BFR EJRH glue

[subsonic]

Loc-Tite 7075 activator and 324 speedbonder

McMaster Carr # 7614A131 (7075) and 7614A11 (324)

That's what they use at Magnum Research to hold the ejector rod housings on.

[Frank]

Good info. I need to get some of that next. Thanks for sharing. No need to catapult the ejector housing when the screw comes off. [smilie=l:

[subsonic]

I don't think I'll need any for my .475, as there looks to be plenty already on it!

But I may want some for my.500 and my Rugers.

It's about $50 worth of glue from McMaster.

[tek4260]

So how exactly does recoil cause a screw to loosen? I know we have all heard it for years, but how does it do it? Maybe it stretches the screw which makes it loose. Then with a "loose" screw, the ERH has enough movement to give it some ability to shear the screw when fired.

[subsonic]

Well, the EJRH tries to stay put, while the gun moves. It side-loads the screw, slightly stretches it, and then it is loose. Pretty simple. Screws do not do well with side load.

I wonder why they never put a bushing around the screw that went half-way into the barrel and half-way into the EJRH. Seems like an easy fix - if you have a machine shop.

[fecmech]

Why not try just gluing the EJRH with clear silicone caulk?? Makes for a very strong slightly flexible joint and would only cost about $5 to try.

[tek4260]

I wonder why they never put a bushing around the screw that went half-way into the barrel and half-way into the EJRH. Seems like an easy fix - if you have a machine shop.


You mean like Ruger used to do? :)

Or simply make the ERH out of aluminum to reduce the mass and help eliminate the stress on the screw. Or pin it, or .....

I guess the glue is the easiest/cheapest fix, since a steel ERH is a "sign of quality" to most and BFR knows it. All my hard kicking Rugers have aluminum housings and I have never had one fly. I started to replace them with steel since everyone else was doing it and calling it an upgrade, then I thought about the increase in pressure on the screw.

[Whiterabbit]

wow. Complete with Mcmaster part numbers. You are the man, subsonic.

[subsonic]

If you shop around you might beat McMaster. A local hardware supplier had it for about $10 less total and no shipping. They had to special order it though. Got some coming.

[subsonic]

Why not try just gluing the EJRH with clear silicone caulk?? Makes for a very strong slightly flexible joint and would only cost about $5 to try.

The flex would let the screw loosen and then the silicone would be the only thing holding it, I think. But wouldn't hurt to try it.

[fecmech]

The flex would let the screw loosen and then the silicone would be the only thing holding it, I think. But wouldn't hurt to try it.
You might be right there but it would not surprise me at all that the silicone adhesive alone would hold it.

[Whiterabbit]

it would shock me. Metal adhesion via the chemical method is a bastard. I would LOVE if someone were to try a silicone, then pull the ERH screw and go for a shooting session with a magnum cartridge. That would be all the data required right there.

[fecmech]

it would shock me. Metal adhesion via the chemical method is a bastard. I would LOVE if someone were to try a silicone, then pull the ERH screw and go for a shooting session with a magnum cartridge. That would be all the data required right there.

If I had one I'd try it. I did try something similar a few years back. I D&Td my SBH .44 mag for the Weigand scope mount and just for the heck of it I glued the mount on (no screws) with a 2 part aircraft caulk called Pro Seal. I put a cheapy $20 red dot on it that I had laying around and shot 50 rds of mag loads( 25/296/429421). The mount and sight stayed on. I took a pair of channel locks,padded them with a cloth and peeled the mount off. There was a slight mark in the anodizing on the shoulder of the mount where it bears on the frame but no damage. There seems to be a big difference in the ability of adhesives to hold if they can flex a bit. I cleaned the Proseal off and installed the mount with the normal screws. I like to try goofy stuff like that every now and then.

[frankenfab]

So how exactly does recoil cause a screw to loosen? I know we have all heard it for years, but how does it do it? Maybe it stretches the screw which makes it loose. Then with a "loose" screw, the ERH has enough movement to give it some ability to shear the screw when fired.

Vibration. I had a 8 hour class on Loc-tite products at one of my former employers. The guy teaching was from Loc-tite, complete with white lab coat.

He had a bunch of neat gadjets with him, but the one he used to demonstrate how bolts loosen was a couple pieces of 16 ga. about 1.25" x 10", There was a hole in one end of the 2 pieces with a 1/2" bolt and nut run through. He would let any body in the class tighten the bolt and nut as tight as they could with wrenches, then bang it on a block of wood 2 or 3 times and you could unscrew the nut by hand. Even with a lock washer. He said lock washers are useless.

The thread compound fills the void between the threads and dampens the vibration. There's lots of stuff that will work.

[subsonic]

Lockwashers are useless. Nylock nuts aren't bad.

[frankenfab]

The property of Loc-tite that makes it useful for fastener retention is that it is anaerobic.

Not disagreeing with subsonic about the side loading. Doweling the ERH is definitely the best fix.

[looseprojectile]

the silicone. There are many different kinds of silicone.
Get the kind that says "adhesive". Murder to remove and strong.
I have used silicone on boats and some of the removable kinds are not any better than chewing gum.

Life is good