With the new advancement in aluminum brake rotors I feel a similar alloy would definitely withstand pure lead pellets
Just how much weight would it save vs a skinny steel barrel with a carbon fiber wrap?
A most interesting thread. Would the Teflon coating/filler be subject to removal by cleaning solvents?Jesse
Any conversion coating that is applied with an electric current is going to be tricky due to the large aspect ratio, of bore diameter to barrel length. A means to insert a very straight, exactly central anode will be required. Else, the anodizing or metal plating will build up unevenly.You will need a system to flush fresh electrolyte through the barrel rapidly, else the chemistry at the far end of the bore will be depleted or "used up", creating an uneven conversion or plating depth.The sharp corners of the lands (assuming convention rifling) will preferentially etch or plate because that is the nature of electricity - to discharge from sharp points or lines preferentially.My suggestion is to use electroless nickel plating. There are several variants. Some of them can be baked afterwards at medium temperature to reach Rc 70. Some EN plating can be had with teflon impregnation.In any event, the idea that the bore need to be super hard is incorrect. Steel barrels used in firearms typically have a surface hardness of 20 to 40 Rc. Harder than that, and you risk fracturing from the shock of firing. Yes, there are Satellite inserts that may be harder than that, for sustained high temperature operation in some machine guns.Airgun barrels are often made from what is essentially mild steel. It is so soft it does not register on the Rc scale. As long as it is not abused, it works just fine. I would aim for an aluminum barrel that matches typical steel air rifle capabilities and wear life. Going way beyond that answers the question below, thus:How can one improve the wear life of an aluminum barrel in a predictable, repeatable cost effective manner? Use steel. Or a steel liner.Coating an aluminum barrel bore with diamond dust to improve abrasion resistance will not make it less prone to dings caused by lumpy steel cleaning rods. The aluminum under the coating will simply yield, if you push hard enough.The OP needs to sate his goals for value add, over the state of the art. Else, he is chasing a bunch of contradictory requirements. Doing something different as an experiment is a perfectly good reason. But, that is not justification for producing it on a large scale; unless it solves real problems for real customers.
Quote from: subscriber on December 12, 2020, 09:27:20 PMAny conversion coating that is applied with an electric current is going to be tricky due to the large aspect ratio, of bore diameter to barrel length. A means to insert a very straight, exactly central anode will be required. Else, the anodizing or metal plating will build up unevenly.You will need a system to flush fresh electrolyte through the barrel rapidly, else the chemistry at the far end of the bore will be depleted or "used up", creating an uneven conversion or plating depth.The sharp corners of the lands (assuming convention rifling) will preferentially etch or plate because that is the nature of electricity - to discharge from sharp points or lines preferentially.My suggestion is to use electroless nickel plating. There are several variants. Some of them can be baked afterwards at medium temperature to reach Rc 70. Some EN plating can be had with teflon impregnation.In any event, the idea that the bore need to be super hard is incorrect. Steel barrels used in firearms typically have a surface hardness of 20 to 40 Rc. Harder than that, and you risk fracturing from the shock of firing. Yes, there are Satellite inserts that may be harder than that, for sustained high temperature operation in some machine guns.Airgun barrels are often made from what is essentially mild steel. It is so soft it does not register on the Rc scale. As long as it is not abused, it works just fine. I would aim for an aluminum barrel that matches typical steel air rifle capabilities and wear life. Going way beyond that answers the question below, thus:How can one improve the wear life of an aluminum barrel in a predictable, repeatable cost effective manner? Use steel. Or a steel liner.Coating an aluminum barrel bore with diamond dust to improve abrasion resistance will not make it less prone to dings caused by lumpy steel cleaning rods. The aluminum under the coating will simply yield, if you push hard enough.The OP needs to sate his goals for value add, over the state of the art. Else, he is chasing a bunch of contradictory requirements. Doing something different as an experiment is a perfectly good reason. But, that is not justification for producing it on a large scale; unless it solves real problems for real customers.I think the spell checker bit here. the material is Stellite K-6. It has very high cobalt and tungsten carbide jn it. I've make a few knives out of it and it is a bear to work! It's Rockwell Hardness is hot very high, however the abrasion resistance it increasable! It makes a very good barrel for machine guns as it withstands high heat and abrasion far better than typical, well just about any bun barrel material. I can see no reason 7075 alu. wouldn't work. After all, it is much more abrasion resistant than the Sheridan air gun barrels of old that were brass. Knife
I think the spell checker bit here. the material is Stellite K-6.
Not opposed to AL. barrels (or whatever materials)....but something like this needs a goal...a "mission statement" if you will....some reason/benefit other than being different.OK..that sounds cool...but it's a lot of words for: "Why?".
The OP needs to sate his goals for value add, over the state of the art. Else, he is chasing a bunch of contradictory requirements. Doing something different as an experiment is a perfectly good reason. But, that is not justification for producing it on a large scale; unless it solves real problems for real customers.
Quote from: KnifeMaker on December 13, 2020, 10:52:57 AMI think the spell checker bit here. the material is Stellite K-6. Thanks Knife. Durn spell checker. I also need to fire my proof reader
Quote from: subscriber on December 13, 2020, 07:57:56 PMQuote from: KnifeMaker on December 13, 2020, 10:52:57 AMI think the spell checker bit here. the material is Stellite K-6. Thanks Knife. Durn spell checker. I also need to fire my proof reader Me too! Seems I keep posting that I am shooting Sluts. I've never shot a slut in my life. but I have shot a target oull of Ho's a few times. Mike/Knife
Troy,If you can make a brass airgun barrel, then you can make an aluminum airgun barrel.The hardness you quote is for the anodizing layer. That is thin and brittle. The aluminum underneath is much softer: https://www.mcmaster.com/aluminum/shape~round-tube/Even so, 2024 T3 has a higher yield strength than mild steel, and that is used for airgun barrels all the time. It is the hardness of 120 Brinell that might be a problem. If the rifling is swaged in by hammer forging or by button, the resultant work hardening should make the barrels more abrasion resistant.Now, if you get back to hard anodizing, abrasion resistance goes way up. However, anodized surfaces may end up slightly rough, and lead badly - unless one can polish the bore after anodizing, without cutting through it.Electroless nickel plating is another option to produce very high surface hardness, if the bare barrel or anodizing can't be made to work.This guy makes a gun barrel from 7075 aluminum. Its yield strength is twice that of mild steel. How well does it stand up to jacketed bullets? How well would it stand pure lead ones? Watch on:I think that steel lined aluminum barrels might be a better idea, but that has been done many times.When you screw two anodized aluminum parts together aggressively you can hear part of the anodizing flaking off. Then the silver colored metal underneath starts to show. Ditto if you bend a thin anodized aluminum section. In other words, the surface may be very hard, but its bulk hardness is not much improved by the very thin brittle conversion coating.Wear in an aluminum airgun barrel when shooting only clean pure lead pellets should not be excessive. Make a habit of dropping your pellets or mags in the sand and then all bets are off...By the way, the "wear" seen with copper jacketed bullets in the aluminum barrel in the above video may just be a reverse of how the rifling was impressed. A sort of smooth button un-rifling process, if you will.
Brass is self lubricating and aluminum is not. How much weight would be saved from using a liner such a s FX uses with CF glued to it?