Best Bedding Material

xsn10s

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I think the shrinkage was greater with JB Weld. But that doesn't matter much to me since this is practice bedding epoxy in lieu of the more expensive beddings.
 

Hugnot

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I have epoxy bedded many wood, laminated, & plastic stocks during the past 50 years. I remember when the Brownell's Accraglass (sp?) came with a packet of powder that might have been asbestos to make it less runny.

Last winter wifey bought a big cast iron pot for stew making in the oven at temps of 350* plus. The precious, high price, pink pot suffered a chipped handle that if left unrepaired would have promoted further deterioration of the delicate, pink enamel coating and presented a rough sharp surface to compromise grasping using oven mitts or pot holders. I was detailed to remedy the situation and, in the process, I selected J-B Steel as a way to restore the item to functional use. Lots of stews at 350* and the J-B Weld Steel still sticking, tight, hard & smooth. The dark gray J-B presents somewhat of a color discontinuity with the pot's soft muted pink color.

The next logical step was to buy several packets of the J-B Weld Steel epoxy for under $6 each for rifle bedding. Kiwi works good for release agent & filling recesses. One pack of J-B steel good for one bedding job. Made nice handles for wood rasps and fixed an awl handle with the excess after the bedding job. I'm not fussy about the dark gray J-B steel color, makes sort of a nice boundry outline. Not excessively runny & ample working time. Glued some fore-end tips onto stocks using J-B steel that flowed into hole drilled into tip & stock joint for strength and clamped together with surgical tubing until set. No shrinkage. Strong hard surface for recoil lugs. "Strength 5020 PSI" Don't have any anti- aircraft artillery so can't comment on extreme compressive recoil force aspects.

Edit: Making J-B Weld Steel in a variety of colors might be difficult but addition of various inorganic compounds containing cadmium, iron, zinc, & others might change the utilitarian dark gray color & provide nicer tones of walnut or certain shades of delicate pink. When toasted at temps exceeding 350* the colors would remain unchanged and remain attractive as part of the non-shrinking, temperature resistant, high strength, surface degradation resistant (like stays smooth) J-B Weld Steel.
 
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BFD Guns

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I think the shrinkage was greater with JB Weld. But that doesn't matter much to me since this is practice bedding epoxy in lieu of the more expensive beddings.
I'm bedding a plastic stock. I won't need to worry about weather. If I was doing a wood stock I liked, I'd do Devcon or Marine Tex.
 

xsn10s

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I used JB on a laminate stock. Free stock and a skim bed.
I figured it's good practice. Later on when I find a nice stainless action I'll drill out, or put the stock on a mill and get the bedding out. I'll bed it with whatever epoxy compound I like using the best.
 

Hugnot

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In general, epoxies don't adhere well to many ejection molded plastic stocks. In this case a mechanical type lock needs to be used & this makes epoxy strength important. I would be confident in J-B Weld Steel.

Seen Devcon used make temporary repairs to eroded water lands in diesel engines. I like the cheap packets of J-B Weld Steel for under $6 each - 1 pack per stock bed job.
 

Dragoon300

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Clean and prep the surfaces as per recommended instructions with whatever product you choose, and choose the one that says it will bond to the material you are working on, and if necessary grind undercuts to hold it in place. Just follow the manufacturers professional instructions. Simple as that!
Of course most red blooded males don't read or follow instructions 🤫
 

Hugnot

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Not all epoxies exhibit equal temperature tolerance ranges - for example Brownell's Acraglas Gel contains nylon particles ("Nylon Derivatives") to increase viscosity (less drippy) and nylon has a limited working temp not to exceed that of boiling water - not usually seen from normal shooting but what if a heat source was used next to the Acraglas Gel for some purpose and temps exceeded 212F*, how would the Acraglas Gel react? Many quick set epoxies have inadequate strength and limited working time for bedding applications.

An explanation from Wikipedia of how the epoxies stick to stuff like to wood & steel:

"As adhesives, epoxies bond in three ways: a) Mechanically, because the bonding surfaces are roughened; b) by proximity, because the cured resins are physically so close to the bonding surfaces that they are hard to separate; c) ionically, because the epoxy resins form ionic bonds at an atomic level with the bonding surfaces. This last is substantially the strongest of the three.[22] By contrast, polyester resins can only bond using the first two of these, which greatly reduces their utility as adhesives and in marine repair."
 
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shortgrass

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Some how, wood stocks have crept into this discussion. I think Coyote Shadow Tracker (he started this tread) is probably more synthetic oriented for F Class and ELR rifles. But, glass bedding an action is the same , either way. I have seen a couple of synthetic stocks and laminates that broke from not being bedded properly.
 

Hugnot

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Sounds like, by "chassis" construction with plastics & metal meaning more reliance on mechanical aspects of epoxy bonding - don't depend on smooth surface to surface with epoxy to plastic. Possibly, epoxy bedding would not be required for "chassis" type stocks if receiver & barrel were to be secured inside "chassis"

Here is another link that explains how this stuff works. Usually, the bond is stronger than the material itself if plastics not bonded. Epoxy sticks to aluminum real good - just get the aluminum real clean.

 
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shortgrass

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The exposed inletting in a McMillian, Brown Precision, Manners or AG Composite isn't 'plastic'. The exposed filler materials in any of these offers extremely good bonding surface for epoxies. Don't know where "chassis" came from, as CST (Coyote Shadow Tracker) said he is moving away from these. The only "chassis" I am really familiar with is made by Competition Machine, Inc., and their design doesn't allow for added 'bedding'. The injection molded 'plastic' stocks aren't worth messing with. Many (most) of the stocks made with an integral aluminum bedding block can benefit from 'skim bedding', as they are not perfectly aligned, sometimes.
 
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