Magnesium body

[Kit]

I've been hoarding this block of magnesium forever. What's stopping me from machining it into a cocker body? Is it going to explode when I gas it up? Burn down the garage while I machine it? Spontaneous combust while playing? Catch fire from friction while bonus balling my people's?

[Trbo323]

The bt tm15 had a magnesium body. But I don't think it really held pressure. Pretty sure it was just the clamshell. Even if it did it was around 200psi so nothing crazy

I don't really see anything wrong with using the material. Looks like your block is shorter than the cocker body though, have a plan for that?

Sent from my motorola edge 5G UW (2021) using Tapatalk

[Cdn_Cuda]

Yes BT TM15 was a clamshell. All airlines are separate from the body itself.

[William the Third]

Empire (BT) D*Fender also used a magnesium clamshell body.

[Brokeass_baller]

SP Epiphanies were magnesium as well. Outer shell and frame.

[Roger7pball]

We use magnesium for our new hybrid bellhousings. The threads like to strip out if you look at them the wrong way. But maybe after anodizing it would be okay.

[tyronejk]

I think the only fire risk here is the chips during/after machining. You'd probably want to keep a chemical fire extinguisher nearby.

[DocsMachine]

First, I'd love to see a solid-magnesium 'Cocker body. I had a chance to buy similar slab years ago- and had the same thought- but I didn't have the funds at the time.

Some things to keep in mind: As noted, one of your biggest risks is the potential for fire. Magnesium is difficult to get ignited- I've TIG welded the stuff, with no issues- but once lit, it's basically impossible to extinguish. You need a Class D extinguisher- which, these days, use salt as an extinguishing powder.

And, the smaller the flake or chip, the easier it is to ignite- powdered mag is damn near an explosive.

It's also reactive, particularly to water. Water causes it to release small amounts of hydrogen, which is of course even more flammable. A cutting oil would be better, but it can react with this stuff too. Shops have gone up in flames working with the stuff, so make sure you do a little homework, first.

Not saying 'don't do it', just saying 'know how to machine it safely'.

Second, as Roger7 notes, it's soft enough that threads are weak. On a 'Cocker, the velocity adjuster, barrel and front block are large enough they should be fine, but the grip frame holes should definitely be heli-coiled.

Third, magnesium can't be anodized- at least, not the color anodizing we're used to with aluminum. An anodic coating on mag ranges from light grey or yellowish green, to dark brown.

You can polish mag, though not to quite as bright as aluminum, but it tarnishes to grey relatively rapidly. (Depending on handling, humidity, etc.)

There's some chromate treatments and others that can be done, but I don't know offhand what those would look like.

All that said, it looks like you have enough there that, with a little careful bandsawing (mind the dust!) you might be able to slice off enough to make the front block, first, too.

And, if you went and bought another piece you could make a matching grip frame, too.

Then, when you're done, throw the chips into a bonfire and make a YouTube video.

Doc.

[Roger7pball]

I was told by our in-house machinist that there’s little chance of starting a fire machining mag if you either dowse it heavily with coolant as you’re cutting or clean the swarf away frequently when cutting dry.

But we do have Class D extinguishers on hand.

[Morgenstern]

shouldn’t the valve be sleeved with steel or aluminum though? My limited experience with magnesium has me worried about it holding up to pressure cycling. It seems much more brittle than aluminum and parts tend to just snap instead of showing fatigue before doing so which leads me to believe the tensile strength, or whatever property a pressure vessel needs, isn’t there.

[Sdawg]

The old Dynasty Ion bodies are magnesium, aren't they?

[SignOfZeta]

I can’t think of a single engineering advantage in doing this. Magnesium is used almost exclusively in applications where weight is critical…as in aluminum is too heavy for the job. These applications are almost totally limited to aerospace and vintage racing. I say vintage racing because carbon fiber completely obsolesced magnesium ages ago at medium and top levels.

I’m also now realizing that every mag part I’ve ever seen was cast or forged…usually gearbox casings or wheel rims. If you’re building an autocross car out of a MkI Golf the four speed gearbox with mag case is the lightest and fastest (no need for fifth in autocross). I don’t think I’ve ever seen a machined magnesium part before…

Weight critical and “cocker body” are kind on opposite ends of the spectrum. A Nelson body made of depleted uranium is probably still lighter than any cocker body. So how do you end up with something that you can actually tell is special?

It seems to be that the only ways you’d ever actually notice that this project was lighter than average would be if you made it a totally slab sided thing with no cuts (in which case you could compare it to a WGP body) or if you machined it down to nearly zero, a skeleton cocker, at which point it could conceivably be the lightest cocker body ever. You still wouldn’t ever really notice or care unless every other part on the gun was also subjected to drastic weight reduction…like having a magnesium grip frame, for example.

[Jordan]

As soon as I hear magnesium I think "GM transfer case" and how rotted out they get from Canadian winters.

I'm sure that won't happen to a Cocker body but I do wonder how corrosion resistant it would be.

[William the Third]

How did VW Beetles (real ones, not the "New" Beetle BS) like Canadian winters? They had magnesium blocks and gearboxes.

[Jordan]

Pretty sure the bodies rotted apart before the engines did. 🙂

[Toestr]

My mother once recalled seeing the road through the floor while riding in my uncle's bug in the late 70s in southwestern Ontario (very mild winters for Canada).

[Axel]

Half the projects on this website are totally pointless and done solely for the purpose of being weird and cool. I say, do your homework and take the proper safety precautions to handle mag (like you are) and go for it

[Pumpytrilly1]

I wanna see it cut up and tubed like a spanky fishbone.

[JeepDVLZ45]

I’m all for more cocker bodies in the world, especially crazy weird ones….but…you have a block of MAGnesium…shouldn’t you using it to build an entire AutoMAG? 🤪

[Axel]

He has a point ☝️