OSAP Part II (AKA hillbilly body armor)

[chopinbloc]

Part 2 in my attempt to find a repeatable, affordable, serviceable open source armor design. Bear in mind, this is just a proof of concept. The goal here was to determine whether:

• PEI grade 4 tiles are sufficiently strong
• Three tiles are enough
• HDPE backer can catch bullet and tile fragments

Spoiler:









The takeaway here is that yes, all the design criteria listed above were met. Next test will also use three PEI grade 4 tiles but will test a steel backer instead of HDPE. The reason is that HDPE is cheaper and lighter, but it may be easier for some folks to find sheet steel.

Once a configuration is found that can stop 7.62x39mm FMJ and .223 FMJ, we will work on refining that design by adding a shooter's cut and we'll look at adhesives that can do a better job at holding the fragments together after a bit fit better multi hit performance. I have confidence that liquid nails should do the trick if allowed to cure fully. I also think a layer of fabric adhered to the strike face ought to help hold the pieces together.

I really want this to be a community effort, so if you have any ideas, please post them. Once we settle on a design, I'd like to see other people test the design. That's where the repeatable part comes in.

 

[strambo]

After adhering it with a better adhesive, coat the whole works with spray truck bed liner. That should really help contain the spall and serve as another flexible adhesive to help keep it all together.

 

[chopinbloc]

I was thinking about that, too, but rattle can bed liner is about ten bucks a can, while liquid nails is like a dollar or two per tube. If the liquid nails doesn't do the trick, we'll try spray on bed liner. Trying to keep cost as low as possible.

 

[entropy]

Call me silly, but chintzin' on body armor ingredients at that level seems unwise. Good Luck!

 

[chopinbloc]

Yeah, way better to not have anything because you couldn't afford it, or left your expensive plates at home.

The point of this project is not as an alternative to proper body armor. The point is to come up with a design that can work for people who live in oppressive locales or for field expedient use in bad situations and primarily to offer an argument against body armor bans.


Oh, and it's fun.

 

[Mayvik]

Steel plates with anti-frag coating are cheap, plentiful, and durable. Aside from "because I can" this does not seem particularly useful.

 

[strambo]

I almost posted something like that but realized the spirit of the testing. He's experimenting and having fun and it is interesting info. Sure, quality AR500 plates can be had for as little as $70 each...but how many people actually have armor of any sort anyway?

 

[dogmush]

That rearside deformation would have caused injury, I think.

Honestly, I like what you're up to, but I think you are using the wrong stuff. Steel is going to be cheaper and easier than porcelain to get the performance you need.

What kind of budget per plate are you looking at? I'm thinking the best crossing of money and performance for build it yourself armor is multiple layers of heat treated yourself steel and the gallon containers of truck bed liner for anti-spall.

 

[chopinbloc]

This test cost me less than $5. I don't think the back face deformation was excessive. It just bumped the water jug a bit. Once the design is finalized and a more effective adhesive is identified, there should be minimal back face deformation. I'll confirm that by placing the plate against a block of clay as per NIJ requirements.

 

[strambo]

A cost-effective DIY, reliable and repeatable heat treat method for steel would be better, I agree, but is that doable? I don't know anything about heat treating steel, I do know bullets slice through un-hardened steel like butter unless it gets too thick and heavy to be practical.

 

[chopinbloc]

I agree. Remember, one of the goals is to make this easy for anyone to build, without any real skill.

 

[dogmush]

A cost-effective DIY, reliable and repeatable heat treat method for steel would be better, I agree, but is that doable?

Yes?

Define "everyone" and "Without any real skill".

I can heat treat steel trivially easily. I regularly do it to tools I have messed up one way or another. It's not alchemy, and the instructions are all over the net, but I'm kinda a crafty guy. If I were trying to make armor (more than one or two plates) I'd probably go to the trouble of making a furnace. For a plate the size of chopinbloc's I'd just use a torch. I would say that if you have the knowledge to build your own armor, then you are probably smart enough to successfully harden and temper carbon steel. But it might take infrastructure you don't have lying around, (but again can make pretty easy).

I might be overthinking this a tic, but I know roughly what it takes to make a real ceramic SAPI plate, and I think those skills are going to be rarer/harder to learn then the skills needed to make comparable armor out of steel. A "real" ceramic armor plate has exotic ceramics, is more then an inch thick, and is wrapped in kevlar. It's not really comparable to floor tiles.

Assuming that the rear face deformation isn't as bad as it looks, chopinbloc has made what? A II or maybe IIIA, single use plate? What good is that when the second round of the controlled pair gets there?

Look, I get it. I really do, it's an awesome project, but I really think in limiting your target audiences skillset so far down, you are limiting your outcome to what is, realistically, useless at it's stated purpose.

 

[chopinbloc]

A. Heat treating isn't alchemy but it's vastly more complicated than gluing some stuff together.

2. SAPI and ESAPI are rated to stop .30-06 AP. I don't expect to stop real AP ammo or high power rifle cartridges, but the "plate" configuration in this test stopped a .223 round. No IIIA can stop rifle ammo.

iii. The roofing cement was a poor choice for adhesive, but in previous tests that used nor effective adhesive, they stayed together enough to stop several impacts.

 

[Baron_Null]

I'm in. Your last thread on the DIY tile armor is what convinced me to go to my local Lowe's and buy some grade 5 tiles. I still have them, and am searching for a less expensive way to glue them together and coat them, since bedliner is pricey.

 

[chopinbloc]

I have high confidence in Liquid Nails for that. I'll use it for my next test. About $2 a tube.

 

[Baron_Null]

I might be willing to put together 3 of my tiles with a couple of tubes of liquid nails. The only question is what to use as a backer, since I don't have access to any 55 gallon drums. If I recall correctly, the HDPE cutting board didn't really want to adhere to anything last time, did it?

 

[chopinbloc]

That's correct. I think 16ga steel would work well, too.

 

[blarby]

Keep up the good work.

Testing is fun, and often looked down on, but its how we make progress.

Never know, might stumble on something like..... the lightbulb, or powder that burns expansively and rapidly under pressure....

ya never know.

 

[230RN]

Great project !

Even a failed experiment is a success.

 

[chopinbloc]

Exactly. "Failure" still yield useful data if you control variables.

 

[230RN]

"Failure" also reveals those intervening, uncontrolled, and unforeseen variables.

All this makes you wish there were a ballistic-grade silly putty, don't it?

Terry

REF:
https://en.wikipedia.org/wiki/Silly_Putty

 

[230RN]

^ Hmmm.... maybe a coating of silly putty would keep the fragents together...??? Hmmmm.

Me go now. Me feel an out-of-box mental session coming on.

 

[Baron_Null]

As dumb as it may sound, and as much as I loathe to be that guy, maybe an outer skin of duct tape would help control fragmentation. It requires next to no discernable skill to use, is relatively inexpensive, is relatively elastic, and is cloth reinforced. The only problems I could imagine would be the tendency to rip across the strands, which could be mitigated by overlapping the layers in alternating directions, and also with the adhesive weakening and melting in high heat.

 

[chopinbloc]

It actually did work pretty well in an earlier test. The only problem I see with it is the adhesive dries out over time.

 

[Baron_Null]

Has anyone tried adhering some sort of ripstop nylon to the plates yet? I would say trying to go with a higher strength fabric, but given the "anyone can do it for cheap" idea, one can salvage ripstop from a variety of clothing items. Perhaps even using heavy duty nylon from commercial backpacks, since that fabric seems to fail and begin to fray at the seams instead of on the solid pieces if cloth.