Bonding a picatinny rail to an action

[adamsls1809]

I bedded a Talley rail on a Cooper stainless M52 earlier this year using regular JB Weld. Pretty much did this like Form describes except for using a release agent, and being extra careful to keep the JB Weld out of the screw holes. First I cleaned everything well with some acetone , and the I used some Hornady Unique case lube as a release agent on the receiver and in screw holes just in case something didn’t go right. First time ever bedding a rail so I was a bit anxious about putting any permanent adhesive on the receiver, and I wanted to have the option to remove the rail in the future if I decide to change something. Put the rail down with the wet JB Weld, snugged the screws without over tightening, cleaned up the fit edges with some toothpicks & w-tips. And let it dry overnight. Next day removed the screws, removed the rail with just a light tap, cleaned the receiver top good, vigorously cleaned the screw thread and holes to be sure no JB Weld was in them, and then properly remounted the rail. Fit was perfect.

Why would you remove the entire rail after putting epoxy dowm, doesn’t that defeat the purpose?

 

[SloppyJ]

Why would you remove the entire rail after putting epoxy dowm, doesn’t that defeat the purpose?

No, just makes it removable. It ensures that the rail is getting perfect contact with your action. Same thing as bedding an action.

 

[adamsls1809]

No, just makes it removable. It ensures that the rail is getting perfect contact with your action. Same thing as bedding an action.

Isnt the idea to make it more rigid w the epoxy AND allow perfect congruent contact? Seems like you should just not even epoxy it if you want to remove, rail manufacturing today seems like the variability and warp is little to none and removavle epoxy’d rail seems like little return of benefit. Just my thought

 

[Carl Ross]

No, just makes it removable. It ensures that the rail is getting perfect contact with your action. Same thing as bedding an action.

People do bed rings or rails for perfect contact, but that isn't what this thread is about. The idea here is to glue them together to strongly reduce the chance that the action-rail interface ever shifts, aiming to eliminate a potential way to lose zero.

 

[SloppyJ]

Lord, he was just asking a question on why you would want to do that so I answered. 90% of people who bed a rail are going to use release agent to be able to remove it in the future. Who knows what you'll want to do 10yrs down the road and maybe that rail needs to come off. I was actually the person who told him to permanently bed it first. Just trying to be helpful for people who are reading. Read the info and make your own decisions.

If you think modern manufacturing can provide a perfect fit every time then you couldn't be more wrong. On my clone actions without integral rails, they fit great. One manufacturer making both pieces at the same place/time. If you go buy a EGW rail for an off the shelf rem700 then I'd be willing to bet that 9 times out of 10 it could benefit from bedding.

 

[adamsls1809]

Lord, he was just asking a question on why you would want to do that so I answered. 90% of people who bed a rail are going to use release agent to be able to remove it in the future. Who knows what you'll want to do 10yrs down the road and maybe that rail needs to come off. I was actually the person who told him to permanently bed it first. Just trying to be helpful for people who are reading. Read the info and make your own decisions.

If you think modern manufacturing can provide a perfect fit every time then you couldn't be more wrong. On my clone actions without integral rails, they fit great. One manufacturer making both pieces at the same place/time. If you go buy a EGW rail for an off the shelf rem700 then I'd be willing to bet that 9 times out of 10 it could benefit from bedding.

I did buy an EGW rail lol! I am definitely bedding but think I will leave intact without release agent for permanent. Thanks for help, just trying to understand everything. Pretty new to tinkering w my 110 UL 7prc.
One question I did have if anyone knew was what to do / use (acetone vs wd40 vs break cleaner) for any JB weld that gets down into the action? Should I put a layer of KIWI wax on the inside of the top of action to prevent epoxy contact and for easy removal. The 110 action has full thickness screw holes that communicate with the action. Which is different than some other actions, I believe. thanks

 

[SloppyJ]

Clear shoe polish works fine. I've also used furniture wax. Put some on your screws and into the threads on the action. You want to leave a bit of space between the the screw holes and your JB weld because it will squish. Line up the rail and place it on there and hopefully you haven't got any compound in the holes.

Alternatively, if you can find some allthread small enough, screw that into your action and have it sticking up out of your gun a few inches. Then put the rail on, use some washers and nuts on the top side against the rail and snug it up. This is how I do my actions and it works better IMO.

Clean all the extra squished out compound from around the rail and wait. Then after it cures you get to pop it off. That's the part that's always makes me nervous but I haven't had anything get stuck yet.

Be sure to degrease everything very well and reassemble.

In your case, if the rail is working loose, you might consider bedding it permanently.

 

[wapitibob]

A pinned and bedded rail isn't going to move enough for anybody to see the difference on a target. There are no scenarios where I'm permanently bonding a rail to a $1,500 action.