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

[Polydamas]

Ok, so this thread has many interesting tangents, but I am trying to spend less time in front of a keyboard. seycyrus, DanHoward, Safisher and I all have slightly different perspectives that come from our experiences so are hard to explain in words, and trying to iron them out would distract from the fun of the awesome ideas in this thread. So I am going to focus on answering Icelander's questions about Vachyslay on page 14 where we cross-posted:

Originally Posted by Icelander

Great! You are quite right that he must, of course, be a devotee of Gothic armour.

Does that mean he'd have to do re-enacting around an appropriate period and cultural milieu, or can you mix and match; be a fan of Khlit the Cossack, Conan the Barbarian, LOTR and Alexander Nevsky?

I think that HMB/IMCF/BOTN have ideas about 'historical authenticity,' but like in the SCA that phrase means something special to them, and there are always people trying to pull in pop culture ideas. And I would expect a pretty high density of fans of fantasy and pulp adventure. I know that in Germany there are fairs and Schaufechter who seem to fill the same cultural space as the SCA does in the USA, complete with merchants selling imitation Weta Workshop products and 'barbarian lances' in beef, chicken, and tofo. So I am sure that the Ukranian medieval battles world has an end which is about metal music, drinking vodka between fights, and being Cossacks and barbarian princesses.

One of the pictures I pulled up checking how those Stahlhelme were made and how thick they are is someone at the Euromaidan in camoflage jacket and a Stahlhelm plastered with double-lightning-bolt SS, a Kalashnikov crossed with a MP40, and a Cyrilic label saying something about Putin and Hitler. So there is definitely some mixing of symbols! https://en.wikipedia.org/wiki/File:E...3-23_13-08.JPG

Originally Posted by Icelander

Also, how long does an apprenticeship last? Wouldn't he have spent some years working for someone else, even after becoming a competent armourer in his own right, as he was young, didn't have capital or an established reputation, etc.?

He moved to Mexico no earlier than 2015, as Vargas wasn't really in a position to house anyone until maybe the second half of that year. Very fluid situation, changes of allegiances and becoming his own master in name ad well as fact. He would have gotten his current home in the Juarez Valley in September 2015 or so, but with August where he knew he was settling down for good as the patrón of a profitable plaza (drug territory) and time during that month for re-organising and setting up for the future.

...

Play is set in February 2017, so he has been there for about a year and a half.

The timeline is not crazy, and mid-to-late 20s seems about the right age for "really good at what he does" but not "settled down with a wife and children or a good day job."

I would guess a few years working for that shop in Kyiv: one armourer got a Bachelor's Degree in art metalworking, another in Germany went through their Lehrling system, but mostly armourers teach each other and take classes on coppersmithing or blacksmithing and watch videos.

Originally Posted by Icelander

He's right. Especially if we assume both Spanish and English at Broken, with maybe a fair technical vocabulary about metallurgy, steelworking, fabrication and smithing, but a thick Ukrainian accent, atrocious grammar and poor vocabulary about the myriad of things he's not interested in. He couldn't talk himself out of a paper bag with airport security or border officials. Not to mention that the road to Ciudad Juarez (and airports, El Paso and the US) has a military roadblock, manned by soldiers that he's sure to have heard are on the CT cartel payroll.

And, yeah, he has no reason not to expect the worst from American spies, as there are sure to be rumours that Vargas is a defector from their famous Fuerza Especial and a wanted fugitive from the US, hunted by nearly supernaturally skilled killer SEALs in black helicopters, like the ones who got Osama bin Laden.

On the other hand, he might have had great-uncle who go live in Brighton Beach. Some cousins who live there now. Say it's not so bad. Cops are soft and judges softer. Almost never get murdered. More money in working garage than stealing back home.

If Vyachevslav was witness against cartel boss, he'd get new identity, like in movies. Maybe move to California, make proper armour for more Lord of Ring movies. Is good.

Of course, if Vargas really wanted, he could probably have a man killed in Brazil. California too. That would be easier. He was born there, grew up there and he knows a lot of people who come from Michoacán who moved there. Europe, however, probably not.

Ok, it looks like your tentative ideas and my tentative ideas work well together here. And of course, for someone with Obsession or Workaholic, leaving work is not easy.

After living in Mexico for a while, he might have heard of Ugo Serrano who is involved in the film, fetish, armouring/armoured combat, and wild-party world in California http://ugoserrano.net/bio/.

Originally Posted by Icelander

Mostly fits. I especially like his poor language skills. What we could do, actually, is use that as an explanation for why he got to know Vargas, not just a flunky, while he was still living in the Ukraine.

Vargas was an early recruit to Delta Force in 1977-1979 or so. Before that, though, he might have served in a Special Forces Group, as he probably didn't go directly from an airborne soldier to Delta (and he was never a Ranger). He spent his career mostly in the 7th SFG (A) after Delta and I frankly just assumed he'd started his career there. But what if he didn't? What if he initially served in a different SFG and when he went to Monterey, to the Defense Language Institute, the Army, in their infinite wisdom, entirely ignored his bilingual Spanish and assigned him to learn Russian?

I believe that a significant number of Ukrainians know Russian and despite Vyacheslav's poor facility for languages, maybe Russian was close enough to his native language to stick better in his head. Maybe having ethnic Russian friends and relatives helped. So maybe Vargas's secretary was not having any luck trying to communicate with someone who spoke awful English and no Spanish. And Vargas got impatient enough to write the next email himself, in quite good Russian, and soon found that using a phrasebook, dictionary and a feel for the language he picked up by becoming a connoisseur of Ukrainian porn, allowed him to adapt his Russian to more-or-less quasi-Ukrainian communication that worked better than trying to speak English with Vyacheslav.

That sounds plausible, especially for someone from south-eastern Ukraine who grew up in a port.

Originally Posted by Icelander

Bad Temper and Sensitive to Social Slights sound pretty dangerous around Vargas, though... Maybe better if he's slightly Impulsive?

Come to think of it, a near inability to be offended by subtle slights would be better. It would explain how he has not provoked a meth-addled killer into murdering him over some status tiff, which Vyacheslav didn't realise woudln't escalate to fighting, but murder. If he's basically oblivious about status and doesn't take part in their vying for favour at court, they'll all view him as crazy, but he'll provoke much less jealousy that way, as well as if he is basically good-natured and fun.

Yeah, I don't remember what GURPS calls blindness to low-level social clues (Clueless?), but that might be appropriate.

Maybe his quirk could be "susceptible to flattery" instead of "sensitive to social slights"? That might work better for someone with a basically cheerful disposition who knows that he is a great armourer and that is what matters. Vargas' 'social secretary' or 'handler' could assign a couple of thugs and a handful of party girls to tell Vyacheslay how awesome he is and steer him away from Vargas when il Jefe is in a bad mood.

I would give someone a bonus to their self-control rolls against Bad Temper to avoid offending their boss the violent psychopath.

Originally Posted by Icelander

As a matter of taste, I'd express his extreme dedication to his work as Obsession, not Workaholic. To me, Workaholic means that you'll perform any work you are assigned with the same intensity and fervour, but will not even have hobbies. Obsession about his craft allows Vyacheslav to devote the same passion to his fighting as his armoury, but to be pretty indifferent to most other things, including work that he technically had to do, but had nothing to do with being the best armourer he could (like all the things he had to do before, filing taxes, doing administrative work, turning out cheap decorative junk to make a living, etc.).

Obsession (build better armour!) would be fine too. My books are in the old country, but I don't remember whether it gives a reaction penalty like Workaholic.

Some of the party girls could have been assigned to help Vyacheslav with his Spanish and cheer him up after that thing with the pit bulls and the meatgrinder, and then one evening over irregular verbs and tequila his favourite started hinting about how Vargas and his sicarios break new girls in. So that could work with your idea that he wants to save his favourite girl, and maybe cut a bloody path through the narco hordes.

[Polydamas]

Originally Posted by Icelander

Well, what's the lowest weight that you would accept for the absolute finest, perfect fit, no wasted materials, field plate harness (without helmet, gauntlets, sabatons or any padding/underlayer), that covers most of the body with 1-1.5 mm thick armour, the fauld and pauldrons slightly thicker, has an armour of proof breastplate of around 5-7 mm and the rest of the cuirass somewhere around 3 mm thick?

These thicknesses will vary somewhat over the covered areas, but these are fair averages, and the thickness I'd be using to calculate DR.

Applying the full modifiers to the product of the 'CEAD' yields something about 40 lbs. Is that implausibly light for such armour, taking into account that the Fluting and Masterful Tailoring options assume that maximum use of made of shaping the armour to deflect likely threats, to strengthen the areas most likely to be hit at the cost of areas less likely to be exposed, etc.?

If you can't imagine such a harness being any lighter than 50 lbs. without helmet, then Masterful Tailoring gives too much of a weight reduction and Expert Tailoring ought to be the limit.

I would be happier with 50 lbs than 40 lbs. The Wallace A68, which is proofed against 17th century bullets in every part, weighs 23 kg (50 lbs) without anything below the elbows or the middle of the thigh.

I would say that saving 10% in weight is routine, the really good armourers today can probably save 20%, 30% makes me want to sing "we wouldn't say you're lyin' but we'd like to see it done (and you'll never meet your bounty on this hitch)." I wouldn't say its impossible, but I would not want to bet on it given the kind of time scale and budget you are talking about (especially since they don't have access to originals, and don't have good ways to geek out with other armourers, and they don't have a boss who understands that every change to the specification sets them back).

[Polydamas]

For a quick reality check, the Wallace A62 'Lord Buckhurst', which probably has those kinds of thicknesses (maybe a bit heavier in the arms, shoulders, and upper legs), weighs 36 kg with the reinforcing over-breastplate against bullets. These guys have better steels and heat-treatment than they did in the 1580s, and are probably just aiming to make the arms and legs proof against swords and fragments (some of those links early in this thread showed 40mm grenade launchers) but they don't have the living craft tradition or the community of peers or get to make nothing but 1580s English armour.

[Icelander]

Originally Posted by Polydamas

I would be happier with 50 lbs than 40 lbs. The Wallace A68, which is proofed against 17th century bullets in every part, weighs 23 kg (50 lbs) without anything below the elbows or the middle of the thigh.

I would say that saving 10% in weight is routine, the really good armourers today can probably save 20%, 30% makes me want to sing "we wouldn't say you're lyin' but we'd like to see it done (and you'll never meet your bounty on this hitch)." I wouldn't say its impossible, but I would not want to bet on it given the kind of time scale and budget you are talking about (especially since they don't have access to originals, and don't have good ways to geek out with other armourers, and they don't have a boss who understands that every change to the specification sets them back).

Originally Posted by Polydamas

For a quick reality check, the Wallace A62 'Lord Buckhurst', which probably has those kinds of thicknesses (maybe a bit heavier in the arms, shoulders, and upper legs), weighs 36 kg with the reinforcing over-breastplate against bullets. These guys have better steels and heat-treatment than they did in the 1580s, and are probably just aiming to make the arms and legs proof against swords and fragments (some of those links early in this thread showed 40mm grenade launchers) but they don't have the living craft tradition or the community of peers or get to make nothing but 1580s English armour.

This sounds like Masterful Tailoring might be theoretically possible enough to exist as a rules option, but not practical or plausible for the situation in the current case.

The team, as I currently imagine it, consists of Caló, Vyacheslav and two to three others, as well as any number of assistants with Machinist. The other team members would be the Texan machinist-fabricator, and a former mechanic / current grad student in metallurgy that Caló sent to college in 2012, to educate him as a potential senior assistant at the light armoured vehicle workshop, as well as help on the 'Black Knight' project. I might also have that guy have a friend from school, college girlfriend or thesis advisor he's recruited to provide expert advice on the metallurgy behind adapting the flash bainite process to making body armour as well as vehicle armour plates.

I do want Vyacheslav to have, in game terms, rolled a critical success when he built Vargas a suit of Gothic plate at the workshop in Kiev around 2011-2013. It explains why Vargas picked him as the armourer he believes in and why he is much more friendly with Vyacheslav than the other members of the team, all with much more marketable skills and higher paid.

Caló probably handled the contracts, but Vargas has probably given Vyacheslav much more lavish gifts than the others, their value coming out of Vargas' normal household budget, not the ca 1% of it I've specifically dedicated to making the armour, as the gifts weren't a part of the cost to get a live-in armourer, they are just Vargas amusing himself by gifting the out-of-place foreigner with fine stallions, expensive furs, gaudy jewelry and authentic historical artifacts bought at online auctions, like White Russian heirloom swords.

As the most perfect example of Vyacheslav's talent and the final flowering of his traditional armourer's craft before he switches over to harder alloys and other materials which he cannot work with without developing and learning new methods, which Low-Tech options would it be plausible to apply to it?

I was thinking it wouldn't have any exotic alloys, just the best steel he could forge in a classic forge, and it didn't come with gold, silver or diamond decorations, but was instead subtly beautiful for the elegance of its craftsmanship. It would be made of thick steel, pistol proofed as widely as possible, and the cuirass and massive helmet would be as protective as 'normal' alloys could make it. Not a direct copy of an extant plate harness, but an inspired combination of the best design features Vyacheslav had seen in all historical armour he had ever examined, online or in person.

The armour would have been contracted to be built, in name, by Vyacheslav's employer at the Kiev workshop, someone with a very good reputation in the field, but during regular email exchanges and then Skype talks over the course of the construction process, Vargas would come to see that the vision, commitment, passion and superior artistic talent were all coming from the less senior employee who handled the day-to-day work, and demand that Vyacheslav be officially put in charge of finishing the armour. In effect, the armour would have been his 'masterpiece'.

Vyacheslav would have finished his masterpiece at the end of 2013. No matter the craftsmanship and the best hardening possible with traditional forging, Vyacheslav couldn't have promised that steel used would be completely proof against rifle fire, however, not even the thick breastplate. Experiments with the same alloy, hardened to as similar levels by Caló Renteria and his assistants, would have shown that high-powered rifle rounds would penetrate that thickness of steel, though they might not always penetrate a backing of ballistic fabric afterwards. The thinner armour elsewhere, however, would probably not be thick enough to stop any rifle round and even with ballistic fabric backing, would probably inadequate protection from typical threats.

Which is why Vargas continued his project despite having gotten the GURPS equivalent of Very Fine plate armour and, when circumstances altered in Mexico between 2014-2015, and Vargas found himself moving to a new place, with more power and autonomy, if technically slightly less revenue, convinced Vyacheslav to move there and see if he could not improve on his masterpiece armour using the best modern tools, methods and materials.

I guess I want Vargas and Vyacheslav to be friends, as far as Vargas is capable of friendship, and give Vyacheslav reasons to love Vargas for his open-handedness, charm, shared hobbies, demonstrated trust and genuine, if untutored and unsystematic, appreciation of his craftsmanship and the artistry of a traditional armourer. I think it makes for a far better dynamic if Vyacheslav loves his charismatic, domineering and mercurial patrón almost as much as he hates the horrible, despicable things he comes to learn Vargas does.

Especially if Vyacheslav is romantic enough to be considering a range of dangerous actions to rescue his Dulcinea even before maybe encountering PCs, and, in imaging a cinematic mano-a-mano confrontation between the wicked patrón fallen from his pedestal and his rebellious subject filled with justified wrath, thinks that having studied historical swordsmanship much more intensively than Vargas will somehow matter in a real fight to the death with a hardened killer who uses machine guns for actual combat. Always good to give players the possibility of potential allies who bring almost as much trouble as aid.

[Icelander]

Originally Posted by Micahel Silverbane

Right. According to This video Flash Bainite steel can be cold stamped into some pretty intricate shapes.

Depending on the steel alloy you start with, there exist flash bainite steels for many applications. The ones with the highest DR per inch and for weight in GURPS terms are also the ones most difficult to work with.

The flash bainite process can be used to turn out various different grades of armour steel in GURPS terms. Anything from the equivalent of TL4 armour steel or the equal of RHA steel to TL6 'Hard Steel', TL7 'Steel, very hard' or TL8 'Ultra-Strength Steel' in terms of David Pulver's Pyramid articles on armour design.

I'm looking to determine which of these approximate grades are easily shaped into articulated plate armour with high-quality, but commercially available, tools and machines suitable for a finely appointed custom machinist workshop or specialised small factory at late TL8, and at what point the hardness levels are high enough to require literal cutting-edge steelworking technology, usually present only in very large, high-tech manufacturing applications, with factories costing hundreds of millions of dollars.

[Icelander]

Originally Posted by safisher

"With superior weldability, lighter weight, improved workability, and strength levels never before seen, Flash® Bainite is truly the future of steel."

This is high strength 4130 steel, perfectly useful for making exceptional medieval armor. It can be welded and will be die formed if they are suggesting using it for aurtomobiles.

Would you call 4130 steel TL6 'High-Strength Steel' in 'CEAD' terms, i.e. approximately equally protective as RHA steel?

Or would it be TL6 'Hard Steel', slightly more protective (ca +10-20%) and slightly more expensive ($3.50 vs. $3 in 'CEAD') than RHA steel?

I expect that the flash bainite process effectively upgrades it by a grade or two in 'CEAD' terms. So 4130 steel treated by the flash bainite process will be somewhere between the protective value of TL 6 'Hard Steel' and TL8 'Ultra-Strength Steel', very probably and conveniently somewhere about the value of TL7 'Steel, very hard'.

Originally Posted by safisher

The AR500 stuff is likely only going to work for a breast/back plate, I suspect.

Yeah, I think I'll accept that they might find a way to make at least the breastplate and backplate out of 'Flash® 500', or an identical in game terms variation on that alloy. A full plate harness made from it or something ever harder* is their ultimate goal, at least, and I figure that they should have reached at least something approaching that, with at least the pieces of armour simpler to shape being quite hard and tough.

Going by side by side ballistic armour testing and other comparisons I can find to titanium-6Al-4V (which I figure is the TL7 'Titanium Alloy' in 'CEAD'), 'Flash® 500' has the stats of TL8 'Ultra-Strength Steel' (it seems to be within 1-2% for all points of reference I can find).

Would it be possible to use the flash bainite process to harden finished pieces of armour, rather than starting with very hard steel alloys and trying to work them into complex armour pieces?

*Going by its performance in US Army testing, AR600 would have WM 0.2 and DR 200+ per inch, at least for ballistic threats, though possibly it has higher DR against piercing than crushing, with maybe 'only' effective WM 0.3 and DR 120-150 per inch for other threats.

Originally Posted by safisher

Assuming the workflow is like I said, maybe a week.

Cool, so most likely anyone among the senior leadership and full-time sicarios of the Caballero Templarios who wants a functioning plate harness for live steel fighting has one that was made in house, by this time. They've had their full set-up, including specialist body armour workshop and the light armoured vehicle factory, with its licensed tooling and machines for the flash bainite process, up and running for more than a year by the time our characters visit Mexico.

I expect that the less senior sicarios have opted for simplified designs of plate armour, made out of whatever steel alloys allow the fastest and most efficient manufacture. That will probably be, in 'CEAD' terms, either TL6 'Hard Steel' or TL7 'Steel, very hard' (from Pyramid #3/52) for the articulated joints and other hard to armour areas and/or maybe smaller plates of high hardness steel, in a brigandine design of overlapping plates.

Originally Posted by safisher

I don't work with ballistic steel. I can't say. I have worked with tool steel, which is very hard, and it typically needs to be annealed before working, and then re-hardened and tempered. Look up D-2 tool steel, for example.

In terms of DR per inch or the weight of a square foot of armour plate per DR, where would it fall on the 'CEAD' scale of rough grades of steel alloys?

WM is the weight per point of DR of a square foot of protection. DR/inch, is, well, the DR for an inch of armour plate made out of that alloy.

'Iron, cheap' (TL2): WM 0.8; DR/inch 52.
'Iron, good' (TL2): WM 0.6; DR/inch 68.
'Steel, strong' (TL3): WM 0.58; DR/inch 70.
'Steel, hard' (TL4): WM 0.5; DR/inch 81.
'High-Strength Steel' (TL6): WM 0.58; DR/inch 70.
'Hard Steel' (TL6): WM 0.5; DR/inch 82.
'Steel, very hard' (TL7): WM 0.45; DR/inch 90.
'Ultra-Strength Steel' (TL8): WM 0.35; DR/inch 116.

For comparison, some other alloys:

'Aluminum' (TL6): WM 0.45; DR/inch 31.
'High-Strength Aluminum' (TL7): WM 0.4; DR/inch 35.
'Titanium' (TL7): WM 0.4; DR/inch 57.
'Titanium Alloy' (TL7): WM 0.35; DR/inch 66.

[johndallman]

If you're willing to dig into armour technology beyond the simplified GURPS model, it may be worth considering "cemented" steel. This is somewhat similar to what the flash Banit process is doing, but also involves adding carbon to the outer face of the armour.

This can produce a surface that is very hard indeed, and can only be worked by grinding, so you do it after shaping the armour. The downside is that the very hard face is somewhat brittle, which may mean you end up with a split DR, higher vs piercing than cutting or crushing.

The canonical process for this is Krupp Cemented armour. It was devised for warships, and may not be practical for human armour, but failed ideas at least add detail.

[safisher]

Originally Posted by Icelander

I expect that the flash bainite process effectively upgrades it by a grade or two in 'CEAD' terms. So 4130 steel treated by the flash bainite process will be somewhere between the protective value of TL 6 'Hard Steel' and TL8 'Ultra-Strength Steel', very probably and conveniently somewhere about the value of TL7 'Steel, very hard'.

It's hard to know the exact benchmarks for FB to the others, but I'd say that would be close enough.

Yeah, I think I'll accept that they might find a way to make at least the breastplate and backplate out of 'Flash® 500', or an identical in game terms variation on that alloy.

The main thing with FB is ease of use and cheap price. Bainite is not new.

Would it be possible to use the flash bainite process to harden finished pieces of armour, rather than starting with very hard steel alloys and trying to work them into complex armour pieces?

From what little I know about FB, sure.

Going by its performance in US Army testing, AR600 would have WM 0.2 and DR 200+ per inch, at least for ballistic threats, though possibly it has higher DR against piercing than crushing, with maybe 'only' effective WM 0.3 and DR 120-150 per inch for other threats.

I've said before that we I think the fundamental problem with GURPS armor designed for hand weapons, rather than on the vehicle scale, is that it's likely that comparatively thin armor still provides good protection at lower DR ranges against hand weapons. Take a typical glossy newstand magazine (Popular Science, etc.) and hold it up with one hand and stab it or slash it with a knife with the other. It ought to give say DR2-3. Versus a .22 it's no DR. Same thing with a typical leather jacket, where you'd be hard pressed to cut through it a knife. The difference between a light leather jacket and heavy one is 1 DR? As it is, the whole things a wash based on the two scales.

That will probably be, in 'CEAD' terms, either TL6 'Hard Steel' or TL7 'Steel, very hard' (from Pyramid #3/52) for the articulated joints and other hard to armour areas and/or maybe smaller plates of high hardness steel, in a brigandine design of overlapping plates.

There's no reason to not give everyone the same thing, once you've set up the process.

In terms of DR per inch or the weight of a square foot of armour plate per DR, where would it fall on the 'CEAD' scale of rough grades of steel alloys?

I'd say it's a TL7 steel veyr hard.

WM is the weight per point of DR of a square foot of protection. DR/inch, is, well, the DR for an inch of armour plate made out of that alloy.

'Iron, cheap' (TL2): WM 0.8; DR/inch 52.
'Iron, good' (TL2): WM 0.6; DR/inch 68.
'Steel, strong' (TL3): WM 0.58; DR/inch 70.
'Steel, hard' (TL4): WM 0.5; DR/inch 81.

I've argued before that I think these are wrong. There's never been enough tests to confirm that hard TL4 steel even exists. Based on some tests it's very shoddy by comparison to modern steels. But I degress.

'High-Strength Steel' (TL6): WM 0.58; DR/inch 70.
'Hard Steel' (TL6): WM 0.5; DR/inch 82.
'Steel, very hard' (TL7): WM 0.45; DR/inch 90.
'Ultra-Strength Steel' (TL8): WM 0.35; DR/inch 116.

I'd like to know what grades the benchmark for the TL7 and TL8 steels are, but all we can do is guess.

[Rupert]

Originally Posted by johndallman

This can produce a surface that is very hard indeed, and can only be worked by grinding, so you do it after shaping the armour. The downside is that the very hard face is somewhat brittle, which may mean you end up with a split DR, higher vs piercing than cutting or crushing.

The extremely hard face is backed by the flexible back, though, and as the back part doesn't have to worry about hardness as much, can be tempered for optimal springiness and toughness. It might get a DR reduction vs. crushing because thin pieces like body armour don't give much metal to work with, but vs cutting the very hard face should work very well.

My main concern with face-hardened armour for body armour is that it'll be quite hard to effectively do to thin pieces, and as there's little research on such applications just how deep to infuse the carbon and how hard to temper the face will be entirely novel territory for the armourers. Also, face-hardening all those intricate parts of a plate harness would be a right pain, and has to be done after they are shaped.

[safisher]

Originally Posted by Rupert

Also, face-hardening all those intricate parts of a plate harness would be a right pain, and has to be done after they are shaped.

A lot of tools and knives are case-hardened like this. Differential heating will cause problems in any heat treatment, and alloy steels like 4130 are tricky. (knives are easier than swords because of this.) What's needed is a forge big enough to put the whole pieces in and most forges are not that big. Mine is about a foot square. I could do bigger pieces in my coal forge, but I have less control over my coal forge. (It's a real pain to work with!) So to do this sort fo face-hardening you need a special forge and a special craftsman than can figure out how to face-harden very thin pieces without differential heating and without burning the plates all the way through. Tricky! Flash bainite looks better all the time.