding to appear on the package. First, it needs to have low shrink. That is normally done by adding steel or some other filler to block shrinkage. It has that. Second, it needs to have pretty long working time like 2-4hours so it cures slow enough to allow fitting the action in it and also for scrapping lightly cured epoxy that is still "chewy". It has that too.

It would be better if it were available in black or brown. I think it is solvent resistent, but that is important too.

Yep on all your points..

I would like to emphasize that JB is quite strong when cured and you aren't going "scrape" it - you need a Dremel.

[Nathan]

Originally Posted by totaldla

I would like to emphasize that JB is quite strong when cured and you aren't going "scrape" it - you need a Dremel.

Yea, I mean scrape during the chewy state. Seems like good bedding epoxy goes from sticky/fluid to chewy/not sticky to hard.

[4V50 Gary]

Don't be a Joe Hobby or Buffing Bob. Nothing screams amateur like JB Weld. Just use acraglass.

[tangolima]

Originally Posted by 4V50 Gary

Don't be a Joe Hobby or Buffing Bob. Nothing screams amateur like JB Weld. Just use acraglass.

Unless I'm getting paid using acraglass, I'm still an ... amateur.

Professional doesn't necessarily do the best job. They need to keep eye on the bottom line. Amateur, however, is doing it for fun. He often doesn't care the cost till a perfect job is done.

If it works, it works. The name or brand doesn't matter.

-TL

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[Nathan]

Originally Posted by 4V50 Gary

Don't be a Joe Hobby or Buffing Bob. Nothing screams amateur like JB Weld. Just use acraglass.

Why? Is there something better about a different filled epoxy?

[4V50 Gary]

Virtually everyone of us in GunRepair I or II at some point came across a firearm that Joe Hobby or Buffing Bob used JB Weld to repair. Mine was a S&W revolver center pin that was lengthened with it. Since it was an older Victory Model (WW II) revolver, I had to turn a new center pin on a lathe. As students we were held to a professional standards.

OK, you're in the jungles of Burma or in the middle off the Sahara and there's no machine shop. Go for it to get your gun to work. Kinda like WW II's U-124 that needed bearings and the engineer collected all the aluminium foil from the cigarette packs to make them.

I'm not here to give Joe Hobby or Buffing Bob level of advice and this forum was intended to promote professional gunsmith level of work and not Third World standards; but if that's what you guys want or would pay a "gunsmith" for, that's your personal choice.

[tangolima]

So if the guy had used arcaglass, instead of JB weld, to lengthen the center pin, you would feel better?

It is a straw man argument. Nothing to do with glass bedding. Doesn't prove it must be arcaglass and nothing else. Professionals botch up bedding jobs with arcaglass all the time too. Actually the very method of glass bedding was rather frawned upon by the older generation of professionals.

I hope I haven't been on the wrong forum for so many years. A lot of things we have discussed here the professionals would never get closed to.

-TL

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[4V50 Gary]

You missed my point about JBWeld. Keep to lower the standards/quality. It's your choice.

[tangolima]

Originally Posted by 4V50 Gary

You missed my point about JBWeld. Keep to lower the standards/quality. It's your choice.

I did use JB weld. It worked pretty well.

I have used up the last bit of JB weld, and will switch to other epoxy putty recommended by professional machinist. They use that in their shop to repair drive shaft. He first recommended an even better product for repairing engine block. It only comes in tub that costs too much. All that doesn't have "gun" in product descriptions. It doesn't have to.

If it works, it works. Says who it must be this and not that?

-TL

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[Shadow9mm]

Define works... Sure you may be able to bed a rifle with it, but you could bed a rifle with hot glue if you really wanted to. Does not make it a good idea, does not mean it will do a good job, and does not mean it will hold up over time.

They make specific products for a reason for many applications, not just those with "gun" on them. Right tool for the right job. Sure you can jerry rig things and make them work. But when there is a relatively inexpensive product that is purpose built for the job, you should probably use that instead of something else.

[tangolima]

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