Pressure Vessel

A sealed steel tank you pump air into with a Powered Bellows. Pump too much in and it explodes.

Crafting

S S S
S   S
S S S

S is a Steel Ingot.

Using it

Put a bellows against it and run the bellows. Air builds up inside: 1000 mB of air is 1 Pu. It leaks back out by itself at 1 mB a tick, so an idle vessel slowly empties.

Pressure	What happens
up to 5 Pu	nothing, however long it sits there
above 5 Pu	each tick there's a chance it explodes, climbing the further over it is
7 Pu	it explodes

The explosion damages blocks around it. A long-throw bellows (30 mB a stroke) needs about 170 strokes to take one from empty to 5 Pu, plus whatever leaks out meanwhile.

The Boiler follows the same ladder.

Canning

Set the vessel on a Firebox (or lava) and it can sterilise jars of food (see Food). Right click with a jarred food to put one in (up to four); sneak with an empty hand to take the last one out; breaking the vessel drops them. Pressure raises the boiling point, so with a fire under it the inside climbs past the 100 Tu a pot tops out at, up to 6 Tu for each Pu. Sterilising needs 116 Tu, which about 2.7 Pu and a fire that hot give. That is well under the 5 Pu danger line: pump to the working window, not to the limit. A jar of food is not a hazard, and jars do not change when the vessel bursts.

Nothing draws the stored air back out yet, and no instrument reads its pressure. For now it's mostly a demonstration that equipment can be pushed past its limits, and a reason to put a Valve or Clutch on a bellows line.