Ever have that problem when you are filling up a large pot or kettle, of knowing how much water you need? This Imgur user has a DIY solution that involves electrolytic acid etching. Using a 9 volt battery, a cotton swab, some wires, and a vinegar solution, they create their own volume markings by removing metal where the current flows.

via imgur by itsgus

The 10 Gallon Pot

Materials Needed for Solution
All you need is something acidic enough like vinegar and an electrolyte like salt – a ratio of 1/4 cup vinegar to 1/4 tsp salt.

9 Volt Battery
A 9 volt battery is needed. Hook up the positive lead directly to the pot, then attached the negative to a cotton swab, making certain that the wires are secured around the part of the cotton swab that will be dipped in the vinegar solution. Be sure to hook them up correctly or else it won’t work.

Cotton Swab
Notice how the copper wire is touching the actual cotton.

Stencils
Stencils for the inside of the pot.

Etching Begins
Dip the cotton swab into the vinegar solution and begin to etch on the pot. You should hear some sizzling and see some bubbling.

Complete!