I typically use Marine Tex when bedding fiberglass stocks which I've always been happy with. Is there something I could add to the epoxy that would lighten it up without weakening it? I know, kind of a weird question but I seem to recall hearing about some product that would do just that. On these ultra-light rifles it helps to shave weight wherever possible (I know, tell the customer to lose a pound and carry a normal weighted rifle I typically tape the barrel and bed the entire barrel channel to have a nice even gap along the free floated barrel and this amount of epoxy does add to the weight of an ultralight stock.

In areas such as the barrel channel where there is no load I start with epoxy resin and add some chopped carbon fiber and then micro balloons to the viscosity desired.

M

If/when you do whatever you decide to due, let us know what your "weight shaving" amounted to.

As Mark said, micro balloons are what you need to get the epoxy lighter.

micro and flocking --
flocking for a paste
micro for flow

How much weight could be saved via bedding material?

Thank you all. I'll give the micro balloons a go.

quote:

Originally posted by Phil McFall:
How much weight could be saved via bedding material?

After lengthly and very detailed calculations the answer I came up with was not very much.

Are you looking to fill the barrel channel?
I would think putting spray foam in the channel, then just a skin of bedding for water proofing.

Microballoons (glass balls) would be a big mistake for a bedding compound- where you want maximum compressive strength.

Glass balls are used to increase "sandability", as in fairing compounds. You can dent the stuff with a fingernail. Bad idea...

For the most part, yes. It seems to have a larger effect on the weight when I'm taking a stock that's molded for a #4 contour and am bedding a #2 contour barrel in. Spray foam is a good idea.

quote:

Originally posted by theback40:
Are you looking to fill the barrel channel?
I would think putting spray foam in the channel, then just a skin of bedding for water proofing.

Good to know. I'll experiment with it.

quote:

Originally posted by Big Gorilla Gunworks:
Microballoons (glass balls) would be a big mistake for a bedding compound- where you want maximum compressive strength.

Glass balls are used to increase "sandability", as in fairing compounds. You can dent the stuff with a fingernail. Bad idea...

Some spray foams are very corrosive to metal.

My brother was crack filling. some leaked through the wall and took the finish off. A couple of his guns that were behind the wall.

Do a search for' light weight epoxy filler '

AdTech makes a filler called tooling compound 323. I used many gallons of this layered between fiberglass skins. It adds strength.

I'm sure it doesn't reduce a lot of weight but for the barrel channel (where there's never any stress or pressure and zero chance of being "dented") I always use copious amounts of microspheres and make quite a thick paste. Super easy to inlet the barrel for that custom looking float once it's cured. Saves on the weight and epoxy use and has worked for decades on dozens of stocks for me.

Zeke

Spray foam is a bad idea.
It is ok for it’s intended purpose of sealing gaps and insulation but it doesn’t cure well in a thick cross section and strength is low.
Two part foams are better and can be had in various densities to suit application.

Micro balloons have essentially zero density so mixing by volume one to one with epoxy will reduce the total density by half.

M