View Full Version : Loctite/Antiseize in AR build
I have heard of these being used when building an AR. I have just started building my first AR and was wondering where you would use these. I can see the loctite on the pistol grip screw and maybe the buffer tube castle nut but is there anywhere else you would want to use these?
thopkins22
02-14-13, 12:40
Loctite on optic mount screws and such...but nowhere on the assembly of the actual weapon.
Moly grease on the castle nut...quite the opposite of loctite! Moly grease on the barrel nut as well.
I'm thinking you should sit on your parts for a while and read some....
Light moly grease on receiver extension threads/castle nut. Torque to 35-39 foot pounds pounds three times(loosening after the first two) and stake receiver plate into castle nut.
Light moly grease on barrel nut and torque to 30 foot pounds several times and then torque to the next gap so that the gas tube passes through without exceeding 80 foot pounds.
Flash hider gets a crush washer and 30 foot pounds ONCE as the crush washer is one time use.
No effing loctite on any of those components....
ETA:Loctite is fine on the pistol grip screw...though in my experience a locking washer does just as well, ditto on ambi safeties and as Kenneth said, things that go on the rail.
I used blue loctite on anything that gets attached to the rail or flat top reciever. On the pistol grip screw and a drop on the Battle Arms safety lever. I used anti seize on the barrel nut.
Light moly grease on receiver extension threads/castle nut. Torque to 40 inch pounds three times(loosening after the first two) and stake receiver plate into castle nut.
Foot pounds. The 40 in-lbs is a typo and is nowhere near proper torque. Come on guys, think about it. Does <3.5 ft-lbs seem like a good amount of torque for a nut on a semi-auto rifle?
thopkins22
02-14-13, 12:52
Foot pounds. The 40 in-lbs is a typo and is nowhere near proper torque. Come on guys, think about it. Does <3.5 ft-lbs seem like a good amount of torque for a nut on a semi-auto rifle?
Absolutely right...35-39 foot pounds.
thopkins22, you are the second person to say the same thing about not using the loctite. Can you explain why this is a bad idea so that anyone who reads this will know? And also do you have a preference of brand of moly grease?
Put some loctite on the threads of your loctite cap. Then stake the cap, and throw the stuff away.
I don't own any loctite and I put a fair amount of guns together.
It's a good idea to apply blue Loctite on the screws that hold together your rail/handguard, too. All the screws that get Loctite should have witness marks. No place for red Loctite on an AR.
The grip screw doesn't really need it since it has a lock washer.
Castle nut needs to be staked, not Loctited. Do a search; this has been discussed a lot already.
The only place I use loctite is red on low profile gas block set screws.
Sent from my iPhone on tapatalk
Red Loctite is only good up to around 500° F. Rocksett is a better choice for gas block screws and muzzle devices.
Put some loctite on the threads of your loctite cap. Then stake the cap, and throw the stuff away.
I don't own any loctite and I put a fair amount of guns together.
Great post. I laughed out loud when I read this. :D
Using Loc-tite is a good thing and a bad thing. When it is applied in the correct way it's great, and when applied improperly (castle nut, barrel nut, etc..) then it's a bad thing.
1. Castle nut- Anti-seize or grease. Tighten the nut and stake it.
2. Barrel nut- Torque the nut to the correct spec and then finish the install.
3. Screws- If you are planning on removing them at some point without massive effort then generally you should use blue Loc-tite. I use it in mounts, rail screws, etc... On the gas block I use high strength red Loc-tite. If they are screws for securing the rail like the Troy VTAC you can consider red as well. I don't put them on USGI grip screws and it's been my experience it isn't needed when using a proper lock washer.
4. BCG- This is a matter of debate, but I generally will apply red Loc-tite and then stake it with a MOACKS.
1. Castle nut- Anti-seize or grease. Tighten the nut and stake it.
2. Barrel nut- Torque the nut to the correct spec and then finish the install.
1. Copper or no copper? Graphite or no graphite? Does it matter at all?
2. Only Moly Disulfide lube here?
Ned Christiansen is working on a LOCTITE MOACKS. :sarcastic:
the_1iviper
02-14-13, 19:22
what about urx rails ?
http://img.photobucket.com/albums/v619/1iviper/instruct2_zpsd818abd2.jpg
I use Loctite for certain applications and Anti-seize on the barrel nut instead of grease. Of course the application of Loctite requires some measure of intelligence and the know how to undo it when the time comes.
DirectDrive
02-14-13, 20:11
The only place on an AR that "officially" sees Loctite is on an A1/A2 buttplate screw.
These screws come with the crap pre-applied and we usually try to scrape most of it off so the screw can be installed.
There are aftermarket parts that may call for Loctite.
If you look at the TM(s) most all of the threaded connections call for moly grease.
Aero Shell 33MS meets the specification and there are other greases that are similar such as Valvoline VV632
Our torque specs are assumed to be "wet" so using grease is important for that, preventing thread galling and separating dissimilar metals.
ARs have been assembled with everything from nothing to KY jelly.
Use whatever floats your boat.
michael word
02-14-13, 20:19
1. Copper or no copper? Graphite or no graphite? Does it matter at all?
2. Only Moly Disulfide lube here?
Copper is fine but no graphite, as it can cause corrosion over time. As said, use aeroshell MS33. Meets the mil-spec for working on AR's.
DirectDrive
02-14-13, 21:18
Copper is fine but no graphite, as it can cause corrosion over time. As said, use aeroshell MS33. Meets the mil-spec for working on AR's.
Actually anything that is a conductor (copper, aluminum, graphite, etc) can enhance/accelerate galvanic corrosion.
In a military weapon that could see a corrosive environment this is a consideration.
In a hobby gun, not so much of a concern.
Actually anything that is a conductor (copper, aluminum, graphite, etc) can enhance/accelerate galvanic corrosion.
In a military weapon that could see a corrosive environment this is a consideration.
In a hobby gun, not so much of a concern.
I can't believe I never made that connection (conductivity) between those two as lubricity agents before, and why they wouldn't be recommended. In my research, there are a lot of sites that will poo-poo one and praise the other, but never be on the same side of the argument (This site not included) and definitely no explanation as to the "why" of it. Though, after hearing the "why" it seems obvious, and I feel dumb.
DirectDrive
02-14-13, 21:31
I can't believe I never made that connection (conductivity) between those two as lubricity agents before, and why they wouldn't be recommended. In my research, there are a lot of sites that will poo-poo one and praise the other, but never be on the same side of the argument (This site not included) and definitely no explanation as to the "why" of it. Though, after hearing the "why" it seems obvious, and I feel dumb.
It's fairly easy to reach for and use the right stuff (moly-fortified grease).
I always have anti-seize compound on hand from engine building but it's full of suspended metals and it's a royal mess to deal with.
It doesn't get near my ARs.
It's fairly easy to reach for and use the right stuff (moly-fortified grease).
I always have anti-seize compound on hand from engine building but it's full of suspended metals and it's a royal mess to deal with.
It doesn't get near my ARs.
Before I did any research, my first instinct was to grab my jar of ARP Ultra-Torque. I love that stuff for engines.
If the manufacturer calls for it then yes. I don't like the rails and have very little experience with them.
what about urx rails ?
http://img.photobucket.com/albums/v619/1iviper/instruct2_zpsd818abd2.jpg
Unless you are doing sustained full auto retard mag dumps its a non-issue.
Red Loctite is only good up to around 500° F. Rocksett is a better choice for gas block screws and muzzle devices.
michael word
02-15-13, 10:40
I believe BCM, from looking at my uppers, just use plain white lithium grease on the barrel nut.
I believe BCM, from looking at my uppers, just use plain white lithium grease on the barrel nut.
Isn't the Mil-Spec grease essentially white lithium grease with 5% Molybdenum Disulfide in it?
DirectDrive
02-15-13, 11:37
Isn't the Mil-Spec grease essentially white lithium grease with 5% Molybdenum Disulfide in it?
Lithium-based
5% moly
Dark grey in color
http://www.shell.com/global/products-services/solutions-for-businesses/aviation/products/lubricants/greases/grease-33ms.html
Has anybody ever used this?
http://www.oreillyauto.com/site/c/detail/MP02/90366/N0417.oap?ck=Search_N0417_-1_-1&pt=N0417&ppt=C0139
I recently was given some.
Has anybody ever used this?
http://www.oreillyauto.com/site/c/detail/MP02/90366/N0417.oap?ck=Search_N0417_-1_-1&pt=N0417&ppt=C0139
I recently was given some.
Just looked up the MSDS on that - it's got 10mg/m^3 of graphite in it.
I see, I assume that would mar the threads on barrel nut or the buffer tube extension then.
DirectDrive
02-15-13, 12:44
I see, I assume that would mar the threads on barrel nut or the buffer tube extension then.
Read the thread.
I only use the weakest blue loctite on optic mounts, the pistol grip screw, bolt-through picatinny rail mounts (BUIS, mounts), and small set screws on set screw gas blocks and aftermarket accessories that have them. Never had a problem removing loctited accessories with a good smith's screwdriver.
michael word
02-15-13, 14:03
Lithium-based
5% moly
Dark grey in color
http://www.shell.com/global/products-services/solutions-for-businesses/aviation/products/lubricants/greases/grease-33ms.html
Yes it is, but the grease BCM uses is straight white lithium with no moly in it.
DirectDrive
02-15-13, 15:09
Yes it is, but the grease BCM uses is straight white lithium with no moly in it.
Yeah, I read that in post #25.
There are probably many different greases that would work fine.
Buy and use what you are comfortable with.
I don't remember what we were using. I just smeared the shit on and torqued the stuff. It was in some kind of silverish colored can.
Yes it is, but the grease BCM uses is straight white lithium with no moly in it.
One small "gotcha" in lube type vs. torque:
The actual purpose of torquing is to pre-load the threads [in tension].
Amount of torque vs. amount of actual pre-load [clamping force] is VERY dependent on the 'slickness' of the lube used. It makes a BIG difference.
I have measured a 25% drop in required torque to get the same preload/tension, when they switched from light oil to a teflon coating.
Thus 40-ftlbs with oil / 'dry' with shipping oil / K-Y, etc. will only be about 30-ftlbs using teflon; about 32# using moly paste; about 34# using lith grease w/5% moly.
NOTE: these are only SWAGS based on the coefficient of friction of these lubes, but I'm 'in the ballpark'.
Moral of this post: adjust your torque based on the 'slickness' of your lube.
thopkins22
02-17-13, 14:15
One small "gotcha" in lube type vs. torque:
The actual purpose of torquing is to pre-load the threads [in tension].
Amount of torque vs. amount of actual pre-load [clamping force] is VERY dependent on the 'slickness' of the lube used. It makes a BIG difference.
I have measured a 25% drop in required torque to get the same preload/tension, when they switched from light oil to a teflon coating.
Thus 40-ftlbs with oil / 'dry' with shipping oil / K-Y, etc. will only be about 30-ftlbs using teflon; about 32# using moly paste; about 34# using lith grease w/5% moly.
NOTE: these are only SWAGS based on the coefficient of friction of these lubes, but I'm 'in the ballpark'.
Moral of this post: adjust your torque based on the 'slickness' of your lube.
The TM calls for the torque value with moly grease. Ergo, don't adjust anything. If that's much higher than 40lbs dry, then so be it.
DirectDrive
02-17-13, 16:00
One small "gotcha" in lube type vs. torque:
The actual purpose of torquing is to pre-load the threads [in tension].
Amount of torque vs. amount of actual pre-load [clamping force] is VERY dependent on the 'slickness' of the lube used. It makes a BIG difference.
I have measured a 25% drop in required torque to get the same preload/tension, when they switched from light oil to a teflon coating.
Thus 40-ftlbs with oil / 'dry' with shipping oil / K-Y, etc. will only be about 30-ftlbs using teflon; about 32# using moly paste; about 34# using lith grease w/5% moly.
NOTE: these are only SWAGS based on the coefficient of friction of these lubes, but I'm 'in the ballpark'.
Moral of this post: adjust your torque based on the 'slickness' of your lube.
Read and follow the TM and none of this nonsense matters.
This does not require a brain fuk.
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