Dust explosion

[Soultpp]

Honestly you are reading way more into what I am saying than in there. First of, Delericho's post listed a trap example based on an equivalent that he might use:

I would treat it, essentially, as a non-magical fireball. So, something like:

Dust Explosion Trap: CR 3; mechanical; location trigger; manual reset; spell effect (fireball, 5th-level wizard, 5d6 dire, DC 14 Reflex save half damage, cannot be dispelled); Search DC 26, Disable Device DC 26. Cost: 2,500gp, 200XP.

He was not saying 'this is how you have to do it', or it 'has these absolute statistics'.

As for my question in post #6, clearly it was worded wrongly in your eyes, but I never said 'why did it have to have a cost?' I asked specifically about why he chose that (I used 'the' instead of 'that', a poor word choice perhaps) cost. As for the part about lowering it, yes I did say that I would look at lowering it, if possible. It could have been not possible to lower it it much, but he presented a CR 3 trap when what I was going for was at best the equivalent of something much lesser in effect and scope. I never said anything about it being ignored IN THAT POST. Delericho mentioned that if I was setting it in a dungeon that the cost could be ignored, (he said, not me and I was just pointing that out in my previous post not arguing for it) and I am assuming it is because he was under the impression that it was meant for an PC group to stumble on. He also admitted that there may not be specific logic behind the cost.

I was looking at a 2 5' square burst at most, burning hands is 3x that in area despite a slightly different shape. I said, 'slightly higher average damage than a Lv1 burning hands'. I also never assumed that I would be doing this at lvl1 like you seem to have been. Perhaps its possible to be done at that level, but I did not say I would be attempting it then.

But whatever, you are right in that we are never going to agree here, and anyways I've already stated that I gave up the idea and even the character concept so there really is no further point in arguing.

 

[Greenfield]

So "Agree to disagree" isn't your thing, eh? Okay.

A "2 5 square burst"? Meaning, it's centered on a square, and covers that single square only?

So it's essentially single target, no attack roll called for and probably a reflex save for half? (Saves are an aspect that has been pointedly ignored up until now.) Note that most area affects start at the corner of a square, not the square itself. Minor quibble.

How big a pressure wave were you anticipating? You did ask for a "bull rush" effect, if I recall. What strength score, what area?

Mechanically, how much air/flour mixture will you expect to get when the square is occupied by someone/something? Another minor quibble, but a one-square area is kind of tiny for a dust explosion. That starts to resemble the "flour in the campfire" things on Youtube: Flash effect, little or no damage.

By the way, you asked why I keep comparing it to a Fireball. You just quoted a good source for that idea.

All in all, my objection stands: You're trying to give a PC (your PC) a no-hit-roll attack that's not accounted for in the rules. It consumes a few coppers worth of flour, so it's cheaper than Alchemist's fire. You say it should be greater than Burning Hands, which is more than Alchemist's fire. In terms of game balance, it's a bad idea, no matter how the backstory is rationalized.

Your rationalization of how the PC came to research this is strained at best, there are no game mechanics that allow for such research, nor are there game mechanics for the special attack itself.

You say you aren't trying to "beat the system", but that doesn't line up with the substance of your argument. You want more for less, with use limited only by the amount of flour you can carry. How is this not adding an imbalance to the lower levels of a game that already suffers that problem at high levels?

Or, to put it more succinctly, how is allowing this not a bad idea?

Sure you don't want to "agree to disagree"? The offer still stands.

 

[Soultpp]

You failed to read the fact that I had agreed that we would never agree, you could have left it at that. And yes I can to, and after this I probably will.

Already you are misreading my statements. I said 2 5' squares. 2 of them, not a single one. That is what I said. Good, bad, I'm not arguing that point any more, just clarifying what I actually said.

I never talked about save throws because it never came up, that's all. In most cases an area effect tends to favor saving throws over attack rolls, and I would likely have continued with that convention

Again, I didn't 'ask' for a bull rush effect, I suggested it as an option. I have never once made statements of fact as to how this should be, merely what it could be.

I quoted another person's suggestion, one that I said was similar to what I was thinking, not 'exactly that'.

I never said this was a no-hit-roll attack. Not once. This is again, purely your own assumptions on the subject. It is at most, comparable in power to alchemist's fire in that the damage is split between 2 targets rather than two rounds. As for the 2 CP cost, that was an argument about research costs, not specifically about the cost of the trap itself as I had never truly set that with a specific cost.

As far as it being 'greater than burning hands', again you are twisting my words, as you have been doing constantly in this thread. I won't repeat myself again, because you will again just ignore it.

Here I will flatly say that you are wrong because the 'rationalization' as you call it is not founded in 'mechanics'. There are so many things that the mechanics do not cover that are still part of a world these are not just numbers on paper, they are supposed to be characters with thoughts and feelings and experiences that are not always just 'dice rolls and mechanics'. All of my arguments on background were not founded solely on 'mechanics'. You seem fixated on 'game mechanics' as the only possibility to such an extreme that I am quite astonished.

Again, you are implying things here. I used flour as a possible example of 'dust' as the most likely source, but it was not the only one that could have been used and even using flour did not necessarily need to be the only factor in final costs. My only real issue with the costs was in finding a practical number. It is not only limited by the amount of flour that can be carried, which is a significant limiting factor considering how much an adventurer already needs to carry. There are many other factors, such as location, that you never seem to pay attention to. It seems exceedingly unlikely that an adventuring party would be in a situation where they could use the same location for multiple battles, even if they were the scorch marks from the initial use would add increasing bonuses to spot and avoid the trap (which would render it completely powerless). The fact that traps are avoidable is something that most spells do not have as a limiting factor by the way. A fireball flies to a specific point and bursts, anyone in that area takes damage whether they succeed on their save or not. (The exceptions are those with evasion of course) For most traps, they can be avoided before they are even triggered.

Let us look at another example: setting up an ambush (which this is what the idea was for) by positioning boulders above where the enemies are going to me, rigged to fall when triggered by, say, a trip line. This would require muscle, a wedge, and a trip line (and skill rolls of course). Is this also unbalancing because it is not limited by spell slots and costs virtually nothing?

 

[Nagol]

This is primarily a question for 3.5, but can cross to Pathfinder, and other systems relatively easily.

Basically what I'm looking at is how much damage would such an explosion cause? I know they can be very dangerous IRL so I had thought about using something like this as a trap, especially when it is so easily and cheaply setup. Assuming that its just common dust (flour most likely) and considering that a 1kg (2.2lb) dispersion is enough to fill almost 1300 sq ft.
But translating it into actual dice numbers, as well as finding suitable DCs for crating, searching, and disabling is where I am lost. I am planning on making a rogue who makes battlefield and other minor traps as a specialty, and this would be such an easy and potent one to manage.

Anyone got any advice/suggestion on how to nail down the numbers here? And maybe even a CR for such a trap.

If we make a few assumptions to narrow down the effects:

• We're talking grain dust.
• The dust has been milled with equipment closer to typical medieval quality than modern day quality.
• A kilo of dust is dispersed in an appropriate amount of air by a tool specifically designed for the job under near ideal conditions (no wind, limited humidity, complete dispersal)

Almost no damage really for anything portable by a person. The first dust explosion I could find on record was in a bakery in 1785 -- and that only blew out the windows of the shop.

First, the particle size is almost certainly too big to create an explosion. A diameter of <500 micrometres is required, but the sources I was able to find suggest ~700 micrometres was more typical for ground grains (I suspect that's why it hit a bakery first -- extra finely ground white flour for pastry).

Even if you did get dust ground finely enough, the lower explosive limit is 125 g /m^3 so 1 kg could cause an flash in 8 cubic metres or about a 5' cube (6' actually, but certainly not 10 -- that would require 8 kg or so). True flour dust (as opposed to grain dust; stripped of bran) requires about half the density so if the society has the modern milling techniques you might be able to get the fuel down to 2 kg per shot to cover 10' cube.

Next you have to get a tool that manages to disperse the dust enough -- but not too much! so that the dust is well distributed inside the flash cube. This would be very tricky. You need to get the dust suspended pretty evenly inside the target area. A bellows-like contraption with dispersal nozzle might be able to do it, but it'd require a fair bit of tinkering I expect.

And finally you have to apply a source to ignite it once the dispersal has reached its maximum. Luckily, typical flame temperatures are enough to ignite grain dust so having a lit torch / open lantern as part of the tool would be enough. Though that's probably bad news to the operator as he will be at the edge of the flash at best and inside the flash at worst.

Since we're not dealing with an confined space, you're much more likely going to get a flash-fire than an explosion. There is nothing to contain the pressure until it builds up to something dangerous.

So I'd say you're probably looking at something like up to 1d6 flame damage in a 5' diameter (Reflex save halves) using equipment that weighs ~15# and consumes 2# of flour per shot. Probably an attribute roll would be necessary to use the device properly (Int, Wis, or Dex depending on how the DM conceives what is required to get the concentration right in the area); I'd go with something like Int DC 12 success and it works, failure and the action is wasted once you've tinkered enough to get the design worked out. And the operator would have to make the same save but get Advantage on it.

 

[Soultpp]

If we make a few assumptions to narrow down the effects:

• We're talking grain dust.
• The dust has been milled with equipment closer to typical medieval quality than modern day quality.
• A kilo of dust is dispersed in an appropriate amount of air by a tool specifically designed for the job under near ideal conditions (no wind, limited humidity, complete dispersal)

Almost no damage really for anything portable by a person. The first dust explosion I could find on record was in a bakery in 1785 -- and that only blew out the windows of the shop.

First, the particle size is almost certainly too big to create an explosion. A diameter of <500 micrometres is required, but the sources I was able to find suggest ~700 micrometres was more typical for ground grains (I suspect that's why it hit a bakery first -- extra finely ground white flour for pastry).

Even if you did get dust ground finely enough, the lower explosive limit is 125 g /m^3 so 1 kg could cause an flash in 8 cubic metres or about a 5' cube (6' actually, but certainly not 10 -- that would require 8 kg or so). True flour dust (as opposed to grain dust; stripped of bran) requires about half the density so if the society has the modern milling techniques you might be able to get the fuel down to 2 kg per shot to cover 10' cube.

Next you have to get a tool that manages to disperse the dust enough -- but not too much! so that the dust is well distributed inside the flash cube. This would be very tricky. You need to get the dust suspended pretty evenly inside the target area. A bellows-like contraption with dispersal nozzle might be able to do it, but it'd require a fair bit of tinkering I expect.

And finally you have to apply a source to ignite it once the dispersal has reached its maximum. Luckily, typical flame temperatures are enough to ignite grain dust so having a lit torch / open lantern as part of the tool would be enough. Though that's probably bad news to the operator as he will be at the edge of the flash at best and inside the flash at worst.

Since we're not dealing with an confined space, you're much more likely going to get a flash-fire than an explosion. There is nothing to contain the pressure until it builds up to something dangerous.

So I'd say you're probably looking at something like up to 1d6 flame damage in a 5' diameter (Reflex save halves) using equipment that weighs ~15# and consumes 2# of flour per shot. Probably an attribute roll would be necessary to use the device properly (Int, Wis, or Dex depending on how the DM conceives what is required to get the concentration right in the area); I'd go with something like Int DC 12 success and it works, failure and the action is wasted once you've tinkered enough to get the design worked out. And the operator would have to make the same save but get Advantage on it.

First off, I want to thank you. This is exactly what I was looking for in terms of assistance in this concept, narrowing down the specifics in a practical, part by part fashion. And I don't see any real problems there. It's clear though, from how you describe it, that it would likely never be practical as a spontaneous set up thing, not if you think it requires ~15# of proprietary equipment. The 1 kilo / 2# of flour was about what I would have expected to be the minimum for this though if it worked. It could still work conceivably as a plot hook, I suppose, and I'll leave it with the DM as that possibility. I will admit though that when I initially thought up the idea, I did probably half think the dispersal to be relegated to the area of 'suspension of disbelief' but that obviously is not good enough.

 

[Greenfield]

You failed to read the fact that I had agreed that we would never agree, you could have left it at that. And yes I can to, and after this I probably will.

Already you are misreading my statements. I said 2 5' squares. 2 of them, not a single one. That is what I said. Good, bad, I'm not arguing that point any more, just clarifying what I actually said.

Sorry, I misread. I though you were posting 2-point-5, implying half a square radius. Mea culpa.

Out of curiosity, how do you get an asymetrical burst? Or are we talking a 2-square line effect?

Again, I didn't 'ask' for a bull rush effect, I suggested it as an option. I have never once made statements of fact as to how this should be, merely what it could be.

The difference between an "ask" and a "suggest" is kind of thin.

I never said this was a no-hit-roll attack. Not once. This is again, purely your own assumptions on the subject. It is at most, comparable in power to alchemist's fire in that the damage is split between 2 targets rather than two rounds. As for the 2 CP cost, that was an argument about research costs, not specifically about the cost of the trap itself as I had never truly set that with a specific cost.

It's an area of effect. That says there's no attack roll. Check the rules.

The alternative is an attack roll against a square, and the occupants just get to go along for the ride? I'm not sure how you would justify a touch-attack. Nor is there any reason why armor would apply to an AoE. That leaves what? "It just sort of happens"?

At this point you're just making excuses.

As far as it being 'greater than burning hands', again you are twisting my words, as you have been doing constantly in this thread. I won't repeat myself again, because you will again just ignore it.

I won't ignore nor misquote you, nor ask you to repeat yourself. Instead I direct you to post 31, your post. Read your own words, exactly as written. No repetition necessary.

Here I will flatly say that you are wrong because the 'rationalization' as you call it is not founded in 'mechanics'. There are so many things that the mechanics do not cover that are still part of a world these are not just numbers on paper, they are supposed to be characters with thoughts and feelings and experiences that are not always just 'dice rolls and mechanics'. All of my arguments on background were not founded solely on 'mechanics'. You seem fixated on 'game mechanics' as the only possibility to such an extreme that I am quite astonished.

Perhaps the term "rationalization" need to be clarified: The unlikely tale based on an unverified event, attributed to something other than magic by someone who has no training in scientific method, and researched using skills that don't exist.

In short, stuff you made up to justify you getting what you want. Things that can't happen in the game world (i.e. no game mechanics to account for your tale.)

So you're right, your rationalization is completely disassociated with game mechanics, and that's the problem. Game mechanics, skill checks, dice rolls etc. are how such things are determined. My complaint has been that you want to ignore that.

Again, you are implying things here. I used flour as a possible example of 'dust' as the most likely source, but it was not the only one that could have been used and even using flour did not necessarily need to be the only factor in final costs. My only real issue with the costs was in finding a practical number. It is not only limited by the amount of flour that can be carried, which is a significant limiting factor considering how much an adventurer already needs to carry. There are many other factors, such as location, that you never seem to pay attention to. It seems exceedingly unlikely that an adventuring party would be in a situation where they could use the same location for multiple battles, even if they were the scorch marks from the initial use would add increasing bonuses to spot and avoid the trap (which would render it completely powerless). The fact that traps are avoidable is something that most spells do not have as a limiting factor by the way. A fireball flies to a specific point and bursts, anyone in that area takes damage whether they succeed on their save or not. (The exceptions are those with evasion of course) For most traps, they can be avoided before they are even triggered.

Okay, I'll bite: What other flamable dust would your character have access to, packaged in bulk, and available outside of an Alchemist's shop?

As for cost: I'm tempted to suggest a meaning for your phrase "practical number". Let's say it should be a cost you can afford at the lower levels where such an attack would be meaningful. Is that okay, or am I misreading or twisting your words again? (Note, so you can't say I ambushed you, there is nothing in the rules that says you should be able to afford everything you wish you could have.)

As for carry limits: Shrink Item, Handy Haversack, Bag of Holding, saddlebags on your horse, a hireling, an adventuring companion with some space in his/her pack. Are all of those unavailable?

As for factors like location: You've never mentioned location limits, so please don't chide me for not pointing out even more flaws in your plan. I did mention that I could take a long time listing them. I was simply polite enough not to.

Let us look at another example: setting up an ambush (which this is what the idea was for) by positioning boulders above where the enemies are going to me, rigged to fall when triggered by, say, a trip line. This would require muscle, a wedge, and a trip line (and skill rolls of course). Is this also unbalancing because it is not limited by spell slots and costs virtually nothing?

This would require a Set Traps skill check, plus whatever else the DM called for. And since deadfall traps are a game standard, already accounted for in the rules, I see no problem with them.

Are you suggesting that this man-portable gizmo/system of yours is comparable to the distinctly non-portable hill and boulders used in your deadfall trap? I shouldn't even have to point out what a bad comparison that is.

Again, though, all of these things, grain dust v flour v pastry flour v something else, one square or two, attack roll v "it just happens in some undefined way", how many bags of flour you and your horse and your party can carry, these are all game-mechanics details. Another excuse to rationalize your way past objections.

My objection was to the principle, which you've already hand-waved without answering.

 

[Nagol]

First off, I want to thank you. This is exactly what I was looking for in terms of assistance in this concept, narrowing down the specifics in a practical, part by part fashion. And I don't see any real problems there. It's clear though, from how you describe it, that it would likely never be practical as a spontaneous set up thing, not if you think it requires ~15# of proprietary equipment. The 1 kilo / 2# of flour was about what I would have expected to be the minimum for this though if it worked. It could still work conceivably as a plot hook, I suppose, and I'll leave it with the DM as that possibility. I will admit though that when I initially thought up the idea, I did probably half think the dispersal to be relegated to the area of 'suspension of disbelief' but that obviously is not good enough.

It's telling that in this mundane world where anything remotely dangerous has been weaponized by somebody, this effect hasn't been,

Your best form of normal dust would be coal. Coal dust has a quarter of the required mass / m^3 and smaller amounts are easier to disperse and would probably drop the mechanism to 10# and 0.5# per shot. Metal dust, like iron, is even better (in terms of ferocity of reaction), but you start running into plausibility issues even considering them flammable and likely a real pain to acquire in quantity.

 

[Greenfield]

I'd like to take a completely fresh approach to this. Let's set aside everything I've written to date on the subject.

What would the DC for a Craft or Profession - Spinner skill check be to spin straw into gold, without magic?

How much would a spinning wheel cost, above and beyond the "Master worked artisan's tool" price, for the wheel needed to spin straw into gold, without magic?

Or, what would the DC of Strength and/or Con check be for a Human PC to flap their arms and fly away, without magic?

You see when we discuss the cost or skill of a research DC to create an effect that can't happen in the game, we're essentially admitting that it can in fact happen, if those DCs are met and that price paid.

When we debate how much the equipment and supplies cost for an effect that shouldn't be allowed to happen in game, we're essentially saying that the effect should be allowed to happen, if that price is met.

This is why I keep saying that these details are meaningless. You can't spin straw into gold in game without magic, no matter how pretty your spinning wheel is and no matter how skilled a spinner you are.

A human PC can't fly by flapping their arms in D&D, no matter how hard they can flap or how long they can keep flapping. Not without magic anyway.

And a human PC should not be allowed to go outside the rules and create thermobaric bombs, large or small, without the use of magic. (Note that even Alchemy requires the user to be a spell caster in order to make anything listed in the book.)

So rather than continue to debate the size or shape of the area of effect, whether there should or shouldn't be a pressure wave/bull rush effect included, what kind of dust or flour you need, how much it weighs, how much it costs or how hard it should be to research, we can (and should) just say "no" from the start. The effect is unbalancing, and there is no way that the rules allow for it. Doesn't matter if a hit need be rolled or what the Save might be, doesn't matter if it is or isn't like a Fireball.

It is neither like nor unlike any spell, there is neither a hit needed nor not needed, there is no cost nor lack of cost. The thing you seek doesn't exist within the rules.

And if your character somehow witnessed a silo fire and/or explosion as a child? Probably evil spirits, or a spell gone wrong. Nothing to see here, move along, move along.

 

[Soultpp]

It's telling that in this mundane world where anything remotely dangerous has been weaponized by somebody, this effect hasn't been,

Your best form of normal dust would be coal. Coal dust has a quarter of the required mass / m^3 and smaller amounts are easier to disperse and would probably drop the mechanism to 10# and 0.5# per shot. Metal dust, like iron, is even better (in terms of ferocity of reaction), but you start running into plausibility issues even considering them flammable and likely a real pain to acquire in quantity.

I see your point here, and I suppose coal dust could have worked too though obviously there are many more dangers with using it. Still not practical as what I had envisioned of course, but that's okay. I'm not going to worry about it too much any more, but thanks again for the help.

 

[Cleon]

I would treat it, essentially, as a non-magical fireball. So, something like:

Dust Explosion Trap: CR 3; mechanical; location trigger; manual reset; spell effect (fireball, 5th-level wizard, 5d6 dire, DC 14 Reflex save half damage, cannot be dispelled); Search DC 26, Disable Device DC 26. Cost: 2,500gp, 200XP.

Looks OK, although I'd make the damage half fire and half bludgeoning - some of the lethal effect ought to come from the concussion.