Bonding a picatinny rail to an action

[Veloci_Wrench]

Just reading through this. I’ve never epoxied a rail to a receiver. I see one person noted doing like bedding an action, which makes sense to me, given that it allows the rail to removed easily. However, I’m thinking the shear strength of the epoxy is what actually desired here as to not “only” rely on the screws securing the base to the action.

Is that the case, or is using a release agent on the receiver going to give the same added strength?


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There is no added strength if you use a release agent. The goal is to bond the rail to the action, in order to decrease the likelihood of losing scope zero.

The only benefit derived from using a release agent is that you effectively glass bed your rail/action joint, which eliminates flex potential from unevenly machined surfaces ( i.e. it keeps everything level and square so that your scope tube is not torqued, bent, or put under tension when installed).

If you bond your rail the right way, you achieve both a "bedding" and a bonding.

 

[onlybrowning]

There is no added strength if you use a release agent. The goal is to bond the rail to the action, in order to decrease the likelihood of losing scope zero.

The only benefit derived from using a release agent is that you effectively glass bed your rail/action joint, which eliminates flex potential from unevenly machined surfaces ( i.e. it keeps everything level and square so that your scope tube is not torqued, bent, or put under tension when installed).

If you bond your rail the right way, you achieve both a "bedding" and a bonding.

Thanks! Makes sense to me. I’m not sure I’m ready to commit lol.


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[rbutcher1234]

It all comes off with heat if you use loctite 380, it’s not permanent.

 

[Schutzprecision]

I’ve always bedded my bases to receiver with Devcon 10110 but after reading this thread and forms drop test I want bond them as well. Most of my receivers are nitrided or cerakoted. Anyone know if loktite 380 will bond to these surfaces?

 

[RockAndSage]

I’ve always bedded my bases to receiver with Devcon 10110 but after reading this thread and forms drop test I want bond them as well. Most of my receivers are nitrided or cerakoted. Anyone know if loktite 380 will bond to these surfaces?

Part of the intent behind the engineering of cerakote is for it to be lubricious, which I believe is the ceramic portion of the formula. It's slick, and for bonding would definitely benefit from at least roughing up the surface. But after having at least one bonded base pop loose on me, I'd strongly consider going right down to the substrate.

I don't have those concerns with nitriding.

 

[jjohnsonElknewbie]

Has anybody used Loctite 480? 380 is expensive as hell and harder to find. Please advise...

 

[RockAndSage]

Has anybody used Loctite 480? 380 is expensive as hell and harder to find. Please advise...

You might try these single-use tubes. There's a lot of really good info about loctite and related issues in this thread, that, among other things, caused me to stop buying larger bottles of technical adhesives almost entirely. If I can get single-use now, I do.

 

[RockAndSage]

I’ve been asked a bunch on how to bond or glue a rail to an action. I had one today to do, so…


This is a Tikka T3x and Leupold Backcountry Rail. The has a lip around the edge of it, it’s not flat with the action. So you lose all friction that would come when the rail and action are mated together. It also does not have recoil lugs. Wouldn’t recommend.
For a bonding agent I’m using Loctite 380 Black Max this time.

First degrease the action, action threads, the rail, every screw, the holes in the rail, etc. Using acetone, brake cleaner, etc get all the oil off.

Then, coat the rail with the adhesive, try to stay away from the screw holes-
View attachment 577944


Set the rail straight down over the holes so you don’t drag the adhesive into them, then put one screw at a time in, just to snug.

Then pull one screw out at a time and clean the screw and the threads in the action well with acetone/brake cleaner to get any adhesive off that might have gotten in. Out of the four screws one got adhesive in it-

View attachment 577946

Clean each one off, then usnibg Blue Loctite, a paint pen, or fingernail polish, put some in the screw and torque down. Repeat for all the screws.
View attachment 577947




Once they are all cleaned, painted and torqued, I go back and put a dab of paint/Loctite around the screw heads. I ran out of orange, so shifted to purple.

View attachment 577948



Finished rail with a line of adhesive showing-
View attachment 577949




Scope mounted, index marked and ring base screws-
View attachment 577950


And on ring cap screws-
View attachment 577951





If something comes loose, it’ll be obvious. But it won’t. Done as shown, this base, ring, scope combo isn’t moving unless I want it to.

Just over 2 years on, how is the 380 continuing to do on rails you're bonding? Any updates or modifications you been trying out?

 

[PathFinder]

I'm interested as well, I've been using 380 on a few things. It's the only thing keeping me from welding integral rings or picatinny bases to all my receivers.

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[Formidilosus]

Just over 2 years on, how is the 380 continuing to do on rails you're bonding? Any updates or modifications you been trying out?

Zero issues. Anything that may need to be removed, but that I can get heat to- it’s the choice for me.

 

[RockAndSage]

Zero issues. Anything that may need to be removed, but that I can get heat to- it’s the choice for me.

Great to know, thank you.

 

[jjohnsonElknewbie]

You might try these single-use tubes. There's a lot of really good info about loctite and related issues in this thread, that, among other things, caused me to stop buying larger bottles of technical adhesives almost entirely. If I can get single-use now, I do.

Roger that and thank you or sending. The single use are good and I just hate paying $20 for shipping for an $8 item. The 480 seems to be more available and is also a rubber hardened product similar to 380.