Armed Polite Society
Main Forums => The Roundtable => Topic started by: MechAg94 on May 05, 2016, 09:44:38 AM
-
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.
-
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. ;)
-
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.
-
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.
-
I have a cracked aluminum wheel, I bet there is enough material there to cast a few receivers. Now to build the forge. :)
bob
-
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
-
A brass lower would be cool.
-
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...
-
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
-
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. ;) :rofl:
-
What I really need to make is a set of risers for my motorcycle handlebars. :)
bob
-
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.
-
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. ;) :rofl:
The scandium frames are actually already a scandium-aluminum alloy. Pure scandium...yeah, you don't want that around...especially if finely divided.
-
A brass lower would be cool.
I'm glad I'm not the only one to think that.
-
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
-
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.
-
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.
(https://armedpolitesociety.com/proxy.php?request=http%3A%2F%2Fimg.photobucket.com%2Falbums%2Fv282%2Fnick1911%2F20151101_184253_zpsu3uwcsrq.jpg&hash=d4b74643ef7c556432e865f2db832c2390c0e764)
-
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.
(https://armedpolitesociety.com/proxy.php?request=http%3A%2F%2Fimg.photobucket.com%2Falbums%2Fv282%2Fnick1911%2F20151101_184253_zpsu3uwcsrq.jpg&hash=d4b74643ef7c556432e865f2db832c2390c0e764)
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.
-
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.
-
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?
(https://armedpolitesociety.com/proxy.php?request=http%3A%2F%2Fmoochiesgunshop.com%2Fimages%2Fimages.jpeg&hash=2d073a5b1c3e50a4a49550a67849e0facf205013)
-
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.
-
Here's an AR lower from stacked steel plates:
http://www.theflatspot.net/ar-15-receiver-flat.html
(https://armedpolitesociety.com/proxy.php?request=http%3A%2F%2Fwww.theflatspot.net%2Fuploads%2F6%2F9%2F0%2F0%2F6900641%2F1042735_orig.jpg&hash=4e17bb68c23f2e889eec99a52269ca504d2e905d)
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.
-
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
-
This kid seems to cast cast aluminum pretty easily, https://www.youtube.com/watch?v=0-BQEhiVf8A :P
-
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.
-
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.
Essential Arms and Olympic sold lots of cast lowers years ago. some even had the happy switch, and as long as you don't use them to break down doors, they work fine.
-
The main issue with casting Aluminum for precision, is you have to figure out a certain percentage for shrinkage.
Not a big deal if it's going to be machined and sized in all it's critical dimensions. However, if a DIY'er is trying to cast an Aluminum AR lower, and intends to do so with a level of precision that'll save him all the milling steps he's not otherwise capable of, like magwell, FCG pocket etc. and only have to do the drill-press steps, having a 3D printer to make your positive for the mold and scaling it accordingly is going to be important.
-
I would think the polymer would take more abuse than cast aluminum (depending on the polymer). Cast aluminum can be brittle stuff.
-
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.
The original Olympic Arms "Plinker" model used a cast aluminum lower receiver. No problems with mine or the one a friend bought.
-
Might want to rethink using polymer lowers. They don't stand up to the flamethrower test. https://www.youtube.com/watch?v=GOWPtxUX-Us
-
The original Olympic Arms "Plinker" model used a cast aluminum lower receiver. No problems with mine or the one a friend bought.
I wasn't implying that it would be a problem in normal use. Either one would likely work for what I use an AR for. Just thinking the good polymer might hold up for more abuse than cast aluminum. Where that line is crossed, I don't know.
-
You have to collect dross that comes to the top, but aluminium is surprisingly friendly to cast, even without flux.
MgCl/NaCl flux is available premixed at WalMart, (Morton's Lite Salt) so it never made sense not to use it when I was casting.
-
Might want to rethink using polymer lowers. They don't stand up to the flamethrower test. https://www.youtube.com/watch?v=GOWPtxUX-Us
Interestingly enough (or not, depending on your interests), neither does aluminum. A building inspector of my acquaintance once showed why aluminum skylights cannot (lawfully) be used in buildings whose construction type is classified as "noncombustible." It seems the test for noncombustibility involves exposing a sample of the material to some established temperature in a laboratory oven for a prescribed period of time.
Aluminum doesn't burn, but it melts at far below the prescribed test temperature and therefore can't pass the test. Which is why aluminum is difficult to weld, and basically impossible to solder.
-
Speaking of casting aluminum...https://www.youtube.com/watch?v=sEc5Jak9jsg
Some naughty words in it.
-
A brass lower and wood furniture. I would like that.
Probably make Tactical heads go 'splody all over the place. :)
bob
I can see that in my head.
It's a thing of beauty.
-
Interestingly enough (or not, depending on your interests), neither does aluminum. A building inspector of my acquaintance once showed why aluminum skylights cannot (lawfully) be used in buildings whose construction type is classified as "noncombustible." It seems the test for noncombustibility involves exposing a sample of the material to some established temperature in a laboratory oven for a prescribed period of time.
Aluminum doesn't burn, but it melts at far below the prescribed test temperature and therefore can't pass the test. Which is why aluminum is difficult to weld, and basically impossible to solder.
Aluminum will oxidize very easily in the right conditions. In elevated oxygen environments, it will burn with great release of energy. Of course, most things will burn with a high oxygen content.
-
Might want to rethink using polymer lowers. They don't stand up to the flamethrower test. https://www.youtube.com/watch?v=GOWPtxUX-Us
Besides not being fireproof, the AR15Mold.com lowers don't appear to be reliable:
https://www.youtube.com/watch?v=D3Asb6Ou6ds (part 1)
https://www.youtube.com/watch?v=yBkX1Bsq22Q (part 2)
In part 2:
Bump fire fail at around the 8:09 mark. Stress fracture near the rear takedown pin (10:08 mark in the video).
Magazine feed lip sheared off @ 10:52 mark.
In fairness, the polymer lowers appear to stand up to a variety of chemicals fairly well, except for acetone (part 1).
-
I can see that in my head.
It's a thing of beauty.
I'm trying to work out how the stock should look.
I'm envisioning something like this, but without covering the brass. I really like the fore-end, here:
(https://armedpolitesociety.com/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FAszr6Dt.jpg&hash=b70445561021785a1817012c9f2f22dc1f859d4f)
Obviously, there would need to be a wooden pistol grip, too.
-
One could even make a receiver out of wood, if so inclined:
http://www.weaponeer.net/forum/forum_posts.asp?TID=8035&PN=1&TPN=1
-
I am thinking more along these lines with a brass lower. That would be very nice.
(https://armedpolitesociety.com/proxy.php?request=http%3A%2F%2Fwww.hunt101.com%2Fdata%2F500%2F9237P1010032a.jpg&hash=962ad055de8638197367fa2fd499372a72eacc10)
bob
-
And I've got a 5 gallon bucket of brass out in the garage....
-
And I've got a 5 gallon bucket of brass out in the garage....
I was going to claim dibs, and then realized I have no means of melting it down and no time, either.
:(
-
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
Na. What Nick said. In practice:
Melt scrap aluminum, haul off the dross, pour into a mold to make ingots. Remelt again when you're doing a pour.
Muffin trays work great if you cook them enough to burn off coatings. Heat with a blow torch before pouring in molten friggin metals.
Use greensand with appropriate ratios.
Have two vent holes. One for pouring, one for air/overflow to escape. Your pour/escape vents should be offset. Even after skimming, any remaining dross gets stuck in this part. Hacksaw off the extra bits and the remaining aluminum should be pretty good to go.
You can use a graphite rod to introduce nitrogen, but not necessary unless you are going for a mirror finish. Even flux isn't necessary if you pour within 3-5 minutes of melt. Less is better. Some fluxes add corrosion problems. Because, well, it's salt. Non-corrosive fluxes are expensive or hazmat. Fluoride salts and/or cesium. "High temperatures" and "fluoride" are things that are awesome but only if you're downwind and have an independent air supply. If you have your mold ready to go before you melt your aluminum it's not an issue. You may end up with some pinholes, but not many. Shrinkage is usually the large problem than fluxing or degassing.
It's not hard to find 'scrap' aluminum from metal shops of the alloy you want. Shavings or cutoffs. I prefer cutoffs, and easy enough to find on eBay. I wouldn't use soda cans for an AR15, because of the vinyl and paint. You'd probably be fine, especially if you did an extra ingot stage. But you wouldn't be saving that much money and adding an unknown element.
-
And I've got a 5 gallon bucket of brass out in the garage....
How much do ya want for it?
-
Na. What Nick said. In practice:
Melt scrap aluminum, haul off the dross, pour into a mold to make ingots. Remelt again when you're doing a pour.
Muffin trays work great if you cook them enough to burn off coatings. Heat with a blow torch before pouring in molten friggin metals.
Use greensand with appropriate ratios.
Have two vent holes. One for pouring, one for air/overflow to escape. Your pour/escape vents should be offset. Even after skimming, any remaining dross gets stuck in this part. Hacksaw off the extra bits and the remaining aluminum should be pretty good to go.
You can use a graphite rod to introduce nitrogen, but not necessary unless you are going for a mirror finish. Even flux isn't necessary if you pour within 3-5 minutes of melt. Less is better. Some fluxes add corrosion problems. Because, well, it's salt. Non-corrosive fluxes are expensive or hazmat. Fluoride salts and/or cesium. "High temperatures" and "fluoride" are things that are awesome but only if you're downwind and have an independent air supply. If you have your mold ready to go before you melt your aluminum it's not an issue. You may end up with some pinholes, but not many. Shrinkage is usually the large problem than fluxing or degassing.
It's not hard to find 'scrap' aluminum from metal shops of the alloy you want. Shavings or cutoffs. I prefer cutoffs, and easy enough to find on eBay. I wouldn't use soda cans for an AR15, because of the vinyl and paint. You'd probably be fine, especially if you did an extra ingot stage. But you wouldn't be saving that much money and adding an unknown element.
Too late, only 1 birdman was wrong point given out per topic.
-
How much do ya want for it?
Come get all you want for free. It is currently stored at the Sig Sauer Academy in Epping, NH. Sig doesn't require shooters to police brass so there is a metric long sh1t ton of brass on the ground there. I have picked up all the 9mm and 5.56 that I can use for a few years. I also scored a bunch of high dollar .308 match brass. The local PDs and military guys don't want their brass, but I do.
-
Too late, only 1 birdman was wrong point given out per topic.
Na, not worried about the points, just sharing some casting info. I used to have one, building another one. I have a small forge already, and figured might as well get back into casting again. I know you're getting into welding, but if you need casting, lemme know. I'm buying a 5 gallon vacuum degassing chamber and with a furnace, should be able to cast pretty decent resin, brass, bronze and aluminum. That and the 'other stuff' is for the coffee table project. Yes, I know how "pants on head" stupid it is to spend hundreds of bucks on equipment for building a friggin coffee table when I could build another inlay marble thingie for a fraction of the cost.
Come get all you want for free. It is currently stored at the Sig Sauer Academy in Epping, NH. Sig doesn't require shooters to police brass so there is a metric long sh1t ton of brass on the ground there. I have picked up all the 9mm and 5.56 that I can use for a few years. I also scored a bunch of high dollar .308 match brass. The local PDs and military guys don't want their brass, but I do.
I'll pay shipping? =)
I do go to NH for vacation, but not going this year.
-
I'll pay shipping?
If the shipper were to flatten the brass out and stuff it into a large flat rate box (max 70 lbs) you could get quite a bit of brass into one I would bet. ;)
bob
-
If the shipper were to flatten the brass out and stuff it into a large flat rate box (max 70 lbs) you could get quite a bit of brass into one I would bet. ;)
bob
But would the value of the brass out weigh the cost of the shipping?
-
But would the value of the brass out weigh the cost of the shipping?
That's a good question. I think scrappers are paying around a dollar a pound for brass, I have no idea what it would sell for if you sold to someone other than a scrap yard. I guess it depends on whether or not the person really wanted the brass and would be willing to pay the shipping. At the very least it is a source of brass, which is sometimes hard to come by depending on location.
bob
-
I'm buying a 5 gallon vacuum degassing chamber ...
Must have been a smart man who recommended getting one for at least resin purposes... =)
-
How much do ya want for it?
Ha !!! I'm thinking of doing a brass AR lower myself. I'll practice on some aluminum ones first.
Normally it gets sorted and reloaded/sold/given away*/recycled. The recycled stuff may get recycled into a lower or three.
*- I have some friends that reload odd-ball calibers so when I find those, they are given to those friends.
-
Must have been a smart man who recommended getting one for at least resin purposes... =)
Ayep. It's not necessary for layers < 1/8th inch, just run a blow torch over the surface. But very necessary for >1/8th inch.
Semi random question, know of any good light defusing resins or additives?
-
Ayep. It's not necessary for layers < 1/8th inch, just run a blow torch over the surface. But very necessary for >1/8th inch.
Semi random question, know of any good light defusing resins or additives?
Do you want it to be scattering, but translucent? Glass microspheres or ground glass in a low concentration so as not to make the surface weird.
-
But would the value of the brass out weigh the cost of the shipping?
IIRC, a medium Flat Rate Priority box would hold a custom poured ingot of lead just shy of the 70lb Flat Rate limit. Always wanted to try that just to see how hard the post office would argue about hauling it for $12.
-
^^^^
I used a flat rate box to mail a piece of railroad track to Guam. The recipient uses it as an anvil for pounding out knives. It was light as far a flat rate boxes go, it came in at about 40 pounds IIRC, the track piece was nearly 12" long. All they had me do was tape it up very securely with duct tape and then covered it with priority mail tape. It got there just fine, which surprised even me.
bob
-
Do you want it to be scattering, but translucent? Glass microspheres or ground glass in a low concentration so as not to make the surface weird.
Ayep
That's what I thought, and ordered. Didn't know if there was something better or cheaper. I bought sample sized lots for bunch of stuff from 70 microns to regular jewelry glass beads. I need to do test pours anyways to test various stains and whatnot. I was eyeing up diamond dust but at a buck a carat, I passed.
-
Semi random question, know of any good light defusing resins or additives?
If your light is exploding, please send me details. I need a good blaster.