SmythBusters: Galvanic Reaction & Your AR-15 - Part 1

Good video

The people that started claiming this or water cooling computers and knew nothing about weapons. Or much about water cooling either as they had a very basic understanding

I’ve never seen it

What about a lapped upper receiver that removed the anodizing and a stainless steel barrel (by its nature no coating)?

If you're going to use grease on the threads anyway you might as well use what the longest mfg of Ars recommends.Peace of mind is worth everything.

I have custom aluminum rims and steel ext lugs,corrosion is real between these two metals.I use the same grease that I use when installing barrels Aeroshell.

Did anyone hear the tale of the two bore snakes? I also heard it from my brother in law. He was number 1!.

lubrication can prevent damage to the surface of the anodized threads - very small cracks can occur. if the surface gets damaged then galvanic corrosion can start. you may also note the stress corrosion thing. quote from the interwebs: "Stress-corrosion occurs when a material exists in a relatively inert environment but corrodes due to an applied stress. The stress may be externally applied or residual. This form of corrosion is particularly dangerous because it may not occur under a particular set of conditions until there is an applied stress."

I've seen and had to employ measures to prevent galvanic reaction when working on tanker trailers attaching bare aluminum to stainless steel.

Regarding lube and torque, as an automotive technician we were always taught NOT to use anti seize on wheel studs when installing wheel & lug nuts specifically because of TORQUE. As the lubricant was supposed to make the torque wrench exceed desired torque spec. But that was anti-seize on wheel studs. A very minimal amount of lubricant is desirable for any application.
However, other barrel installation tutorials recommend using anti-seize on upper receiver threads, though the reason given was if barrel nut needed to be removed in future, and nothing about achieving proper torque was mentioned.

Auto repair manuals even say to use oil or certain types of lube on bolt threads to get proper torque not to prevent a reaction.

What are these guys talking about it happens all the time. My brother-in-law's fourth cousin saw it happen 12 times and he's very tactical.

I used Ford Molly grease when I made mine.

Nope, never seen it in all my 20 years of heavy use in rough conditions with the AR platform. You are absolutely correct.

Decades ago, back in the 1980s, I built my first AR-15 and torqued the barrel to the correct spec, but I knew nothing about actually building one back then, except what parts went where, so I used no line at all. After a few magazines my barrel actually seemed to be slightly loose, so I removed the gas tube and to my surprise it was no longer torqued correctly. What’s when I tracked down a high level armorer in the division that I was in at the time (a military unit) and he taught me how to do it correctly. Information in the 1980s wasn’t as easy to find, but then we also had less prominence of misinformation as well. I love your videos!!!

Trust me, if you live in New England where they put a lot of salt on the road, you will see the reaction between nuts, frames, washers and bolts a lot. Salt helps the reaction and the frame is the ground. We have a lot of rust out here, and you can see where galvanic reactions eat through stuff, or corrode it solid.

You guys keep saying, "galvonic". It's "galvanic". "Van" is pronounced just like the vehicle.

Galvanic Corrosion was the name of my 8th grade heavy metal cover band.

I would assume it take years to happen. I work as a nondestructive inspector and we look at the interactions of two metals all the time and one will corrode before the other for obvious reasons, but mostly we only see problems where corrosive material sits around the metals for a long time. The vessels we inspect that have the worst issues were installed in the 70’s and or house a super corrosive substance.

I have seen. have I received a free used AR 10 hand guard it had galvanic corrosion butt it wasn't caused by two dissimilar metals it was just your basic corrosion the aluminum tubing and aluminum barrel nut. I wast first time butt true galvanic corrosion when I work on a m16a2 it was a white chalky powter like between the barrel and upper receiver and also trigger /sear cross pins. Butt if kept clean dry and taking care or new part hard never seen .these where totally neglected. Any metallurgist know this come naturally from dissimilar metals with open cleaning contacts you really don't even need to have any kind of current passed through just atmospheric

i was ALWAYS taught to brush anti seize compound on barrel and on threads ....

I get a galvanized erection watching these videos

It would take CUSO4 or a similar compound contaminating the aluminum. . Perhaps the copper based anti-seize/grease that contains copper would help but why would someone do that? There are AL/CU alloys that don't self destruct. Steel is less reactive with aluminum. Under an ideal set of circumstances, 1 in a billion, chaos theory level, cascading stupidity it is possible. I'd like to see an example too.

The inside area of the receiver is often not Anodized.

Does this mean i should worry about it if i have a raw upper?

They may be right about torque meaning lubed threads on an AR, but on every other common application (e.g. automotive) torque is always to imply clean and dry threads, not oily, unless otherwise specified. Otherwise you get over-torquing and snapped fasteners.

Dip it in some acid 😋

Do I have to worry about galvanic corrosion on my X Wing?

The grease I used was a black moly grease with graphite. I should remove all of this right away correct?

Threads have 2 torque ratings- dry torque and lubricated torque and they are different. Galvanic corrosion primarily comes from 1 of 2 scenarios- 1) moisture corroding steel and/or aluminum while these two are in contact with each other. Example; the mating surface of aluminum car rims to the steel backing and lug nuts. 2) static current from fluid flow when copper and zinc are touching each other. This is why it’s part of plumbing code to isolate your copper from the zinc coated material when you hang your piping.

I have not read through all the comments but many of the ones that I have read mention anti-seize compound. Be aware that most (but not all) ARE conductive. Most anti-seize compounds contain either aluminum or copper along with graphite (carbon), all of which are conductive. Take a look at manufacturer's specs. I am a grad of MIT and have been a machine designer for 30 years and I can tell you that galvanic welding can and does happen particularly with aluminum (an most especially in contact with brass both of which are highly conductive) Hard coat anodizing is an insulator so that is going to limit the conduction taking place. However, if you can see silver on a dissimilar color of anodizing, that IS bare aluminum and it is conductive.

My brother in law is mad at you guys now!

proper torque ? not on all threads some torque specs are dry torque

I of course know what galvanized metal is, but being a second year/ third year gunsmith, and metal worker for years, can you explain what exactly is the galvanic reaction, and what it would cause? PLEASE....

It's not common but can happen. Use a zinc based anti-seize that contains no graphite when assembling steel to aluminum. The coatings/finish on the steel and aluminum will protect most of the parts anyway.

I saw bigfoot

How have I never seen this video till now? Super interesting to me.

what about when you lap the upper? what happens when the exposed aluminum face contacts the steel barrel extension?

When in doubt lube that baby up!!!🤣

You're totally Wrong. I have worked high performance aircraft since 1978. There are dry torque and wet torque procedures. Lubrication on threads—and a whole host of other factors—can cause fluctuation in torque readings. So, once you add a lubricant of any kind to the threads, all bets are off as to whether the same torque setting will truly secure the threads properly.
Nevertheless, if procedures call out wet torque, definitely follow the procedures with the specific torque lubricant they specify. Lastly, he's talking about all the treatments that protect metal and the threads of that upper show bare aluminum. Come on guys. I watch your VDOs and they're great VDOs. This one requires editing.

How is the steel trunnion attached to the aluminium receiver? Is it through riveting or bolts or welding or through any other means?

I was cleaning my “Ay Ar Fiteen” spelled like this for a reason today and noticed blueish liquid dripping from the barrel… I’m worried 😕

You need electrical charge to experience galvanic corrosion. The best example f galvanic corossion is power boats. An outdrive on an inboard/outboard boat has aluminum and steel both and an electrical charge. You need dissimilar metals and an elecrical charge. You place sacrificial zinc on boat out drives to corrode instead of the aluminum.

Basically its like Electrolysis in car's n engines, thats why they have ground straps in places

In the automotive world, directions consistently say threads should be dry of any oil or grease for proper torque spec, and if any lube is used, there's a significant increase in what 'lbs/"lbs one should use, and it's usually an increase of 15% in my estimation.

There are two types of torque. Dry torque and wet torque. If it doesn’t state wet or dry you dry torque

What about where the steel bolt slides on the aluminum receiver and coatings wear away?

But if you lap the receiver for the barrel you'll wear the anodizing off.

The reason for parkerizing the barrel and anodizing the receiver is to prevent this very thing from happening. You need contact between bare metal. Anodizing is aluminum oxide, which is not a metal. It is a ceramic. It does not conduct electricity. You literally have a layer of a ceramic mineral between your aluminum and the steel, which has also been parkerized to resist rusting anyway.

In the aircraft ind. We call this electrolytic corrosion, when a ferrous and al. Metals com into contact, all they need is humidity or water, to become a battery, and this produces corrosion,

Corrosion Specialist here. You guys are pronouncing galvanic weird. It is a real thing. It eats up aluminum wheels and heat shields on cars all the time but when used to our advantage it protects boat hulls and the interior wall of your water heater.

But it requires certain conditions to occur. Cars, boats and water heaters all have something in common. Electrolyte. In these cases the electrolyte is water. Even worse, hot water. Even worse than that, salt water. With the grease and the protective coatings and construction of our rifles, plus the fact any water that could get in there would evaporate out quickly when you fire a few rounds, it just doesn’t seem to be a problem.

If you wanted to prove a point and make it a problem, I’m sure you could scratch up your protective coatings at the metal to metal contact points and store your rifle in a bucket of hot salt water for a week and get the results you’re looking for but that’s crossing over into intentional damage. And would affect any place aluminum contacts steel, roll pins, detents, back plate, trigger pins, etc. so not exactly proving a point.

Store it in the house, not in the pond, and it’ll be fine. GalvAnic corrosion cells are a thing, but not something we need to be concerned about in this context.

In case you’re interested… in the U.S. corrosion control industry, it’s pronounced GalvAnic, where both A’s are short A’s, like in “and”.

so would it be safe to use any kind of grease, including graphite based grease?