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Old December 14, 2010, 09:52 AM   #1
Gator Weiss
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Best rifle bedding techniques and compounds

It would appear there are many ways to bed rifles. Piller bedding is an interesting method, and there is some disagreement over contoured pillars verses flat top pillers.

It would appear there is much disagreement over bedding compounds. Many experienced gunsmiths like the accra glass bedding compound. Many experienced gunsmiths say they wont use it. Some are really into metal putty compounds ranging from steel to titanium to aluminum. A few use only JB Weld in key points only.

I have a model 91 Argentine that I am about to bed into a laminate stock. I am interested in using a combination of pillars and bedding. I chose the Argentine action because it has a very thick-walled barrel, and the recoil lug is very wide. It was affordable, yet it will be accurate, and I can contionue to make brass from common 30-06 cases if I need to. Not a bad little rig for the handloader. Not a bad little cartridge for bench shooting or occasional hunting of deer. There are better rigs. There are better cartridges. But I like this one.

The stock came from Richards, and it is one of those situations in which too much wood was removed from some places and not enough in others. It came that way. There is no such thing as 99 percent press inlet gunstocks in my opinion. All in all, it is a very good stock, and I expected to have to work it considerably to get it where I need it to be.

I am looking for some feedback on the various stock bedding compounds.

Q: Is there any disadvantage to the mettalic compounds vs the glass?

Q: Of the metalic compounds, is there any disadvantage to Aluminum, vs the steel or titanium?

Q: Is ambient temperature a factor in curing bedding compounds?

Q: I have been advised to put my action into the oven to warm it before bedding it. Some have told me that this is Bull ****. Anyone else ever heard of that before?

Q: Some smiths are using car wax for release agent, some use neutral shoe polish, and some use vaseline. I know of one who users toilet bowl ring wax heated and brushed on and polished off with cloth. We do know there are commcercially produced release agents out there that some smiths seem to want to avoid in favor of improvising with things that were not necessarily meant to use as a release agent. Why is this?

In the case of my stock, there are weak spots in points where too much wood is gone from the action area, and I intend to strengthen those areas by using finely cut glass fiber mixed with a cold metallic paste polymer compound applied in a few strategic points. After that is burnished down to an acceptable elevation, I intend to bed over top of that with a good bedding compound in which to set my action. Fortunately, the lug area is not one of the weak spots. Does anyone have a different technique for such a remedy?
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Old December 14, 2010, 12:01 PM   #2
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Quote:
Q: Is there any disadvantage to the mettalic compounds vs the glass?
As you said, whether or not metal makes a difference depends on who you ask. Metal bedding compounds are epoxy resins with metal powder mixed in. I prefer to use solid resin, or resin with glass fibers mixed in for strength. Metal might make a difference if it were not finely pulverized, but most metal putties use powdered metal. My opinion is that this makes the putty very hard, but brittle. I have seen metal putty bedding break out in chunks, but never seen a solid resin bedding job do that. I knew a man who used stainless steel wool in his bedding jobs, and it worked very well for him.

Quote:
Q: Of the metalic compounds, is there any disadvantage to Aluminum, vs the steel or titanium?
As I am not a fan of metal bedding compounds, I will say no, the metal you mix with the resin makes no difference, but others may disagree.

Quote:
Q: Is ambient temperature a factor in curing bedding compounds?
To a point, yes. Epoxy compounds are catalyzed polymerization chemicals, and since heat accelerates the polymerization, it will generally reduce cure time. At the one extreme, you can make AcraGlas remain liquid for a long time by putting it in a freezer. At the other extreme, by heating it you can accelerate the curing to the point that it becomes clumpy and won't give you enough time to put the barreled action into the stock. Most catalyzed epoxy compounds are made to work within the normal range of temperatures we call "room temperature".

Quote:
Q: I have been advised to put my action into the oven to warm it before bedding it.
Never heard of it, but as long as you do not heat the barreled action too much, it shouldn't hurt.

Quote:
Q: Some smiths are using car wax for release agent, some use neutral shoe polish, and some use vaseline. I know of one who users toilet bowl ring wax heated and brushed on and polished off with cloth. We do know there are commcercially produced release agents out there that some smiths seem to want to avoid in favor of improvising with things that were not necessarily meant to use as a release agent. Why is this?
Most commercial release agents are polyvinyl alcohol mixtures. As such, they do not stick to the metal, but will stick to epoxy and leave filmy strands everywhere, and they give you one more thing to clean up before the job is done. Car wax will work, as will shoe polish, Pledge furniture polish, or virtually any other wax. Wax compounds stick to the metal and epoxy will not stick to them, so they give a smooth, perfect fit to bedding jobs. Most waxes are also inexpensive, and you can look at a metal part and tell if it has been waxed or not. I have had bedding stick to an action using commercial release agent, but never when using wax.

Quote:
I intend to strengthen those areas by using finely cut glass fiber mixed with a cold metallic paste polymer compound applied in a few strategic points. After that is burnished down to an acceptable elevation, I intend to bed over top of that with a good bedding compound in which to set my action. Fortunately, the lug area is not one of the weak spots. Does anyone have a different technique for such a remedy?
What you are describing is called "fairing", essentially filling an area to make it smooth. I usually just do it as part of the bedding job, but I have had stocks come in that were broken, had missing pieces, holes, loose knots, etc, and with those I may fill them if they are too big to fill reliably when bedding.

Your stock is rough inletted, and may have areas 1/16" wide where the person running the cutter got a little wild, but there should not be any big holes. Use your judgement on those areas.
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Old December 14, 2010, 06:43 PM   #3
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I use devcon steel putty and neutral kiwi shoe polish rubbed on lightly. I've had very good luck with it.
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Old December 14, 2010, 08:26 PM   #4
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Devcon Steel Putty

.

+1 on this choice. It's all I've used for the past 20 years. Devcon
steel putty. Paste wax for release agent. This compound is hard/tough
and has very little shrinkage. Many benchrest gunsmiths will use
nothing else. My second choice would be AcraGlass Gel from
Brownell's if you have to use a 50/50 type compound. You will
have to weigh the Devcon components on your powder scale.

Metal filled epoxy compounds are superior to resin only.

Here's a link --

http://www.devcon.com/products/produ...m?familyid=101

For metal prep, clean your metal twice with alcohol or acetone. Then wipe on a thin coat of paste wax or neutral shoe polish. Buff. Recoat. Buff lightly with kleenex. You are ready. Epoxies will NOT stick to wax. Wax coat any metal that you even think might come in contact with epoxy. Do your thing inside at room temperature. That's total crap about putting the metal in an oven for warming.

Pillar bedding is a great idea for an action that it caters to. Definitely the way to go for a target rifle. May be overkill for a hunter or plinker. I bedded many rifles that shot aces before Dave Hall came along with pillar
bedding. But I do it now as standard. I even pillar bedded my K31.


good shooting, dxr







.

Last edited by DoctorXring; December 14, 2010 at 08:56 PM.
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Old December 15, 2010, 03:50 AM   #5
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Be sure to note the difference between Acraglas and Acraglas GEL. Acraglas is very thin. Great for seeping into cracked stocks, terrible for bedding. Acraglas GEL is the consistency of peanut butter. Easy to work with and dyeable, great for bedding stocks.

Pillars are a good thing. However, 90% of the benefit of a bedding job comes from the bedding. If you have to tooling to do pillars right, with nice 90 degree cuts and the proper length, great. If you don't, you'd be better off without.
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Old December 15, 2010, 05:38 AM   #6
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Pillar bedding is a great way to reinforce you action bedding. Fiberglass or metal makes the resin stronger. I like to use steel shavings from my brake and rotor lathe (sifted through a screen) and mixed with slow setting epoxy (24 hour set). For a release agent, wax works best. I happen to use pledge spray wax because it gives and even coat and releases well. Usually 3 thin coats.
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Old December 15, 2010, 07:19 AM   #7
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I like Acraglas for wood stocks, especially older ones that may have oil-soaked soft spots, because it will run into the grain and strengthen the wood better than the paste bedding compounds. Ideally, Acraglas would be used as the first layer, followed up with a paste like Devcon. Over the years, I've used about every compound available. Preparation by routing out and roughening areas at least 1/16" deep, while leaving small positioning wood pads, is necessary to increase stiffness. Painting existing surfaces just takes up air space, but does nothing for accuracy longevity and stability under stress.

I've often managed to use Acraglas for the complete job by using hand-cut fibreglas insulation batts to keep the mixture from running as much, while retaining the penetration qualities.

Steel tubing from the hardware stores, about 1/2" diameter makes good pillars. I usually leave them flat and about 1/16" below the receiver, so bedding material can better cradle the action. It's more important to have the pillar touch the trigger guard/base plate/steel escutcheon area at the bottom of the stock, since that area is smaller and tends to compress the wood when screws are tightened. The upper section has a much bigger bearing area that needs more uniform pressure.

The trick to a good bedding job is to use enough tape on the bottom, front and sides of the recoil plate, so they won't touch as the rifle is fired and will allow the action to be removed easily. The rear of the plate is the only vertical surface that should touch bedding. Screws must be relieved by drilling out their holes in the stock, so the only places they touch are at each end.

Also, be sure to clean out any bedding material that gets into blind receiver screw holes. Accuracy of many bedding jobs is ruined by lack of screw or recoil plate clearance.
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Old December 15, 2010, 07:30 AM   #8
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Yesterday I used PC-7 to epoxy in a steel stock liner. Good stuff but it dries slowly.
Today Acraglas Steelbed which has worked fine for me in the past.
The release agent from Acraglas for both.
Works for me.
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Old March 12, 2013, 11:53 AM   #9
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I'm about to do my first bedding job. I'm an engineer with 30 years of field experience and a bit of a geek so I'm doing all my research first. My thought on the metal impregnated epoxies is this: the metals are added for wear and abrasion resistance, not strength or resistance to compression. So the metals might actually be a negative. OTOH, the metal bearing epoxies are very expensive so the epoxy carrier is probably very high end/high strength.

I still haven't decided which epoxy to use but I think I have some free titanium devcon so I may use it before it's shelf life expires. I think colored is better for looks. I think the consistency of the epoxy while the work is being done should be a significant consideration. Easier to work with means a better job.

I haven't decided for sure if metal pillars are important or not. I have bought an in-lb torque wrench. skipping the pillars will allow the wood to compress a little and keep tension on the guard bolts, however, this could change will temperature. I'm thinking I'll make some pillars out of aluminum or brass.

Grey will look good with the blue laminated stock which will probably be the first one I do. Not sure if I'll bed it before or after I cut it apart and install adjustable cheekpiece.

I really appreciate all the experience here and feel like this thread gave me the answer on the release agent. I think I'll wax the action and probably put some shoe polish over that.

thanks,
Jerry
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Old March 12, 2013, 12:55 PM   #10
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Most very accurate rifles are epoxy bedded with Devcon or MarineTex plastic steel. Brownell's had a steel filled mix that also worked well. These have also proved in my shrinkage tests to do so the least. Which means they'll have a better (harder?) grip on the receiver. The reason metal-filled epoxy's shrink the least is epoxy shrinks when curing; the metal does not. Adding a tiny bit of baking flour to the runny mix makes it thicker and easier sometimes to use.

Pillar bedding came about when the first synthetic stocks' core in the receiver area was too soft for conventional bedding. It compressed to easily when stock screws were torqued to 60 inch-pounds or so. Gluing in metal pillars in those soft cores helped quite a bit. But they're not needed on synthetic or wood stocks these days as proved by folks winning matches and setting records with conventional epoxy bedding shooting against pillar bedded systems.

Putting wave washers on your stock screws will help compensate for stock dimensional changes with temperature. Or just take a small torque wrench with you and retorque as temperture changes. But always loosen torque on stock screws when the rifle's stored unless the barreled action's in a solid metal stock.

The thinnest possible coat of Simonize car wax on receivers has ended up making the tightest fitting bedding jobs for me.
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Old March 12, 2013, 02:09 PM   #11
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Bart,
Thanks for your comments. Yesterday I printed out two items. One was the "how to" from midway, which I thought was a good starting point as these generic instructions usually are and the second was a thread I found in rec.guns archive from 1994:

http://yarchive.net/gun/rifle/bedding.html

which I thought sounded like the most knowledgeable post I had found on the subject.

I assume you are the same BartB. I've been on the internet long enough to know when to listen and I think I've found everything I need to know for now.

As for the metal epoxies, I didn't think about shrinkage. Good point.

So I will NOT use metal pillars in my wooden stock and I'll use just the car wax and I'll have at it.

thanks much for your help,

Jerry
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Old March 12, 2013, 02:22 PM   #12
Bart B.
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Carlsbad, yup, that's what I wrote the year before I retired from Hewlett-Packard.

My best reference on conventional epxoxy bedding comes from a family of four people who, among them, have probably won more matches and set more records than any other group of four folks on this planet. Their stocks are all conventional bedded and ammo's all made with full length sized cases.
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Old March 12, 2013, 03:20 PM   #13
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Bart, I had to save that to my favorites, I have a wooden stocked mauser that'll get bedded next winter, and thanks to you I will do it myself, Bravo fine sir.

P.S. I use 1/8 inch Black Iron Pipe nipples cut ten thousands over length to pillar bed my synthetics, I use a dremel tool and a cutting wheel to cut grooves all the way around at about 1/8 inch intervals, this seems to let the epoxy have a rigid grip on the nipple to the stock.
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Old March 12, 2013, 04:42 PM   #14
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The materials are important, the epoxy choice must be very hard, and non-shrinking. I've used JB Weld with no problems, but it is runny- the Devcon putty is a better choice.

It's equally important to position the receiver correctly, that the proper depth of epoxy is achieved where it's needed, and that it's done in a stress free manner.
I use electrical tape wrapped around the barrel and stock, for even pressure.
Don't use clamps...
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Old March 16, 2013, 09:47 PM   #15
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Have done match .22 and M1 Garand, ...

using Bisonite compound. At that time it was the choice of the USMC Rifle team.

The .22 is an Anschutz and it was bedded to a walnut stock, using 1" aluminum pillars, the front pillar was machined to fit the cross-wise slot of the action acting as the recoil lug and the two pillar were bedded first with business cards
after drying the the action was filled and completed for full contact.

The M1 was bedded into a surplus birch stock using the standard procedure for the M1. [Ref: Kunhausen book on the M1 /M1A]

I now have a M1a that need to rebed the rear mag lugs as the origanl 1983 bedding has deteriorated.

I have used the Bisonite for my Win M88/M100 rifles, and have three deer rifles that will place three shots @ 200yd using prone position, within the circle of the "X" using my handloads.
What was involved here was the minimizing the movement of the action, by bedding the forward magazine lug, using a "U-shape"configuration, and then
barrel tendon was bedded to give a solid bed and the barrel channel was relieve.
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