Carbon fiber stocks

Discussion in 'Equipment Discussions' started by RockyMtnMT, Mar 29, 2012.

  1. RockyMtnMT

    RockyMtnMT Official LRH Sponsor

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    Anybody know how to build them? I can't find anything from google, and I would like to learn how to do this.

    Thanks,

    Steve
     
  2. kiwi3006

    kiwi3006 Well-Known Member

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    Yep, I have made 6 now. Essentially they are the same as making a fibreglass stock. You won't find much on the net about them but it is just fibreglassing.
    Read up all you can about how to make a two piece mold off a plug.
    There is lots out there about using carbon fibre you just have to adapt it to rifle stocks.
    I make a two piece mold off the stock. 4 layers of 6oz carbon fibre with west Systems 105/207, put 3-4 extra layers through the pistol grip area, then put it in a vacuum storage bag and suck the air out with a vacuum cleaner. join the two halves together once it is set (next day).
    I make a cast of the action area of the original stock using a silicon modelling resin Wacker 4670. Put the cast in the stock and pour thickened resin around it, watch out it will get really, really hot if you pour too much in at once.
    Once the halves are stuck together i glue in the swivel studs and then fill the butt and forearm with expanding polyurethane foam.
    I make a fibreglass cast of the barrel channel and then lay several pieces of carbon fibre on it and put it into the stock.
    Then tidy up all the areas where the resin and fibre didn't quite stick properly.
    Then shape up the recoil pad and glue on using thickened resin.
    It takes me about 6 weeks from go to whoa to do a stock.

    Flick me a PM if you want.

    Stu.
     

  3. Montanan

    Montanan New Member

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    Any further information that you are willing to share on this subject? I am specifically trying to find out how many layers of CF are needed to withstand recoil force w/.308 bolt action. I am not trying to make a stock that has the same shape and dimensions as traditional stocks do so I need to know what a minimum, "safe" thickness is.
    Thanks for any and all input.
    Matt
     
  4. kiwi3006

    kiwi3006 Well-Known Member

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    I use 4 layers of 6oz/200g carbon fibre and put 3 extra layers (7 total) through the pistol grip area.
     
  5. Montanan

    Montanan New Member

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    Are you also using CF for the bedding and for sole support of pillars?
    From what you write it sounds like the there is very little total thickness required to provide the strength that is needed. That in turn really opens up what can be done with "radical" design of the rifle stock, which is what I am researching. Am I interpreting what you wrote correctly?
    Thanks.
     
  6. kiwi3006

    kiwi3006 Well-Known Member

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    The action area is epoxy thickened with West Systems 403 micrfibre. I tend to use 1 tablespoon of microfibre for every 20g of resin used.
     
  7. Montanan

    Montanan New Member

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    Thanks. Can you also give me a general idea of the actual thickness of the thickest portion of CF that you recommend? Also, what about other areas of the stock such as the butt, handguard, etc? That helps me with design in terms of the minimum thickness dimensions that are required.
    BTW, I've read elsewhere that people are for some reason advising against bedding the action with CF, although none give a reason for that so I have been assuming it is just a matter or preference or "this is the way we always do it" type mentality. Have you encountered any empirical data relating to the pros and cons of the type of CF bedding you mention?
    Thanks.
     
  8. kiwi3006

    kiwi3006 Well-Known Member

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    It is 4 layers over the whole stock, apart from the pistol grip area. I use epoxy in the action because of the way I cast the action area. Haven't heard anything about not using carbon fibre to bed the action
     
  9. 375rifleman

    375rifleman Well-Known Member

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  10. 375rifleman

    375rifleman Well-Known Member

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    By the way I was really just wondering how to make a custom mold and how much the resulting molded in carbon fiber will differentiate from the wooden pattern stock that was used to make the mold ? Also how does someone acquire tw carbon fiber which makes the actual stock? Thanks
     
  11. jfseaman

    jfseaman Well-Known Member

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    I have a little experience but very little, helping make one of my radio controlled planes that is molded.

    The RCGroups.com: The ABCs of Radio Control - Aircraft, Boats, and Cars! site should have lots of info.
    There is shrinkage but it is miniscule.
    AIUI Making the 'blank' and mold are the hardest part. A stock would be like a fuselage.

    Carbon fiber 'prepreg' is a viable option. Search for it.

    I hope that helps move you to the next phase.
     
  12. 375rifleman

    375rifleman Well-Known Member

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    Would a "homemade" carbon fiber rifle stock be able to handle the recoil of a 50 BMG ?
     
  13. jfseaman

    jfseaman Well-Known Member

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    Sure, with metal inserts for recoil lug location and pillars. A larger aluminum 'frame' inside the CF would be better.

    That is an engineering and manufacturing problem not a materials problem. The materials can take a great deal. Especially in compression.
     
  14. 375rifleman

    375rifleman Well-Known Member

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    Ok thanks can the stock be drilled for a mercury recoil reducer without weaking the stock?