Where to find information on material DR

[SClay]

A player brought up an obvious but glaring oversight in my knowledge. He wanted to consider various metals for armor or weapons.

Like Brass swords or armor of a given type VS Iron or steel of the same type sword or armor

I have assumed the mass change is negligible enough that damage really won't change in most cases, though it should affect DR of an object and possibly it's ability to keep an edge.

Is there a good place to find this kind of info. and while I am at it I guess I should go ahead and expand my knowledge to common Fantasy materials if possible such as Mythral.

[johndallman]

Originally Posted by SClay

A player brought up an obvious but glaring oversight in my knowledge. He wanted to consider various metals for armor or weapons.

Low-Tech, pp. 106-110 has solid historical information. Brass is not significantly different from bronze for these purposes, although bronze is easier to make in predictable quality grades without advanced metallurgy.

Mithril and other fictional metals are defined by the GM or the setting. Fantasy has an example in Orichalcum. on p. 26.

[Anaraxes]

Dungeon Fantasy 1 has some more fictional materials for armor and weapons (silver, dragonhide, orichalcum, meteoric iron). Also fantasy ethnic cool adjectives like "Elven" and "Dwarven". Your setting can of course do whatever you like with the adjectives; SJG publications stay away from stepping on toes with some specific words like "mithril".

Superior metallurgy like better steel is usually lumped into the Fine / Very Fine categories.

The tables on B558 aren't specific to weapons and armor, but might give you some ideas of how some stranger materials compare so you can scale the Basic stats accordingly.

[SClay]

Thanks, that is a good place to start.

I saw the things in BS and they seem to scale up well but they do not scale down well. Armor is not normally half inch thick and if I scale it down then it seems no better than leather.

As far as fantasy materials yes it is my call in the end but if I can have a base to start from then I can make a more uniform informed call

[zoncxs]

Low tech is great because it breaks down what material can be used to make armor, but it only goes for the mundane/realistic stuff. Dungeon Fantasy 8 has more fantasy stuff in it. A few Pyramid Articles have even more material (The ones that have the armor design articles for high tech and ultra tech). I think Fantasy Tech 1 and 2 have a few more materials (I got Azzalum from one of those I think).


Here is what I have:

ARMOR

Bone/Horn, Dragonbone/horn
Cloth, Silk, Giant Spider Silk
Leather, Dragonhide
Wood, Spirit Wood, Paper
Stone, Jade, Tempered Glass
Metal(Steel), Bronze, Iron, Orichalcum, Azzalum, Meteorite



WEAPONS

Wood
Horn/Tooth
Bone
Stone
Obsidian
Bronze
Iron
Steel
Tempered Glass
Orichalcum
Spirit Wood
Dragonbone/horn
Azzalum
PoisonWood
Poison Metal


How much DR does each have? irrelevant for armor, but for weapons it matters. This is because for armor you are aiming for a specific DR rating (usually between 1 and 9). So what matters their is how much the weight changes or any other effects. For example Orichalum, as a weapon it "won't break" and other weapons have +2 to their chances of breaking (so instead of 1 in 6 its 3 in 6 for most weapons). As armor it reduces the weight to only 1/3 but at 30x the price.

So a DR 6 plate torso armor costing $3000 and weighing 21 lbs (mostly made up numbers) would be, as an Orichalcum one, $90,000 and weigh 7 lbs. The cost would be a lot more if you wanted to keep the same weight (21 lbs) because you would need to start with armor that is 63 lbs.

Shields are unique, the CF is +149 instead of +29. This is because you first need to make the shield metal (+4 CF from either Low Tech 2 to make it metal or from DF to make it "Dwarven"), then you make it Orichalcum. 1+4 = 5 *30 = 150.

DF has the weight reduction be 2/3 instead of 1/3 because you first make it "dwarven" which doubles the weight, THEN Orichalcum which reduces it to 1/3, which leaves you at a weight that is 2/3 the original. (if you started at 9 lbs, double to 18 lbs, then 1 third of that is 6 lbs which is 2/3 of 9 lbs). If you use Low Tech then the weight is 0.25 the original (3/4 times 1/3 is 1/4)

[SClay]

Interesting reasoning. rather than use the same amount of a material to get a different DR you change the amount of the material to get the same DR.

While this has its uses doesn't this mean that where damage is concerned there is no point in using higher grade materials?

what if you pile on the tougher material till it is comparable weight to the original, how would you calculate the gains? they can't be linear if that were the case a sacrifice in weight you would have three times the DR. that seems excessive.

I want to state I am not planning to do this but sometimes players want to break things and knowing in advance helps damage control.

[SClay]

I think DR is a reflection of material hardness/toughness and
HP is a reflection of its mass.

you would have to flub numbers for imaginary materials with greater than or less than a real counterpart but this seems to be a rational way to go about coming up with the numbers.

[Rupert]

Originally Posted by SClay

Interesting reasoning. rather than use the same amount of a material to get a different DR you change the amount of the material to get the same DR.

While this has its uses doesn't this mean that where damage is concerned there is no point in using higher grade materials?

what if you pile on the tougher material till it is comparable weight to the original, how would you calculate the gains?

You can do this with plate in Dungeon Fantasy and with plate, segmented plate, and brigandine in Low-Tech.

Doing this with a LT heavy plate breastplate would mean it goes from DR3, 8 lbs, and $1,000 up to a maximum of DR14, 52 lbs, and $6,500.

[Anaraxes]

Canonically, you add the DR of multiple layers (B286); also, DR of objects is rated per inch (B559). So, doubling thickness doubles DR.

I'd just use the layering armor rules for thicker armor. Since such isn't really two layers, I'd ignore the bit about the "inner" layer needing to be flexible when you're talking about double-thick plates. So, just linearly scaling DR, as well as multiplying weight.

One useful modern material for this purpose is aluminum. There are alloys that are nearly as strong and tough as steel, but 1/3 the weight. So, you could double the thickness and get 2xDR (minus a bit) for 2/3 the weight. Normal low tech isn't going to produce aluminum, of course, but you could put it in if you wanted to handwave around magic (to supply the electricity if nothing else) or are happy with mysterious secret techniques. I used aluminum once for a fantasy game where the iron-averse fey needed some alternative materials.

(I also made up a rule for osmium / iridium plating, just because that stuff is so dense. In that game, I just gave the plating a small +DR and a ridiculous price tag. But at least you didn't have to touch the steel underneath, and fey nobles got to show off their wealth. Weird realms of faerie get to be weird.)

There is of course a practical limit to increasing thickness. You can't make your super articulated plate just by making each plate 100x as thick, no matter how strong you are. You'll need to redesign the way the pieces fit and interconnect, at the least. At that point you're into the gadgeteering and invention rules.

Which is just as well, because as long as the changes are limited to a small factor, 2-3 in either direction, you don't have to worry as much about the performance of the material qualitatively changing. It's no doubt true that DR isn't a linear function of thickness over all possible thicknesses of all possible materials. But it's close enough to true (for me, anyway) not to sweat the difference.

And if you are looking at those factor of 5, 10, 50, 100 differences in thickness and DR, then you're into the realm of Rule of Cool and supers costume design anyway, so again there's not much reason to sweat exact realism of the physical simulation.

[Plane]

one thing I'm interested in about "conductive metal" as a characteristic of the exotic advantage "Damage Resistance" is whether or not that would be a limitation of some kind to DR, or represented as some kind of separate fixed-cost disadvantage.

B105 for example has "Surge" interact with things that have the Electrical disadvantage...

PU4p21/PP19 is basically not a penalty at all if you only have DR 1 that's from conductive metal, it just reduces higher amounts to DR 1.