Bedding question

Discussion in 'Gunsmithing' started by shadowdrak, Aug 6, 2008.

  1. shadowdrak

    shadowdrak Active Member

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    I recently had a Remy 700 PSS glass bedded and had a question on it since this is the first time I have had this done to a rifle.

    I can see the glass bedding extending 2 1/2" from the chamber into the barrel and then an inch from the chamber back towards the bolt. I thought when you glass bedded, it was done (with the option of going 2" or so forward of the chamber and then all the way back to where the rear of the bolt is. Is this a proper bedding job or some half-butt job?

    Thanks for any help on this.
     
  2. dirtball

    dirtball Well-Known Member

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    Check out this link, it will tell you how it is done and show what it "should" look like. Now granted the pictures are of a single shot rifle but you get the idea.
    Dave
    Stress-Free Pillar Bedding
     

  3. NesikaChad

    NesikaChad Well-Known Member

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    There's an almost infinite number of ways to do this and every gun plumber has his/her own way of doing stuff. I float my barrels all the way to the receiver. (certain rimfires being the exception) and I've never had an issue. My actions literally fall out of the stocks unless the guard screws are inserted. Again, no issues. Some of these guns hold world championships and Olympic gold yet I know there are builders out there who shake their head when they see it.

    Where it matters is when you go pull the trigger. shoot it and then carefully log what the gun does, then shoot it again after an abrupt weather change. Compare the two groups for both size, and more importantly, change of zero.

    ensure you use the same lot of ammo and don't alter the gun in any way between these tests. If you clean the bore after the first test, shoot some foulers before going for record on the second test.

    A well done bedding job will have almost no zero shift and it should tighten the groups up a little bit. No bedding in the world is going to suddenly make a bad gun shoot great however. It'll take a good gun to really good, really good to great, and great to exceptional.

    Turds are still turds however.

    Good luck.
     
  4. shadowdrak

    shadowdrak Active Member

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    Groups didn't change too much, maybe opened up a little bit (over 3/4 moa). Took the stock off of it to and you wouldn't believe the shock on my face. Bedding was extend backwards the same length and case ejecting side had more bedding than the non-ejecting side, causing unequal pressure. After running the bedding two and a half inches past the chamber, instead of abruptly ending, it seemed like he took a step down and then tapered it of (running about an inch and a half longer). This runout had warping/pitting on both sides and were contacting the barrel. The bedding towards the action had several rough/protruding spots that were providing unneccassary contact. Also, there was also bedding contact on both front and sides of the recoil lug. This is one hell of a mess up job and now I got to find another gunsmith and pay again to have it rebedded properly.
     
  5. kfrye

    kfrye Well-Known Member

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    Chad,

    Great article at firearms forum on bedding. For better or worse, I am going to try tackling a bedding project and would like your direction on a couple loose ends I have before I start:

    You mention making sure the action is sitting in the stock at waterline- do you have a picture that shows this or can you explain sitting at waterline?

    With the 10ml pipe around the barrel, how do you make sure the tang of the action is sitting level with the front?

    Once the action is in the bedded stock, how do you securely hold everything together while the epoxy cures- stock makers screws, electrical tape?

    Lastly, do you wait until the epoxy is fully cured before pulling the gun back apart for clean up, or do you monitor what gets squeezed out and start trimming before the bed is fully cured, followed by pulling the action out and trimming the excess out? Studying your photos, have you graduated to machining out the excess with a program?

    Thanks for your help Chad, I am going to try and measure up to the fine work you have posted. I am hoping I can speed the learning curve along.

    Ken
     
  6. NesikaChad

    NesikaChad Well-Known Member

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    If the mods deem it worthy, maybe this can turn into a sticky.

    I've hit on this subject on a number of forums. I bounce around trolling these sites when the slow part of the day comes here in Baghdad. I don't manage it very well and as a result a lot of the questions from folks become a bit redundant.

    Rather than make you all hunt and search, I'll just lump all the crap together in one busket.

    How's that?

    Here goes: From "The Firearms Forum"

    The Firearms Forum.Com - View Single Post - Epoxy Bedding

    Dev Con HVAC is a product I've had good success with.

    Some tips to making this less painful.

    Heat up the resin/hardener first. Use a 100 watt light bulb for this. Just place the two tubes under a bulb until they are hot enough that it becomes uncomfortable to hold them in your hand. (remove the plastic screw on caps first, the tubes are sealed so its ok)

    Get a glass plate. Will only cost a few bucks. Make it a big one. Like two feet by two feet. You'll be happy you did cause you want the room.

    Buy wide puddy knives. 4". Get a couple of them.

    Gallon of denatured alky or acetone too. (for clean up, NEVER NEVER attempt to dilute epoxy, it screws it up!)

    Mix the resin by folding it onto itself. NEVER stir!

    Folding helps keep the air out. Stirring just adds to it.

    Bedding jobs fail for one primary reason. people don't mix the resins long enough.

    Give yourself a solid 3 minutes (set an egg timer) of mixing that stuff.

    Your hand should be sore and feeling like it might have blisters.

    Don't be a pussy either. Vigorously mix it. Epoxies cure by a chemical reaction. They don't dry from evaporation.

    If you don't get the stuff mixed, you'll have hard and soft spots.

    I've been building guns professionally for about 8 years now. I can honestly say that never once has a customer brought back a rifle for a warranty bedding job because it only lasted a year. In fact, I life time warranty against failure.

    Devcon HVAC has a pretty high Shore Hardness, shear strength, compression strength, and is low in shrinkage and sensitivity to chemicals. One package is enough for two guns if you keep you inlet work on the stock conservative.

    All depends on how much you hog out of the stock. There are arguments that go both ways regarding this. More bedding material aids in dampening. Less bedding ='s less shrinkage. I've done em both ways and haven't seen a bit of difference.

    Xcept for one little experiment I tried on a Palma gun that I'm not ready to share yet even though the reality is I doubt its the bedding that made the gun that exceptional. The owner is a Palma maniac and suffers chronic obsessive syndrome at the reloading bench. This particular rifle holds under a 3rd of a minute of elevation at the 1000. It's crazy to watch the guy shoot it. That's with irons too btw. (now if he could just stay on the wind. . .) Here's the gun. Charles Clark's (2003 US Palma Team) Palma Rifle:

    [​IMG]



    Once mixed, don't pile it up in the middle of the plate. Spread it into a thin film over the glass. You only have so much open clamp time before the stuff starts to go off (cure) on you. Spreading it out maximizes the time because you deny the stuff the ability to make much heat. The heat you add prior to mixing is to help aid in getting the "esters" in the resin bonded with the hardener. You'll find it cools back to ambient temp pretty quick. Don't get fooled into thinking that the stiffening up is the chem reaction. It's the stuff cooling off. Like I said, you have a solid hour of time as long as it's a room of normal ambient temp.

    Do ALL of your prep work and test fitting work FIRST. Make sure your action sits on waterline, make sure the pillar holes in the stock are the same C to C location as the screw holes in the action (exactly why I insist on doing my own inlet work- no exceptions) If it's a feature or a hole, it better have clay packed into it. Don't even waste the time speculating that you don't have to clay something up. Just do it. The best clay is the Clean Clay brand stuff that Brownells sells. About 8 bucks a pack but worth every penny.

    Tape. not all masking tape is created equal. Go to a body shop supply and get the green 3M ****. If it's something that will contact the resin itself, I use that 10mil thick wide electrical tape stuff that 3M also makes. Awesome for recoil lugs. Nice slick surface finishes this way.

    Following this regiment can yield these kind of results if you take your time and pay attention to the little stuff.

    It's ALL about prep work. The bedding process itself is pretty easy actually and goes pretty quickly.

    Removal:

    I spent a solid weekend machining a jack set up for yanking actions out of stocks. I won't kid you, it's bad ass. It lifts the action out with no rocking motion.

    But before you ever get that far, you have to ensure there are no mechanical locks. Be very careful when "picking" at things around show line. that's where stuff loves to chip out and that's the difference between a pro job and amateur night.

    Once you get the action out and you start knocking down the edges, don't be so quick to get in there and clean the dust out. It'll scratch the bedding cause there's abrasive media mixed in with it. Just let it pile up. It won't hurt anything as long as you don't fuss with it.

    Use hot soapy water when your DONE and just do it once.

    Good luck!

    Another post:

    The Firearms Forum.Com - View Single Post - Epoxy Bedding

    I used acraglass for a long time. Never had any real issues with it. I used the creamy stuff. Again, where people get into trouble is they don't mix it enough prior to application.

    I had serious callouses on my hands from mixing that chit!

    I like Dev Con because its runny. Very runny compared to A/G. This lets it wick into the fibers better and allows it to flow into the corners. This is where air tends to get trapped the most it seems.
     
    Last edited: Aug 12, 2008
  7. NesikaChad

    NesikaChad Well-Known Member

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    Yet another one of my rants. . .

    Here is what I'd do with your rifle.

    I'm assuming the masking is all done and the action is packed full of clay and hosed with a good coat of release agent.

    Prep work is everything.

    I see no reason why a rifle should be bedded in stages. Hose the receiver with release agent. Clean your pillars real well after scuffing them with 120 grit paper.

    If they are aluminum, scuff them and wash them in alky/acetone/lacquer thinner/ immediately prior to applying the epoxy. Aluminum will oxidize its outer surface very VERY quickly. This oxidation ends up being a boundary that prevents optimal adhesion. You scrub it with 120 to make sure the etched surface is clean and free of oxidation. Leave them submerged in the solvent until right before your ready to apply the epoxy to them.

    Next.

    Yes, install your pillars to your action so they are clocked properly. My pillars are not flat. Remember, I said these things are way over engineered. I'm not ready to tell the world what they look like yet. We all have our little secrets, regardless of how dumb they are.

    Anyways. Your bedding screws should be hosed with release also. In fact, use wax on the threads. Once you snug up the screws pack the hex head or what ever you are using with clay. Don't want resin getting in there.

    Now coat the entire underside of the action with bedding, to include the pillars. Coat everything evenly and pay close attention to where the pillar meets the receiver and where the recoil lug meets the receiver. Remember what I said about 90 corners.

    Apply a coat of bedding to the stock. Rub it into the wood with your finger at first so that it really gets in there and bonds to the fibers real well. Pack it down around the recoil lug area with a stick. Again, 90* corners need extra attention.

    Put a light bulb over it and let it warm stuff up. If you are using DevCon it'll start to form bubbles in places. this is trapped air rising. Use a tooth pick and pop the bubbles. If you are smart, you'll be careful when applying the resin to the action and to the stock. How you glob the stuff on/in there directly relates to how much air gets trapped.

    Mixing it properly is important too. Never whip this stuff in a cup. NEVER!

    Be careful with the light. Don't get it too close or you'll "cook" the epoxy in that spot and then you have a mess. Keep the light about 18" away from the stuff. (100 watt bulb) No longer than about ten minutes either.

    When you stuff the action into the stock go straight down. Don't "rock" it in.

    Your pillar holes should be oversized slightly. Remember, you want a tension free nest. A bound up pillar kind of defeats the purpose.

    Here is something that will raise some eyebrows to some.

    TRUST ME, people have been doing this wrong and it screws things up bad.

    You should clearance your recoil lug. (??)

    Wrap two to three layers of good quality (the 3M green stuff is the best) masking tape or electrical tape (3M again is really good) around the outer edge of the recoil lug.

    Think about it.

    If the lug area is super tight what happens? The lug is potentially (almost certainly) going to scrape the bedding going in and/or coming out. this will pile up under the lug and cause a pressure point.

    Think of the kids story "The Princess and the Pea."

    Same thing applies here.

    If the whole length of the action is nesting against a precision casting, why do you need the recoil lug to be boxed in?

    You don't.

    Some argue, what about retaining the clock position of the receiver and the stock? This is what your action screws decide. not the bottom of your recoil lug. The ONLY place a recoil lug should contact the stock is on the back side where it transmits recoil to the stock during the shot sequence.

    That's it!

    You should not have to wrestle with an action to get it out of the stock. This whole "tight" thing on bedding is silly and I personally think it carries over from the days of building M-14's and M-1 Garands. Neither of these guns follow the rules and they have nothing to do with bolt guns.

    A rifle action should be able to go in and out of a stock an infinite number of times with no detriment to accuracy. If it doesn't, something is wrong.


    Ok, enough beating my chest.


    Once your barreled action is in the stock and epoxy is oozing all over the place begin your clean up. Scrape the excess off and ensure the receiver is sitting on "waterline" with the stock. If the action is 1.350" in diameter, then .675" should be sticking out of the stock. No more, no less. Same goes for the barrel, it should be "waterline" all the way down the forend.


    You don't want to trim the gooey bedding right down to showline. This is because ALL epoxies shrink some during curing. Can't be helped. If you trim it right to show line you'll have a nice sag everywhere once it cures. Allow the bedding to climb up the side of the action slightly. Think of how water clings to the side of a glass. The resin should look much the same.

    You can chip this very thin layer off after it's cured.

    I made myself a set of scrapers and "razor" blades out of brass just for this purpose. Cuts through the epoxy but doesn't scratch actions.

    Plastic works too and can be sharpened with 400 grit paper pretty easily.

    Brass just lasts a little longer between tune ups. I use 220, 320, 400, and finally 600 for sharpening these things. Just glue (3M aerosol contact cement works best) your sheet of sand paper to a piece of marble tile. Works great.

    Some guys like to stick the gun outside in the sun to cure. I don't. The slower the resin cures, the less shrinkage there will be.

    Put it in a room that's about 70-80 degrees and then leave it be for at least 24 hours. The little pieces of epoxy stuck to the sides should flake off and be very brittle. If they are at all pliable, stop and wait some more.

    When you pop this thing out first thing is to get the screws out of there. Ideally, they will unscrew and just fall right out. This doesn't always happen though. What you don't want to do is have a screw be loaded up with epoxy inside and then unscrew partially and then strip out the action.

    this is why I use a long stud and a nut instead of a screw. With a stud I have something I can get a hold of to pull on if it acts stubborn. In fact, I use a Dewalt drill to remove my pillar studs. Works great and I don't break a sweat.

    Remingtons are 1/4-28 thread pitch for guard screw holes. This is common to any decent hardware store.

    Next, give the receiver a couple good whacks with a brass hammer. This "shocks" the cohesive bond (notice I didn't say adhesive) between the bedding and the receiver.

    Shove a long 3/8 drive socket extension up the arse of the receiver where the bolt goes.
    This gives you some leverage on the back of the action.

    Now the idea is to separate the two parts without rocking it. Rocking just destroys the interface between the back of the recoil lug and the bedding. This is BAD.

    I have a nice jack/cradle contraption that I made for splitting the receiver from the stock.

    Once you get the halves apart, clean up begins. Get the clay out of the action and then get yourself some stiff bristle brushes and go to town with some hot soapy water.

    It's light years better than solvents and doesn't turn your hands into dried up bleeding eye sores.

    Most guys use a file to knock the bedding down to show line on the edges. I prefer a sanding block with 220. Sand Paper does not "load" the razor thin edges the way a file can and it works in any direction. I reduce the risk of chip outs while saving some time.

    You do have to be a bit more careful though. It's easy to slip and scratch the bedding down inside. Use your judgment. This is purely personal.

    Clean everything else up as best you can. the trigger wells, mag ports, bolt handle inlets etc.

    As a note. the bolt handle MUST not touch anything other than the receiver. If its hitting the stock ANYWHERE you are going to have a gun that kicks out random "orphans" from the shot groups.

    It's got to be clearanced!!!

    I never use a "used" stock to bed a gun. All my rifles start on uninletted blanks. So, I wait to do all the cuts and reliefs afterward on a vertical milling machine. I get the stocks cheaper this way and I get them sooner. It actually saves me work in the long run cause I don't have to mask off much during set up.

    It's faster too and that means more money in the wallet.

    Notice through all of this I didn't once mention anything about cleaning out the funk from the stock.

    It's going to be all gunked up with clay, release agent, and dust from you sanding and filing.

    I leave all this in there and then clean it out at the very end. The reason being every time you go at with a paper towel or rag soaked in solvent/hot water you risk a chip or a flake of something harder than the epoxy being embedded in the rag. You can scratch things too easily this way.

    I'm anal about this cause I feel I have to be. My guns start at about $4,000.00 dollars and they just get more insane from there. In my mind, I owe it to a customer to have everything right for what I'm charging them. This means having it right on the inside and the outside. Some could care less, but the folks out there who spend more for something tend to be more critical. The higher price entitles them.

    Well, this got long winded, but hopefully you were able to pick some things out of it that will work for you.

    Good luck. Post some pics when your done. I'd like to see it.
     
  8. NesikaChad

    NesikaChad Well-Known Member

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    "Waterline" is a term I coined up cause I'm too lazy to say "showline."

    Lets use a Nesika round action for this example as its the easiest for me to describe.

    A no frills Nesika Model J is 1.350" in diameter. That means it has a radius of .675"

    "Waterline"/"showline" is nothing more than the flat top portion of the stock where the barreled action rests. A gun built right will have the radius of the receiver and the barrel below this reference plane.

    That's it. so, if you using a Remington 700 (also 1.350) half of the front receiver ring should be in the stock and half should be sticking out.

    In the rear, you must measure from the bottom of the action to centerline of bore because Remington does that goofy thing on the rear portion of their actions. It's not the same height.

    Basically it rolls like this. As your doing this work and your dillgently making sure all your little "I"s are dotted and "T"s are crossed. Just take a big step back, light a smoke, drink some coffee, listen to a song, what ever. Just get your face away from the gun for a moment and LOOK at it.

    Does it Look right?

    A human healthy human eye has the resolution to detect a 2mm deviation at 50 meters. This is proven. By that logic no one should have a challenge standing ten feet from a gun on a bench and be able to tell if it's buried or sitting proud in the stock.

    I used to be very very anal about checking all the measurements and making sure it was just so. Now, I just stand back and look at the dumb thing to make sure I didn't screw it up. I check with a small level laid on the receiver and the stock.

    That's it.
     
  9. NesikaChad

    NesikaChad Well-Known Member

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    Tape and holding an action in the stock while the resin cures:

    I tape the barrel up front to center it in the channel. I use a little bit of tape on the receiver ring of the barrel to act as a damn to keep resin from flowing up the barrel channel. I also use a bit of clay to damn the stock there as well.

    The pillars are bolted to the action via studs. I don't use screws. I use a 1/4-28 stud that I make myself that has just enough thread on the action side to get full purchase in the receiver, then it steps up to 5/16 diameter so its almost a slip fit inside the pillar. then it necks back down to 1/4 20 and I use a cheap o hardware store flange nut to tighten everything. I tighten the studs to the action hand tight and I use just a bit of pressure to tighten the nuts. Just enough to keep stuff from moving or working loose.

    The particulars regarding clean up and holding the action in the stock while the resin cures is covered in those long winded rants of mine posted here. I'll let ya go looking so this thread doesn't turn into a chapter from the Bible.

    Tape: The green 3M shit is awesome. Auto body supply shops sell it. Get some! Get a few rolls in different widths.

    I mask the entire stock when I bed a gun. Everything, from one end to the other.

    Nothing, and I mean nothing SUCKS more than having a rifle all done, your ready to apply finish and all the sudden the wood looks like its got a metallic paint job cause some aluminum or steel based bedding material got sucked into the wood fibers and you missed it and now its covered with finish.

    Experience is never cheap. . .I've lived this nightmare and I learned from it. It's well worth the extra ten minutes and 2 dollars in tape to avoid the headaches. I do it synthetics as well just cause its one less thing to have to sand off the stock. Digging that crap out of the checkering on a grip is no fun either.

    On my pillar holes I make "pull tabs" out of tape. I tape off the bottom of the hole so epoxy doesn't go oozing out the bottom. when I squish the action into the stock, the tabs get peeled off and I'm done. The pillars I make start off longer than needed. I flip my stocks over and finish mill them when I install the trigger guard or floor metal.

    This is an entire process and it doesn't lend itself well when you start using stocks that have already been inletted for trigger guards and floor metals.

    I suggest you get some firm/squishy type foam from a hobby store. Make damns and stuff them down your mag wells and trigger inlets. This will help mitigate the resin from taking off on you. Don't be afraid to use clay either although clay will displace if enough pressure is put on it. The foam tends to stay put better.

    Hope this helps.
     
  10. kfrye

    kfrye Well-Known Member

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    Thanks for the wisdom and experience Chad. I will be starting this work soon, still assembling everything that I think I need. Be careful in the sandbox.

    Ken