Filling synthetic stock with expanding foam ?

FatCatsDad

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What benefit does filling the stock with low expansion foam give a shooter ?

I've seen a couple of guns within the last few months with this modification.
 
FCD, it depends on the type of expanding foam you use.

Some folks use the same type of foam used for sealing window openings around the window frame or other air leaks in the home.

Others use the foam sprayed in houses and other buildings as insulation.

Insulating foam can be quite rigid and add strength as well as reducing sound. All of them reduce sound to some extent.

I use the same foam that comes in the "rattle cans" for replacing the insulation/sound abbreviating qualities in vehicles. It's available in big box as well as specialty auto stores and is reasonably cheap.

It seems to add more strength (not much) than household expanding foams and is more like the rigid Styrofoam insulation sheathing used on the outside walls of houses before installing the finishing material.

I like this type because it doesn't expand as much as others and if you need to add a sling swivel, you can drill out a hole, fill it with epoxy, which forms to the hole as well as binds to the stock, then attach your sling swivel studs.

Noise dampening is better, because this type of foam is denser and developed for the purpose as well as insulating.
 
Noise is why I've done it. I have experimented with dumping a tube or two of Daisy BB's into the foam to add extra ballast to lighter rifles, worked fairly well. Can be terribly messy stuff though.
 
I've strengthened a stock with carbon fibre rods and JBweld. Wonder how foam would work in conjunction with carbon fibre rods. Sure would be lighter. Hmm...
 
It will stiffen the stock a bit, make it less noisy when things rub/scrape/bang against it, change the vibration characteristics during a shot (not sure this will be noticeable, though) and maybe others.


Mark
I've got an XPR in 223 and a new can of low expansion window foam in the garage leftover from a small wondow replacement project.
I think I'll give it a go.

Wrapping the stock in saran wrap and carefully taping off the opening should make for a mess free foam application
 
I'd suggest putting a 'bread-bag' inside the stock BEFORE spraying that foam into there. Maybe you'll want to remove some, like for storage or to replace it with something heavier -or lighter. The spray foam I've used is messy and sticks to everything, esp what you don't want it to.
 
I'd suggest putting a 'bread-bag' inside the stock BEFORE spraying that foam into there. Maybe you'll want to remove some, like for storage or to replace it with something heavier -or lighter. The spray foam I've used is messy and sticks to everything, esp what you don't want it to.

And if it does get where you don’t want it, clean up once dried is MUCH easier and less messy than attempting to clean it up while still wet
 
I've strengthened a stock with carbon fibre rods and JBweld. Wonder how foam would work in conjunction with carbon fibre rods. Sure would be lighter. Hmm...
I wondered about the same - I have a synthetic stock - very easy to "close the gap" to the barrel by squeezing with thumb and finger - so I thought to "stiffen" the stock - it was "honey comb" made with many cross bars, but that obviously was not working. Then I noticed the forearm seemed to "hinge" at the slot for the recoil lug - so as if the receiver area to the forearm area needed to be stiffer connection. I bought some arrow shafts - carbon fibre, I think - I can wiggle them alongside the rifle's fixed magazine and the recoil lug - so it will be my intent to "stiffen" that stock by using those carbon fibre "tubes". Up until I read this thread, I was going to use JB Weld epoxy to hold the rod ends - mostly because the local NAPA store carries the stuff - so it is easy for me to get - now I'm thinking some sort of spray foam in the receiver area and the forearm to hold the ends of those rods. I have not done it yet - still thinking my way through, why that would not work?
 
Foams come with either 'large' or 'small' bubbles, generally speaking. i'd expect the 'large' ones to be less durable - not sure, likely depends on the brand too. more 'air space' i would think would weaken the stuff ?
 
I find this thread very interesting. Structurally it would make it far more rigid. It would reduce flex and vibration, possibly aiding in many aspects of the users shots. Both of my Browning X-Bolt carbon fiber stocks are foam filled from the factory.
I learned many years ago from another hard core off roader who built his own tube frame bumpers that foam filling prevented dents in the tube quite considerably. I have owned and still own several ATV's. Two of which, I have foam filled the frames and tube components. Bumpers and racks. This prevents mud, soil and water from filling in very difficult to clean components. As a side benefit it helps with floatation. One of my Kodiaks can be driven in a lake/pond if I air up my tires to about 20 psi. and I don't have a load. No snorkel needed. Cheers
IMG_0711 (1).JPG
It sits much deeper than this but will float and move forward very slowly. No lean, LOL.
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