Seems I've seen more threads here lately where Loc-tite is being recommended for optics mounting screws (specifically talking red dots to pistol slides). My understanding and what FCD still recommends is Vibratite. What's the deal?
Seems I've seen more threads here lately where Loc-tite is being recommended for optics mounting screws (specifically talking red dots to pistol slides). My understanding and what FCD still recommends is Vibratite. What's the deal?
Food Court Apprentice
Semper Paratus certified AR15 armorer
CHPWS included vibratite with my plate as well
I have never had Vibratite work to secure an optic/plate/slide combo long term. Maybe I'm doing it wrong somehow but I'm always careful to clean the parts well and use the Vibratite according to the directions on the bottle. My theory is that on really small screws the VT gets pushed out and doesn't keep good contact with the actual threads. I've had it work fine on larger threads like rail-to-barrel nut screws. I even bought an expensive German calibrated torque wrench and torqued per CHPWS specs. Screws came loose fairly quickly using Vibratite and Loctite. I think it was 10 in-lbs but I can't remember, it was whatever CHPWS said to use.
I currently use the following procedure with no loose plates/optics: Clean the parts well with brake cleaner, let them dry and reach room temp (to avoid condensation), apply low strength (blue or purple) Loctite per directions, torque screws (plate then optic) using the German spec: gutentight (actually I torque using the short end of an Allen wrench by pressing on the tip of the long end until the long end starts to bent a little). I go around and repeat tightening the screws one then the next sort of like lug nuts on a car wheel. Then wait at least 12 hours but ideally 24 hours for the Loctite to cure.
Screws are single use items. Witness marks are a good idea.
So far so good. No stripped screws, no loose plates. I have a decent round count on a couple Springer P320 to Romeo3Max plates for USPSA carry optics using this method without issue, maybe 5000 rounds on one gun and 1500 on the other. I have used it on three RMR/SRO Glocks using CHPWS plates. Much lower round count on those (probably 1500 combined) without issues. Just my experience, I'm not an engineer. Maybe there's a better method but this is what I've settled on.
Last edited by Super77; 06-24-2021 at 01:50 PM.
I've been using Vibratite for everything and have had good luck. Used it for two pistol mounted RDS that each have a 2000-4000 rounds on them so far without issue. Also used it for the CROM on my 1301 - it only has a couple hundred rounds so far but nothing has loosened.
I apply it to clean parts, let it dry, then torque to spec.
Vibratite is tricky with small screws. If you apply it too thickly to those tiny, shallow threads it will shear off as it is screwed in and not hold properly.
My general sense of things is I see more threads and posts here and elsewhere that mention issues with RDS mounts with Vibra-tite. I don't see hardly any threads or posts mentioning issues using blue loctite.
I ended up using blue loctite, and torqued to spec using a Wheeler FATwrench, then witness marked the screws with white sharpie oil based paint pen. No issues to date, but I've only been shooting dots for a few months, and only have had two of them, both Holosuns.
I have concluded, through my own use, that perhaps Vibra Tite works, but I am not smart enough to use it properly. Blue loctite works well for me.
Likes pretty much everything in every caliber.
This is pretty much my experience as well.Originally Posted by GJM
Third this. Perhaps the Loctite has wider margin of error for achieving acceptable results.
Harumph!
I used Vibratite for a 10,000+ round formal handgun optic test and it held. I’ve had it fail a couple other times including the C&H mount for my G17/SRO. I recently switched the optic after nearly a year of use and several thousand rounds and found one of the plate-slide screws was a quarter turn loose. Same with my Tango Down ACRO mount that had pre-applied VC-3. I’ve seen several other optics come loose when installed with VC-3 and I reinstall with Loctite 248.
Not a Vibratite fan. I vote 248 for the win.
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