Something to add material to a synthetic stock

[T.Lex]

Hello INGO gunsmithing forum! Long time reader, first time new-post starter.

I have a synthetic stock that I want to do some customization to. I'd like to start by putting a rail on the forend for either a light or a bipod. Particularly for the light, I'd like it to be parallel with the barrel. Alas, the stock itself is tapered.

Now, I know I could file the area I want to "level," but then I'm concerned that the wall would be too thin in the "deepest" part of the cutaway. So, I'd like to add some material toward the front, then contour and file it to my taste.

Is there anything that fits this application?

Thanks in advance!

-T

 

[gmcttr]

I would be looking for a thicker rail that I could shape to fit the stock rather than adding material to the stock to fit the rail.

MOUNTING SOLUTIONS PLUS PICATINNY RAIL BLANK | Brownells

IWI US TAVOR SAR FOREARM PICATINNY RAIL | Brownells

 

[red_zr24x4]

Or shim the front of the rail to the level position and filling in behind it with epoxy

 

[T.Lex]

Or shim the front of the rail to the level position and filling in behind it with epoxy

Hmmmm.... I like this idea. Like, shim with wood (can rattle can it black) then epoxy? Is there a particular epoxy that will best bind the wood to the plastic?

 

[red_zr24x4]

Wood would work. heck for a few dollars you could buy a pack of shims from Lowes then the taper is already done. epoxy them together when you get the right angle.
Epoxy them to the stock and paint

 

[T.Lex]

Yeah, that makes sense. Probably some sort of marine epoxy/resin combo, since I'd want it waterproof, but paintable/sandable? Or are most of them like that anyway?

Looking around, good old fashioned Bondo seems to be an option, too.

 

[Old Dog]

I wouldn't use wood myself due to the possibility it would shrink, swell, or fracture. I would recommend finding a piece of aluminum stock/scrap that could be cut and ground to fit, and drilled without risk of damage. You could still use the epoxy and paint to make everything look tight. For light shims I use old Indiana license plates (aluminum). I also save good chunks of aluminum scrap for stuff like this.

 

[Leadeye]

Bondo and some of the new variations of it will probably work, but epoxy is a safer bet for adhesion. I would check adhesion on a small area of the synthetic stock if you can.

 

[Cpt Caveman]

Taper the shim under the mount not the stock. Rattle can is your friend.

 

[rabidsquirrel]

I would be looking at a marine epoxy fairing compound, similar to Bondo but better adhesion and much more stable. Bondo is a polyester resin that tends to crack when subjected to too much load stress. If you need to build up more than .5 inch you may want to look into a vinyl ester compound with short hair fiberglass in it, but beware its a PITA to sand.

 

[BIGE7.62]

You can get hard plastic tapered shims in the plumbing department at Menard's . You should also be able to find a 2 part epoxy in a" syringe " It will self mix .
Trace the mount onto the shims ,cut , do mock up and apply epxoy as needed
I would use a backer plate with screws through the mount, shims and plate if possible
JM2C

 

[T.Lex]

I've been looking for a reason to get a tap/die set, too. This seems like a good reason.

Well.

A reason.

 

[KittySlayer]

Look around for some sort of plastic shim and cut/modify to fit your needs. I used one of these for shimming an appliance where there may be moisture and I did not want to use wood. This is the first thing that came to mind but I am sure you can find something with the thickness and density you are looking for.

 

[Mgderf]

All of the major box stores, Menards, Lowe's, Home Depot... will all have small vinyl shims in their flooring department.
These are often used to space ceramic tile or wood flooring away from a wall.
They are small, thick, and ribbed (not for your pleasure!). The ribbing helps them stay stacked together.
I use these a lot to shim toilets on uneven floors because they cannot absorb moisture.
Also, being vinyl, I would bet the marine epoxy would have a great bond.

These small vinyl shims are easy to cut, but I'm not sure if they will take paint.
That's another issue.
If you want to paint something, pretty much ANYTHING, and you can't get paint to stick, never fear, there IS a solution.
It's called "Fast Prime" by a company named Zinsser.
Fast Prime is an oil based primer. It's cousin, Fast Prime 2 is water based and easier cleanup.

Fast Prime, or Fast Prime 2 can be used to prime most any surface including glass and ceramic tile.
Once primer is dried, either will accept ANY paint, oil or water based.
Great stuff.

 

[T.Lex]

So, I tried the first option that I came up with:
Repair Putty from Loctite Adhesives

I had some synthetic pic rail segments and fasteners left over from a prior project, so decided to use those to fashion a "chin bulge" for a forend rail for my CETME. Ideally, it will be able to handle a hunting green light and/or a bipod.

In reading the directions, it sounded like it would adhere directly to the forend and the synthetic rail. Because I wasn't sure, I arranged it so the fasteners would be part of the assembly, too, so I could screw into it. Because of that, I also needed enough depth in the material so that I wouldn't have to drill into the forend.

That's along way around to say that I used the entire tube for about a 4 inch rail section. The good news is that I can file it to the profile I want. I also figured that if it was going to break off, it would probably break away from the forend completely. I'll try to post some pics, but after having it cure overnight, it seems to be on there really solidly. Need to sand and paint it, but I was able to get it pretty parallel with the barrel angle through the Mark I eyeball and a small level.

We'll see.

Anyone know where to find the best deal on a CETME/G3 hand guard?