AR15 Receiver Mold Kit

[MechAg94]

http://ar15mold.com/
I couldn't remember if we had discussed this or not.  It looks interesting.  I saw an article in Firearms News (formerly Shotgun News).  It isn't a polymer receiver, but a kit to make your own polymer receiver.  It includes some support braces and apparently the base kit can pour 5 or more receivers.  Apparently some have experimented with fiberglass and other stuff to add to the resin to enhance the product.

This seems a lot easier make than an 80% lower for most people. 

[HankB]

I know that AR receivers aren't highly stressed - in the firearms sense - components when used in .223/5.56 applications, but I still have reservations about cast polymer - plastic - receivers.

I don't know that cast polymers will equal or approach the strength of plastics like ABS, polycarbonate, or fiber reinforced receivers.

On the other hand, I don't see much of a strength problem if you're building up a .22 lr training rifle. 

[Hawkmoon]

Considering how easy it is to finish the 80% polymer receivers, I can't imagine that messing with casting your own could possibly be easier.

[MechAg94]

Considering how easy it is to finish the 80% polymer receivers, I can't imagine that messing with casting your own could possibly be easier.

I imagine that for people who have never done machining at all, the casting process might be easier. 

[BobR]

I have a cracked aluminum wheel, I bet there is enough material there to cast a few receivers. Now to build the forge. :)


bob

[Scout26]

An Aluminum foundry.

https://www.youtube.com/watch?v=hHD10DjxM1g

Convert it from Charcoal to Propane:

https://www.youtube.com/watch?v=eO8NwseRxSA

Make an AR Lower mold (although I've though of using AJ's Lego mold with expanding foam for the investment lower.

You could do it in Brass:

https://www.youtube.com/watch?v=kS949QQDtWQ




Oh, should Hillary or Trump succeed in banning stuff:

https://www.youtube.com/watch?v=t_7LWCFH5Gc

[MechAg94]

A brass lower would be cool.

[birdman]

Casting aluminum is harder than other metals if you want good strength due to its reactivity...inert gas it or use some sort of flux, or all you are gonna get us well mixed slag...

[BobR]

I am thinking that whatever my wheel is made out of is already mixed with something. I don't really know but I don't think they would use pure (mostly) aluminum to make wheels for cars and trucks. I could be wrong though. I will probably have enough problems getting pieces small enough to throw into a small foundry. At least it should be a learning experience. :)

bob

[HankB]

I am thinking that whatever my wheel is made out of is already mixed with something. I don't really know but I don't think they would use pure (mostly) aluminum to make wheels for cars and trucks. I could be wrong though. I will probably have enough problems getting pieces small enough to throw into a small foundry. At least it should be a learning experience. :)

bob

Just get a bunch of scandium frame S&W revolvers and melt them down to make a scandium-aluminum alloy AR lower - if done properly, strength won't be an issue.     

[BobR]

What I really need to make is a set of risers for my motorcycle handlebars. :)

bob

[Scout26]

Casting aluminum is harder than other metals if you want good strength due to its reactivity...inert gas it or use some sort of flux, or all you are gonna get us well mixed slag...

True, but again, the lower is not a high stress part on an AR.  You could cast (anynumber>1) and have plenty of spares on hand.  Should you break one, then you simply re-melt the broken ones and cast more.   And since I'm not an expert, would Zinc and Aluminum make a better strength lower then pure aluminum ?   I'm asking for a friend.

[birdman]

I mean if you melt it without inert gas, etc, you get a cookie that you can break with your bare hands.

And zinc is already a part of some aluminum alloys.  Pure aluminum is -really- soft, it's effectively never used

Just get a bunch of scandium frame S&W revolvers and melt them down to make a scandium-aluminum alloy AR lower - if done properly, strength won't be an issue.     

The scandium frames are actually already a scandium-aluminum alloy.  Pure scandium...yeah, you don't want that around...especially if finely divided.

[makattak]

A brass lower would be cool.

I'm glad I'm not the only one to think that.

[BobR]

A brass lower would be cool.

A brass lower and wood furniture. I would like that. 

Probably make Tactical heads go 'splody all over the place.  :)


bob

[makattak]

A brass lower and wood furniture. I would like that. 

Probably make Tactical heads go 'splody all over the place.  :)


bob

It's frightening how much people on this forum think like me.

[Nick1911]

I mean if you melt it without inert gas, etc, you get a cookie that you can break with your bare hands.

You have to collect dross that comes to the top, but aluminium is surprisingly friendly to cast, even without flux.  Molten aluminium will start to absorb gas, but it's rarely a concern if you pour within a few minutes of everything melting.

I've poured several parts with a primitive "backyard foundry" setup and had very good results.  A few minor inclusions were found in a few places during machining, but not unexpected or unacceptable.  I wouldn't use it for like, high stress airframe parts, but from my experience it would work fine for AR lowers.

[birdman]

You have to collect dross that comes to the top, but aluminium is surprisingly friendly to cast, even without flux.  Molten aluminium will start to absorb gas, but it's rarely a concern if you pour within a few minutes of everything melting.

I've poured several parts with a primitive "backyard foundry" setup and had very good results.  A few minor inclusions were found in a few places during machining, but not unexpected or unacceptable.  I wouldn't use it for like, high stress airframe parts, but from my experience it would work fine for AR lowers.

Okay, I was just being overly cautious.  But for first time folks, who don't get the need to heat fast, don't let it sit, skim dross, pour properly, etc etc, it's a recipe for problems.

I do stand corrected though, you get a Birdman point, treasure it, they are rare.

[dogmush]

I've successfully cast some one off aluminium parts.  It's kinda middle of the road as far as amateur casting goes.  As was mentioned there's a couple more steps then pouring lead in a mold.  Then you have to get around the anodizing issue.  Remember the added hardness of the anodizing is actually useful in some parts of the unstressed lower.

The thing is, for something like an 80% AR lower, the machining is pretty dead simple.  Dimensions don't really matter all that much.  The only really critical parts are the pin holes and even those have functionally pretty loose tolerances.  The Polymer 80% lowers are even easier.  People routinely successfully "Machine" (hog out by hand) them with a cheap jig and a dremmel. So for something like an AR lower, there's not really all that much to be gained, other than custom colors and a cool story, from the kit in the OP.  The other options are really pretty beginner friendly.

I've even seen a functioning AR that was done on a drill press with pieces of steel flat stock stacked together.  No machining at all.

[Hawkmoon]

I've even seen a functioning AR that was done on a drill press with pieces of steel flat stock stacked together.  No machining at all.

Sort of like a Leinad derringer on steroids?

[dogmush]

As I recall it wasn't that....refined. it looked mor Kybher Pass than that pistol. It's sole virtue, other than launching a small projectile, was that the lower was 100% sourced from Home Depot. Tools and materials.

[bedlamite]

Here's an AR lower from stacked steel plates:

http://www.theflatspot.net/ar-15-receiver-flat.html



I remember casting an aluminum hack saw handle in shop class when I was in junior high, it wasn't that hard.

One of these days I'm going to make an AR-15 lower out of walnut.

[lee n. field]

A brass lower and wood furniture. I would like that. 

Probably make Tactical heads go 'splody all over the place.  :)


bob

It's frightening how much people on this forum think like me.

+1

[freakazoid]

This kid seems to cast cast aluminum pretty easily, https://www.youtube.com/watch?v=0-BQEhiVf8A 

[dogmush]

It's also worth mentioning that AR lowers are normally  forged not cast. The two processes give you different characteristics. I'm not at all sure a cast aluminum lower would hold up well.