Grease spell confusion

[Pielorinho]

I strongly dislike physics, and believe the rules should only be based conceptually on them, as beyond that magic breaks down. Some grease burns. I don't think very many people here will argue with that.

Simple choice: if my wizard is creating grease, it's going to be the kind that burns. Beyond that, all I can say is that your reasonable interpretation of the rules is significantly different than my reasonable interpretation, and until a rules reference can be cited one way or the other, that's fine with me.

Thing is, this isn't complicated physics, any more than recognizing that normal paper burns when a dry sheet of it is held above flame is complicated physics. The explanation of why the paper burns might be complicated, but the fact that it does burn is simple.

Similarly, the explanation of why a puddle of grease doesn't ignite may be complicated, but the fact that it shouldn't is simple. Ignition when exposed to brief flame is not a property of normal greases (assuming there's a lot of grease, the grease starts off at room temperature, the grease is not in a thin coat on a highly combustible surface, etc.).

If your DM allows you to create an unusual grease that ignites when briefly exposed to flame, booyah! But there's nothing in the spell's description to suggest that the grease created by the spell has that particular unusual quality.

Daniel

 

[Rel]

So, Quasqueton, does that answer your question?

 

[isoChron]

1. Heat Metal on the Fullplate wearing fighter
2. Grease on the fullplate of the fighter
3. Ignition with Aganazzar's Scorcher, or Burning Hands or the like
4. Lift Off ...

Grease won't burn if it covers the floor except the floor is hot enough to EVAPORATE the grease. Not liquid grease is burning but grease in gaseous form. That's why you must heat grease to ignite it !
Now gasoline evaporates at room temperature, so no problem igniting it.
Diesel oil is a little bit harder to ignite. Fill diesel oil in a flat bowl and try to ignite it with a match you throw in ... Hard, isn't it ? Now if you hold a lighter long enough near it it will catch fire sooner or later.
Wax ... Heat on the candle wick will liquefy and then evaporate the wax before it will burn. Note... the candle itself won't burst into flames, just the wick will provide enough surface to hold the flame.
(Organic) grease is somewhat easier to ignite than wax. But you still have to produce a significant amount of heat to evaporate (and thus be able to ignite) it.
Now the flaming grease must constantly produce enough energy (heat from exothermic oxydation) to evaporate the thin layer of grease on the (still) cold rock surface. It could be hard to burn the grease hot enough to keep the flame burning ... or add some wicks . It will be a nice visual to see little burning wicks all over the surface of the floor. A little bit romantic ...

What I try to say is:
1. Grease (from the spell) is most likely combustible under the certain conditions !
2. It is unlikely that grease produces silikone grease.

BYE

 

[Camarath]

What I try to say is:
1. Grease (from the spell) is most likely combustible under the certain conditions !

If it is real grease and not a magical facsimile.

2. It is unlikely that grease produces silikone grease.

Why? It seems as good a base assumption as any other. The nature of the grease is ambiguous. IMO no assumtions should be made about it's nature and that any additional rules based on the nature of the grease would be presumptive.

 

[Camarath]

So, Quasqueton, does that answer your question?

I agree with LokiDR's answers to Quasqueton's original questions with the execption of the flammability issue.

 

[LokiDR]

Magical paper could be inflammable or even an approximation of paper with no real chemical structure. You can not just make these assumptions.

If you don't want to think, why not? Now, for the rest of us: can ray of frost freeze water? Can a mount summoned by the spell of the same name eat food? The spells don't say they can, so by Camarath's theory, they can't. I will assume that any property not listed in the spell is going to be covered by material properties as appropriate to setting. Hence, frost freezes, mounts eat, and paper burns.

Why shouldn't a fantasy setting have silicone grease? It is a real substance and everyone is always talking about realism. Magic is not possible in the real world so I find it odd to demand that its effects function according to real world physics (or at least peoples perceptions of real world physics).

When was silicon grease invented? Does that fit your game world? It doesn't fit in mine. Consistance of the setting is important, you know.

This is not true. "Burning" is an exothermic oxidation reaction and many oxidation reactions are endothermic. Also Helium cannot be made to chemically combine with oxygen by the aplication of heat and pressure.

With enough heat and preasure, you can theoretically break nearly any law of physics. But if you don't like jokes, I won't make anymore

It is a legal definition of the word flammable (with a double m so it is a real word) and serves as a resonables guide for if a substance can be ignited quickly.

Almost nothing a person will ever carry is flammable. Oil is not flamable. That is a worthless definition because it doesn't add anything to the discussion. Even lantern oil isn't flammable, and if that doesn't burn at the touch of a torch this whole discussion is pointless.

By the way, if you can't stand my simple misspelling, I can switch entirely to bad 133t-eez. Would that make you go away? Wait, you don't like jokes, nevermind.

I am saying that you are making assumptions that are not backed by either in game mechanics or real world physics. Yes grease will burn but most will only ignite at temperatures greater than a normal party of adventures could mundanely apply especially in a short period of time (2 minutes at level 20). You also can not assume the nature of substances and effects created by spells beyond what the spells and supporting rules specify.

Take a can of motor oil, dump it in a pan, apply a lit blowtorch for 12 seconds. If it doesn't burn, I'll give up.

It is a house rule. I have no problem with it as a house rules. But, I find it distasteful that it should be presented as normal (non-house ruled) game mechanic since it is based on supposition.

*sigh* House rules are not "grease burns". They are specific damage and lenght of burn. The fact that grease burns is the non-house rule. In any game I play, I expect the grease spell cast into a large heat source to flare.

A torch will also not be able to light most greases. Larger or higher temperature fire might be able to quickly ignite grease. But with small low temperature fires, such as a torch, most greases would be very hard to ignite.

I have said this before, but thank you for agreeing.

It adds new functions to the spell so should be a house rule. It is also is a very large simplification of "realism". I agree that it could be a good addition to the spell and the game but I don't think the rules as written cover it.

Because this use was not forseen, you can not do it? You don't like being creative, do you? Your mount (from the spell) can not eat grass. Your flaming sphere can not burn a rope bridge down. Hey, if that is the way you play, more power to you. For myself and others, the rules do not present every action possible, only the limits. Creative play should be encouraged, not banned.

 

[LokiDR]

Similarly, the explanation of why a puddle of grease doesn't ignite may be complicated, but the fact that it shouldn't is simple. Ignition when exposed to brief flame is not a property of normal greases (assuming there's a lot of grease, the grease starts off at room temperature, the grease is not in a thin coat on a highly combustible surface, etc.).

On average, I agree. If a DM doesn't let me do the grease/tindertwig firetrap, I am fine with that. But I will stick to the following 2 points:

1) There are at lease some greases (oil) that this will work on. It is a nifty effect that is not overly powerful. This is a perfectly valid house rule.

2) Grease, as understood by fantasy settings, will burn if it is hot enough. Casting grease into a furnace, forge, or large fire elemental should cause a flare up of the fire. This is not a house rule.

 

[Pielorinho]

Take a can of motor oil, dump it in a pan, apply a lit blowtorch for 12 seconds. If it doesn't burn, I'll give up.

1) Motor oil is a highly refined substance; if we're talking "normal grease" here, I think it's just as much out of the running as is silicone grease.
2) Dumping it in a pan is a poor analogy: you'll end up with a lot of oil compared to the conductive surface. Pour it instead on some pavement, where the heat is much more readily conducted to the underlying surface.
3) A blowtorch is pretty dang hot, usually white-hot; I'd suggest that most fire in D&D spells isn't that hot. But of course we can't know for sure, so I'll concede that point.
4) Few spells create focused fire for 12 seconds. If this example is to provide us parameters for setting grease on fire, it excludes fireball, burning hands, and all other instantaneous flame effects. Are you okay with that exclusion? If not, do you think the motor oil would catch on fire with a single second (or less) of blowtorch application?

Daniel

 

[Pielorinho]

1) There are at lease some greases (oil) that this will work on. It is a nifty effect that is not overly powerful. This is a perfectly valid house rule.

Sure, valid house rule. I already think the spell is plenty powerful enough, however, and don't want to make it more powerful.

2) Grease, as understood by fantasy settings, will burn if it is hot enough. Casting grease into a furnace, forge, or large fire elemental should cause a flare up of the fire. This is not a house rule.

I agree with this. In fact, if a clever caster decided to cast grease on a fire elemental she'd just summoned, I'd grin happily and increase the elemental's fire damage by 1d6 for a round or two, as the grease burnt off.

The difference is that if the grease is cast on a very hot surface, and there's enough energy in the surface to heat up the grease without cooling down the surface itself too much, then sure, flames result.

IMC, it's normal grease, meaning it can burn, but doesn't under normal applications. Using the spell like this would be specific to very particular situations, but it would be possible.

Daniel

 

[LokiDR]

1) Motor oil is a highly refined substance; if we're talking "normal grease" here, I think it's just as much out of the running as is silicone grease.

I would say crude oil, but you can't normally buy that in a store. I am willing to bet that motor oil is pretty close to crude oil, and there is not medieval equivelant to silicone gel.

2) Dumping it in a pan is a poor analogy: you'll end up with a lot of oil compared to the conductive surface. Pour it instead on some pavement, where the heat is much more readily conducted to the underlying surface.

I metioned a pan for safty reasons, but pavement would work. The important factor is you have a lot of oil to burn/cause oppents to slip.

3) A blowtorch is pretty dang hot, usually white-hot; I'd suggest that most fire in D&D spells isn't that hot. But of course we can't know for sure, so I'll concede that point.

More heat, more damage. *shrug*

4) Few spells create focused fire for 12 seconds. If this example is to provide us parameters for setting grease on fire, it excludes fireball, burning hands, and all other instantaneous flame effects. Are you okay with that exclusion? If not, do you think the motor oil would catch on fire with a single second (or less) of blowtorch application?

Daniel

A single second of a blowtorch will not kill (and then some) most average people the way 5d6 will. And blowtorches are not white hot. They can get most metal to a bright red but that is about it.

If you want to more accurate, a better analagy would be oxy-asetiline (sp?) welding torch. That should light oil in a single second and better reflect the amount of heat to flash fry a person.

So, anyone who has a welding torch, a decent amount of cude oil, and driveway want to try this? Let us know how it goes after you get out of the hospital.