Stack Furnace Coal Amount?

[Willberfollower]

Without using the bellows how many coal does it take to smelt ore in the stack furnace. Don't want to waste any so.

Help appreciated thanks.

[EnderWiggin]

Same as proper Smelter - 12 (or 9 if ore is Well mined). All bellows do is speed up the process to match smelter, without affecting amount of coal. Without bellowing it takes twice as long as Smelter does.

[waga]

You can use wood.
I know it's not your question but I see no reason to use coaI instead of wood, especiaIIy when you mention not having nough coaI to waste any.
30 branches without using beIow.

[Willberfollower]

Same as proper Smelter - 12 (or 9 if ore is Well mined). All bellows do is speed up the process to match smelter, without affecting amount of coal. Without bellowing it takes twice as long as Smelter does.

Alright thanks for the info. ill put 12 in then.

You can use wood.
I know it's not your question but I see no reason to use coaI instead of wood, especiaIIy when you mention not having nough coaI to waste any.
30 branches without using beIow.

I'm using coal because its higher quality then the wood and sticks I can get. Made a q50 tar kiln. I will say its not by much though 25 sticks vs 28 coal. When I get a better axe ill switch.

[Wingedjustice]

The stack furnace needs at least 13 branches (or 7 coals in your case) if you are on top of your bellows (gives you a bit of leeway if you're not). One bellow round gives you 27 mins of boost, which is about 53% progress. If you have a timer, just use it around 27-28 mins again and it'll be done it no-time.

Edit: The reason you only need 7 is cuz coal is worth 2 points of fuel, while branches are just 1. For normal smelters, one coal is one point of fuel, hence the 12.