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  #16  
Old 10-16-2019, 06:56 PM
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Quote:
Originally Posted by SailDesign View Post
Our local boatbuilding supplier sells single 4 x 8 ft sheets - prices here:

https://www.jamestowndistributors.co...ct.do?pid=1588

I'm sure it can be had cheaper in larger amounts from suppliers like Composites One, but they sell to commercial boatbuilders in large quantities.
I bet you probably have a scrap pile of the stuff.
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  #17  
Old 10-16-2019, 09:10 PM
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I bet you probably have a scrap pile of the stuff.
Not personally, but I'm sure there are a few I could access if required.
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  #18  
Old 10-16-2019, 10:21 PM
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So, how to make your own personal foam core composite stock on the cheap.

First step is the hardest- take the foam you have and lay up something. My first was to take some pink insulation foam, cut it to a 1”x1”x10” core and vacuum bag a few layers of 6k carbon fiber with West System boat epoxy. That was it and I still have the tube. It ain’t perfect, but it’s my first and I learned from it (and I still have it in my drawer at work). Also a good idea to prototype with fiberglass. Autozone is cheap and everywhere. Really cool to do one each and compare- CF is pretty cool stuff.

Now there’s some background on this- vacuum pump, vacuum bagging stuff, epoxy resin and carbon fiber. Sound like a lot, but it really isn’t. It ain’t free, but it won’t break the bank to get started.

My pump was (and still is) a throw away from an old fridge (cost = free) with some clear pipe and a few parts from online. Craig’s List Curb Alert is your friend.

The resin is on amazon - I started with West System and it has worked well. Lasts for years, holds up to harsh weather and above all- go with the Slow Hardener! Trust me. Stick with epoxy that cures at room temperature to start with.

Vacuum bagging- cheap stuff to start off with. Stretchlon 200, Blue Peel Ply, White Batting (soaks up excess resin), black sealing tape, and a good releasing agent.

Carbon fiber- is $20-$25 a yard too much. Check out Soller Composites- simple website, really good prices, good materials. Anthony is really helpful.

Home Depot insulation foam is pretty weak stuff. It crushes easily and layering it together with glue doesn’t sand well. The cheapest, best foam is Smooth-on rigid foam it 5. Simple to make a box to pour it into to form a rigid foam core to sand and shape. It holds up reallly well to vacuum bagging and can be dissolved out with acetone.

As for bedding the action- way easier than you think. Duct tape and brush on releasing agent to mask everything and you’re good to go. I’ve got one on the bench right now getting prepped for a final layer of 12k CF.

That’s the primer. If you’re still up for it, you can fabricate a stock that fits your desires and ergonomically fits better than anything you have ever shouldered.

Best advice I ever received was to take it a few hours at a time, think about your process in between and take your time.

Last edited by Gobber; 10-16-2019 at 10:29 PM.
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  #19  
Old 10-17-2019, 12:34 AM
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Thanks Gobber.
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  #20  
Old 10-17-2019, 11:35 PM
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Forgot to mention a key component- something to use as a hard point core material. To make things much easier, best to use something in the center of the receiver area to- bed the action to, run the mounting screws through and laminate the composite to (CF, Fiberglass, etc).

Wood is easy to obtain and cheap. I was turned onto Coosa board from the beginning and it is the ticket. Takes resin very well, sands and cuts easily and weights 40% less than plywood. Totally impervious to moisture and rot.

Let me know if youíre still interested and Iíll be happy to share lessons learned.
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  #21  
Old 10-18-2019, 07:55 AM
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Quote:
Originally Posted by Gobber View Post
Forgot to mention a key component- something to use as a hard point core material. To make things much easier, best to use something in the center of the receiver area to- bed the action to, run the mounting screws through and laminate the composite to (CF, Fiberglass, etc).

Wood is easy to obtain and cheap. I was turned onto Coosa board from the beginning and it is the ticket. Takes resin very well, sands and cuts easily and weights 40% less than plywood. Totally impervious to moisture and rot.

Let me know if youíre still interested and Iíll be happy to share lessons learned.
Warning to all: NEVER use wood as a core material if the part is to be vacuum-bagged and/or heated. I warned my prepreg guys not to, as it would explode in the oven, but they ignored me. 1/4" aluminum, oven totally trashed..

Low pressure + high heat = steam. Boom!
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Old 10-18-2019, 10:11 AM
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IMG_0245 2.jpg

IMG_0246.jpg

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IMG_0250.jpg

This is the concept. Three piece with the most important being the chassis. I figure I'll make the chassis out of steel cuz I have some already. I like the idea of making the forend and stock being interchangeable but I doubt I'll make it happen this go around.
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  #23  
Old 10-18-2019, 02:48 PM
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Very cool! Good to know the hardest part is over- you started

Fully agree that the center chassis section is the most involved component to fabricate. If steel or aluminum is easy for you to work, this is going to be really cool build. If you would like to try a section of Coosa, shoot me a PM. The clamshell approach I took with my last project greatly simplified the workflow for my lighter weight build.

Also, make sure your cheek piece / comb is high enough to give you a comfortable sight picture to your scope. I like to shoulder my rifle with my eyes closed and the scope at max magnification. When I open them, the crosshair should be dead center. Thatís why I went with the detachable cheek riser- if I change scope or rings, I can adjust cheek weld. It also cuts a lot of weight. Itís not pretty in the classic stock look, but Iím more about function than looks. Just a thought

Good call going with an AR style grip. Gives lots of off the shelf options.

Let those chips fly and keep us up to date.
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  #24  
Old 10-18-2019, 03:00 PM
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Quote:
Originally Posted by SailDesign View Post
Warning to all: NEVER use wood as a core material if the part is to be vacuum-bagged and/or heated. I warned my prepreg guys not to, as it would explode in the oven, but they ignored me. 1/4" aluminum, oven totally trashed..

Low pressure + high heat = steam. Boom!
SD- that is a really valuable pearl of wisdom! It would have never occurred to me there would be enough moisture in a chunk of wood to flash explosively, but with the super low pressure, it makes perfect sense. Definitely a lesson to learn from someone elseís experience

And the timing of your comment is really good for me as I will be moving in to heat cured resin in the near future.
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  #25  
Old 10-18-2019, 09:16 PM
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Quote:
Originally Posted by Gobber View Post
SD- that is a really valuable pearl of wisdom! It would have never occurred to me there would be enough moisture in a chunk of wood to flash explosively, but with the super low pressure, it makes perfect sense. Definitely a lesson to learn from someone elseís experience

And the timing of your comment is really good for me as I will be moving in to heat cured resin in the near future.
Always glad to help. I calculated that at 12% moisture (standard enough for most store-bought lumber) there would be 36 cubic feet of steam generated. Plenty to blow up a well-sealed hatch.
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  #26  
Old 10-19-2019, 11:28 AM
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The clamshell comment got me to thinking. Still not convinced I want to do the chassis part out of steel. I like the fuller look.

Another option are these stocks http://www.troupsystems.com/product/para-stocks/

I like the AR trunion and the trigger guard. I would only need to reshape the front to accept my forend. I could then have a chassis system of sorts where I could change out the stock and forend to go from bench rest to field situations.
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  #27  
Old 10-20-2019, 01:26 AM
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Speaking on core materials,

I love coosa, but not for stock work. Deck of a boat crab pots run across, it's bomber. Built some bulkhead and a deck out of it. Really is awesome, but were talking beyond what is necessary for rimfires.

I love the h80 weight divinycell foam for gun stocks, it bags great, carves well and stays pretty stable. Probably my favorite core material for a one off stock.
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  #28  
Old 10-20-2019, 08:40 AM
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Speaking on core materials,

I love coosa, but not for stock work. Deck of a boat crab pots run across, it's bomber. Built some bulkhead and a deck out of it. Really is awesome, but were talking beyond what is necessary for rimfires.

I love the h80 weight divinycell foam for gun stocks, it bags great, carves well and stays pretty stable. Probably my favorite core material for a one off stock.
If you can find any A500 Corecell, give that a try. It's less crushable than Divinycell and just as shapeable.
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  #29  
Old 10-20-2019, 05:31 PM
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Quote:
Originally Posted by comfisherman View Post
Speaking on core materials,

I love coosa, but not for stock work. Deck of a boat crab pots run across, it's bomber. Built some bulkhead and a deck out of it. Really is awesome, but were talking beyond what is necessary for rimfires.

I love the h80 weight divinycell foam for gun stocks, it bags great, carves well and stays pretty stable. Probably my favorite core material for a one off stock.
Fully agree that 5lb foam is the ticket when fabricating a lost foam carbon fiber piece. I use two part Smooth-on 5lb foam to make my hand grips for the same reasons.

The place I use Coosa board is in the barreled action area where I need a ďhard pointĒ that is solid enough to directly take screw mounts and bedding without having to make an inner lining CF structure. Itís so easy to router, sand and drill as well as bonding with any epoxy / adhesive. It was recommended by a stock maker as an alternative to a wood or foam core that has served very well.

However, by using a clam shell approach, if light weight was the main requirement, a foam core would work really well, but not be as forgiving once the CF was applied to all surfaces. JMHO, YMMV, etc.
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  #30  
Old 10-20-2019, 06:28 PM
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Getting closer to the end. I had some carbon arrows I decided to repurpose and use them to straighten and strengthen the stock. Next step is filling some gaps and finish shaping. Still have to inlet for the grip screw and pillar mount. Then it will be on to glassing.

What are your opinions on balsa? Either as a core material or shaped then stabilized?
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