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Posted: 1/17/2015 12:09:26 AM EST


Okay, I was watching this video on lost foam casting and noticed the huge BFL on the back of the truck.

Who is this? I have a couple of questions about the process.


Link Posted: 1/17/2015 12:14:38 AM EST
Link Posted: 1/17/2015 12:20:42 AM EST
whoever posted the make-your-own foundry the other day is going to cost me a lot of time this summer.

this thread isn't helping.

Link Posted: 1/17/2015 12:24:02 AM EST
A little surprised he's not putting on some venting.
Link Posted: 1/17/2015 12:25:00 AM EST
Conventional way is using wax. Lost Wax Method.
Link Posted: 1/17/2015 12:27:49 AM EST
Its not a official BFL.
Link Posted: 1/17/2015 12:29:20 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By sirensong:
whoever posted the make-your-own foundry the other day is going to cost me a lot of time this summer.

this thread isn't helping.

View Quote



Yeah, that was me.

I ordered my crucible today - 25 bucks.

Just the start of it, I'm afraid.




Link Posted: 1/17/2015 12:30:18 AM EST
The video opens with "556raven presents"...

Sooooo maybe it's 556raven?
Link Posted: 1/17/2015 12:33:40 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By jacobsk:
The video opens with "556raven presents"...

Sooooo maybe it's 556raven?
View Quote



No member shows up under that user name.

Link Posted: 1/17/2015 12:39:21 AM EST
cool
Link Posted: 1/17/2015 12:41:02 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Johnny_Reno:



Yeah, that was me.

I ordered my crucible today - 25 bucks.

Just the start of it, I'm afraid.




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Originally Posted By Johnny_Reno:
Originally Posted By sirensong:
whoever posted the make-your-own foundry the other day is going to cost me a lot of time this summer.

this thread isn't helping.




Yeah, that was me.

I ordered my crucible today - 25 bucks.

Just the start of it, I'm afraid.







the first object i'm going to cast is a club with which to beat you for infecting me with this sickness.

called dad last night, and we're already making plans for what we're going to work on when i come visit this summer. i want to start with aluminum as per the vids, but dad is already planning on brass. frankly, it'll be a miracle if he doesn't get so impatient as to start without me. old coot.
Link Posted: 1/17/2015 12:43:06 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By sirensong:



the first object i'm going to cast is a club with which to beat you for infecting me with this sickness.

called dad last night, and we're already making plans for what we're going to work on when i come visit this summer. i want to start with aluminum as per the vids, but dad is already planning on brass. frankly, it'll be a miracle if he doesn't get so impatient as to start without me. old coot.
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Discussion ForumsJump to Quoted PostQuote History
Originally Posted By sirensong:
Originally Posted By Johnny_Reno:
Originally Posted By sirensong:
whoever posted the make-your-own foundry the other day is going to cost me a lot of time this summer.

this thread isn't helping.




Yeah, that was me.

I ordered my crucible today - 25 bucks.

Just the start of it, I'm afraid.







the first object i'm going to cast is a club with which to beat you for infecting me with this sickness.

called dad last night, and we're already making plans for what we're going to work on when i come visit this summer. i want to start with aluminum as per the vids, but dad is already planning on brass. frankly, it'll be a miracle if he doesn't get so impatient as to start without me. old coot.



I better start working on my sword then.



Link Posted: 1/17/2015 12:43:46 AM EST
I think this is the same guy that did the anthill castings.

There was a thread posted about them a few months ago, dude popped in to talk about it.
Link Posted: 1/17/2015 12:48:31 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Johnny_Reno:



Yeah, that was me.

I ordered my crucible today - 25 bucks.

Just the start of it, I'm afraid.




View Quote View All Quotes
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Originally Posted By Johnny_Reno:
Originally Posted By sirensong:
whoever posted the make-your-own foundry the other day is going to cost me a lot of time this summer.

this thread isn't helping.




Yeah, that was me.

I ordered my crucible today - 25 bucks.

Just the start of it, I'm afraid.




Got some stuff I really want cast in stainless, but I think that's out of the capabilities of the bucket foundry.
Link Posted: 1/17/2015 12:50:34 AM EST
Link Posted: 1/17/2015 12:51:45 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By shade_1313:
Got some stuff I really want cast in stainless, but I think that's out of the capabilities of the bucket foundry.
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Discussion ForumsJump to Quoted PostQuote History
Originally Posted By shade_1313:
Originally Posted By Johnny_Reno:
Originally Posted By sirensong:
whoever posted the make-your-own foundry the other day is going to cost me a lot of time this summer.

this thread isn't helping.




Yeah, that was me.

I ordered my crucible today - 25 bucks.

Just the start of it, I'm afraid.




Got some stuff I really want cast in stainless, but I think that's out of the capabilities of the bucket foundry.




I believe you're correct on that.

Link Posted: 1/17/2015 12:53:27 AM EST
Could one make lower out of foam and then pour it?
Some finish work may be required.
Link Posted: 1/17/2015 12:54:06 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Johnny_Reno:




I believe you're correct on that.

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Originally Posted By Johnny_Reno:
Originally Posted By shade_1313:




Got some stuff I really want cast in stainless, but I think that's out of the capabilities of the bucket foundry.




I believe you're correct on that.

Which puts a serious crimp in the sword hilt I want made.
Link Posted: 1/17/2015 12:55:12 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By JRCmx:
Could one make lower out of foam and then pour it?
Some finish work may be required.
View Quote
Saturn made engine blocks using this method.

Cast lowers are the lowest grade of aluminum lowers, but it'd be useable.
Link Posted: 1/17/2015 12:57:18 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By JRCmx:
Could one make lower out of foam and then pour it?
Some finish work may be required.
View Quote



There's no way I'd put it next to my face.


Link Posted: 1/17/2015 1:02:45 AM EST
hmm, interesting thread. i want to see where it goes.
Link Posted: 1/17/2015 1:03:41 AM EST
Link Posted: 1/17/2015 10:23:10 PM EST


Bumpage.

Link Posted: 1/17/2015 10:33:34 PM EST
Hey OP, company my family used to own did some lost foam work. We made the foam for lost foam for casting intake manifolds and other things. Here is a link to their site and that can give you some info that may light your path a little further.

Lost Foam!
Link Posted: 1/17/2015 10:39:23 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By dangerdan:
Conventional way is using wax. Lost Wax Method.
View Quote


Casting wax is a lot more expensive & can't be picked up at Wal Mart.
Link Posted: 1/17/2015 10:39:40 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Johnny_Reno:



There's no way I'd put it next to my face.


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Originally Posted By Johnny_Reno:
Originally Posted By JRCmx:
Could one make lower out of foam and then pour it?
Some finish work may be required.



There's no way I'd put it next to my face.





I would put a cast lower next to my face a whole lot faster than a poly lower....

Link Posted: 1/17/2015 10:42:58 PM EST
Neat
Link Posted: 1/17/2015 10:45:30 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Kevv:
Hey OP, company my family used to own did some lost foam work. We made the foam for lost foam for casting intake manifolds and other things. Here is a link to their site and that can give you some info that may light your path a little further.

Lost Foam!
View Quote



Interesting.


Link Posted: 1/17/2015 10:48:37 PM EST
[Last Edit: 1/17/2015 10:48:56 PM EST by pcsutton]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By JAD762:


Casting wax is a lot more expensive & can't be picked up at Wal Mart.
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Originally Posted By JAD762:
Originally Posted By dangerdan:
Conventional way is using wax. Lost Wax Method.


Casting wax is a lot more expensive & can't be picked up at Wal Mart.
It also requires a centrifuge or vaccuum.
Link Posted: 1/17/2015 10:49:06 PM EST
Dam it now I have to figure out how to do this......thanks op
Link Posted: 1/17/2015 10:56:43 PM EST
Saturn car engine blocks were made this way. Neat method. I've only messed with it in school. I did a lot more sand castings.
Link Posted: 1/17/2015 11:01:00 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Johnny_Reno:



There's no way I'd put it next to my face.


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Originally Posted By Johnny_Reno:
Originally Posted By JRCmx:
Could one make lower out of foam and then pour it?
Some finish work may be required.



There's no way I'd put it next to my face.




Why?

I have to ask, since I know nothing of metallurgy or any of that. Why would it be inferior?

Why is an AR lower that is machined from a solid block of aluminum better than a lower that is molded from melted aluminum?
Keeping in mind the solid block of aluminum was poured from melted aluminum to begin with?
Link Posted: 1/17/2015 11:05:21 PM EST
I've seen commercial lost foam castings that look just like the styrofoam patterns they were made from, the detail is that good.
(Ferrous castings, FWIW)

Link Posted: 1/17/2015 11:49:57 PM EST
It has to do with the molecular structure, in cast it's all over the place with hard and soft spots and porosity or inclusions, billet is formed under pressure and has a more uniform structure.
Link Posted: 1/18/2015 12:17:28 AM EST
awesome, but as mentioned in the other thread i would likely burn my dick off
Link Posted: 1/18/2015 12:21:18 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By groovyrascal:


Why?

I have to ask, since I know nothing of metallurgy or any of that. Why would it be inferior?

Why is an AR lower that is machined from a solid block of aluminum better than a lower that is molded from melted aluminum?
Keeping in mind the solid block of aluminum was poured from melted aluminum to begin with?
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Originally Posted By groovyrascal:
Originally Posted By Johnny_Reno:
Originally Posted By JRCmx:
Could one make lower out of foam and then pour it?
Some finish work may be required.



There's no way I'd put it next to my face.




Why?

I have to ask, since I know nothing of metallurgy or any of that. Why would it be inferior?

Why is an AR lower that is machined from a solid block of aluminum better than a lower that is molded from melted aluminum?
Keeping in mind the solid block of aluminum was poured from melted aluminum to begin with?


It has to do with the molecular structure, in cast it's all over the place with hard and soft spots and porosity or inclusions, billet is formed under pressure and has a more uniform structure.
Link Posted: 1/18/2015 10:37:52 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By pcsutton:
It also requires a centrifuge or vaccuum.
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Originally Posted By pcsutton:
Originally Posted By JAD762:
Originally Posted By dangerdan:
Conventional way is using wax. Lost Wax Method.


Casting wax is a lot more expensive & can't be picked up at Wal Mart.
It also requires a centrifuge or vaccuum.
I've never seen anyone use a centrifuge or a vacuum when doing the lost wax method.

Mold your piece, remove piece from mold, coat the inside of the mold repeatedly with wax, open the mold - you now have a wax model of your part.
Make passage ways and vents using wax...basically wax sprues.
Apply a liquid ceramic compound over the wax and let cure.
Bake ceramic/wax piece in a furnace until all the wax has poured out
Pour in molten metal - let cool - and hulk-smash the ceramic coating. You now have a casting of your piece.

And since you still have your original mold, it can be repeated.





My aunt was a bronze sculptor. It's really neat. I was wanting her to tech me, but she burned her hand with molten bronze and doesn't do it anymore.
Link Posted: 1/19/2015 10:49:55 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By groovyrascal:


Why?

I have to ask, since I know nothing of metallurgy or any of that. Why would it be inferior?

Why is an AR lower that is machined from a solid block of aluminum better than a lower that is molded from melted aluminum?
Keeping in mind the solid block of aluminum was poured from melted aluminum to begin with?
View Quote View All Quotes
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Discussion ForumsJump to Quoted PostQuote History
Originally Posted By groovyrascal:
Originally Posted By Johnny_Reno:
Originally Posted By JRCmx:
Could one make lower out of foam and then pour it?
Some finish work may be required.



There's no way I'd put it next to my face.




Why?

I have to ask, since I know nothing of metallurgy or any of that. Why would it be inferior?

Why is an AR lower that is machined from a solid block of aluminum better than a lower that is molded from melted aluminum?
Keeping in mind the solid block of aluminum was poured from melted aluminum to begin with?


Wrought aluminum alloys such as 6061, 2024 and 7075 get their strength from cold working the material after the ingot is made. An as-cast ingot with the chemical makeup of 7075 won't have nearly the same strength as a wrought piece that has been worked and heat treated.

Forged lowers are not cast, i.e.: the material is not melted when they are made. They are forged (smashed in a set of dies) while the material is in a solid state, introducing cold work, which improves grain structure and therefore strength in the material. In fact, there are some properties of the forging process that can make it better than machining from billet - you can use the dies to arrange grain structures to promote anisotropic behavior (i.e.: I can make the material stronger in one direction than another), whereas with billet, you don't have that. The surface grain structures made by forging vs. fully machined billet can also promote improved fatigue strength, similar to the way rolled threads are different in strength from cut threads.

Beyond this, castings, as has been mentioned, have porosity and generally poor homogeneity compared to wrought alloys. Cast parts of the same geometry will usually have lower fatigue life than an equivalent wrought alloy because of this. Beyond that, typical yield strengths for cast aluminum alloys are very low compared to wrought alloys. One of the most common casting alloys, A356, has an average yield strength around 25,000 psi. 6061-T6, one of the most common wrought alloys, has an average yield strength around 42,000 psi. The alloy specified for use in AR-15 lower receivers, 7075-T6, has an average yield strength around 74,000 psi. These differences are quite significant, especially when considering alternating stresses in the buffer tube thread area of the receiver.

Casting is an awesome process, useful for a LOT of applications. An AR-15 lower receiver isn't one of them. An investment cast lower for a 22 might be though
Link Posted: 1/19/2015 11:14:46 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By RocketmanOU:


Wrought aluminum alloys such as 6061, 2024 and 7075 get their strength from cold working the material after the ingot is made. An as-cast ingot with the chemical makeup of 7075 won't have nearly the same strength as a wrought piece that has been worked and heat treated.

Forged lowers are not cast, i.e.: the material is not melted when they are made. They are forged (smashed in a set of dies) while the material is in a solid state, introducing cold work, which improves grain structure and therefore strength in the material. In fact, there are some properties of the forging process that can make it better than machining from billet - you can use the dies to arrange grain structures to promote anisotropic behavior (i.e.: I can make the material stronger in one direction than another), whereas with billet, you don't have that. The surface grain structures made by forging vs. fully machined billet can also promote improved fatigue strength, similar to the way rolled threads are different in strength from cut threads.

Beyond this, castings, as has been mentioned, have porosity and generally poor homogeneity compared to wrought alloys. Cast parts of the same geometry will usually have lower fatigue life than an equivalent wrought alloy because of this. Beyond that, typical yield strengths for cast aluminum alloys are very low compared to wrought alloys. One of the most common casting alloys, A356, has an average yield strength around 25,000 psi. 6061-T6, one of the most common wrought alloys, has an average yield strength around 42,000 psi. The alloy specified for use in AR-15 lower receivers, 7075-T6, has an average yield strength around 74,000 psi. These differences are quite significant, especially when considering alternating stresses in the buffer tube thread area of the receiver.

Casting is an awesome process, useful for a LOT of applications. An AR-15 lower receiver isn't one of them. An investment cast lower for a 22 might be though
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Discussion ForumsJump to Quoted PostQuote History
Originally Posted By RocketmanOU:
Originally Posted By groovyrascal:
Originally Posted By Johnny_Reno:
Originally Posted By JRCmx:
Could one make lower out of foam and then pour it?
Some finish work may be required.



There's no way I'd put it next to my face.




Why?

I have to ask, since I know nothing of metallurgy or any of that. Why would it be inferior?

Why is an AR lower that is machined from a solid block of aluminum better than a lower that is molded from melted aluminum?
Keeping in mind the solid block of aluminum was poured from melted aluminum to begin with?


Wrought aluminum alloys such as 6061, 2024 and 7075 get their strength from cold working the material after the ingot is made. An as-cast ingot with the chemical makeup of 7075 won't have nearly the same strength as a wrought piece that has been worked and heat treated.

Forged lowers are not cast, i.e.: the material is not melted when they are made. They are forged (smashed in a set of dies) while the material is in a solid state, introducing cold work, which improves grain structure and therefore strength in the material. In fact, there are some properties of the forging process that can make it better than machining from billet - you can use the dies to arrange grain structures to promote anisotropic behavior (i.e.: I can make the material stronger in one direction than another), whereas with billet, you don't have that. The surface grain structures made by forging vs. fully machined billet can also promote improved fatigue strength, similar to the way rolled threads are different in strength from cut threads.

Beyond this, castings, as has been mentioned, have porosity and generally poor homogeneity compared to wrought alloys. Cast parts of the same geometry will usually have lower fatigue life than an equivalent wrought alloy because of this. Beyond that, typical yield strengths for cast aluminum alloys are very low compared to wrought alloys. One of the most common casting alloys, A356, has an average yield strength around 25,000 psi. 6061-T6, one of the most common wrought alloys, has an average yield strength around 42,000 psi. The alloy specified for use in AR-15 lower receivers, 7075-T6, has an average yield strength around 74,000 psi. These differences are quite significant, especially when considering alternating stresses in the buffer tube thread area of the receiver.

Casting is an awesome process, useful for a LOT of applications. An AR-15 lower receiver isn't one of them. An investment cast lower for a 22 might be though


Now I know.
Link Posted: 1/19/2015 11:25:22 AM EST
[Last Edit: 1/19/2015 11:26:53 AM EST by captainpooby]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By RocketmanOU:


Wrought aluminum alloys such as 6061, 2024 and 7075 get their strength from cold working the material after the ingot is made. An as-cast ingot with the chemical makeup of 7075 won't have nearly the same strength as a wrought piece that has been worked and heat treated.

Forged lowers are not cast, i.e.: the material is not melted when they are made. They are forged (smashed in a set of dies) while the material is in a solid state, introducing cold work, which improves grain structure and therefore strength in the material. In fact, there are some properties of the forging process that can make it better than machining from billet - you can use the dies to arrange grain structures to promote anisotropic behavior (i.e.: I can make the material stronger in one direction than another), whereas with billet, you don't have that. The surface grain structures made by forging vs. fully machined billet can also promote improved fatigue strength, similar to the way rolled threads are different in strength from cut threads.

Beyond this, castings, as has been mentioned, have porosity and generally poor homogeneity compared to wrought alloys. Cast parts of the same geometry will usually have lower fatigue life than an equivalent wrought alloy because of this. Beyond that, typical yield strengths for cast aluminum alloys are very low compared to wrought alloys. One of the most common casting alloys, A356, has an average yield strength around 25,000 psi. 6061-T6, one of the most common wrought alloys, has an average yield strength around 42,000 psi. The alloy specified for use in AR-15 lower receivers, 7075-T6, has an average yield strength around 74,000 psi. These differences are quite significant, especially when considering alternating stresses in the buffer tube thread area of the receiver.

Casting is an awesome process, useful for a LOT of applications. An AR-15 lower receiver isn't one of them. An investment cast lower for a 22 might be though
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Originally Posted By RocketmanOU:
Originally Posted By groovyrascal:
Originally Posted By Johnny_Reno:
Originally Posted By JRCmx:
Could one make lower out of foam and then pour it?
Some finish work may be required.



There's no way I'd put it next to my face.




Why?

I have to ask, since I know nothing of metallurgy or any of that. Why would it be inferior?

Why is an AR lower that is machined from a solid block of aluminum better than a lower that is molded from melted aluminum?
Keeping in mind the solid block of aluminum was poured from melted aluminum to begin with?


Wrought aluminum alloys such as 6061, 2024 and 7075 get their strength from cold working the material after the ingot is made. An as-cast ingot with the chemical makeup of 7075 won't have nearly the same strength as a wrought piece that has been worked and heat treated.

Forged lowers are not cast, i.e.: the material is not melted when they are made. They are forged (smashed in a set of dies) while the material is in a solid state, introducing cold work, which improves grain structure and therefore strength in the material. In fact, there are some properties of the forging process that can make it better than machining from billet - you can use the dies to arrange grain structures to promote anisotropic behavior (i.e.: I can make the material stronger in one direction than another), whereas with billet, you don't have that. The surface grain structures made by forging vs. fully machined billet can also promote improved fatigue strength, similar to the way rolled threads are different in strength from cut threads.

Beyond this, castings, as has been mentioned, have porosity and generally poor homogeneity compared to wrought alloys. Cast parts of the same geometry will usually have lower fatigue life than an equivalent wrought alloy because of this. Beyond that, typical yield strengths for cast aluminum alloys are very low compared to wrought alloys. One of the most common casting alloys, A356, has an average yield strength around 25,000 psi. 6061-T6, one of the most common wrought alloys, has an average yield strength around 42,000 psi. The alloy specified for use in AR-15 lower receivers, 7075-T6, has an average yield strength around 74,000 psi. These differences are quite significant, especially when considering alternating stresses in the buffer tube thread area of the receiver.

Casting is an awesome process, useful for a LOT of applications. An AR-15 lower receiver isn't one of them. An investment cast lower for a 22 might be though



There used to be some cast lowers on production rifles way back when. I forget who made them but I remember the debates on here about them VS forged. If you google it you'll come with some of the archived discussions.


ETA: Seems to me with a 3-D printer you could make some awesome and complicated stuff out of foam for this process.
Link Posted: 1/19/2015 11:37:59 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By sirensong:
whoever posted the make-your-own foundry the other day is going to cost me a lot of time this summer.

this thread isn't helping.

View Quote


I know I'm gonna regret this, but....

link?
Link Posted: 1/19/2015 11:44:58 AM EST
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Originally Posted By Johnny_Reno:



No member shows up under that user name.

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Originally Posted By Johnny_Reno:
Originally Posted By jacobsk:
The video opens with "556raven presents"...

Sooooo maybe it's 556raven?



No member shows up under that user name.


He used to:

He also has posted several ant hill casting videos on youtube.

Link Posted: 1/19/2015 11:46:00 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By captainpooby:



There used to be some cast lowers on production rifles way back when. I forget who made them but I remember the debates on here about them VS forged. If you google it you'll come with some of the archived discussions.


ETA: Seems to me with a 3-D printer you could make some awesome and complicated stuff out of foam for this process.
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Originally Posted By captainpooby:
Originally Posted By RocketmanOU:
Originally Posted By groovyrascal:
Originally Posted By Johnny_Reno:
Originally Posted By JRCmx:
Could one make lower out of foam and then pour it?
Some finish work may be required.



There's no way I'd put it next to my face.




Why?

I have to ask, since I know nothing of metallurgy or any of that. Why would it be inferior?

Why is an AR lower that is machined from a solid block of aluminum better than a lower that is molded from melted aluminum?
Keeping in mind the solid block of aluminum was poured from melted aluminum to begin with?


Wrought aluminum alloys such as 6061, 2024 and 7075 get their strength from cold working the material after the ingot is made. An as-cast ingot with the chemical makeup of 7075 won't have nearly the same strength as a wrought piece that has been worked and heat treated.

Forged lowers are not cast, i.e.: the material is not melted when they are made. They are forged (smashed in a set of dies) while the material is in a solid state, introducing cold work, which improves grain structure and therefore strength in the material. In fact, there are some properties of the forging process that can make it better than machining from billet - you can use the dies to arrange grain structures to promote anisotropic behavior (i.e.: I can make the material stronger in one direction than another), whereas with billet, you don't have that. The surface grain structures made by forging vs. fully machined billet can also promote improved fatigue strength, similar to the way rolled threads are different in strength from cut threads.

Beyond this, castings, as has been mentioned, have porosity and generally poor homogeneity compared to wrought alloys. Cast parts of the same geometry will usually have lower fatigue life than an equivalent wrought alloy because of this. Beyond that, typical yield strengths for cast aluminum alloys are very low compared to wrought alloys. One of the most common casting alloys, A356, has an average yield strength around 25,000 psi. 6061-T6, one of the most common wrought alloys, has an average yield strength around 42,000 psi. The alloy specified for use in AR-15 lower receivers, 7075-T6, has an average yield strength around 74,000 psi. These differences are quite significant, especially when considering alternating stresses in the buffer tube thread area of the receiver.

Casting is an awesome process, useful for a LOT of applications. An AR-15 lower receiver isn't one of them. An investment cast lower for a 22 might be though



There used to be some cast lowers on production rifles way back when. I forget who made them but I remember the debates on here about them VS forged. If you google it you'll come with some of the archived discussions.


ETA: Seems to me with a 3-D printer you could make some awesome and complicated stuff out of foam for this process.


You could cast a receiver out of a high strength alloy, for sure, but dollar for dollar, forgings will pretty much always come out on top in this application.

And yes, yes you can. I'm working on having my students doing investment casting with 3d prints in one of my design classes. Use the print to make a silicone negative, use the silicone negative to make multiple wax positives, coat in investment, melt wax, and go.
Link Posted: 1/19/2015 11:51:29 AM EST
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Originally Posted By veritas_rasa:
A little surprised he's not putting on some venting.
View Quote



yeah.
I've used styofoam blocks to hol cores up to create a void, and venting was needed, or at least we did provide venting holes to allow gas to escape..
Link Posted: 1/19/2015 12:06:34 PM EST
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Originally Posted By AZ_Sky:

He used to:
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Originally Posted By AZ_Sky:
Originally Posted By Johnny_Reno:
Originally Posted By jacobsk:
The video opens with "556raven presents"...

Sooooo maybe it's 556raven?



No member shows up under that user name.


He used to:

He also has posted several ant hill casting videos on youtube.

He was a real post whore. Probably a 24/365 dude.
Link Posted: 1/19/2015 12:06:45 PM EST
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Originally Posted By LightningII:



yeah.
I've used styofoam blocks to hol cores up to create a void, and venting was needed, or at least we did provide venting holes to allow gas to escape..
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Originally Posted By LightningII:
Originally Posted By veritas_rasa:
A little surprised he's not putting on some venting.



yeah.
I've used styofoam blocks to hol cores up to create a void, and venting was needed, or at least we did provide venting holes to allow gas to escape..
typically this requires a "loose sand" casting and the gases ideally vent through the sand. It doesn't always work perfectly, but that is the idea.
Link Posted: 1/19/2015 4:32:37 PM EST
[Last Edit: 1/19/2015 4:33:08 PM EST by captainpooby]
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Originally Posted By RocketmanOU:

And yes, yes you can. I'm working on having my students doing investment casting with 3d prints in one of my design classes. Use the print to make a silicone negative, use the silicone negative to make multiple wax positives, coat in investment, melt wax, and go.
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Could you do an old, air cooled, two stroke motorcycle cylinder?
Link Posted: 1/19/2015 4:48:13 PM EST
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Originally Posted By TokerM:


I know I'm gonna regret this, but....

link?
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Originally Posted By TokerM:
Originally Posted By sirensong:
whoever posted the make-your-own foundry the other day is going to cost me a lot of time this summer.

this thread isn't helping.



I know I'm gonna regret this, but....

link?



It's my fault.

http://www.ar15.com/forums/t_1_5/1707119_My_14_year_old_son_wants_the_two_of_us_to_make_this.html

Link Posted: 1/19/2015 4:49:30 PM EST


I wonder if I could use a Styrofoam drink cup as a mold?

I'm think that perhaps it might be too thin to get a good pour.


Link Posted: 1/19/2015 4:50:49 PM EST
Link Posted: 1/19/2015 5:50:53 PM EST
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Originally Posted By Johnny_Reno:


I wonder if I could use a Styrofoam drink cup as a mold?

I'm think that perhaps it might be too thin to get a good pour.


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Paint the resultant cast Aluminum Styrofoam cup white and watch people's expressions as they pick it up
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