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Thread: Department Issue/Authorized RDS

  1. #11
    Murder Machine, Harmless Fuzzball TCinVA's Avatar
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    Quote Originally Posted by SoCalDep View Post
    The 24hr cure time is based on the technical data provided by Loctite.

    http://www.farnell.com/datasheets/319969.pdf

    While I can’t say for sure, the optics we’ve had come loose using these procedures were almost always shot a good amount prior to the 24hrs, so I’d err on the side of caution and strongly recommend letting it cure prior to shooting.
    I'll second that. Using Vibra-Tite or LocTite you absolutely want it to go for at least 24 full hours before shooting. Every time I've not allowed that minimum I've had fasteners loosen up during shooting.
    3/15/2016

  2. #12
    Vibra-tite VC3 (which is what is commonly supplied by some plate makers) is completely different from Loctite 248 in chemistry and function. Loctite 248 solid (which is the best solution for this application, in my opinion) is a true anaerobic bonding agent that needs to cure as specified, provides stable long term behavior, and is relatively insensitive (within reason) to contamination.

    Vibratite VC3 is essentially an acrylic polymer dissolved in solvent (MEK, in the case of VC3), which is painted onto the threads. Once it dries (less than 30 minutes in normal conditions) it is ready to install and shoot. However, over time, the polymer will change in terms of adhesion and elasticity particularly after being exposed to heat. It is specifically designed to allow screws to be adjusted- like eyeglass screws- so think about what that means in the context of an RDS install.

    This datasheet provides some additional insight on the cure time curves and behavior of Loctite 248 with different fastener/substrate coatings. Generally, most common fasteners used in RDS installations will reach a significant percentage of ultimate strength within 8 hours when the 248 is cured at room temperature.

    I’m not saying VC3 isn’t a good product for its intended uses- like eyeglass screws. I’m saying it’s not an optimal choice for an RDS.
    Last edited by Archer1440; 08-22-2021 at 11:26 PM.

  3. #13
    Quote Originally Posted by Archer1440 View Post
    Vibra-tite VC3 (which is what is commonly supplied by some plate makers) is completely different from Loctite 248 in chemistry and function. Loctite 248 solid (which is the best solution for this application, in my opinion) is a true anaerobic bonding agent that needs to cure as specified, provides stable long term behavior, and is relatively insensitive (within reason) to contamination.

    Vibratite VC3 is essentially an acrylic polymer dissolved in solvent (MEK, in the case of VC3), which is painted onto the threads. Once it dries (less than 30 minutes in normal conditions) it is ready to install and shoot. However, over time, the polymer will change in terms of adhesion and elasticity particularly after being exposed to heat. It is specifically designed to allow screws to be adjusted- like eyeglass screws- so think about what that means in the context of an RDS install.

    This datasheet provides some additional insight on the cure time curves and behavior of Loctite 248 with different fastener/substrate coatings. Generally, most common fasteners used in RDS installations will reach a significant percentage of ultimate strength within 8 hours when the 248 is cured at room temperature.

    I’m not saying VC3 isn’t a good product for its intended uses- like eyeglass screws. I’m saying it’s not an optimal choice for an RDS.
    I had to find out about these differences the hard way. Love vibratite for holster retention screws, not so much for optic mounting.

  4. #14
    Quote Originally Posted by SoCalDep View Post
    My department has a similar policy regarding modifications to firearms. One of the few exceptions is that we do allow our people to change their sights. When we first started our optic program we allowed the user to mount their optic, or they could bring it to us on the first day of class and we mounted the optic for them.

    By that time we'd been using 36 optics among the various subgroups of the weapons training unit with round counts ranging from a few hundred to almost 40,000. We only had two optics come loose, and we didn't know what we didn't know.

    Once we started to see the trends in mounting failures as more and more people started coming through the class (it's a 1,000 - 1,200 round class so if there's a problem we often see it during the class - but not always) we started looking into best practices. There had already been several discussions here on PF and after talking to several people including @Wayne Dobbs, consulting with a mechanical engineer, and experimenting with different methods and products, we came to what we think is a good mounting procedure to minimize problems. The procedure has been revised a couple times, once specifically because of input from a member of this forum who suggested test-fitting the screws and plates and such to make sure everything fits before going too far in the process.

    We tracked information about the implementation of the program last year, sent surveys to participants, tracked scores during the class and on a mandated later date, and did a bunch of research, testing, and experimentation. We tested aftermarket screws from McMaster-Carr (and are still testing stainless steel versions) and found them to be at least as good if not better than those provided by most manufacturers. This testing involved firing 10,000 rounds through a pistol with an optic mounted with the screws, corrosion testing, and various other procedures that I won't bore you with.

    All that to say we learned from our mistakes and the experiences of the participants in the program and narrowed most mounting failures to failure of the thread-locker. This included not using any threadlocker, using products that suck, not putting the threadlocker where it needed to be, using too much (especially in the case of Vibratite VC-3), not allowing it to cure, and not removing oil, solvent, or grease from the interacting components prior to assembly.

    When it comes to optics we don't have the compressive force as if we were driving a screw into two pieces of wood, and we're not using the torque we would when putting on wheel lugs, so in order for things to stay where they should under the violent reciprocation of the pistol's slide, everything needs to stay in place. This is one reason I don’t like plastic plates. I believe that they have a higher potential for movement between the optic and slide which can cause the screws to vibrate loose.

    We had the procedure largely formed about three months into the program and sent out an email to all optic participants letting them know the proper procedure. We also started encouraging people to not mount their own optic prior to the class.

    Early this year we started mandating that all optics be installed by our armorers at least 24 hours prior to the class to ensure they are mounted properly and to allow inspection of the pistol to ensure it complies with policy. We recommend they wait 24 hours prior to zeroing in order to allow the threadlocker to cure, but sometimes that isn’t practical, so we’ll have them zero immediately after installing and then we’ll re-check the torque once they’ve zeroed. We’ve had very few optics come loose since.

    Optic Mounting Steps:
    1. Inspect pistol to ensure it is compliant with policy and has backup iron sights
    2. Inspect the optic to ensure it is an authorized model and is functional
    3. Test fit the optic, plate (if applicable) and screws to ensure they are compatible
    4. Degrease all interacting parts (slide/plate threads, screws, excess oil in optic cut or on plate)
    5. Apply Loctite 248 to the screw threads where they will engage with the plate and or slide threads
    6. Tighten the screws until resistance is felt then apply alternating torque until the specified torque spec is reached
    7. Apply indicator marks (I prefer oil-based paint pens – put the paint on something and then apply with a toothpick unless you really like taking risks)
    8. Co-witness the reticle to the backup iron sights to make zeroing easier
    You guys running any red dots on force on force guns? If so what route did you guys go for that?

  5. #15
    Site Supporter Erick Gelhaus's Avatar
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    Quote Originally Posted by Utm View Post
    You guys running any red dots on force on force guns? If so what route did you guys go for that?
    I'm not SoCalDep ... At Gunsite, last year a Sims FX Glock was modified for a RMR with an after-market mount that went into the rear sight dovetail. Not enough Sims FX rounds were fired to develop an opinion. This year, the on-site gunsmith milled a Sims FX slide for a RMR and mounted one on it. As of now, not enough rounds through it for an opinion either.

  6. #16
    Member SoCalDep's Avatar
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    Mar 2016
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    The Secret City in Tennessee
    Quote Originally Posted by Utm View Post
    You guys running any red dots on force on force guns? If so what route did you guys go for that?
    Our tactics guys purchased some RMRs out of the unit budget along with Dueck Defense mounts. In fact, I gave them my old one a few months ago so they could set up an additional pistol (we use M&P and Beretta sims guns). I had run that one on a 2.0 Compact for about 8 months in 2019 until I finally snagged a couple COREs. I like the design for a dovetail mount, and I was impressed with the ability to make practical hits even with the short ~2" iron sight radius. The only thing that never made sense to me was that one of the set screws sat directly over the firing pin/striker block plunger. I never tested whether cranking it down all the way would impede the pistol's ability to fire and I simply discarded the right side set screw.

    Using it that way I never had an issue and I haven't heard of any issues from our tactics guys. Since the RMR is more low profile than some other optics there doesn't seem to be an issue with holsters and I know they work with Safariland 6360 series holsters for the 2.0 CORE. The guns go (obviously) to those who are optics certified when they come in for those classes, which honestly isn't that often. We have probably certified somewhere between 250-300 personnel on optics, but that's still less than 5% of the department. I think with mine there are four of the optic sims guns set up right now but may be wrong.

  7. #17
    Quote Originally Posted by SoCalDep View Post

    Optic Mounting Steps:
    1. Inspect pistol to ensure it is compliant with policy and has backup iron sights
    2. Inspect the optic to ensure it is an authorized model and is functional
    3. Test fit the optic, plate (if applicable) and screws to ensure they are compatible
    4. Degrease all interacting parts (slide/plate threads, screws, excess oil in optic cut or on plate)
    5. Apply Loctite 248 to the screw threads where they will engage with the plate and or slide threads
    6. Tighten the screws until resistance is felt then apply alternating torque until the specified torque spec is reached
    7. Apply indicator marks (I prefer oil-based paint pens – put the paint on something and then apply with a toothpick unless you really like taking risks)
    8. Co-witness the reticle to the backup iron sights to make zeroing easier
    What is the torque spec (ft-lbs) that you are using?

  8. #18
    Member SoCalDep's Avatar
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    Mar 2016
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    The Secret City in Tennessee
    Quote Originally Posted by DamonL View Post
    What is the torque spec (ft-lbs) that you are using?
    The torque spec (in/lbs) depends on the optic, plate (if applicable), and slide (handgun manufacturer) being used. They vary significantly.

  9. #19
    Quote Originally Posted by Archer1440 View Post
    Vibra-tite VC3 (which is what is commonly supplied by some plate makers) is completely different from Loctite 248 in chemistry and function. Loctite 248 solid (which is the best solution for this application, in my opinion) is a true anaerobic bonding agent that needs to cure as specified, provides stable long term behavior, and is relatively insensitive (within reason) to contamination.

    Vibratite VC3 is essentially an acrylic polymer dissolved in solvent (MEK, in the case of VC3), which is painted onto the threads. Once it dries (less than 30 minutes in normal conditions) it is ready to install and shoot. However, over time, the polymer will change in terms of adhesion and elasticity particularly after being exposed to heat. It is specifically designed to allow screws to be adjusted- like eyeglass screws- so think about what that means in the context of an RDS install.

    This datasheet provides some additional insight on the cure time curves and behavior of Loctite 248 with different fastener/substrate coatings. Generally, most common fasteners used in RDS installations will reach a significant percentage of ultimate strength within 8 hours when the 248 is cured at room temperature.

    I’m not saying VC3 isn’t a good product for its intended uses- like eyeglass screws. I’m saying it’s not an optimal choice for an RDS.
    Great info, thank you.

    So, you recommend loctite 248 versus VC3? I've had limited success with VC3 and complete failures in other applications. I cannot get my Holosun 509 to stay put with a C&H plate. It was good for a while and now its just not staying put.

    My direct mill slides have been awesome with VC3 and have surpassed 50K rounds on each gun.

  10. #20
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    May 2014
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    Central PA
    I'm assuming the Loctite 248 that is being referred to is the stick form as that is all I can locate, correct?
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