Level 2 artificer. Create infusions for alchemy jug and bag of holding. Every day, have jug produce a quart of oil, thats 2 pint flasks of oil, per day. Each flask can do 5 damage per turn for 2 turns. Each pint weighs a pound. 2 pounds of oil a day for 20 points of fire damage.
10 days of oil production from the alchemy jug will produce 20 flasks, which will do 100 fire damage per turn for 2 turns.
Oil costs 1 silver per pint. So 1 gold will get you 10 flasks of oil. Get as many as you can afford and can buy.
Store flasks in bag of holding.
Level 5 artificer, create homunculus servant. It is your delivery mechanism and possibly your detonator. It has an int and wis of 10, so its smart enough to operate semi-autononus. It has a fly speed of 30. And it is immune to exhaustion, meaning it could fly forever or hover above a target forever, or hunker down in some hidden spot and listen for your command to detonate 24/7. You have direct control of it with telekenisis if within a mile. Or create infusion for sending stones to get unlimited range and 25 words of instructions for how/when to attack.
Buy one flask of alchemists fire.
For oil, you can target the ground a creature is standing on. Have the homunculus turn the bag of holding inside out and dump all flasks of oil in one turn. On impact all oil flasks will shatter. When the vial of alchemist fire hits the ground it will shatter and ignite the oil.
500 pounds of oil would cost you 50 gold to purchas, would just fit in a bag of holding, and would do 2500 points of fire damage per turn, for 2 turns.
If homunculus can drop the oil from the air, the only thing you lose is the 25 gold it cost to buy one flask of alchemist fire.to ignite everything, and 50 gold to purchase the oil.
If the homunculus is destroyed in the fire, thats another 100gp to replace.
A barrel weighs 70 pounds and can carry 40 gallons of liquid. That would translate to 320 flasks (pints) (pounds) of oil.
When full, the barrel and oil will weigh 390 pounds and do 1600 fire damage a turn for 2 turns.
EDIT TO ADD:
barrel is so you can use thr bag of holding to store more than oil. Someone suggested that a standard barrel is too big to fit into mouth of bag of holding. If so, use carpentry tools to craft a crate that is 2ft x 2ft (2 ft square) and 4 feet deep.that is the max size single object that can fit into a bag of holding. Then build 4 of them for full volume. The weight of the crates will reduce the total amount of oil you can carry, but its an option to be able.to use your bag of holding for oil and other equipment.
Alternatively, if you dont need to store anything in bag of holding but oil, then you could just dump the oil directly into the bag. Rules say you can dump water into the bag without a container. So you should be able to dump other fluids, like oil.
“If multiple effects impose the same condition on you, each instance of the condition has its own duration, but the condition’s effects don’t get worse. Either you have a condition or you don’t. The Exhaustion condition is an exception; its effects get worse if you have the condition and receive it again.” - D&D Beyond Basic Rules
This doesn’t work at all, both in theory and practically. A [magic items]Bag of Holding[/magic items] has a size of 2 feet square and is 4 feet deep on the inside, because of how a barrel works, you cannot contain a barrel inside a bag of holding unless it is especially small. You are incapable of doing that much damage as stated above and that is just an insane waste of money, it works as a blunt damage option, but water is literally a better alternative in every way.
"This doesn’t work at all, both in theory and practically. A [magic items]Bag of Holding[/magic items] has a size of 2 feet square and is 4 feet deep on the inside, because of how a barrel works, you cannot contain a barrel inside a bag of holding unless it is especially small."
Doesnt work at all? Because the barrel doesnt fit? You're an artificer. You have proficiencies in nearly every tool possible. Can you imagine a simple workaround that gets the ship in the bottle? Or is it really that this doesnt work at all? I mean, what if you use carpentry tools and craft a barrel thats 2 foot on a side (2 foot square) and 4 ft deep? Just small enough to fit. If you craft 4 of these barrels, you have 64 cubic feet of volume. or, ya know, just put the oil in flasks.
Actually, rules as written say you can put water into a bag of holding without a container. So if you werent so fixated on proving the idea wrong, you might have come up with the solution to the "barrel is too big" problem by just pouring the oil directly into the bag.
The barrel was my attempt to be able to use the bag of holding for things other than oil.
Level 2 artificer. Create infusions for alchemy jug and bag of holding. Every day, have jug produce a quart of oil, thats 2 pint flasks of oil, per day. Each flask can do 5 damage per turn for 2 turns. Each pint weighs a pound. 2 pounds of oil a day for 20 points of fire damage.
10 days of oil production from the alchemy jug will produce 20 flasks, which will do 100 fire damage per turn for 2 turns.
Oil costs 1 silver per pint. So 1 gold will get you 10 flasks of oil. Get as many as you can afford and can buy.
Store flasks in bag of holding.
Level 5 artificer, create homunculus servant. It is your delivery mechanism and possibly your detonator. It has an int and wis of 10, so its smart enough to operate semi-autononus. It has a fly speed of 30. And it is immune to exhaustion, meaning it could fly forever or hover above a target forever, or hunker down in some hidden spot and listen for your command to detonate 24/7. You have direct control of it with telekenisis if within a mile. Or create infusion for sending stones to get unlimited range and 25 words of instructions for how/when to attack.
Buy one flask of alchemists fire.
For oil, you can target the ground a creature is standing on. Have the homunculus turn the bag of holding inside out and dump all flasks of oil in one turn. On impact all oil flasks will shatter. When the vial of alchemist fire hits the ground it will shatter and ignite the oil.
500 pounds of oil would cost you 50 gold to purchas, would just fit in a bag of holding, and would do 2500 points of fire damage per turn, for 2 turns.
If homunculus can drop the oil from the air, the only thing you lose is the 25 gold it cost to buy one flask of alchemist fire.to ignite everything, and 50 gold to purchase the oil.
If the homunculus is destroyed in the fire, thats another 100gp to replace.
A barrel weighs 70 pounds and can carry 40 gallons of liquid. That would translate to 320 flasks (pints) (pounds) of oil.
When full, the barrel and oil will weigh 390 pounds and do 1600 fire damage a turn for 2 turns.
EDIT TO ADD:
barrel is so you can use thr bag of holding to store more than oil. Someone suggested that a standard barrel is too big to fit into mouth of bag of holding. If so, use carpentry tools to craft a crate that is 2ft x 2ft (2 ft square) and 4 feet deep.that is the max size single object that can fit into a bag of holding. Then build 4 of them for full volume. The weight of the crates will reduce the total amount of oil you can carry, but its an option to be able.to use your bag of holding for oil and other equipment.
Alternatively, if you dont need to store anything in bag of holding but oil, then you could just dump the oil directly into the bag. Rules say you can dump water into the bag without a container. So you should be able to dump other fluids, like oil.
END EDIT
“If multiple effects impose the same condition on you, each instance of the condition has its own duration, but the condition’s effects don’t get worse. Either you have a condition or you don’t. The Exhaustion condition is an exception; its effects get worse if you have the condition and receive it again.” - D&D Beyond Basic Rules
This doesn’t work at all, both in theory and practically. A [magic items]Bag of Holding[/magic items] has a size of 2 feet square and is 4 feet deep on the inside, because of how a barrel works, you cannot contain a barrel inside a bag of holding unless it is especially small. You are incapable of doing that much damage as stated above and that is just an insane waste of money, it works as a blunt damage option, but water is literally a better alternative in every way.
"This doesn’t work at all, both in theory and practically. A [magic items]Bag of Holding[/magic items] has a size of 2 feet square and is 4 feet deep on the inside, because of how a barrel works, you cannot contain a barrel inside a bag of holding unless it is especially small."
Doesnt work at all? Because the barrel doesnt fit? You're an artificer. You have proficiencies in nearly every tool possible. Can you imagine a simple workaround that gets the ship in the bottle? Or is it really that this doesnt work at all? I mean, what if you use carpentry tools and craft a barrel thats 2 foot on a side (2 foot square) and 4 ft deep? Just small enough to fit. If you craft 4 of these barrels, you have 64 cubic feet of volume. or, ya know, just put the oil in flasks.
Actually, rules as written say you can put water into a bag of holding without a container. So if you werent so fixated on proving the idea wrong, you might have come up with the solution to the "barrel is too big" problem by just pouring the oil directly into the bag.
The barrel was my attempt to be able to use the bag of holding for things other than oil.
"If multiple effects impose the same condition"
Damage isnt listed as one of rhe possible conditions.