Carbonfiber TRG22 forend.

VargmatII

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Minuteman
Sep 16, 2020
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This project has been going on for a while, but I figured that I would share some along the way.

Meta: I shoot a TRG22 with a KRG foldingstock as my main rifle this year. Its a dream rifle of mine, and it took me some time to get around to get one. I was caught up in running Tikkas, Sauers and Remingtons, but I found my way.
I did a small carbonfiber project a few years ago and made a comb-riser for another rifle, since then I had more cloth and epoxy laying around but I never figured out a good project to get going, until this one.

The main criteria is to make a front section for my TRG wich lines up with the KRG pistol grip panels. Its nice if it is light, but it does not really matter, however, it needs to be sturdier as the moulded Urethane that Sako uses is not extremely durable, just good enough.

So, as far as I know, you can make carbonfiber parts in two ways, either you have an expensive mould made from CNC cut alloy and use pre-preg cloth go lay the structure up. You can also go the low-tech way and make something with a foam core and do carbonfiber laminate on top of or around it. If you are an expert at this stuff, bare with me. I am making this at home, with a moderate amount of tools and posibilities.

Step 1.
Get some high density foam and make the shape. I found two different grades and got both to get going. The blue one is ligher than the gray one.
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Step 2.
Measure twice, draw and start cutting.
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Step 3.
It starts to take shape.
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VargmatII

Private
Minuteman
Sep 16, 2020
31
41
Step 4.
I made a magazinewell by doing a carbon fiber laminate around the original magazine wrapped in a few layers of tape to get some clearence.
I should have had another layer or two of tape, but it works. But it is a tight fit.
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Step 5.
Glue the magazinewell in place in the forend. I used the magazine as an alignment tool. It worked great.
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308pirate

Gunny Sergeant
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Minuteman
  • Apr 25, 2017
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    Are you going to spray the foam with mold release and use it as a throwaway layup mold?
     

    VargmatII

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    Sep 16, 2020
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    Are you going to spray the foam with mold release and use it as a throwaway layup mold?
    No, the foam will stay inside. I know of a guy who built a complete bicycle frame this way, but he melted the foam out with acetone. Im going to leave it where it is.
     

    VargmatII

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    Minuteman
    Sep 16, 2020
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    Step 6.

    I decided to take it down to shape, a bit at the time. I figured it would be easier to do it this way and keep things straight and aligned.
    I was also very keen on trying a new cloth I bought. It is carbonfiber "fleece" and is used in modell airplane and similar. It weighs a whooping 8 grams per square meter and turned out to be very easy to work with.

    1605717411833.png

    Step 7.
    A bit more.

    1605717487173.png
     
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    VargmatII

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    Minuteman
    Sep 16, 2020
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    Step 8.
    By now I had pretty much taken care of the outside shape and covered much of it in carbonfiber fleece material. While I did this I was pondering on how to do the inlet, how to get it straight and if I should disasemble my TRG and use the actual main beam... But after a while I figured that I could make a mock-up piece with the measurements of the original beam. So now I had a new thing to make.

    1605976852811.png

    Step 9.
    With some cutting and a lot of sanding I did the inlet channel with some room to spare for the carbonfiber cloth and glue.
    1605976920288.png
     

    VargmatII

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    Minuteman
    Sep 16, 2020
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    Step 10.
    Now the inlet was covered in carbon fiber cloth and it acctually worked. Time to look at it and se how it fits on the rifle.
    1606035040476.png
    As you can see, I went a little over the top on some measurements. I dont really know how I managed to get the front section longer than the aluminium main beam of the TRG and there is way too much material around the magazine well. So time to do some more cutting and sanding.
    But it lines up pretty good, better than I thought it would.
     
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    VargmatII

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    Minuteman
    Sep 16, 2020
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    Step 11.
    The magwell reshaped and ready for carbonfiber fleece.

    1606204864715.png

    Step 12.
    Cover sides with carbon fiber fleece. Its a complex shape and I was worried about the outcome but it worked.
    The shitty photography is another story. It looks better in person.

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