[Cutting-Edge Armor Design] Real World SCA-legal Armour and Ballistics Armour

[Icelander]

Originally Posted by Polydamas

Ok, I was finally able to buy Pyramid 3-85 and have a look.

Excellent! Thanks.

I must admit that 'Segmented Plate' being much more expensive and less protective for its weight than 'Scale' has me scratching my head a bit. This is the reverse of how Low-Tech armours work, after all. And with DR 5+ 'Scale' doesn't have any weaknesses over 'Segmented Plate' in the CEAD.

I'm sure some change in how body armour is manufactured between the period covered by TL1-4 and the period covered by TL6-8 explains why Pulver chose to reverse the relative Cost and Weight factors from Low-Tech for 'Scale' and 'Segmented Plate' made at higher TLs.

Not knowing what assumptions about different manufacturing processes this is based on, though, leaves me wondering if one should use these CW and CC modifiers for recreations of historical armour as well. That would make recreations of scale and lamellar much more effective than the originals, but making replica designs incorporating bands of metal, like lorica segmenta or many historical faulds, as well as any design with multiple smaller plates of armour plate, like coats of plates or brigandines, very inefficient.

Technically, CEAD doesn't provide any incentive to make metal armour 'Segmented Plate' rather than 'Plate', as there are no rules about certain hit locations being more difficult or more expensive to armour with 'Plate', nor are there rules requiring less thickness or a design better adapted to moving with the user for the abdomen, neck or joints.

By the rules, you can make plate faulds at no greater Cost for the same protection and coverage as breastplates. And your entire limb can have the same thickness of plate armour as your breastplate, too. Obviously, I'd want to discourage Munchkinism and illogical results by applying appropriate Cost (and possibly Weight) modifiers, as well as giving penalties for designs where certain positions are hard or mobility is otherwise restricted.

Low-Tech, Instant Armor and Loadouts have lots of such notes, and small modifiers, in Loadouts, for specific armour pieces which restrict mobility somewhat. None of those rules are designed to be universal or easily generalised to all TLs or styles of armour. I don't quite know which of them should apply to TL8 methods used to design and manufacture armour which merely needs to appear TL4-ish.

So, you know, asking forumites who'd know how modern methods of manufacturing and design change specific rules for Low-Tech armour. I assume heavy and bulky leg armour will give a penalty to running and other activity involving the legs, as it generally does in Loadouts, but when does leg armour become heavy or bulky enough to trigger a penalty?

And do you still have to use segmented plate construction to cover the Abdomen with metal armour if working at TL8? And is it really more expensive and less protective than an equal weight of metal scale, when made in styles that look right for historical armour, albeit possibly with modern manufacturing?

And are there no modern materials used in armour that are easier and thus cheaper to work into multiple smaller pieces linked together for full coverage, i.e. 'Segmented Plate', rather than being able to make 'Plate' armour that can cover any area of the body?

Originally Posted by Polydamas

Under Low Tech's assumptions, generally plate armour for the limbs will be DR 3-5 (average thickness 1-1.5 mm), armour for the torso, neck, shoulders, and head DR 5-8 (average thickness 2-3 mm).

Are there any issues with wearing 1/4" and maybe up to half an inch on some locations, of soft body armour under such reproduction armour, assuming the measurements it was made to were taken in such 'padding'?

What about wearing modern trauma plates over your chest under a breastplate or cuirass designed to fit over it?

Would the combined thickness be too much for any kind of useful activity or would it just be really heavy and give -1 or -2 to DX for armour layering, exact penalty depending on how well they were designed to fit together?

Considering less expensive options for sicarios and subordinate jefes de la plaza, as well as 'earlier generation' armour the inner circle might have tried, before Vargas developed his own in-house R&D team and a workshop for working with advanced materials.

Originally Posted by Polydamas

Maybe a superman like Vargas could double that thickness.

Weight wise, certainly. But at what thickness will limb armour become too bulky or inflexible? When does it start to give mobility penalties over and above Encumbrance?

Originally Posted by Polydamas

My bracers (covering what CEAD calls Arms minus Shoulders) are 4 lbs each. Cutting-Edge Armour Design would give them DR 7 in Hard Steel with the Plate modifier (DR 7 x 2.8 sf x 0.4 WM = 7.84 lb). So in theory, Vargas could have arms and legs which will stop 5.56 x 45 mm from a short barrel. I am not sure if 2-3 mm of shaped and hardened 1045 or 1050 spring steel, 4130 chromoly, or 410 stainless will really do that, but maybe if they are smart about putting the thickest metal in the parts that go towards the enemy when he has a rifle at his shoulder ...

I don't think Vargas expects steel alloys commonly used in SCA/HEMA/HMB to stop rifle rounds in any practical wearable configuration.

That's why he's been looking into using alloys more commonly used for ballistic protection, such as in armoured luxury vehicles, although these alloys are much harder to work with, or using some revolutionary process like flash bainite to harden individual pieces while still being able to form them into historical-looking armour.

Stainless steels or even the better steels for high-quality historical armour reproductions (like 1050 spring) would be used to armour areas impractical to cover with stronger materials and/or as a cosmetic external 'costume' armour (that still protects against swords, knives and maybe even fragments and low-power pistols) over more conventional ballistic protection.

The less expensive Eastern European options in SCA-legal armour, worn over conventional TL8 ballistic protection approaching or exceeding Level III for the most vital areas, look to be about the only viable options for 'sort-of-right' armour that is affordable to young sicarios looking to rise in status. If such layered solutions aren't prohibitively heavy, restrictive and uncomfortable (that they will be somewhat so is a given, even absent full coverage).

Originally Posted by Polydamas

Your figures for underarmour don't look crazy, and there are sports fighters who like a whole padded legging under their legharness.

Good.

[DanHoward]

Originally Posted by Icelander

I must admit that 'Segmented Plate' being much more expensive and less protective for its weight than 'Scale' has me scratching my head a bit. This is the reverse of how Low-Tech armours work, after all. And with DR 5+ 'Scale' doesn't have any weaknesses over 'Segmented Plate' in the CEAD.

Scale armour is the least efficient of all the metal armour constructions. Weight:DR ratio is the worst. There aren't any modern materials or assembly methods that can change this.

[Icelander]

Originally Posted by Rupert

In the modern world, I assume you'd use some kind of glue/cement if welding wasn't practical.

Of course! That should work well enough. I'm sure there are very respectable TL8 methods of glueing or cementing layers of metal together, which ought to be up to the task and cost the tiniest fraction of the total budget.

Of course, if you want to use separate individual pieces of steel alloys with different properties (harder and tougher for less complicated and less curved shapes), for which you otherwise might have to use methods similar to historical brigandines or segmented plate to achieve full coverage, but form them instead into a whole one-piece breastplate, your glue/cement will be the only protection for any Chinks, as well as being directly exposed to attacks rather than behind DR connecting two layers of armour.

Maybe some kind of synthetic laminate, ballistic plastic, epoxy-equivalent kind of thing, making an inner shell that secures the individual pieces in place?

Originally Posted by Rupert

As for face-hardening, it's main advantage is that you can harden the face without regard for its resilience, as the back of the plate provides that. In turn, the back of the plate need not be very hard, as the face provides the raw hardness.

TL6 and TL7 face-hardened plate was slowly baked in a furnace with carbon held against the front face (or blown over it as a carbon-bearing gas) so that the plate absorbed carbon, creating a plate with different levels of carbon front to back. The plate was then hardened, followed by the back being annealed to reduce hardness and improve toughness. Face-hardening was a replacement for compound armour where multiple plates with different characteristics were welded together.

I expect you could design a face-hardening regime for some modern alloys that would produce the same effect whilst taking advantage of the alloy's superior general characteristics. That said, a cursory search suggests that in plates under 3"/76mm thick face hardening vs simple RHA only adds 3-8% resistance.

Well, face hardening steel armour doesn't sound like it adds enough protection. Even RHA with +10% to +20% to DR by weight and thickness would need prohibitive amounts to provide rifle protection anywhere. The stats Pulver gives the best TL4 armour steel and TL6 'Hard Steel' are at this level of performance, and such steel alloys are not a practical ballistic body armour at TL8, though fine for vehicles (other than luxury automobiles or other wheeled vehicles where increased weight will quickly adversely affect performance and simply making thicker plates is thus contraindicated).

The flash bainite article Dan linked made claims of effectively 33% to 50% better performance than steels previously used for the same purposes, by weight and thickness, which would make it about equivalent to TL8 'Ultra-Strength Steel' from Pulver's 'CEAD' article in Pyramid #3/85.

AR500 and other equivalent steel alloys designed for ballistic protection, i.e. to resist High-Velocity Penetrators (HPVs), are rated for DR against piercing damage, at least, that's 50% (thickness) to 100% (best examples by weight) better than RHA steel. They're very hard to work with, especially for armouring complicated shapes, but maybe that's solved by making compound armour, with the outer, harder layer having less coverage.

Titanium alloys or various ceramics and composites are generally more effective in terms of DR than steel, at least by weight, but not necessarily by thickness. And for someone maybe twice as strong for his weight as a very fit human, maybe avoiding too much inconvenient and motion-restricting bulk is an equally important consideration as weight.

[Icelander]

Originally Posted by DanHoward

Scale armour is the least efficient of all the metal armour constructions. Weight:DR ratio is the worst. There aren't any modern materials or assembly methods that can change this.

I suspect that the 'Scale' armour construction method given in Pulver's article is meant to represent Pinnacle's DragonScale. More traditional reproductions of metal lamellar or scale armours might need to use different modifiers.

Edit: Nope, both 'Scale' and 'Segmented Plate' originally appeared in the 'Low-Tech Armor Design' article in Pyramid #3/52, with the same values, i.e. with 'Scale' being significantly lighter and cheaper for the same protection.

I have no idea why that decision was made, but while I think that the Low-Tech weights for DR 4-5 scale armour are on the high side for historical lamellar, I'm pretty sure that making TL4 brigandine a much inferior design to TL1 scale is going too far in the other direction.

[DanHoward]

Originally Posted by Icelander

I suspect that the 'Scale' armour construction method given in Pulver's article is meant to represent Pinnacle's DragonScale.

Which seems to be based on Pinnacle's hyped press release rather than empirical test reports.

[Icelander]

Originally Posted by Polydamas

Icefalcon (kind of ugly but takes a pounding, run by a SCA and IMCF fighter) and Armstreet (lots of bling, not always the strongest/most protective) are fine places to start. Lorifactor carries medieval bling, but more fancy belts than armour.

Yeah, Icefalcon are ugly. They are going to need that ability to take a pounding, as I can see the more fashion-conscious vatos making a point to hammer anyone wearing chunti armour.

Originally Posted by Polydamas

Armory Marek does some etching and gilding http://armorymarek.com/
ArtArmor -> ArmorySmith in Ukraine http://www.armorysmith.com/ has statistics and leans towards HMB armour

Ooh, they have a brigandine with the plates made from titanium! How modern of them. Titanium ot4 alloy, to be exact, which I'm not sure whether would get the stats for 'Titanium Alloy' in Pulver's 'CEAD', or whether it is a less impressive alloy than that and should use inferior stats (but still probably lighter than RHA steel for the same protection).

Originally Posted by Polydamas

Moving into the kind of people who have a 1 to 3 year backlog, Tomala, Piotr Feret, and Roman Terechenko of the depends-on-who-you-ask-ian Crimea (he just has a FB page).

Cool!

The hypothetical Ukrainian armourer NPC that this thread has given me the idea for would be from the Crimea. An apprentice at one of these armouries in 2011-2012, something like that, when Vargas was first reaching out, seeking to have armour for him custom made. HEMA/HMB style fighter, gamer, re-enactor and generally someone who'd be posting to this thread if he was real.

Maybe he was a machinist during his conscript service, if they trained conscripts in useful trades in the 2000s/2010s in the Ukraine, that is. Smart, imaginative, chronically short of money to do all the really cool things he wants to do. Maybe less wise than he is smart, with a penchant for getting into trouble and making ill-considered decisions that, in retrospect, might have had a bit of a skewed risk-reward analysis going on.

During his time as an apprentice with a custom armoury which Vargas was trying to get to build him a rifle-proof medieval-style plate harness, this NPC would have been really into the challenge and the cool factor of building a plate harness from high-tech materials, with modern manufacturing methods. With one thing or another, after having done some work for Vargas and his men for several years, he would eventually have moved to Mexico for the chance to put together his own workshop, working with some people skilled in using higher-tech manufacturing methods.

Also, there might have been other reasons he was not eager to stay in his home country after 2014. Not so much the chance of personal danger, which he quite likes, on occasion, but more painful personal experiences having to do with political and ethnic division amounting to civil war in some locales. It can be exciting in the abstract for a young man to contemplate going off to war to test his skills and match his courage against some imaginary scowling, ugly foeman with no discernable human characteristics. It's no fun at all to have to consider the reality of maybe having to shoot and be shot at by old school friends, a favourite coach, his in-laws or some distant cousins.

Originally Posted by Polydamas

Grettir the Slow is probably the most 'high tech' gauntlet maker who talks about his work in public: I think he uses computer-controlled kilns and other tools from his background as a machinist.

Awesome. I assume his name is like a SCA-handle or something, rather than him actually being Icelandic?

[seycyrus]

Originally Posted by Icelander

Ah, well, looks like hopes for a futuristic manufacturing process are dashed. Have to make do with a new method of hardening steel alloys more cheaply and easily, instead of an armour printer partway to Star Trek replicators.

Is there a reason you appear are shying away from ceramic body armor?

Originally Posted by Icelander

What is a good way to do it?

Assuming that you wanted to link together multiple pieces of steel alloys that have been hardened to BHN around 500 and are tough enough to make working with them really hard. You'd use softer steels for any part of the armour which required more complex shapes, but you'd want the breastplate to be one piece, even if not all of it was made from the same kind of steel.

Note, I'm assuming that using flash bainite to harden steel alloys that are easier to work with will eliminate the problem, as then the breastplate could simply be made as one piece (or at least the pieces connected before hardening).

Why not assume a process that can be used on pre-shaped pieces without affecting the desired properties for more common geometries. Your flash-bainite seems to be a good candidate.

Originally Posted by Icelander

I'm just wondering if you could get an extreme level of ballistic protection over the vitals by using gently curving steel plates of a hardness much higher than anything you were prepared to work with for areas requiring more complicated shaping.

Ceramic materials have hardness that are almost an order of magnitude higher than what you have been referencing. Of course, they have their own problems associated with them. Perhaps it would be best to assume some progress in addressing these shortcomings, if you were to include these materials.

Originally Posted by Icelander

Or, for example, using titanium alloys or composites as the interior (and not visible) layer of the rigid armour, with high-quality, hardened steel as simply the outer layer.

Some might argue that this is NOT what you would want to do, due to some Ti alloys tendency to spall on the rear surface when ballistically interrogated.

Originally Posted by Icelander

That would also require a way to combine different metals into a solid breastplate, somehow attaching them to each other, despite working with materials that would be impossible to cast and retain any of their desired qualities and at least extremely challenging to smelt.

How do you make an armour with an inner layer of titanium and an outer layer of steel, for example?

Or whatever modern MBT armours are made out of, as that seems to be several different materials somehow bonded together?

The joining of dissimiliar materials is problematic. Welding and brazing etc. can be used, but many good armor materials just aren't that weldable. Weakness in the joints and interfaces are generally bad, but can be catastrophic when you are talking about ballistic events.

Note: I believe that MBT's use RHA, with stuff on top to counter specific threats.

Originally Posted by Icelander

Is it something any workshop can do or an insanely expensive and hard thing to do with materials of this strength, something only huge military-industrial factories do?

There is a technology gap, it is not just a matter of throwing money at it. There are cycles in government funding which result in generals being able to say, "Give me the BEST body armor possible - DISREGARD cost.", that have not resulted in superduper ballistic "plate armor" that we are discussing.

I think what you are wanting would be assumed microleaps in technology in very specific areas either attained by sheer luck, or prodigy.

It looks like to me that we are talking about.

A) The steel (metals?) genius (lucky).

B) The making things stick together genius (lucky).

C) The guy who takes the above and makes them into an armor (ballistic) solution. Maybe this guy, had a stroke of luck decades ago, and was just waiting for technology drop to enable him to do it again. Or maybe it was just a theory all this time, up until now ...

[Icelander]

Originally Posted by seycyrus

Is there a reason you appear are shying away from ceramic body armor?

Well, they won't look very much like Knight Templar armour, for one thing. What's the point of being a wealthy drug baron if you can't get toys with absurdly impactical specifications?

Also, most modern ballistic inserts will be ruined by repeated impacts and not fixable by an armourer, but instead must be replaced. That is a very bad feature to have in a medieval style plate harness mostly designed to make you look really cool, which you will use for fighting in semi-improvised Historical Euopean Martial Arts full-contact matches, with other drug war sicarios using knives (quite expertly) and swords (at default from knives, probably).

Yes, Raul Vargas, El Jefe, the Big Boss, wants his plate harness to be functional SCA/HEMA/MHB armour and also have ballistic protection equalling modern body armour with inserts, but, that's mostly for similar reasons that he owns a stable of fine Andalusian horses, despite being a clumsy rider who rarely sees them, and why he has the inside of luxury SUVs finished in gold-etchings with engravings of himself as a conquering warlord.

In general, when someone from their faction of Los Caballero Templarios cartel uses body armour for their operations, as with the soldiers of any other cartel, they will use whatever modern tactical gear they have managed to acquire through corrupt military quartermasters, deserters, police or smuggling.

However, their inner circle has always included a disproportionate number of apparently delusional men with extremely cult-like practices and it has become fashionable among sicarios seeking to win the approval of their crazy warlord patrón to wear some cosmetic 'knightly' apparel and, in the most extreme cases, medieval style armour over conventional ballistic vests (and inserts if they can fit), even on raids using TL8 tactics and weaponry.

Trusted bodyguards of Vargas may have some intermediate step between these two technological solutions, i.e. something that looks fairly authentically medieval or Renaissance, but which will prove useful against pistols and maybe offer rifle protection to the vitals and upper torso.

Ok, sure, maybe knife strikes aren't going to break a ceramic ballistic plate all that often, but neither can I imagine that they can stand up as well against all the abuse involved in HEMA-style fighting as hardened, impact and wear-resistant steel alloys. Plus, it's just really sad if your ultra-fancy, decorated 'Black Knight' suit of armour gets shot and cracks into shards instead of just getting a little discolouration on a small spot.

Originally Posted by seycyrus

Why not assume a process that can be used on pre-shaped pieces without affecting the desired properties for more common geometries. Your flash-bainite seems to be a good candidate.

Excellent.

Originally Posted by seycyrus

Ceramic materials have hardness that are almost an order of magnitude higher than what you have been referencing. Of course, they have their own problems associated with them. Perhaps it would be best to assume some progress in addressing these shortcomings, if you were to include these materials.

No new materials or technological inventions. The only R&D involved is using materials and methods that are proven to be successful in fields with actual commercial applications and applying them to a very impractical vanity project, i.e. making medieval-esque armour with the hardness, strength and toughness of some very good modern alloys.

Originally Posted by seycyrus

Some might argue that this is NOT what you would want to do, due to some Ti alloys tendency to spall on the rear surface when ballistically interrogated.

Just a thought. It saves weight and the inability of Ti to be hardened to the same levels as various steel alloys actually used in ballistic armour (e.g. for vehicles) is less important if you don't use it for the surface facing the threats.

Originally Posted by seycyrus

The joining of dissimiliar materials is problematic. Welding and brazing etc. can be used, but many good armor materials just aren't that weldable. Weakness in the joints and interfaces are generally bad, but can be catastrophic when you are talking about ballistic events.

What about glueing or cementing different layers together? Layering with some kind of highly advanced, but commercially available plastic composite thingy to attach them to each other?

Making an epoxy, polycarbonate, laminated polycarbonate or any other, perhaps from stronger and more effective materials that can still be easily moulded, synthetic inner shell to hold individual pieces of outer breastplate together?

Originally Posted by seycyrus

Note: I believe that MBT's use RHA, with stuff on top to counter specific threats.

Including, or so I understand, steels with BHN with a hardness around 500 for those applications where resisting high-velocity penetrators is considered important. I think this is mostly for lighter vehicles, APCs, up-armoured 4WD trucks and the like, but I found some list of applications for such abrasion resistant steel alloys with extremely high hardness, which mentioned MBTs among such uses. No idea what MBT, when or from what country.

Originally Posted by seycyrus

There is a technology gap, it is not just a matter of throwing money at it. There are cycles in government funding which result in generals being able to say, "Give me the BEST body armor possible - DISREGARD cost.", that have not resulted in superduper ballistic "plate armor" that we are discussing.

I think what you are wanting would be assumed microleaps in technology in very specific areas either attained by sheer luck, or prodigy.

It looks like to me that we are talking about.

A) The steel (metals?) genius (lucky).

B) The making things stick together genius (lucky).

C) The guy who takes the above and makes them into an armor (ballistic) solution. Maybe this guy, had a stroke of luck decades ago, and was just waiting for technology drop to enable him to do it again. Or maybe it was just a theory all this time, up until now ...

We have any number of alloys in the real world which have the requisite protective value. They just mostly aren't used for body armour which looks anything like medieval plate harness, because no modern military has much need for such armour. That being said, there have been Russian body armours made from titanium alloys and other, less expensive, types of body armour are made from various steel alloys.

Which is why someone wanting a full harness of 'Black Knight' armour that can also resist rifle fire over the most vital areas, as a vanity project, needs to do the R&D and design work to figure out how to apply materials and methods developed for a variety of other applications to making body armour. Not to invent new things, but to figure out ways to make use of things that already exist to build something no one else has much use for. Ideally, they'd order off the shelf as much as possible, figuring out ways to do the rest themselves.

Mass-produced military issue armours can use inserts that are Semi-Ablative in GURPS terms and replace them as neeeded, for one thing. For another, performance in live steel fighting with swords is pretty low down on the list of requirements for military armour. And, of course, looking like a really badass Black Templar doesn't feature on military RFIs at all.

[seycyrus]

Originally Posted by Icelander

Well, they won't look very much like Knight Templar armour, for one thing. What's the point of being a wealthy drug baron if you can't get toys with absurdly impactical specifications?

Cutting edge ceramic plates cam take on more complex geometries besides flat. Breastplate-like at least. Put on a metallic coating, perhaps through a cold or thermal spray technique. It should take a bit of a shine.

Originally Posted by Icelander

Also, most modern ballistic inserts will be ruined by repeated impacts ...

Quite. This is one of the disadvantages that I referred to, but I am not sure how much ballistic value is lost by hitting it with a sword for instance. Even low velocity impacts move a lot faster than a swing or thrust.

Originally Posted by Icelander

Yes, Raul Vargas, El Jefe, the Big Boss, wants his plate harness to be functional SCA/HEMA/MHB armour and also have ballistic protection equalling modern body armour with inserts.

Not possible, without a stroke of innovative luck, or prodigy.

Originally Posted by Icelander

Ok, sure, maybe knife strikes aren't going to break a ceramic ballistic plate all that often, but neither can I imagine that they can stand up as well against all the abuse involved in HEMA-style fighting as hardened, impact and wear-resistant steel alloys.

I don't know. I've never seen a real study. I have hit SiC with a hammer over and over a few times and it shot just as well. Didn't look damaged either.

Originally Posted by Icelander

Plus, it's just really sad if your ultra-fancy, decorated 'Black Knight' suit of armour gets shot and cracks into shards instead of just getting a little discolouration on a small spot.

Damage localization is better than that. But even in your extreme example I'd suggest that the messy ceramic would be preferable to a slight discoloration. Because the slight discoloration would be around an entrance hole and an exit hole whereas the messy ceramic would stop the round.

Originally Posted by Icelander

No new materials or technological inventions. The only R&D involved is using materials and methods that are proven to be successful in fields with actual commercial applications and applying them to a very impractical vanity project, i.e. making medieval-esque armour with the hardness, strength and toughness of some very good modern alloys.

This type of sentiment is the one that seems to be confusing me. The US army(or whatever army you prefer) would dress its soldiers up in steel tutus if it worked, vanity be damned. There are NO "good modern alloys" that perform as well ballistically as the ceramics used. I am talking about the small calibre world here.

Originally Posted by Icelander

What about glueing or cementing different layers together? Layering with some kind of highly advanced, but commercially available plastic composite thingy to attach them to each other?

Making an epoxy, polycarbonate, laminated polycarbonate or any other, perhaps from stronger and more effective materials that can still be easily moulded, synthetic inner shell to hold individual pieces of outer breastplate together?

Ehh maybe. Bonds that work in the normal work, fail under ballistic load. This is floating into the world of technological innovation that you want to avoid. How many "ifs" are you willing to accept? It seems like 0 is what you want.(Although you already accepted the flash bainite that can take on any geometry).

Originally Posted by Icelander

Including, or so I understand, steels with BHN with a hardness around 500 ...

We have any number of alloys in the real world which have the requisite protective value.

What requisite protective value? Static hardness is certainly not the sole and probably not the primary consideration in ballistic protection. I'd be interested in any data that shows any alloys that have the ballistic performance of modern ceramic plates.

Originally Posted by Icelander

They just mostly aren't used for body armour which looks anything like medieval plate harness, because no modern military has much need for such armour.

Every modern military has the need for head-to-toe ballistic protection that can stop the best modern military rounds.

Originally Posted by Icelander

Which is why someone wanting a full harness of ... armour that can also resist rifle fire over the most vital areas, ... needs to do the R&D and design work to figure out how to apply materials and methods developed for a variety of other applications to making body armour.

This is the luck or prodigy part. Technical innovation at its best.

Originally Posted by Icelander

Not to invent new things ...

Making such things work together effectively in a new way IS a new thing. That is almost the definition of technological innovation.

[safisher]

Originally Posted by Icelander

Ah, well, looks like hopes for a futuristic manufacturing process are dashed.

I don't think that's the case. This is a fast moving field. Part density of 99% or more is now possible. All of these links below demonstrate various types of armor or body armor research, some of which were created and tested, with AM.

https://3dprintingindustry.com/news/...t-time-107151/

https://www.3ders.org/articles/20160...ody-armor.html

https://3dprint.com/56694/scale-inspired-body-armor/

https://www.cmtc.com/hs-fs/hub/10382..._opt_flyer.pdf

https://www.extremetech.com/extreme/...ace-chain-mail

https://books.google.com/books?id=Kp...0armor&f=false

This is a 3d metal printer for under $100k.
"According to Mark, the system is already capable of 3D printing with 17-4 and 303 stainless steel. The company has stated that other metals are already under development, including A-2, D-2 and M-2 tooling steel for injection molding, as well as 6061 and 7075 Aluminum and 6AL 4V Titanium."
I should point out here that tool steel is very hard steel, comparable to AR500, though not as hard.
https://www.engineering.com/3DPrinti...nder-100K.aspx

https://3dprint.com/178423/nanosteel...teel-material/

You can read here about the limits of the metal AM tech currently, and how those limits are being dealt with:
https://www.engineering.com/3DPrinti...-Printing.aspx

You'll be making an AM armor suit in the smallest pieces possible (in many, just as the same sizes you would make them by hand). It may be that you have to make the larger segments m in multiple pieces within the specs of the printer's dimensions. You'll then have to machine some of the pieces, possibly with a CNC machine, and/or heat treat the parts, as well. The you'll assemble them, possibly using 3d printed connectors, and possibly then coating the parts. In the end, there seems to be no fundamental obstacle to using the technology for the project, given these assumptions. It would be outrageously expensive, require exotic tools and skills, but not impossible.