Thread Lock or anti seize for gas block?

silversquirrel

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Repairing my Radical Upper. Original gas tube hole drilled UPSIDE DOWN! (Or offset bent upside down?)
New gas tube, and pin. Dry threads from Radical. I have some blue locktite, and some copper anti sneeze on hand. Suggestions? Or doesnt it matter?
20210225_112507.jpg
 
I use 600F red loctite (272) on the bottom half of the barrel (careful to make sure it does not get in the hole). I use purple loctite (222) on the set screws themselves. The problem with using blue is that the torque required to break blue is higher than the maximum torque of the hex set screws so you risk stripping the head when you remove it.

The red on the barrel is not "necessary" but means you are not relying on the set screws solely to keep the gas block in place. If you have a dimple on the barrel in the right place (a dimple in the wrong place is worse than no dimple) then the set screw is giving some legitimate mechanical support. The other option is to drill the block/barrel or get a block predrilled and just drill the barrel. That will give you true mechanical support.

But the short answer is 272 on the barrel (avoid the gas opening) and 222 on the setscrews is what I do
 
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since you are not using dis-similar metals there is no need for anti seize

That is the only reason to use it IMHO, if you need lubrication, most torque specs are done assuming the threads are lightly oiled.

If you need retention, my "go to" is blue 243 loktite because it tolerates contamination a bit better and does not need a primer when used on stainless hardware
 
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I use 600F red loctite (272) on the bottom half of the barrel (careful to make sure it does not get in the hole). I use purple loctite (222) on the set screws themselves. The problem with using blue is that the torque required to break blue is higher than the maximum torgue of the hex set screws so you risk stripping the head when you remove it.

The red on the barrel is not "necessary" but means you are not relying on the set screws solely to keep the gas block in place. If you have a dimple on the barrel in the right place (a dimple in the wrong place is worse than no dimple) then the set screw is giving some legitimate mechanical support. The other option is to drill the block/barrel or get a block predrilled and just drill the barrel. That will give you true mechanical support.

But the short answer is 272 on the barrel (avoid the gas opening) and 222 on the setscrews is what I do
Ok, sounds good. There is a dimple on the barrel, at 6 o'clock.
Thanks!
 
Ok, sounds good. There is a dimple on the barrel, at 6 o'clock.
Thanks!
Hopefully the dimple aligns to the set screw with the block flush against the collar. I have seem them off so you end up unable to use the set screw because it will offset the gas block and cause it to be out of alignment with the gas hole in the barrel.
 
Hopefully the dimple aligns to the set screw with the block flush against the collar. I have seem them off so you end up unable to use the set screw because it will offset the gas block and cause it to be out of alignment with the gas hole in the barrel.
It does. I put a mark on the gas block, and one on the barrel to align the holes, then tightened it up slowly and the set screw seated in the dimple.
I also checked the hole centers front to back from the shoulder with a caliper, so its lined up both ways.
All back together now.
 
If your really worried about them coming loose stake the SOBS. I also index mark my black and barrel so I can tell easily if its moved even a tad.
Loctite? Use what ever you need in the temp range your going to operate in.
If you need to disassemble it , heat is easy to apply
 
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