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The qualities you want in a bedding epoxy (no matter which one you like) are a very low percentage of shrinking and a very high compression strength.

Stock bedding is not really subject to any shearing forces but it is subjected to compression and shock and that's where some products rise above the others.

Marine-Tex does not list either the shrinkage rate nor the compression strength...only the shear strength and tensile strength of the cured product.

Brownells lists the shrinking specs but not the compression strength of their products.

Devcon, by far, has the most extensive tech specs of any epoxy I have used. The compression strength of Devcon Titanium putty is 18,800 psi!

Not really, just flipping the rifle upside down is not failproof. I'm not saying you are wrong but I have never seen anyone clean their rifles that way especially at the range with a scoped rifle.

The Varmint Hunter Magazine, Jan 2000

Some Thoughts on Load Development - Part III by Steve Timm
What To Do If The Rifle Won't Shoot Accurately
"If the rifle has been in service for a while, take a dental probe and check that the synthetic bedding compound is hard. Sometimes sloppy cleaning procedures allow solvents to creep into the bedding. The solvents of course, attack the bedding compound and eventually leave it with a puttylike consistency. If the compound is soft or questionable in any way, then replace it"

Now before you say any more wise-a$$ comments check this out:
Bartlein Barrels on Breakin/Cleaning



Do these folks lack common sense for cleaning their rifles in the upright position? I clean my own rifles upright, muzzle slightly down and simply stuff a small piece of cotton under the boreguide/chamber area as a precautionary measure. But some folks might not know that solvent can creep into their rifle bedding and may be ruining their bedding job.

MtnHtr

Like I said, I was taught that in boot camp 45 years ago and never really knew that it was all that esoteric or unknown. Shows you how naive and out of touch I am I guess.

I clean scoped rifles like that all the time and have never really thought it was weird or difficult at all.

Now...before you say any more wiseass comments...get down and give me fifty private for insulting the Corps!

Sir, Yes Sir!



MtnHtr

See there...you do actually have a sense of humor!

I like Acraglas gel mixed with powdered aluminum and Marine Tex for the skim coats. I have never tried the expensive Devcons as this aforementioned work fine.

Mel Smart- who started what is now Serengeti used red-box acraglas and used steel wool as "rebar" in the stock. I have found that red-box acraglas with Kevlar chips added makes for a fantastic bedding job and looks good too- it's just a lot of work to cut up that Kevlar small enough to use it that way. I sent Mel a lot of it and he loved it. Used up until he died.

There's a lot of good products out there for bedding. Richard's Micro fit isn't one of them!

I'm not trying to be contentious, or shill for Devcon, but I doubt that Devcon is more expensive than the Brownell's products when you consider the cost per quantity in the standard containers of each. IIRC, Brownell's is a few ounces, whereas Devcon putty comes in one pound cans. Brownell's also sell in bulk quantities.

Epoxy ain't cheap, and if you buy Brownell's in the kits, you're paying for the packaging and little doo-dads. I'm just an amateur who does an occasional job, so the cost differential doesn't drive my preferences anyhow. I've been happy with both brands mentioned.

I've never used Micro-Fit, but thanks for the heads up.

Paul

FWIW...I believe that Devcon is the only epoxy out there with a Mil-Spec rating. I'll leave that up to each person to gauge the value of that when making their choice, but what it means to me is that their products have undergone and passed an independent battery of tests that can be viewed and evaluated as to their relevance for your intended use. With the other products you pretty much have to rely on the manufacturers advertising claims and word of mouth from users.

The trouble with word of mouth, IMO, is that you seldom know what criteria the speaker is using when claiming that Brand X is the "best." I have heard people claim that JB Weld is the greatest stuff around for bedding but when pushed for an explanation the low cost and availability seems to always be the deciding factors for their evaluation.

I've done a few with JB and never had any problems. Only reason I used it was because it was recommended to me for being easy to work with and not prone to voids/air bubbles. Haven't used it on any hard-recoiling rifles. That being said, I have a box of Devcon steel putty on my bench for a tryout.

Air bubbles and voids are the result of poor mixing and application procedures...and have nothing to do with the material being used.

This is sort of what I was referring to by "word of mouth" endorsements for a product.

I agree with the first part of your statement, but not the second. I have found that the texture and consistency of the mix do make a difference, and that's I why I developed a dislike for Acraglas Gel many years ago, because of its stringy, taffy-like texture. The thicker compounds seem more likely to trap an air bubble than the more fluid mixes like original Acraglas. One thing I have found that helps is to load your epoxy into a fairly large syringe, and carefully inject it into the bottom of the recess, gradually moving toward the top. Of course, you still have to watch for bubbles, and deal with them on the spot.

I do agree that technique matters, a lot.

Paul

I just did a Savage rimfire using Devcon Plastic Steel Putty. It costs $32 a lb. here in Canada. You can find it at industrial supply places. It works very well, and compared to fiberglass resins I've used in the past, it is a pleasure to work with. It does not flow much at all on it's own. I used my reloading powder scale to measure the putty and hardner to get the mix right. If you want to read the gory details, I documented the process here.

http://www.rimfirecentral.com/forums/showthread.php?t=223949

The specs on the Devcon are here:

http://www.devcon.com/prodfiles/pdfs/fam_tds_101.pdf

Yes, it is a bit gritty if you rub it between your fingers, but it moulds to a glass like finish equal to what is against it when it sets up. There is no doubt that is what I would use again next time.

Ron

Rick:

I have used both Devcon and JB Weld. The Devcon I used in the past was white, and 24 hour cure. I would still use it, but none of the hardware stores in my area carry it any more. I don't think it had any steel filler or any other filler in it.

JB Weld is plentiful, and I use it now. The grey kind that dries overnight.

But, although I have bedded rifles and shotgun stocks with it, I use it for another purpose.

I make knives, and I glue the handle scales onto the full tang of the knives. I also use rivets, but I use glue 'just in case'.

Occasionaly, I make a slight error and have to remove a handle. I clamp the blade, point down, in a vice and drive a chisel down between the steel tang and the handle material. Most of the time, the wood, or whatever handle material I use breaks before the glue comes loose from either the knife tang or handle, then I have to grind the glue off.

These two glues are the only two I have used that bond this well, and that includes Accuglass and all other brands of epoxy glue that I have tried, which has been several.

When I grind the handle material down to the steel, sometimes I get careless and grind too much, getting the steel extremely hot. I don't know how hot, but too hot to hold. So far the Devcon and JB have held, even after heating. IIRC, JB will hold up to 300 degrees F.

If I did this with other epoxys, and I have, including Accuglass, the knife and handle seperates before it even gets warm.

It has been my experience that very few glues, of any type, will securly bond metal, except these two. Accuglas might, but the heat resistance, for my purposes, is lacking.

Before applying the glue to BOTH surfaces, I degrease both surfaces with rubbing alcohol, and let dry.

I realize that bonding strength does not necessarily make for a good bedding material, nor the other way around, but I wouldn't hesitate to use either epoxys for either purpose, and I have and do.

As far as the 5 and 30 minute clear stuff, in either brand, for my purposes they could quit making it and I wouldn't miss it.

In a perfect world bedding should allow the receiver to do it's flexing when the shot goes off...and then let the receiver settle back to the exact same place it was before the shot was fired (every time). To do that it needs to have very good resistance to compression and impact. Shearing strength (which is what you describe with your knife handles) isn't really a factor with rifle bedding.

Just about all the epoxies will withstand temporary heating to 250�-300� F without any problems.

The five minute epoxies are handy for "tacking" pillars in place so you can move right on to bedding without having to wait overnight for the pillars to be solidly anchored in place.

I've been reading this thread with interest and don't want to hijack it, but does anyone know where to find a good tutorial on bedding? Thanks!

Anyone tried the "blackmax" cyano-glue?

This is the best one I know of. In it there is a discussion of the pros and cons of the different bedding materials, and release agents.

http://www.6mmbr.com/pillarbedding.html

Ron

Thanks, Ron. Now THAT'S a good tutorial. Unlike the one-size-fits-all-exclusively smiths I mentioned in an earlier post, this guy explains the how and why of what he does and recommends. His comments about soft brown bedding compounds and not trying to get by on the cheap with epoxies are especially worth reading and heeding.

Also, Rick made a good point about mil-spec standards for epoxies.

dennisinaz, with due respect to what appears to be have been a close relationship between you and the deceased founder, and with the current owners of Serengeti, if I was prepared to spend thousands on a high-end rifle and learned that the makers were bedding with Acraglas and steel wool "rebar", I would go elsewhere post haste. Ditto on the kevlar fill.

It's not that homebrewed epoxy fillers don't work, I've used them myself, but for the main bedding I wouldn't trust fillers added to the mix. I'd be concerned with uniformity, among other things. I have much more confidence in manufacturered products with the filler added by the factory, to consistent specifications.

As the saying goes, YMMV.

Paul

All jokes about "military intelligence" aside...the advantage to Mil-Spec testing is that they conduct the tests under every conceivable environmental condition on the planet. Having a product tested in extremes of temperature, humidity, altitude, etc, can be very helpful when making a decision.

Devcon has been making epoxies for the military and the aviation/aero-space industry since the 1950's when the technology started...and that says something to me.

Everyone should make their own decisions, but having all the specs available sure helps you to make "informed" decisions.

Exactly!