Sealant between carrier and key?

[tom12.7]

Part of the spec is the torque required to remove the fastener after staking.
With proper staking, there really isn't a need for an additional locking compound on the threads. It may not hurt anything, but would add a layer of difficulty if you use removal torque on the fastener to determine if a sample was staked correctly. How much torque would then be the range? With a tolerance added, how would you determine how much of what portion of fastener retention is done by either part?
Staking doesn't have to be pretty to be in the proper range. Just enough displacement of the key into the fastener to put you in the proper range without "real" damage to the key.

[tom12.7]

Another point I should have made is that the job of the 2 fasteners is to hold in tension the key to the carrier. The clamping force isn't much different than if you compared it to a spring holding tension toward the key and carrier interface.
Sure, an additional compound may prevent fastener rotation to keep it from coming loose, but you could be adding problems down the road.
The main issues I saw was fastener fail by either breaking, and/or stretching. Most of these could be traced to base fastener issues (don't go cheap here) and improper initial torque that damaged the fasteners.
It is pretty easy to service a key that is staked by breaking the mechanical bond of the key to the fastener. If a fastener snapped, they normally spin out pretty easy. Nothing is any tension then and nothing has been added to make it worse.
If you add a locking compound to the threads, you can add extra complications if the fastener breaks, making it more difficult to remove.
Why would you want that when proper staking with a good key will hold with proper support?
I'm not getting why that would be done?

[556Cliff]

LMT is currently sealing their gas keys with Loctite 518 sealant. No threadlocker on their key screws though.

[lysander]

Another point I should have made is that the job of the 2 fasteners is to hold in tension the key to the carrier. The clamping force isn't much different than if you compared it to a spring holding tension toward the key and carrier interface.
Sure, an additional compound may prevent fastener rotation to keep it from coming loose, but you could be adding problems down the road.
The main issues I saw was fastener fail by either breaking, and/or stretching. Most of these could be traced to base fastener issues (don't go cheap here) and improper initial torque that damaged the fasteners.
It is pretty easy to service a key that is staked by breaking the mechanical bond of the key to the fastener. If a fastener snapped, they normally spin out pretty easy. Nothing is any tension then and nothing has been added to make it worse.
If you add a locking compound to the threads, you can add extra complications if the fastener breaks, making it more difficult to remove.
Why would you want that when proper staking with a good key will hold with proper support?
I'm not getting why that would be done?

I would just like to add that as long as metal has flowed to make good contact with the bolt head, staking has been accomplished. There is no need to make two craters a 1/16" deep on each side of the key.

Many people (and manufacturers) go a bit overboard when staking the carrier and castle nut.

This:


will not hold any better that this:

or even this:

(Although I wouldn't use YFS bolts...)

AND...

Over-torqueing the carrier key bolts in probably worse that under torqueing. The AR gas system is surprisingly tolerant of small leaks. Just as a point of reference, the average person can get 30-35 in-lbs with a screw driver, or about 1/3 pound force on the end of a a foot wrench, that's not a lot.....

[curious1]

I have purchased carriers with both sealant and something that looked like red locktite gooped under the key and in the screw threads. Pain cleaning it off of them. The red thread locker stuff was still wet. Only dried around the edges. Likely would have blown out and left leakage after awhile. Sealant stuff was thicker but still gooey. Had doubts about how it would last. checked the Colt Canada manual and it said this about sealant.

b. Apply a light layer of sealing compound,
to the under surface of the bolt carrier
key around the gas port, to form a seal;
Apply the sealing compound sparingly and
only to the area immediately surrounding
the gas porthole. DO NOT allow it to enter
the gas port or screw holes. Ensure that
the gas port is not plugged.

I had to dig the stuff out of the gas hole on the bottom of the key when I removed it. It had filled part of the key and was plugging it partially closed.

[tom12.7]

That quote is correct.

[SDSwoll]

Colt Manual Gas Key.jpg

Not saying anyone is right or wrong, picture from the Colt Manual (2014) issued 10/15, showing sealant used and a picture of the tub of Loctite sealant.

[tom12.7]

Loctite bought Permatex.

[lysander]

Loctite bought Permatex.

....in 1972.....

[26 Inf]

....in 1972.....

And then sold it.......

Did a little bit of research, for those interested. As far as I can tell Henkel still owns Loctite and Permatex is currently owned by Illinois Toolworks, Inc.

1972 – From Permatex History: The Permatex Company was sold to Loctite Corporation. The business was moved to Cleveland, Ohio and integrated with the Woodhill Chemical Company. In the late 1970's, Woodhill Permatex launched Permatex® Blue Silicone which went on to become the largest selling blister carded chemical item in the American auto parts business.

From Loctite History: Loctite also expanded its industrial product base through several key corporate acquisitions. Most notable among these acquisitions was Permatex, an automotive line acquired in 1972, and Woodhill Chemical Sales Company, purchased in 1974. Permatex's gasket dressings made it a leader in the automotive repair market; Woodhill's product line of adhesives opened up new markets for car and home repairs. It was Woodhill that introduced Super Glue to hardware stores across the country. The two companies were combined into the automotive and consumer division of Loctite in 1974.

The importance of adhesive and sealant activity in Europe took on greater significance in late 1996, drawing the attention of all those working at Loctite headquarters in Connecticut. In November, Dusseldorf-based Henkel KGaA announced its intention to acquire Loctite, proposing a takeover that industry observers valued at more than $1 billion.

Henkel concluded the acquisition of Loctite in January 1997, marking the beginning of a new era for the Connecticut company.

Substantial changes were in the offing as Loctite pressed forward under Henkel ownership, highlighted by the decision made in 1999 to abandon the automotive aftermarket business. Loctite sold the business to PBT Brands, Inc.

SEC Document: Automotive Performance Group (OTCBB:RACG) today announced it has purchased a 22% equity ownership position in PBT Brands, Inc. (PBT), a new company which was formed to acquire the Automotive Aftermarket Business of Loctite Corporation(Permatex).

1999 – From Permatex History: Permatex was purchased by a group of private investors in 1999. As a private company in 2000, Permatex introduced an unprecedented fifty new products, acquired the No Touch® tire care line, bought the Loctite Mexican Hardware Business, and purchased the NOS® (Nitrous Oxide Systems) fuel additive and treatment product line. In 2002, Permatex re-entered the industrial market with its broad range of products.

2005 - Permatex was acquired by ITW (Illinois Tool Works Inc.), a NYSE listed U.S. based corporation. ITW was founded in 1912 and is a Fortune 200 diversified manufacturing company with more than a 90 year history. ITW's decentralized business units in 49 countries employ 50,000+ people focused on creating value-added products and innovative customer solutions.

I thought it was interesting and answered the age old quaestion, 'are Loctite and Permatex the same?"