Wall penetration...

[layusn1]

So..how much metal can a 9mm, or maybe 45ACP penetrate? If you were like totally paranoid and worried about rounds penetrating your walls in a home defense scenario, could you (not would it be feasible) put a desired thickness of metal behind the walls of you house to prevent penetration? I know that would be a wee bit overkill...just opening the question for debate.

[Oreo]

I'd be a little concerned for ricochet in that scenario. I would think it would be much cheaper & safer to line the walls with wood. If you could fill the hollow space in a standard 4" thick wall with some cheap plywood, I think you'd be in good shape. For that matter, if you wanted to use steel, perhaps a couple sheets of plywood in front of the steel might be enough to prevent ricochet.

[ISUSteve]

Fill your walls with dirt or sand. Should pay for itself in heating/cooling too!

[Oreo]

That's an interesting idea except that the weight of the sand / dirt would almost certainly be enough to bow or even break the sheetrock. And I'm not so sure 4" of sand with an unreinforced back is enough to stop a pistol bullet.

[MakeMineaP99]

Lenny,

I shot some .125" mild steel in November with the following load:

9x19mm

115gr Win FMJ
6.2 grs WSF
WSP
1.160" OAL
Mixed

Made a nice dent but didn't go through. I also shot the same plate with .30 Carbine

110 gr LC FMJ
12.5 grs 2400
Rem 6.5
LC brass
1.680" OAL

Went right through.

I also had some .375" plate with me, stopped all handgun rounds, 9mm, .45, .30 Carbine dead in their tracks, LC M2 ball went right through.

If I remember, I'll get pics this weekend when I'm home (and if I can find the plates).

[layusn1]

Hmm, sandwiching a plate between wood could be interesting. What if you carbon fiber reinforced the back of the sheetrock? That carbon fiber experiment they did on Smash Lab was interesting....took a heck of a beating.

[MakeMineaP99]

Kevlar would be better in a ballistic application than CF.

[Oreo]

The problem with any composite base would be expense. Not that steel or wood wouldn't be expensive, but kevlar or carbon would be obscenely expensive. I still say 7 layers of 1/2" plywood would be your best bang 4 buck. I'd only consider steel if you were concerned about rifle bullets. & then you're probably looking at 1/4" - 3/8" minimum. Ricochet would be even more a concern & I'm not sure wood would do much to curtail it.

The one place Kevlar would be of use would be curtains for windows. Kevlar fabric has shown to be pretty decent in that application & probably less expensive then bullet resistant windows.

[MakeMineaP99]

14" of wood ain't going to stop anything but handgun rounds.

[layusn1]

Not that I am actually contemplating any of this, just bored and thinking out loud. What if you gave up a little square footage and made your walls thicker? If stuck with traditional wall thickness and you had the funds what about a compromise...carbon fiber the sheet rock AND fill the void with sand. The first layer of carbon fiber might take some umpf outta the round, the sand would slow it down more, if not stop it, and the next layer of carbon fiber (on the back of the opposing wall) could be backup to completely stop it? Would that actually be enough to stop traditional handgun rounds? The carbon fiber could also serve to keep the sheetrock from buckling under the stress of the sand.

[Oreo]

I don't think so man. You have to also consider... this is going to be the place that you primarily LIVE. Which means hanging things on walls, remodeling walls, & repairing walls with some frequency. Not to mention, going with thicker walls pretty much means building a house from scratch. I would think it more practical to find ways to modify existing homes in ways that once installed, will never have to be fooled with or noticed ever again. Wood or steel serve nicely that way.

Now... if you're building a fort... that changes the rules entirely.

OH... here's another idea... How about a brick or cinderblock house? You might be able to fit bricks in a standard sheetrock wall. But some older houses were build entirely- even interiror walls, with cinderblocks. If I had to build a new house with the utmost security in mind, I'd build completely with cinderblock (filled with concrete & rebar.)

Or you could consider an adobe type home. Mike Rowe on Dirty Jobs helped that guy build that house made if mud & straw. I bet those walls would easily & safely stop a bullet. Those walls are much thicker as you asked about.

[layusn1]

I could see the cinderblock idea. That would be interesting, probably fairly well insulated too but I guess that brings up the what do you do if you want to run new wiring, plumbing, etc question. Would adobe really stop a bullet or would it be more likely to shatter like pottery once it is dry? I am thinking more about internal walls though, so if you have to shot inside the house you don't somehow put a round through a wall and into your kid, etc.

[Anvil]

Log cabin?

[Oreo]

Well, the adobe wouldn't shatter like a ceramic because it's not fired in a kiln. It would act more like really hard-packed dirt. It could be repaired fairly easy as well.

Ceramic is an interesting idea all by itself though. You could probably commission some custom teracotta bricks that could be stacked in a normal 14" x 3.5" x 8' wall cavity. That might work reall well too. Since ceramic would shatter- absorbing energy I'd bet ricochet would be much less of a problem.

Any time you start talking about filling all the wall cavities in a house you're going to have real problems with wiring & plumbing. It would be a major problem for anything but new construction. However, if you go with a brick or cinderblock interior frame, 2x2 boards can be mounted on the cinderblock every 16" like normal wall studs & sheetrock hung from that. Parts of my house are constructed that way. This leaves just enough room for normal electrical fixtures & wiring. But you're probably talking about 10" thick walls at that point.

A cinderblock or similar masonary type structures are particularly dangerous in earthquake prone areas. So... this would not be an option in CA for example.

Paper or phone books packed into a standard wall cavity might provide some protection. See BoxOTruth Chapter 31 (http://www.theboxotruth.com/docs/bot31.htm)

[DCGoth]

I live in an apartment and have no problem reaching for my G33 first. Something about a 1450 fps muzzle velocity .357 Sig round makes me feel safer. If someone is going to break in, I like to know that the rounds will continue through to a second intruder if there is one.

[mitchshrader]

fwiw.. guns penetrate most common building materials just fine. the thing they don't penetrate well is sand. nice dry sand is a tough one for guns, and the easiest cheapest method I know to add both thermal mass and bulletproofing is about a foot of sand. disguise it or don't, that's an answer that works, for ordinary guns, including most hunting rifles. not sure how to implement that in a sensible way most places, it'd be a lot easier to build in than add on discreetely. It ain't EXPENSIVE, however, compared to kevlar or steel, so worth knowing.

[ept000]

I can tell you a little about shooting wood. I stood a four foot piece of 4x12 on one end and shot ten rounds of 9mm WWB at it. All ten rounds went through it and didn't even tip it over. The guy watching me thought I missed it ten times because it was just sitting on it's end, but when we walked to it there were ten holes clean through it. Kind of surprised me!

[Jammer Six]

Speaking as a retired general contractor, I would LOVE to have the contracts you guys are talking about-- the lightest load outside of the kevlar would require engineering, re-wiring, re-plumbing if it's there, shoring, and you to move out while the work happened.

The projects you guys are talking about are HUGE jobs, particularly if we're talking about the second story. Don't get me started about painting. I hate painting. :chainsaw:

Sand in a wall is a really, really bad idea. Makes me itch just to think about it. It's an open invitation for things that live in sand and like warm, sheltered sand, it's heavy, and if you leave any moisture in it (and you will) it will start to grow things immediately.

Cinderblock is actually quite fragile. It's strength is all compressive. The way you cut it by hand is to score it and hit it-- it breaks apart very easily. A bullet hitting it probably wouldn't lose much energy at all.

Kevlar is by far the best idea, in my opinion, even including cost as a consideration. If you can't afford insurance, you can't afford to drive, and I think the same principle applies here.

Finally, I think it's pointless. Even if you did manage to build a barrier that would stop a 9 or a .45, a .357 would go right through it. We use a half inch water pipe in our intro classes that has a nice, neat .357 hole in it, placed there by a customer, drenching the line in water (it was a sprinkler system) to demonstrate what handguns will penetrate. We also have a 1/4" piece of rolled steel that was shot with a .45, a 9 and a .357 to use as a training aid-- all nice, neat holes.

[Oreo]

http://www.theboxotruth.com/docs/buickot6_2.htm

Cinderblocks would do just fine in a typical home defense scenario. Just like the fancy boron-carbide ceramic armor plate, the cinderblock would indeed absorb a lot of energy as it shatters. It would also be quite abrasive & would fragment any round that would penetrate. You just have to understand that any one cinderblock couldn't take more then a couple rounds before giving way. That should be plenty in a home defense situation.

[918v]

I have personal experience with this sort of thing. I actually shot through a wall one time. The load was a 69gr SMK doing 2850 FPS. It went through one layer of sheetrock and the exterior plaster, then made a half-inch crater in the cinderblock wall outside.

Dirt in the walls, steel plates, etc are impractical. You cannot add weight to the walls. You will compromise the foundation.

I vote for kevlar blankets for the wife and kids.

[Oreo]

Now, I DO really like the idea of a large kevlar bullet resistant blanket. Something the wife & kids can crawl under together. That would be very practical & probably affordable enough to be within reach of most middle class folks.

Actually, steel wouldn't be as good of a choice as aluminum for armor plating. Weight would still be a concern for such large chunks but thick aluminum plate cores could easily be added to doors & other targeted (no pun intended) areas.

[MakeMineaP99]

What armor plate have you seen made out of Al? Al is pricey and not up to steel quality for armor plate.

[Oreo]

You may be right about the price I didn't think of that.

Unlike steel, aluminum will deform absorbing a considerable ammount of energy. In fact, many layers of thinner sheets will be more effective then one solid sheet of the same total thickness. I seem to remember reading an article a long time ago about this kind of technology being developed for spacecraft where high speed collisions with small pieces of space debris was a concern. But it's been a long time- so my memory may not be totally accurate. I'll see if I can dig something up on the subject.

http://www.key-to-metals.com/Article90.htm
http://www.defense-update.com/features/du-3-04/feature-light-armor.htm

[MakeMineaP99]

Are you an engineer? Hopefully this won't sound to foreign.

A similar concept is used in vehicle design, called crumple zones. The underlying theory being, that energy is expended to deform the crumple zones, transfering energy away from the passengers.

Al has a different stress strain curve from steel, where it experiences more plastic deformation before failure. However, why would you want that from you're material in an armor plating application? You want something hard and brittle, which causes the projectile to deform and ultimately fail.

[Oreo]

I mentioned aluminum as a counter to the point of excessive weight.

The plasticity of aluminum would reduce the risk of ricochet, and I wouldn't consider the capability of withstanding multiple hits in the same exact spot a requirement for armor plate in the home. This is a home after all, not a military fortress. Not to mention that aluminum can be repaired just as easily as steel if you want to patch things up for the next bad guy to bust through the door, guns-a-blazin'.

PS: In one of those articles they mentioned an aluminum-ceramic armor being capable of defeating AP rounds. I'm certainly no expert, but I would look into the posibility that this aluminum ceramic composite being resistant even to rifle rounds. That's a major advantage over steel armor in the thicknesses we're considering.

[MakeMineaP99]

I'll check the articles tomorrow, I'm going to bed.

Closing thought:

Keep in mind, you're comparing composites to conventional alloys, apples to oranges.

[Oreo]

Are you an engineer?

I'm an arm-chair engineer in the back of my man-cave. :supergrin:

Keep in mind, you're comparing composites to conventional alloys, apples to oranges.

Well, I tend to think practially i.e. what ever I can get out of the home depot or the yellow pages gets considered equally. I know where to get 4'x8' sheets of 1/8" thick aluminum in several different alloys, and I can find ceramic tiles at home depot. So... I figure if I needed some impromtu AP resistant armor I could throw that stuff together in a hurry.

[918v]

How about reactive armor? Now that's the **** right there.

[Oreo]

:rofl:Sure if you want high explosives packed into your walls.:chicken:

[layusn1]

I doubt this would work so that is why I am asking...what about this stuff? I don't know that it would hold up to such a high velocity and focused impact though.

http://www.diywindowsecurity.com/product_info.php?products_id=38&osCsid=b25c2dd96ee6ee289f61451b03fada66

I didn't realize this stuff was so expensive, they use so much of it on It Takes A Thief you would think it was much less expensive. I sure do plan on getting this stuff when I buy a house though.

[Oreo]

I think that stuff would be very similar to a car windshield- which is capable of withstanding incredible impacts but not bullets.

That does remind me of another option for walls though... bullet resistant glass- you know that 1" thick plexiglass stuff. It too would be heavy but I'm not sure how it would compare to the weight of steel or aluminum. It would be a solution with prooven ability though.

[MakeMineaP99]

I think that stuff would be very similar to a car windshield- which is capable of withstanding incredible impacts but not bullets.

That does remind me of another option for walls though... bullet resistant glass- you know that 1" thick plexiglass stuff. It too would be heavy but I'm not sure how it would compare to the weight of steel or aluminum. It would be a solution with prooven ability though.

Agreed, the impact would likely induce failure.

Bullet resistant glass is good for handgun rounds. Once again, rifle rounds will punch through it, in all but the upper grades. From what I remember, that stuff is neither cheap, nor light, once again creating problems putting inside a wall, not to mention, it takes up space where the insulation goes.

[918v]

Why don't you get that plexiglass stuff banks use?

[MakeMineaP99]

$$$$

[Oreo]

If you really want your home to be a fortress, I would think the best bang for your buck would be to build it from scratch with roof to foundation cinderblock walls filled with concrete & rebar. For the exterior walls, lay brick over the cinderblock. The cinderblock interior walls (If you chose to take it that far) could be covered with 2x2 studs which would provide enough space for typcial residential electric, & then sheet rock over that. Plumbing would have to be planned ahead of time so that space could be left in the cinderblock for the pipes. That would basically just mean not filling those cinderblocks with the concrete.

This would look nice & inconspicuous from the exterior & you'd just have really thick walls on the inside. Insulation would NOT be an issue. This type of construction would be way less expensive then other exotic type materials like kevlar or even steel plate. Most construction companies are very familiar with how to use them. Handgun rounds would easily be stopped & most likely, all but the highest powered rifle rounds available to civilians would be stopped as well- as long as repeated shots to the same spot were not a major issue.

If you're going that far, bullet resistant glass in all the windows, & 1/2"+ thick steel plate in the doors with high security grade locks & hinges. Then, you'd have to consider what to do with the flooring & the roof- if you're concerned about taking fire from aircraft. Other then steel or aluminum plate in the roof I'm not sure what the best option would be. I'd probably not worry about the floors.

For the exterior, you'd want a 20' clear perimeter with a 20' deep x 20' wide moat with a draw-bridge built into your driveway. Outside the moat you'd want a 10' brick wall with motion sensors tied to an alarm system followed by 100 yard perimeter with a 15' steel picket fence with an electronic gate either manned with a security guard or protected by a retinal scan biosecurity system. Motion sensors at the picket fense as well.

If anyone gets within 100yards you'll have enough warning to grab your long guns. If they get in the house it probably means you pissed off Dubya & in which case... you're screwed 'cause I don't know how to build a nucular proof bunker.

[layusn1]

Do you think I should put alligators or sharks with laser beams on their head in the moat? The question wasn't about rounds coming in, it was about interior wall penetration...sheesh...everyone has to take everything to extremes around this place...some people's children...





LOL

[Jammer Six]

2x2 studs aren't enough, they would need to be 2x4s.

I don't see any advantage to cinderblock with concrete, a solid concrete wall would be cheaper, and more durable.

[MONTEGOD7SS]

Do you think I should put alligators or sharks with laser beams on their head in the moat? The question wasn't about rounds coming in, it was about interior wall penetration...sheesh...everyone has to take everything to extremes around this place...some people's children...





LOL

Ill-tempered Sea Bass, definitaley.

[Oreo]

2x2 studs aren't enough, they would need to be 2x4s.

I don't see any advantage to cinderblock with concrete, a solid concrete wall would be cheaper, and more durable.


2x2s would be plenty. I live in a townhome community where the walls I share with my neighbors on either side are exactly like this. Works just fine.

I said cinderblock w/concrete just because that's usually how I've seen foundations done around here, as well as major commercial construction projects around my old college campus. The dorms were made that way sans the drywall & I have to tell you... I've never felt more secure. A steel reinforced concrete wall would work also though.

As for the moat... I'd have to go with sharks w/LASER beams. Definitely. I'd also have a large treadmill installed on the roof with an airplane fueled & packed with SHTF supplies.

[Jammer Six]

You can't plumb in a 2x2 wall. You can't put forced air in a 2x2 wall.

The compromises make it unviable. You don't have 2x2 everywhere, unless you don't have any plumbing.

[Oreo]

You don't plum in the 2" space. You have to plan cavities in the concrete for plumbing. With cinder block there is enough space in the hollow blocks for plumbing but you'd have to plan that ahead of time so that those runs aren't filled with concrete. In a normal sized house you'd even have enough room in those blocks for a central air system.

The best way to work that out would be to have a main structural wall in the middle of the house carry the plumbing straight up from the basement & branch out through the floors to the kitchen, bathrooms, etc. This one wall would have a 4" drain pipe that would run right up to the roof for a vent, in one vertical cinder block column. In another column you'd have two 3/4" supply lines for hot & cold water, and for the HVAC supply & return you could use yet another 2-4 vertical columns.

Once the water supply lines branch off of the 3/4" trunk, you can just run them through the 2x2 studs to get where they need to go. This would simplify repairs or modifications. Cinder blocks would have the advantage over solid concrete in that they can be relatively easily chipped out to access the pumbing lines if needed & then patched up again.

[Jammer Six]

:rolleyes5:

[Oreo]

:smilewinkgrin:

[45auto]

Old post... but.. What about cement?
You could fill it little by little to avoid bowing of the support plywood, but once done, put up the dry wall. :D
You could also use fragmenting rounds for HD... :)

Cement is fun, I had a lot of fun with it while working for my uncle at a supply house with the cement I swept up from the floor.

[MakeMineaP99]

Concrete handles well in compression, poor in tension.

[cohutt]

Surprised that The Box O' Truth (http://www.theboxotruth.com/) wasn't mentioned 8 months ago when the thread was active.

[BigSlick]

That setup at Box o Truth does work.

Amazing to see the .308 rounds get stopped like that.

Sand seems to disperse the energy better than I imagined it would.

You could prolly make a few bucks off that at the range bettin da local Mall Ninja his .223 steel core won't penetrate it ;)

[45auto]

I gots some steel core .223! :bp:

I have a few rounds hanging off a magnet for fun! :sifone: