Is bedding the AR barrel a myth? What's the best way?

[WeR0206]

Have a new SOLGW M89 handguard coming middle of next week, was going to do it then. But curiosity got to me. Decided to take out barrel from upper today that was bedded-in with the green permatex 640. It was bedded beyond my expectations. Heavy mallet and wood dowel to break it loose, and Several 'heavy handed' blows to get driven out .
The data sheet you linked say's 24 hr. cure, But I remember when I bedded this one, and it seemed wet a long time that day.I just let it sit in the corner of the shop for few days before I even went out to sight it in.
.

I recently bought 3 of the same handguard in various lengths for a few builds, love them especially the barrel nut

 

[softcock]

I recently bought 3 of the same handguard in various lengths for a few builds, love them especially the barrel nut

I actually never used the SOLGW before. I'm swapping out a Fortis 'switch' handguard for SOL brand on this upper. I got not bitches about the Fortis, and I like the feel and shape of them to . But I am re barrelling to Rifle length gas. So going Long handguard and people say the SOL have best lockup/rigid in the market.

 

[610yd]

Have a new SOLGW M89 handguard coming middle of next week, was going to do it then. But curiosity got to me. Decided to take out barrel from upper today that was bedded-in with the green permatex 640. It was bedded beyond my expectations. Heavy mallet and wood dowel to break it loose, and Several 'heavy handed' blows to get driven out .
The data sheet you linked say's 24 hr. cure, But I remember when I bedded this one, and it seemed wet a long time that day.I just let it sit in the corner of the shop for few days before I even went out to sight it in.
.

I suspect the "how easy" part for separating the 640 or 620 cured fitment is subjective. All I know is, I don't need to whack a wooden dowel against the barrel to get it out. This does not make 640 or 620 a bad choice, just part of the Pros & Cons list.

640 still wet? Where, just on the edges outside of fitment? With O around the stuff stays wet, but these products should start to lockup fast on the inside, it's another Con for 640 620, you need to move fast, wet the surfaces, make the fitment, wipe good, lockup the nut to at least 50%, let that cure for 24hr(min), then come back to finish the nut using whatever procedure you choose.

The 24hr spec is based on the substrate. Not all substrates allow for a full cure. IIRC (maybe from Henkel emails long ago), these products don't technically "fully cure". I think when they state it that way it's in reference to some "full cure" strength numbers. Once the stuff can reach those strength numbers they call it "fully cured", 24hr perhaps chosen for convenience or marketing reasons. If I wanted my product to "fully cure" faster than yours, I just take the "fully cured" strength down some, this way if you need a faster full cure you choose my product, etc. The guys at the trade shows love to tout their products.

 

[610yd]

SOLGW M89 handguard ?
Seems ok, I prefer the Aero M4-ENHANCED setup. To each their own as they say.

 

[610yd]

Well, you can call it differential, or whatever you choose; to my thinking, it shows a definitive, quantitative change from un-bedded.

But I'll say again, there are enough really good uppers that will make up to a thermal fit with a typical barrel extension, so no "goop" is required at all, making this whole exercise in conjecture more or less moot.

MM

The discussion was around Pros & Cons of the various goops, only the diff between them matters. You would not choose something that is 10x the effort to yield only 0.05% gain, if it could even be measured, etc. In the context of the goops mentioned, they are all about the same effort for installation, but not same effort to separate, yet all produce about the same gains you get from "bedding".

There's no argument from anyone saying bedding is a waste of time.