Items that can be abused.

[mikeejimbo]

And if you use transmute water to acid, then you still have a water-balloon filled with acid. And that's just cool.

[Riffington]

Except that the decanter keeps pushing out water, even if physics would say it couldn't. That's why you use a resiliant sphere, made of force, an unbreakable material. If the water can't escape, it has to compress, even if it can't.

The description is intended to describe the "usual" function of the item, not its function "when stopped up". Whether it generates infinite pressure or simply stops flowing depends on what is best for the story.


/swallow a Heward's Handy Haversack. Then you can spit out whatever you want as a move action.

[Curmudgeon]

Except that the decanter keeps pushing out water, even if physics would say it couldn't. That's why you use a resiliant sphere, made of force, an unbreakable material. If the water can't escape, it has to compress, even if it can't.

The Decanter only pushes out water with this limitation:

The force of the geyser deals 1d4 points of damage but can only affect one target per round.

We don't deal with real-world physics when we have D&D physics supplying the rules.

Repeat after me, people:

It's a Decanter of Endless Water, not a Decanter of Endless Pressure.

No matter how long you let the Decanter operate in a container, when the water comes out it still only has the pressure specified in the item description: enough to do 1d4 points of damage to one target in one round.

[Recaiden]

Let's kill a few catgirls here...

Pressure doesn't work that way. Let us assume the decanter is a conduit to the elemental plane of water. So now that means that the decanter, whatever material it is made of, obviously already does survive the pressure.

Let's not assume that. The elemental plane of water doesn't have gravity, so i'm pretty sure there would not be very much pressure. Thus, the water must be created by the decanter, and is forced out by the pressure of having water in the decanter over how much it could normally hold. If it keeps creating more water in a finitely sized container, that would eventually increase the pressure. Whether the decanter can stand much pressure is unknown.
Also, i vote for thought bottles.
Instant fortress is abusable too.

[Chronos]

Also, since water doesn't compress, you do not get an instant lake.

Water does compress. It just doesn't compress very much, for any sane value of pressure. Which means that if you do, nonetheless, compress it by any significant amount, your pressure is no longer sane.

However, on thinking about it more, the Decanter's output is specified in terms of volume, not mass. Once the sphere is full, it can't continue outputting 30 gallons per round, since the sphere is already holding as many gallons as it can (about 1343 of them, assuming minimum caster level). It could, in principle and with great difficulty, continue to output 240 pounds of water per round, but that's not what the description says it does. So strictly speaking, putting a decanter of endless water into a resilient sphere results in a rules contradiction.

[Collin152]

Water does compress. It just doesn't compress very much, for any sane value of pressure. Which means that if you do, nonetheless, compress it by any significant amount, your pressure is no longer sane.

However, on thinking about it more, the Decanter's output is specified in terms of volume, not mass. Once the sphere is full, it can't continue outputting 30 gallons per round, since the sphere is already holding as many gallons as it can (about 1343 of them, assuming minimum caster level). It could, in principle and with great difficulty, continue to output 240 pounds of water per round, but that's not what the description says it does. So strictly speaking, putting a decanter of endless water into a resilient sphere results in a rules contradiction.

Rules Contradiction = Tearing the fabric of reality asunder.

[monty]

The Decanter only pushes out water with this limitation: We don't deal with real-world physics when we have D&D physics supplying the rules.

No, it also says,

"Geyser" produces a 20-foot-long, 1-foot-wide stream at 30 gallons per round.

So, it puts out 30 gallons per round.

No matter how long you let the Decanter operate in a container, when the water comes out it still only has the pressure specified in the item description: enough to do 1d4 points of damage to one target in one round.

No, that's how much damage the geyser function itself does, not necessarily how much damage the accumulated water in the sphere would do.

Water does compress. It just doesn't compress very much, for any sane value of pressure. Which means that if you do, nonetheless, compress it by any significant amount, your pressure is no longer sane.

However, on thinking about it more, the Decanter's output is specified in terms of volume, not mass. Once the sphere is full, it can't continue outputting 30 gallons per round, since the sphere is already holding as many gallons as it can (about 1343 of them, assuming minimum caster level). It could, in principle and with great difficulty, continue to output 240 pounds of water per round, but that's not what the description says it does. So strictly speaking, putting a decanter of endless water into a resilient sphere results in a rules contradiction.

That's hard to visualize without knowing exactly how the decanter works (where specifically the water forms, etc.) so it's hard to argue. For example, if there's some magical, untouchable space inside the flask where the water forms and is then forced out, measuring the volume from that point could quite easily lead to producing more water, and insane pressure.

[Signmaker]

Lyre of building.

We built this city, we built this city on rock an' roll
Built this city, we built this city on rock an' roll

[Conners]

Hey, thanks guys. Now I know JUST what to equip my character with in the next adventure .

[Talic]

Lyre of building can negate all damage to stone structures. Combine with wall of stone (entrapping dome effect), and have the person negating damage on the outside, and you have an indestructable wall.

Extra fun if you have a Necropolitan or warforged bard or rogue hitting up a +14 to perform for a neverending indestructible wall.

I've used this in a party setting to raise 2 walls of stone "trapping" my party in a corridor long enough for the cleric and wizard to memorize spells. Very abusable to say: "can't go extradimensional? suck it."

[mikeejimbo]

There's actually some sort of loophole involving switching off performers with the lyre of building, so that you can keep it up constantly.

Or something like that. I suppose Necropolitan or Warforged works too.

[Frost]

Lyre of building can negate all damage to stone structures. Combine with wall of stone (entrapping dome effect), and have the person negating damage on the outside, and you have an indestructable wall.

Extra fun if you have a Necropolitan or warforged bard or rogue hitting up a +14 to perform for a neverending indestructible wall.

I've used this in a party setting to raise 2 walls of stone "trapping" my party in a corridor long enough for the cleric and wizard to memorize spells. Very abusable to say: "can't go extradimensional? suck it."

Seems a lot easier to just use a Wall of Force and have some Planar Bound Creature slap a permanency on it.

[Jade_Tarem]

Seems a lot easier to just use a Wall of Force and have some Planar Bound Creature slap a permanency on it.

Except you don't lose XP with the lyre. Binding planar creatures costs XP, too, in most cases.

I didn't mean to start a fight on the decanter. Considering that the game fosters such abominations as the candle of invocation, I didn't think that a giant water-bomb would be too bad. It's mostly a theoretical exercise - if your DM lets you do this, you should just go the whole hog and summon several cubic feet of antimatter through Major Creation to end the world.

For another abusable item: any weapon with the shocking enchantment on it. It doesn't seem too bad, but you combine it with a frenzied berserker shambling mound for a warrior who just won't die, ever. Granted, you'll never play as a shambling mound frenzied berserker, but my group did fight this fiendish combination once.

[Talic]

Seems a lot easier to just use a Wall of Force and have some Planar Bound Creature slap a permanency on it.

Rods of cancellation will stop that. Same with Negation. A Disintigrate won't get rid of that stone sphere.

[Frost]

Rods of cancellation will stop that. Same with Negation. A Disintigrate won't get rid of that stone sphere.

Actually, Disintegrate doesn't do damage to stone, it just removes it, check the spell. It gets through your scheme just fine.

[Jayabalard]

Thus, the note that you should spring for the decanter to be made of adamantine, <snip>
Of course, your DM can always rule that the decanter can't be made from adamantine, at which point you're sunk.

A decanter is a decorative glass or crystal bottle, so there's no reason to assume that you can make one out of adamantine.

[kjones]

What about it? [they Lyre of Building]

13000 GP + ability to make a DC 18 Perform (Strings) check = 300 man-days of work. That's probably enough to build a sizeable house.

Go into the real estate business. Sell each house for 50000 GP.

???

Profit!

EDIT: Forgot about the "swapping-out-performers" trick, but a reasonable interpretation of the rules would be that it's the lyre that's the limiting factor, not the performers. I know, I know, RAW is RAW...

[SilverSheriff]

Close, but no cookie for you.

actually I do get a cookie, its for drowning all of my Party while I escape with a bottle of Air on my mouth until they drown, then I just close the decanter, find a door I can open and leave...

[Elixia]

Ring of invisiblity .... which i own MWAHAHAHAHA

[Draco Ignifer]

Y'know, there's a serious problem with the whole "decanter of endless water bomb" trick besides any questions on whether or not the decanter would keep pumping. To whit, you're not going to get it to that high pressure. Assuming you extend the spell, and are level 20, you can get it to last for 40 minutes. The decanter pumps out 30 gallons per round, for a total of 12,000 gallons. One gallon is ~0.134 cubic feet, giving you a total of 1608 cubic feet. At level 20, you create a sphere with diameter of 20 feet (it does not say that the diameter is "up to," and if you want to limit caster level to increase the diameter, you're carving away at your duration). This means that the sphere will have a radius of 10 feet, which means a total volume of (4/3)(pi)(10^3) cf. Your sphere, in other words, will be 4189 cubic feet, and you won't have even filled it a third of the way.

The best thing you can do, then, is minimize the radius, and so cast at level 7, with extend spell. This gets you 4,200 gallons, however, which is a mere 563 cf. The sphere can only hold 180 cf, of course, but that's still not going to be a very large explosion - that water, expanded, has a radius of 5.1 cf, so you're going to be looking at an explosive expansion of 1.6 cf before the water is no longer compressed. After that, it's not going to be compressed anymore - still forceful, I'm sure, but I doubt any more than a large wave in any direction but down.

OK, yes, it can be pretty potent at smashing things. But why not just wait two levels, cast disintegrate, and not buy the decanter?

[Sstoopidtallkid]

OK, yes, it can be pretty potent at smashing things. But why not just wait two levels, cast disintegrate, and not buy the decanter?

OR BUY 12!

[Chronos]

Do you have any idea of the kind of pressure needed to compress water by a factor of over three? If you have something at that pressure and release it, it will explode, and it will do a very great deal of damage in a very large radius.

The compressibility of water depends on the conditions, but it's somewhere in the vicinity of 4 to 5 times 10^-5/bar, which means that, to compress it to a third of its normal volume, you'd need a pressure of tens of thousands of bars, or something times 10⁹ Pascals. For comparison, a third of a bar pressure wave is enough to destroy a typical masonry building. I'm having a tough time finding the figures, but tens of thousands of bars is probably comparable to what you'd find in the core of a nuclear explosion.

[monty]

Assuming you extend the spell, and are level 20, you can get it to last for 40 minutes.

Or you could persist it. With a cheesy enough build, you could probably do that at minimum CL.

[Collin152]

Or you could persist it. With a cheesy enough build, you could probably do that at minimum CL.

Doesn't persist only work with spells with a personal range?
Or something like that?

[Jade_Tarem]

actually I do get a cookie, its for drowning all of my Party while I escape with a bottle of Air on my mouth until they drown, then I just close the decanter, find a door I can open and leave...

Alright, you can have a really evil cookie, I guess...

And as for the decanter thing... Holy mother of Chaos....

Very well, I'll adjust the tactic to make everyone happy.

You'll have a decanter made of riverine, which is a kind of glass (so it can be a decanter - an invincible, pressure proof decanter, mind you, since it's mostly made of force). Instead of ORS, we will be casting force chest from the Spell Compendium, which is not a ten foot diameter ball but rather a small box 2 feet on a side. This box lasts for twenty four hours per caster level and is available at the same level as ORS, so two levels higher you can cast the extended version and this bad boy will stick around for eighteen days, instead of eighteen minutes, which should let you build up some wicked sick pressure. Does that satisfy all the requirements?

As to the other arguments - yes, this is physically impossible. But you know what? So is getting thirty gallons of water out of a handheld flask in six seconds. Water will compress under enough pressure like that, because - physics and all the little catgirls be damned - this tactic was to force ever more mass into a finite space that can't normally contain it. Things that are not compressable (like solids) will compress under extreme circumstances (like black holes). Yes, your DM can rule that the decanter doesn't work that way, but by RAW it's just volume of water per unit time, and there is nothing in there about a point where the water pressure is too great for the decanter to continue functioning.

Also, the impact and pressure of the moving water will not suddenly stop when you reach the uncompressed volume that the amount of water created was supposed to have - that's the point where the momentum stops increasing (and starts decreasing, yes). You end up with a huge ball of water accelerating very quickly in all directions, which carries with it a momentum and "pop" suitable to do some real damage. This was not likely one of the intended uses of the decanter of endless arguments water, which is why I put it here.

Edit: And for the grand finale, let's go nuts and chuck several riverine decanters into the force chest (in fact, let's just pack the force chest full of 'em in the most efficient way possible - you can actually do that with force chest, because you have a good bit more fine control over it than ORS), which not only multiplies the water output but also drastically reduces the available volume left in the container for the water to compress into.

[monty]

Change the title of this thread. "How to make a black hole"

[Emperor Tippy]

Change the title of this thread. "How to make a black hole"

We have already had a few of those.

[Yahzi]

It was always pretty obvious to me that a Decanter was just a small, portable gate to the plane of Water. Hence it would not continue to build pressure infinitely.

[Chronos]

You won't actually make a black hole that way, in the lifetime of the Universe. But you will certainly make something interesting. Crystals of metallic hydrogen and solidified oxygen, maybe?

[Collin152]

Metallic Hydrogen?
Please, don't go scaring me with that possibility. I'd rather have the black hole.