Fine sand particles offer compressive strength and allow the mold to hold its shape under injection or pour pressure. It behaves like clay allowing complex cavities and features to be formed.

Cornstarch binds the sand slightly, improving consistency without making it rigid. It absorbs moisture and helps the mold retain its form, especially when compressed, while still being flexible enough for demolding.

Kinetic sand can withstand the curing heat of JB Weld (usually under 300°F). It's chemically inert relative to the epoxy’s curing process, so it won’t interfere or degrade.

[-]

Adventurous-Scale871@reddit

So would this work essentially the same way as sand molds for casting metal but using JB welds or other similar epoxies? In your opinion .

[-]

heatheninuniform@reddit

It could work, if the epoxy cures at a low enough temperature. High heat will betray you. The oil in magic sand will heat up, leach out, the structure will crumble, and the mold will fail

[-]

Seared_Gibets@reddit

Saving this! Brilliant, thank you kind, engineering hat adorned person!

[-]

heatheninuniform@reddit

Be aware, this is all theorcrafting.

We made this for our kids to play with. Until I saw this thread, the idea of applying it to engineering never crossed my mind. Then came the question: Could this soft, pliable substance have a place in industry? Could it serve in molds, in castings, in resistance against adhesion?

I believe so.

[-]

MrBigBoy1@reddit

Bam!

[-]

Peacemkr45@reddit

injection mold? Just use pam spray oil. It's effectively what they use anyways as a mold release and you can save that delicious spam juice for martinis

[-]

bill_bull@reddit

I need to know if this works. Instead of 80% lowers they could sell -100% lowers, aka molds.

[-]

PixeltatedNinja@reddit

shoe polish? i used that when bedding the lower on my 10/22 with some jb-weld type stuff

[-]

Carlweathersfeathers@reddit

You know that juice in the bottom of a can of spam? I’d use that

[-]

Seared_Gibets@reddit

Uh... I'm... I'm not sure we're using the same Spam...

[-]

Carlweathersfeathers@reddit

I’d hope not, then only one of us would get spam! Get your own spam!

[-]

firearmresearch00@reddit

Considering people have made fully functional lowers out of a 2x4 I'd imagine it would be ok

[-]

dem0lishr@reddit

A fucking 2x4?

[-]

FrankHJaeger@reddit

Lower receivers can be made out of pretty much anything aslong as the buffer system and trigger assembly can stay on.

[-]

dem0lishr@reddit

Oh, I believe it can. I just never thought about it.

[-]

AdIcy4546@reddit

Im guessing it was probably a 3x3 but I have seen one too a while back.

[-]

firearmresearch00@reddit

Yea I'd have to dig to find it but legit, just dremeled out the 2 pockets in a block of wood

[-]

dem0lishr@reddit

MauskARt

[-]

Mynplus1throwaway@reddit

Legos

[-]

BluesFan43@reddit

Use a Belzona product. Some are machinable.

[-]

Ninja_rooster@reddit

‼️‼️‼️‼️‼️BELZONA MENTIONED!!!!!!

[-]

chemicalgeekery@reddit

Holy shit I never thought I'd see a Belzona thread pop up in a gun forum

[-]

Ninja_rooster@reddit

ALL MY HOMIES USE BELZONA

[-]

wheredowehidethebody@reddit

Imagine being the fool that doesn’t mix BELZONA 2311 until it is a uniform color in a figure 8 pattern.

[-]

WiseDirt@reddit

gif

[-]

Suddenly_silent856@reddit

I use belzona at work from time to time it’s pretty incredible how strong it is. Pretty pricey though if I remember correctly.

[-]

This-Bad-2189@reddit

Belzona 1111

[-]

five_5six@reddit

Probably would work well as a ar9

[-]

Mouseturdsinmyhelmet@reddit

https://www.thefirearmblog.com/blog/2016/02/08/cast-mold-your-own-ar-lower-receiver/

[-]

oh_three_dum_dum@reddit

It would be objectively terrible and would probably also be a safety hazard for the operator and everyone nearby who isn’t being some sort of solid barrier or earthen berm.

[-]

Ok_Complex4374@reddit

Someone get this idea to project farm on YouTube

[-]

oh_three_dum_dum@reddit

I suggest Hubba Bubba or Bubblicious instead. They’re still sticky but have a lot more structure to them before the curing phase is over.

[-]

RedditPoster05@reddit

Some chewing tobacco for strength

[-]

HaroldTheSloth84@reddit

I think it needs to be duct tape-reinforced, honestly. Where are your engineering skills?

[-]

kingsevenin@reddit

Out of curiosity, can someone explain what the goal was here? Is this some 80% lower that needs to be milled out to function?

[-]

BroccoliLegend@reddit

That's some serious expert work there 🤢

[-]

Mexicangod03@reddit

Bro wha happened😂

[-]

Tight_Refrigerator78@reddit

I hope you claimed this on the dog

[-]

Just_gun_porn@reddit

There I was sitting on the porch whittling my AR lower, and sipping sweet tea!

[-]

Bigfoot3r@reddit

Jesus fucking chirst, did you had a crackhead work on that or something?

[-]

haikusbot@reddit

Jesus fucking chirst,

Did you had a crackhead work

On that or something?

- Bigfoot3r

^(I detect haikus. And sometimes, successfully.) ^Learn more about me.

^(Opt out of replies: "haikusbot opt out" | Delete my comment: "haikusbot delete")

[-]

mzrdisi@reddit

You used a flathead screwdriver and a pair of toenail clippers to do this, didn't you?

[-]

Whole-Lingonberry-74@reddit

I hope the question is a joke. Does the poster hate aluminum?

[-]

SwedishFool@reddit

What did you do with it, used it as a fucking hammer?

[-]

jjking714@reddit

Someone please take this person's drill press away for everyone's sake....

[-]

what-name-is-it@reddit

More like someone get this person a drill press

[-]

GasHistorical9316@reddit

More like someone get this person a mill, edge finder and some prints

[-]

Demon-of-Razgriz@reddit

I think ray Charles couldve done better job

[-]

Over-Body-8323@reddit

Yeah, i think so

[-]

CardiologistSharp438@reddit

Nothing JB weld can't fix

[-]

tehringworm@reddit

He milled that with an acetylene torch.

[-]

YaKillinMeSmallz@reddit

Who was your gunsmith, Michael J Fox?

[-]

tremab19@reddit

At least he could go back in time and try again 😂

[-]

NTBcheerios@reddit

He couldn't even fuck up a lower this bad

[-]

Aggressive_Maize9249@reddit

What else can you expect from a shitty plastic lower?

[-]

MArkansas-254@reddit

That answers my immediate question. Is that f-ing thing plastic? 🤣

[-]

NTBcheerios@reddit

Not to look like it was used as a puppy chew toy would be a start lol

[-]

hepatitis_@reddit

I spit my drink out laughing. You got me.

[-]

Carsalezguy@reddit

I split my dick laughing

[-]

Flat_Assistance1724@reddit

gif

[-]

djmere@reddit

Bubba Bondo it

[-]

TheHancock@reddit

Can we make this show up when people google “80% lower” so the gun grabbers will take pity on us?

[-]

1995ShakerGT@reddit

First gun ive ever seen that I might bring to a gun buyback

[-]

HolyShitidkwtf@reddit

Why did you not reach a point and think, "Maybe Im not doing this right?"

[-]

Dukeronomy@reddit

ya gotta know when to fold em. Godamn. Chaulk this one up to a learning experience and start over. holy shit

[-]

singlemale4cats@reddit

I usually power through those doubts

[-]

Ok_Refuse_3318@reddit

Nice blem lower! Tumu?

[-]

FlawlessNinjaKitty@reddit

How does something get THIS bad? Did you mill it with a dremel?

[-]

sandmansleepy@reddit

There is a famous example of an 80 on AR-15 forums that was done with completely with a Dremel that wasn't half bad actually.

[-]

FlawlessNinjaKitty@reddit

Can you drop a link, I absolutely need to see this

[-]

sandmansleepy@reddit

https://www.ar15.com/forums/general/Can-you-finish-an-80--lower-without-a-jig-using-only-hand-tools-/5-2244481/

The original post I can't find, but there is a link to pictures from it here. There were more pictures before. Probably better than most people do unless they have an actual mill. Someone with too much patience and experience with a Dremel. I wouldn't suggest it unless you are a good dentist.

Also, there is this. Turns out more than one weirdo has done it.

https://www.mdshooters.com/threads/completed-my-ar-lower-with-a-dremel-very-photo-heavy.112860/

[-]

FlawlessNinjaKitty@reddit

Holy shit, if we aren’t being duped that seems like an actual serviceable lower

[-]

sandmansleepy@reddit

I personally know one of the guys who went shooting with him, and he said that it is real and that it was legit.

I value my time enough that even spending a few extra hours on an 80 percent by not buying the proper tools would make it not worth it, let alone spending whatever he did lol.

I don't know if you have seen the finishing work that people do by hand making machining dies; it can be really impressive.

[-]

FlawlessNinjaKitty@reddit

Can’t wait to see someone do an ak using entirely hand tools

[-]

sandmansleepy@reddit

There is the infamous AK made out of a shovel, you seen that one?

And just made out of hand tools is just called the Khyber pass lol.

[-]

FlawlessNinjaKitty@reddit

Yeah I’ve seen the shovel ak

[-]

WiseDirt@reddit

I think OP might've used his teeth

[-]

out_lined@reddit

Bóbr-15

[-]

blackspike2017@reddit

I don't think they were his teeth.

[-]

EastwoodRavine85@reddit

I fucked the 80% percent until it was 1 hunnut

[-]

Impossible_Pizza_948@reddit

gif

[-]

BlkSmth@reddit

Some Big League bubble gum and go!

[-]

NoOnesSaint@reddit

literally how

[-]

AlphaTangoFoxtrt@reddit

I would think a broken tool. Whatever tool they were using broke but the program kept running with it.

[-]

NyeSexJunk@reddit

He melted the plastic and the big wad kept cruising around attached to the tool, probably

[-]

AlphaTangoFoxtrt@reddit

OHHHH didn't even notice it was polymer at first.

[-]

gittenlucky@reddit

gif

[-]

jdmgto@reddit

No, no matter how many antiwalk pins you put in you'll still be a dumbass.

[-]

Joker741776@reddit

Interesting, I've never seen someone attempt to finish an 80% lower with firecrackers before.

To answer your question, probably not. You'll have better luck with nuts, bolts, and washers at this point.

Or you know, start over and try again with actual tools and without a blindfold.

[-]

oh_three_dum_dum@reddit

Probably best to be sober as well.

[-]

Joker741776@reddit

Naw, I prefer to work with steady hands

[-]

oh_three_dum_dum@reddit

Maybe start there instead then. The tremors usually take at least a few days to start getting less intense and the worst of the detox is past in a couple of weeks or so… Unless you’re one of those super alcoholics with Slavic DNA and it takes a whole team of doctors to figure out how you’re even alive still.

[-]

bp305@reddit

No, but some ramen noodles and super glue or epoxy will…

[-]

robt_neville@reddit

It’s worth a shot

[-]

Mdmrtgn@reddit

First ones like ehhh then you swipe and it's like.......hmmm

[-]

singlemale4cats@reddit

[-]

Johnny_English_MI6@reddit

[-]

UnkownMalaysianGuy@reddit

Stick a tumb it it 👍🏻

[-]

JuanT1967@reddit

Wood lowers

https://www.reddit.com/r/guns/s/4OP2fdwqMD

https://www.reddit.com/r/brandonherrara/s/URZxZAVHiB

[-]

Ornery_Scholar_5779@reddit

Amish 80% with a hammer and chisel

[-]

liberaltearsfall@reddit

Michael J Fox Precision Machine lower?

[-]

slapnuts4321@reddit

CW/CCW??? What’s the difference?? It’s plastic anyways

[-]

FLARESGAMING@reddit

What the fuck happend here

[-]

stylusxyz@reddit

I feel bad that I am laughing about this.

[-]

Reality_Lies4@reddit

Used a hand crank drill eh...even the Amish could do better.

[-]

Wannabe_Operator83@reddit

Parkinson arms

[-]

Smart_Station323@reddit

🫨🫨🫨🫨

[-]

blueOwOfox@reddit

This is the equivalent of those pins that blind people make

[-]

Dankberg_TV@reddit

Hate to break it to you, but I don’t think anti-walk pins are going to fix those holes brother.

[-]

Severe_Islexdia@reddit

[-]

TheBigChungoos@reddit

Look at this stoner

[-]

InExcelsis9@reddit

Only thing that will fix that is a garbage can.

[-]

BelowAvrgDriver907@reddit

gif

[-]

Comfortable-Job-6236@reddit

Holy Christ

[-]

Beaverthief@reddit

Looks like a bca

[-]

Ice_is_frozen_water@reddit

How do you fuck up a lower that bad , on a side note I did not know they made polymer lower receivers .

[-]

rimpy13@reddit

The KP-15 is the only good polymer lower.

[-]

rynosaur94@reddit

The CAV Arms lowers they are essentially copies of are good too.

[-]

cornfarm96@reddit

I got an 80% poly lower as a bday present from my father when I turned 21. It came with a jig and all the bits to finish. I still haven’t touched it after 8 years lol

[-]

electrobrodude@reddit

That's what I was thinking.

[-]

Proof_Bathroom_3902@reddit

Milled it out with a dull beaver i see

[-]

aidancrow654@reddit

Made me cackle

[-]

anonymouslosername@reddit

Chainsaw

[-]

InfinitePossibility8@reddit

Gunsmiff

[-]

oh_three_dum_dum@reddit

Gumsmiff

[-]

Antykain@reddit

Was this trigger pocket milled with a spoon? 🥹

Cassette/drop-in trigger would probably be the best bet.. most of them include Anti-walk/rotation pins with the trigger.

[-]

oh_three_dum_dum@reddit

Looks like it was milled with a woodworking gouge and a chisel.

[-]

totheteeth@reddit

Go play in the street.

[-]

T-dog530@reddit

3D printed lower?

[-]

oh_three_dum_dum@reddit

…just what the fuck did you do to accomplish this?

[-]

whaletimecup@reddit

gif

[-]

FunTXCPA@reddit

Came here to make sure this gif was posted, was not disappointed! A+ job!

[-]

turtstar@reddit

Well, today I learned about polymer AR lowers I guess

[-]

justfirfunsies@reddit

My first AR was a polymer rifle from bushmaster… it sucked.

The mags wouldn’t drop.

[-]

s_mart6@reddit

We need the story

[-]

tubadude2@reddit

Cassette trigger and anti walk pins. Good as new.

Did Stevie Wonder get an 80% lower?

[-]

404-no-fund@reddit

Now it’s 50%

[-]

qelbus@reddit

Now it’s 50¢

[-]

Samuel_Payne@reddit

gif

[-]

jake-xavier@reddit

Is this an airsoft lower?

[-]

ej1030@reddit

They make polymer ar lowers

[-]

MarkDoner@reddit

And this is why they should be made from 7075 forgings

[-]

DrZedex@reddit

Is now

[-]

harbourhunter@reddit

kevin is that you?

[-]

DanTalent@reddit

IS IT CAKE?

[-]

HALF-PRICE_@reddit

Op’s username checks out.

[-]

Stevil4583LBC@reddit

That’s suboptimal

[-]

DNCOrGoFuckYourself@reddit

Bro just built a 30% lower

[-]

ThisOneTimeAtKDK@reddit

If you have a friend w one of those 3D pens….you’d might be able to fill it in w PLA PRO. Block the parts you want flat w aluminum or steel or something.

[-]

N2Shooter@reddit

If your gonna do all that, might as well just print a new one. 🤷‍♂️

[-]

ThisOneTimeAtKDK@reddit

Doesn’t look printed. (No layer lines, holes are clean especially the rounded parts aren’t showing layers, can’t see anywhere the supports were removed….etc etc)

Looks like a polymer 80% to me. Parts that are messed up aren’t load bearing at least. They can be patched without too much hassle.

[-]

N2Shooter@reddit

It's not printed. But you'd be really surprised what you can get out of printed parts with the right post process steps. 😃

[-]

ThisOneTimeAtKDK@reddit

I have a P1P and ALL of my Filament is PLA pro or PLA+….guess why

[-]

N2Shooter@reddit

😃

I'm running Polycarbonate CF, and you already know why!

[-]

Darc_vexiS@reddit

Is this plastic?

[-]

AnonymousWombat229@reddit

Wattle and daub actually.

[-]

OUsnr7@reddit

Is this chocolate?

[-]

xj98jeep@reddit

Yeah dude they sure will

[-]

PrevBannedByReddit@reddit

Did you mill that out with a butter knife?

[-]

Extension-Mall-7292@reddit

if this was a human, I'd shoot it in the face.

[-]

Severe_Islexdia@reddit

Yes.

[-]

TankerKing2019@reddit

Jesus Autistic Christ! What kinda blind monkey bubba fucked that thing!

[-]

ha1fway@reddit

I’m assuming you tried to roll an 80% because your crippling meth addiction made a 4473 complicated

[-]

LuridRequiem@reddit

Please find a trusted adult to help you

[-]

HarleysAndGuitars@reddit

Jesus christ

[-]

CorvidxQueen@reddit

All I got is a Big Ooooof

[-]

TacTurtle@reddit

Eh, some Bondo could fix this.

[-]

BGMcGee@reddit

Just run it. It should be fine as is.

[-]

Wildcard556@reddit

How…?

[-]

Cephrael37@reddit

I could be wrong but I do believe that is fucked.

[-]

13NeverEnough@reddit

Is this the Stevie Wonder special? It should be illegal for you to be around anything firearm related

[-]

ChevyRacer71@reddit

You may notice a slight rattling noise

[-]

PR3SID3NT_NIX0N@reddit

That’ll buff out

[-]

_Hashtronaut_@reddit

Bit of Ramen, some super glue, and a file

[-]

brachus12@reddit

atf labs proving they could force nfa parts into an ar

[-]

Ninja_rooster@reddit

Bro what the fuck. I thought this was a failed print.

[-]

sxrrycard@reddit

Is it made of chocolate??

[-]

bolivar-shagnasty@reddit

[-]

Edge-Evolution@reddit

How? Just how??? It’s like when someone plucks an eyebrow hair and tries to even it out, and in the end you look surprised all the time. 😮

[-]

Idoallthejobs@reddit

[-]

bolivar-shagnasty@reddit

[-]

Libido_Max@reddit

Did you shoot your lower to see if it survives?

[-]

l0pper@reddit

Classic

[-]

ospfpacket@reddit

gif

[-]

Night_Raptor_22@reddit

“I have a dream! (And a dremel)”

OP, 2025

[-]

Ill-Purchase-3312@reddit

gif

[-]

Lick_My_BigButt_1980@reddit

'Cause they know I'm the king of a Cool Jerk! (Whoo!)… 🎶🎵

[-]

DrFranknMrStein@reddit

gif

[-]

GunnCelt@reddit

gif

[-]

steveHangar1@reddit

Stevie Wonder Gunsmith LLC

[-]

dudechickendude@reddit

Please post this in r/machinists

But, to answer your question, that will most certainly buff right out.

[-]

bownt1@reddit

i competed in a pinewood derby when i was a child. they gave a kid a trophey because they felt bad for him. his parents were alcolholics and he was very poor, it was obvious he did all the work himself with almost no tools. his little car looked just like this lower.

[-]