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Old 09-17-2019, 08:55 PM
Gobber
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Been a while…

Sometimes life gets in the way of the fun stuff…you know the story…

Now back at it.

Finally- it’s on to the grip.

This is one of the coolest parts of the build. Seriously, because this is how you can make all kinds of great parts.

I realize that these posts are getting down into the weeds so-

TLDR - Formed a grip using a foam core with carbon fiber overlay.



For the details - read on...

A while back I made the initial foam block with a rough cutout.

Now it’s time to shape it into the internal core of the grip.

The Smooth On rigid foam is the medium custom designed for making a piece like this.


You have already seen how to make the initial ‘blank’, which is a block set on a section of poly pipe.

Poly pipe is great because the foam will cling to pipe’s surface but it will pull loose when clamped in a vice.

Basically the surface is a built in releasing agent.

To get the base shape started, mark off the lines where the contours of the hand will lay.


All these grip contours can get really technical, but that’s the beauty of a removable grip- I can get as picky as needed later on.

A really good write up on grip design from a guy who knows his stuff - https://www.pyramydair.com/blog/2019...-stock-part-3/

For now, this stock needs a grip!


Also mark off where the grip will mount to the chassis so there is a comfortable reach to the trigger.


Then determine where the internal grip screws will be located. I know- a bit out of sequence, but you get the point.
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The plan is to sand the plug down to the general shape and then take it down even a bit further to create a skinny core that can be built up.




Next step is to sculpt the final shape of the grip core.
However, trying to get the exact desired shape from sanding down the foam alone is a pretty lengthy process and when (not if) you remove too much material, it is a pain to glue a chunk back on just to sand it back down.
Been there, done that.

The stuff that makes this so-o-o much easier is a very light-weight epoxy dough.

This stuff is the bomb!


It is really easy to work with by kneading together two equal balls of the dough.
This will give about 70-90 min of worktime depending on temperature.


Wear gloves with this stuff as it starts out quite sticky and limp but as it starts to cure, it gets firm like modelling clay.
Sorry- no pics as it is a mess to work with.
With just a bit of practice, it is very easy to shape, trim and smooth with a bit of water.
It is very light weight and once cured, it is rock hard.




After curing overnight, it is easy to shape and sand to precisely what you want afterward.
Trick is to lay it on thick so you can sand it away.


Strap sanding gives nice contours and flat sanding give good planes.








Note that the dimensions of the final mold plug should be a bit smaller in all areas as the CF builds it back out by 1-2mm.
I am realizing that a narrower grip is more comfortable for extended use- just my $0.02 worth, YMMV, etc.

Once the shape is good, a wet layup with 2 layers of 12K CF gives a nice, rigid structure.


Next morning it’s cured solid enough to de-bag and unwrap.
Lesson Learned - to get the CF to better lay down in corners, mold a slug of clay then wrap it in cellophane. This gives pressure where needed and comes out easy.
It still feels a bit like unwrapping a present to see what you have.


This one came out this morning early (couldn’t wait!)


After a bit of trimming with the diamond wheel and belt sander touch up – it's looking like a proper grip.
Since I can only add 21 pics, refer to TLDR

Last edited by Gobber; 09-18-2019 at 04:11 PM.
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