Heat Metal metallurgical question

[Pentallion]

This is beyond my scope of knowledge.  My players are discussing the idea of their shaman casting Heat Metal (it's not in RQG, but it's in RQ3 as a Lodril spell, so I allowed it) on a spear tip and using the shaman power of spell extension to make it last for as long as they want it to.  Not hot enough to melt the spear, but hot enough to get the extra damage should the spear impale (I ruled the idea of Heat Metal is the damage comes from being exposed to the metals heat an entire round, so it would take an impale to get any damage out of it).

My question to any of you grognards out there with metallurgy, is how hot is too hot for bronze/iron that prolonged exposure would weaken the spear?

[metcalph]

RQ3 p83 (big Book) had the following values for the melting point. 

Zinc 4D6

Aluminium 6D6

Bronze 8D6

Silver 9D6

Rock, Glass  12D6

Nickel 14D6

Iron 15D6

I'd saw that the softening point is one or two d6 below that point (ie Bronze becomes soft with a heat of 6D6).

 

[soltakss]

Yeah, what @metcalph says would work well. You could also just halve the D6s for a less powerful version, so Aluminium would become softer at 3D6 but Bronze would top out at 4D6 and Iron would stand 8D6.

Whichever you prefer would work.

[jps]

41 minutes ago, Pentallion said:

I ruled the idea of Heat Metal is the damage comes from being exposed to the metals heat an entire round, so it would take an impale to get any damage out of it.

 

If you take the RQ3 version, don't forget that it is a touch spell, nothing prevents your player from casting this variable spell on the opponent's metal armor, dealing 1D6 damage per "level".

In this case, the damage will be dealt each round until the armor is removed.

[soltakss]

13 minutes ago, jps said:

If you take the RQ3 version, don't forget that it is a touch spell, nothing prevents your player from casting this variable spell on the opponent's metal armor, dealing 1D6 damage per "level".

Sure, but you have to overcome POW/Magic Points for it to work. But it's a good attack spell.

[David Scott]

Heat Metal is still part of Lodril's cult spirit magic in RQG and will appear in GoG. It's got a better scale, so you don't need ridiculous levels to melt bronze. Still variable with 1point being too hot to hold and 1D6 damage per round. At level 5 Bronze, copper, gold, and silver become workable at 6 they melt. Takes a minute to become red hot. So level 4 would have bronze red hot, but not soft and 4D6 damage per round of contact.

Remember it's the shaman who controls the spell extension and it's one spell per level (I'm sure the shaman has better spells to keep up permanently, like countermagic, protection glamour or vigour ). If they aren't around, you would have to use dispel magic on it or be really careful putting it down or inside any normal building. At night it would glow.

[Joerg]

1 hour ago, David Scott said:

Heat Metal is still part of Lodril's cult spirit magic in RQG and will appear in GoG. It's got a better scale, so you don't need ridiculous levels to melt bronze. Still variable with 1point being too hot to hold and 1D6 damage per round. At level 5 Bronze, copper, gold, and silver become workable at 6 they melt. Takes a minute to become red hot. So level 4 would have bronze red hot, but not soft and 4D6 damage per round of contact.

Speaking as a chemist with lab experience, "too hot to hold" means "I will rather take 2 points of heat damage to the hand than 2D6 acid damage from dropping this hot vessel.."

 

There are also tricks around handling too hot items. Robert Bunsen famously held blobs of liquid lead in his hand by letting them move around, not staying long enough in one place to do any damage.

You don't have to be Man-and-a-Half to be able to handle something too hot to handle. (And in case any of you who met me in real life might accuse me of sharing some of that ability due to my size, I am way too pale to fit into that niche, and I drink way too much tea to qualify.)

 

1 hour ago, David Scott said:

Remember it's the shaman who controls the spell extension and it's one spell per level (I'm sure the shaman has better spells to keep up permanently, like countermagic, protection glamour or vigour ). If they aren't around, you would have to use dispel magic on it or be really careful putting it down or inside any normal building. At night it would glow.

All it takes to keep it from lighting everything is a clay jar that easily fits around the weapon.

If this is limited to a single, signature party item, why not allow it. The Temple of the Wooden Sword set an example how heroic parties ignore limiting rules.

[womble]

Your spear shaft would have to be made of something pretty special to avoid becoming frangible charcoal in the socket of the head, and breaking off as soon as it struck anything with even small force. Firespear (another Lodrili spell) is meant to be cast on fighting weapons, is Rune Magic and could be Extended to year-long duration (followed by a short downtime before it gets recast, and the spear shaft wouldn't suffer, because the effect is 'designed' that way. Repurposing a Heat Metal as an ersatz Boon of Kargan Tor should take a similar investment in time, sacced POW and MP.

[Darius West]

You will be pleased to know that Heat Metal is a spell featured in the forthcoming RuneQuest: Gods of Glorantha.  Presently the spell softens bronze at 5pts and melts it at 6pts. 

[Brootse]

On 2/14/2019 at 11:52 AM, metcalph said:

RQ3 p83 (big Book) had the following values for the melting point. 

Zinc 4D6

Aluminium 6D6

Bronze 8D6

Silver 9D6

Rock, Glass  12D6

Nickel 14D6

Iron 15D6

I'd saw that the softening point is one or two d6 below that point (ie Bronze becomes soft with a heat of 6D6).

 

I checked that table recently to see what one of my players' wizards can melt with his Finger of Fire, and realized that the melting point damage dices are the melting points in celsius degrees divided by hundred.

[RHW]

On 2/14/2019 at 11:44 AM, womble said:

Your spear shaft would have to be made of something pretty special to avoid becoming frangible charcoal in the socket of the head, and breaking off as soon as it struck anything with even small force.

I was going to point this out as well. If secured to a wooden spear shaft, the shaft would smolder and then burn. If the shaft is metal, the heat from the point would be conducted and the wielder would burn her hands too. Leather or rope wraps aren't going to last long either.

Why not just extend a Fireblade spell?

[Joerg]

1 minute ago, RHW said:

I was going to point this out as well. If secured to a wooden spear shaft, the shaft would smolder and then burn.

Not so sure about fire hardened spears whose contact area would already be charcoal.

1 minute ago, RHW said:

If the shaft is metal, the heat from the point would be conducted and the wielder would burn her hands too.

Metal spear shafts defy the purpose of spears - to save the valuable metal for the business end.

1 minute ago, RHW said:

Leather or rope wraps aren't going to last long either.

Depends on the leather. Thinking of Gloranthan associations, horse hide and feathers might be a good isolator against strong heat, as they belong to fire creatures.

 

My thought on this is "why bother with heating metal if you can have lava?" If you have to heat the spear point to get the lava, you will have something like obsidian when cold. Pretty useful, too.

1 minute ago, RHW said:

Why not just extend a Fireblade spell?

Fireblade doesn't do double damage on impales.

[HreshtIronBorne]

Why wouldn't fireblade double on impale?

[Richard S.]

Wouldn't Firespear do pretty much the same thing as casting Heat Metal on your spear but without the danger of melting it? I don't see the reason for using Heat Metal in that case.

Edited March 28, 2019 by Richard S.

[RHW]

1 hour ago, Joerg said:

Fireblade doesn't do double damage on impales.

That may have once been true, but I don't see that anywhere in the new RQG rules. Just says Fireblade damage can't be resisted because it's real physical damage, damage bonus applies, incompatible with Bladesharp. Seems like an impaled or slashing Fireblade would both do 6d6.

[Kloster]

2 hours ago, RHW said:

That may have once been true, but I don't see that anywhere in the new RQG rules. Just says Fireblade damage can't be resisted because it's real physical damage, damage bonus applies, incompatible with Bladesharp. Seems like an impaled or slashing Fireblade would both do 6d6.

Description is (almost) the same as the one in RQIII: No change in the rules, and impales or slashing are possible. I don't have my RQ2 at hand, so I can not check, but I think there was no possibility of impale in it.

[RHW]

4 minutes ago, Kloster said:

Description is (almost) the same as the one in RQIII: No change in the rules, and impales or slashing are possible. I don't have my RQ2 at hand, so I can not check, but I think there was no possibility of impale in it.

Firearrow is the one that can't impale, which is still true of RQG. Probably the source of confusion.

[Kloster]

14 minutes ago, RHW said:

Firearrow is the one that can't impale, which is still true of RQG. Probably the source of confusion.

You're right, probably.

[Steve3742]

5 hours ago, Joerg said:

Not so sure about fire hardened spears whose contact area would already be charcoal.

But they're not tipped with bronze. And, at any rate, charcoalisation is a process that continues when you get wood hot enough. The rest of the spear, not just the tip, would turn into charcoal over the course of weeks. Soft, coal-like charcoal, the stuff you put on your barbecue. 

And that's assuming you kept the spear deprived of oxygen. The temperatures we're talking about here are enough to ignite wood.

My feeling is that this couldn't be done with a wooden-shafted spear.

[Joerg]

5 hours ago, Steve3742 said:

But they're not tipped with bronze.

Duh. It should have been clear from the context that the charcoal hardening was to be below the metal.

5 hours ago, Steve3742 said:

And, at any rate, charcoalisation is a process that continues when you get wood hot enough. The rest of the spear, not just the tip, would turn into charcoal over the course of weeks.

You can take a metal frying pan from the stove and place it on wooden surfaces without reaching that brittle structure. You wouldn't heat the metal tip to the melting temperature, meaning that your bronze spear would only have very weak red glow, if visible at all.

Yes, there will be wear on the spear shaft, and some maintenance, but the wood away from the massive metal tip won't be subjected to charring temperatures.

5 hours ago, Steve3742 said:

Soft, coal-like charcoal, the stuff you put on your barbecue. 

Rather "hard and brittle". Always depending on the wood used in the process.

5 hours ago, Steve3742 said:

And that's assuming you kept the spear deprived of oxygen. The temperatures we're talking about here are enough to ignite wood.

Wood with volatile flammable exhausts (like methanole), sure. Once you have gotten these out by careful charring, we are talking about ignition temperatures of charcoal, which takes some encouragement (and forced aeration) to get started.

5 hours ago, Steve3742 said:

My feeling is that this couldn't be done with a wooden-shafted spear.

My opinion is that most soft woods are unsuitable, but guess what - this lumber is unsuitable for long-lived spear shafts anyway. What may be tolerable in javelins and arrows to allow some flexibility that same flexibility is unwanted when you push about a pound of shaped metal at some distance from you.

[Steve3742]

16 hours ago, Joerg said:

Duh. It should have been clear from the context that the charcoal hardening was to be below the metal.

Well then, you've invented an entirely new process. Spears are normally fire-hardened or tipped with metal. You're saying do both. Lets see if that would work.

16 hours ago, Joerg said:

Rather "hard and brittle". Always depending on the wood used in the process.

These guys here tried making some fire hardened spears and found that it became rather soft. At any rate, even if they're hard and brittle, this means the spearpoint - which you've attached a bronze head to - is likely to snap off. This is probably why people don't do both - metal tipped spears are much more effective than fire-hardened ones and fire-hardening a spear and then attaching a metal head to it is worse than useless, as it actually weakens the area you've attached the head to, not something you want to do. My point about this spell is that it's like a continuous fire-hardening, weakening the area the metal is attached to continuously.

16 hours ago, Joerg said:

You can take a metal frying pan from the stove and place it on wooden surfaces without reaching that brittle structure. You wouldn't heat the metal tip to the melting temperature, meaning that your bronze spear would only have very weak red glow, if visible at all.

Sure. But the metal frying pan starts to cool down the moment you take it off the stove. This bronze tip will be at full temperature all the time. And it might be below the melting point of bronze - 6D6 instead of 8D6 - but that's still 600 degrees Celsius. Enough to charcoal wood (if it's deprived of oxygen), enough to ignite wood if it's not (430 Celsius should ignite most wood in a minute or less) or even charcoal (which should start burning at 349 C.)

Really can't see this working.

[Joerg]

11 hours ago, Steve3742 said:

Well then, you've invented an entirely new process. Spears are normally fire-hardened or tipped with metal. You're saying do both. Lets see if that would work.

These guys here tried making some fire hardened spears and found that it became rather soft. At any rate, even if they're hard and brittle, this means the spearpoint - which you've attached a bronze head to - is likely to snap off.

I was coming from my experience with fletchery which uses sticks with a point put into a metal conus. Now, if I wanted to fireharden that, I would just push it into embers for a short while before quenching it, possibly repeatedly, in effect leaving a central cone of non-charred wood with a crust of charred wood. I would probably subject it to non-combustion levels of heat beforehand to avoid explosive release of volatiles in this process.

Your comment assumes that the entire tip would have been charred through and through - and I agree that would be so brittle that it would break off after a few strikes at most.

11 hours ago, Steve3742 said:

This is probably why people don't do both - metal tipped spears are much more effective than fire-hardened ones and fire-hardening a spear and then attaching a metal head to it is worse than useless, as it actually weakens the area you've attached the head to, not something you want to do.

The fire-hardened tip of an all-wooden spear (or javelin) is a bit like a made-to-break-off spear tip, a concept re-invented with the Roman pilum.

11 hours ago, Steve3742 said:

My point about this spell is that it's like a continuous fire-hardening, weakening the area the metal is attached to continuously.

And my solution was to give it a contact area which has taken all the hardening it can while dissipating the worst of the heat, above a core retaining the flexibility of the wood that makes it suitable spear shaft material in the first place.

Yes, such a socket would deteriorate over time.

Now, let's consider a two-partite spear head, say with a hard bronze head and a weaker but more heat resistant copper socket that isn't the direct target of the Heat Metal and already acts as a radiator.

 

11 hours ago, Steve3742 said:

Sure. But the metal frying pan starts to cool down the moment you take it off the stove. This bronze tip will be at full temperature all the time. And it might be below the melting point of bronze - 6D6 instead of 8D6 - but that's still 600 degrees Celsius. Enough to charcoal wood (if it's deprived of oxygen), enough to ignite wood if it's not (430 Celsius should ignite most wood in a minute or less) or even charcoal (which should start burning at 349 C.)

Really can't see this working.

Enough to charcoal wood - which is why the "wood" inserted would be pre-charred. Deprived of oxygen simply by design - there is way more fuel than oxigen in the spear tip.

Then the concept of heating the bladed point, but not the socket, leaving the socket and thereby the contact area with the shaft at a lower temperature already.

Then choose a Heat Metal duration roughly compatible with the time you expect the spear shaft to last (you wouldn't want to transfer the hot spear point to another shaft).

Lastly, in a world where there are creatures that withstand fire, their body parts will be great for an isolating layer inside the socket.

 

I have no data on breakage of spear shafts, but they wouldn't have lasted indeterminately anyway. At some point, any spear will need repair or maintenance, or replacement.

[gochie]

I agree that regular wood wouldn't work with such a Spear, but of course in Glorantha you could find some magical material (dragon bone?) or spell to make it work.