Hand Laid Carbon / Kelvar Stock

[wachtelhund1]

Though I would share this with members.

Here is my CZ 527 .223 Rem. Love this gun. This last spring I laid up my own carbon / kelvar stock with epoxy resin. I imbedded aluminum for the action and floor plate; aluminum support for the sling studs, 3/4 walnut plate for the butt pad and then filled it with low density expanding foam. Total weight - 28 oz. I was going to paint it textured tan, but it looked neat, so I sprayed it with UV protecting clear.

The black strands were the carbon filaments and the yellow were the kelvar stands in the carbon/kelvar fabric.





I built this stock for two reasons: First, I had a PVS-2 night vision scope mounted on this rifle for coyotes. The PVS-2 is a Vietnam vintage night scope which performs very well, but weighs 6 plus pounds. And is why I added the higher comb. Second, I have a H&K 630 that I would like to build another stock for it. So this was my test.

So how did I make this? I started with a casting of the original CZ 527 stock. I began with the inside for the action and barrel channel. First I taped off the outside with clear packing tape. Next, I applied liberal amounts of axle grease to the inside and out side as a release agent. Then the scary part; I mixed and packed the inside with Bondo in two steps. First from the top because of a step in the original stock. After it set, smeared more axle grease on the Bondo from the bottom floor plate area and then packed in Bondo from the bottom. After it set, several minutes, I sanded off the top of the Bondo flush with the stock, not standing through the clear tape, next the bottom floor plate. I had put straws in the action screw holes. I drill a hole through the bottom Bondo and used a 1/4" bolt to gently hammered out the upper Bondo casting. This was not easy, but the top inside of the stock came out in one piece as did the bottom. This gave me a casting of the action and barrel channel.

Next step was a plaster casting of the outside of the stock. I had made a casting box with some 1/8" clear plastic, a box about 2" larger than stock when laid in on its side and 4" high. This was just taped together with packaging tape. I re-inserted the Bondo casting and again, I smeared liberal amounts of axle grease over the clear plastic tape on the outside of the stock and Bondo castings, and the inside of the box. I mixed several quarts of plaster of paris and quickly poured about 2" high into the box. I pressed one side of the stock into the plaster of paris while still liquid. The stock on its side was half way into the plaster. I stood bullets into the plaster paris for registration pins. Next day, I smeared more axle grease over the top of the plaster of prais and cover it and the stock with more plaster of paris.

I let this cure for a day, then cut the seems of the box and peeled away the plastic. Gently, I pried the top plaster of paris off the stock and bottom plaster of paris. This was a casting of one side of the stock. Then I lifted out the stock leaving a casing of the other side of the stock.

This gave me four castings; top inside of the stock, bottom of the stock, and two sides of the stock.

For the lay up: I purchased one yard of carbon / kelvar cloth, 36X45" off EBay, about $35.00. I used about a 5th of this. Cutting it was difficult as the woven fibers separated when cut. I used epoxy resin left over from a duck boat build several year earlier. I used about a pint of resin. Use epoxy resin as it does not smell like polyester resin and cleans up with vinegar.

I started with the upper Bondo casting turned upside down on wax paper taped to a piece of plastic. First applied axle grease and then several coats of resin. Then started applying small pieces of the carbon / kelvar cloth, 1x2" pieces. You want to press the cloth into the resin so it is saturated, applying more resin. With one layer of cloth over the action, I placed a piece of flat 1/8" alumimum, cut out to fit over the action openings, but not stud and support areas. Then more resin and cloth until it was an 1/8 to 3/16" thick. I imbedded some 1/2 x 1/16" aluminum from the action area extending over the barrel channel for stiffness. Always working while the resin was wet. The next day when cured, I removed it from the Bondo and I had the action and barrel channelcasting. This was very stiff and I could hit it on a surface with no flexing, it weighed about six ounces.

Next, I greased each stock side casting. Applied two coats of resin and laid in pieces of cloth, resin and cloth. Here a thickness of 1/16 to 1/8" is enough. After these had cured, I trimmed the three pieces where needed so that they would fit together, the action and barrel channel, left and right stock sides. I epoxied the two sides together at the bottom seams by laying in several layers of resin and cloth, including some flat aluminum for the sling studs. In the grip area, I shaped and epoxied in two pieces of 1/2" high density insulation board. Epoxy was mixed with wood flour to a peanut butter thickness to glue in the foam and fill any voids in the grip area. I also inserted the grease floor plate casting. At this time the action and barrel channel was just taped into place. After the two sides set, the action and barrel channel was epoxied into place.

The front of the action area was epoxied closed with the epoxy and wood flour mixiture. This left a hollow forend. Holes were drilled in the barrel channel to spray in expanding insulation foam, then sealed with epoxy resin. A piece of walnut wood was cut to fit into the butt area and epoxied in to provide a flat surface for the butt pad. I just epoxied on a piece 1/4" rubber mat, sanded to the shape of the stock. A center hole was drilled into the wood and expanding foam sprayed in the butt area. And a stock is made!

[tobnpr]

Nice.

As a stockmaker and "boat guy" with more time working with fiberglass and polyester/epoxy resins than I care to think about I can appreciate the amount of time spent on that endeavor. Just making the mold...not to mention all the radius corners/edges. Yikes

Gotta wonder why you took such a shortcut on the recoil pad, though. I would have glassed in a piece of wood (or structural foam if wanting to stay with all composite const) to hold fasteners for a quality recoil pad.



If you don't mind me prying, about how much did the glass run $ for the project?

[FrankenMauser]

Very nice.


"Industrial Camo"

[wachtelhund1]

Nice.

As a stockmaker and "boat guy" with more time working with fiberglass and polyester/epoxy resins than I care to think about I can appreciate the amount of time spent on that endeavor. Just making the mold...not to mention all the radius corners/edges. Yikes

Gotta wonder why you took such a shortcut on the recoil pad, though. I would have glassed in a piece of wood (or structural foam if wanting to stay with all composite const) to hold fasteners for a quality recoil pad.



If you don't mind me prying, about how much did the glass run $ for the project?
__________________

There was no problem with radius and curves. Resin and cloth filled them pretty well.

On the recoil pad, I went to my gunsmith and went through all of his new and used recoil pads, all would have added 4 to 5 or more ounces. Didn't want that so I just used some 1/4" mat. As I said this was a test. I figure I can make the next one about 3 to 4 ounces lighter. It turned out about 10 ounces lighter than the factory stock.

The carbon / kelvar cloth was bought off EBay, one yard 36X50" . It cost about $35.00. I have enough to do several more stocks. Here is an example:

http://www.ebay.com/itm/Carbon-Fiber...item1e9184c4db.

Cutting the cloth was the most difficult part. Used a razor knife on several layers of cardboard with a steal straight edge to hold down the fabric, but the fibers still pull and separated; causing the odd patterns. Scissors might have worked but they dull up pretty quick on just normal fiberglass cloth.

When I do the next one, I'll use a casting RTV Liquid Urethane
Mold Rubber. That will create a re-usable mold to make multiple stocks. the plaster of paris was not re-useable. Edges broke in places requiring filling and extra sanding. But it worked for my first attempt.

Yes this was tedious, but I did it after a total knee replacement, when I was laid up and couldn't do anything more physical. It was about a week project. I also built a 5 1/4 # AR during that time.

[tobnpr]

How many layers on the layup do you need for strength (bashing it into a tree stump by accident).

Cloth says 5.7 oz, but I know you can't equate weight with carbon fiber to fiberglass mat or roving- and what was the finished weight of the stock?

[wachtelhund1]

How many layers on the layup do you need for strength (bashing it into a tree stump by accident).

Cloth says 5.7 oz, but I know you can't equate weight with carbon fiber to fiberglass mat or roving- and what was the finished weight of the stock?

How many layers? Gee that is hard as I was laying in small pieces 1X2" and this cloth is not much thicker than a human hair. Mix the epoxy in small amounts, the amount of one shot glass at a time. Always working wet on wet. Important is several coats of epoxy first, wait until it almost sets then start pressing cloth and resin in so that it is saturated, bush epoxy over the pressed in cloth. You don't want any trapped air bobbles. This allows for sanding the outside. If you sand through the outer epoxy and into the cloth, the cloth will fuss up.

The action area: I had two flat pieces of 1/8" aluminum shaped and drilled out to support the bottom of the action and top of the floor plate, between them were two pieces of aluminum arrow shaft cut for the action screws. This was epoxied together first. This was set onto action and barrel casting after two layers of epoxy and cloth. I built up around this and the action area until it was about 3/16" to 1/4" thick, the barrel channel an 1/8" thick. Not too thick as it has to fit into the two stock halves. Also imbedded in these areas was 1/2 X 1/16" aluminum vertical between the two plates and strips of balsa wood, two pieces of 3/8 X 1/16" aluminum along the barrel sides for stiffening. When doing this, after the first coats, the resin was thickened with wood flour.

The stock exterior was built up to an average of three or four overlapping layers of cloth, no more, a 1/16" of an inch. Coat the mold with several coats of epoxy wait until it starts to set, then start laying the saturated cloth in. Again, several inches of 1/2 X 1/16" aluminum was imbedded in the bottom of the forearm and butt area for sling studs. Bottom stock seam and top of butt stock was epoxied together on the inside with several layers of resin and cloth pieces, below the aluminum and above. Thicken epoxy was used when gluing the seams together, building up to 3/16' no more. The action and barrel channel was just glued in with epoxy.

I used too much wood at the butt area and too much thicken epoxy when gluing the stock seems together. My stock weighed 28 ounces. If done again, my goal would be 3 to 4 ounces lighter.

[wachtelhund1]

A side note, I drive a re-built and re-powered 1988 Suzuki Samurai daily, especially during the hunting season. Purchase for hunting it had a rag top. I built my own hardtop with in capsuled 3/16" Lauren plywood. This allowed me to secure firearms in the vehicle, also warmer and quieter. No bigger than a UTV, but street legal and cheaper.

Here is a link to pictures and the build process:

http://bbs.zuwharrie.com/content/top...tml#msg1241325

http://bbs.zuwharrie.com/content/top...tml#msg1058304

[Clark]

I used to design electronic circuitry, sometimes for aerospace. Schedules are suspect for Carbon fiber aircraft design and development in any company whose previous design has been Aluminum alloy fuselage. Typically the schedules are right on the money for the next Aluminum frame aircraft, but Carbon fiber surprises them with an extra year or two of development. If you read the newspapers you would think it was caused by some errant subcontractor.

Right now I am buying laminated stocks, High Tech Specialties stocks, and Walnut stocks. If I tried to copy wachtelhund1's stock, I might have one shooting in a couple years.

[1stmar]

How's it shoot compared to the factory stock?

[wachtelhund1]

I used to design electronic circuitry, sometimes for aerospace. Schedules are suspect for Carbon fiber aircraft design and development in any company whose previous design has been Aluminum alloy fuselage. Typically the schedules are right on the money for the next Aluminum frame aircraft, but Carbon fiber surprises them with an extra year or two of development. If you read the newspapers you would think it was caused by some errant subcontractor.

Right now I am buying laminated stocks, High Tech Specialties stocks, and Walnut stocks. If I tried to copy wachtelhund1's stock, I might have one shooting in a couple years.

OR, in a week. I did mine while I was recovering from a total knee replacement. But then I've never had problems mastering new skills.

[wachtelhund1]

How's it shoot compared to the factory stock?

It shoots the same, CZ's are awesome shooters, no matter what you feed it, it groups under an inch; only it is lighter to carry.