Below is an excerpt about cartotanks taken from my blog article, "Proper Terminology...Is it a tank, or what?" More articles like this can be found in my blog, click the link under my avatar.
CARTOTANK
A cartomizer can be placed into a tank to allow longer periods of vaping than when used alone.
Holes are required to allow juice from the tank to enter the cartomizer. Juice levels can be easily monitored in the tank.
The above pic is of a "pre-punched" cartomizer. Note the small hole near the bottom of the cylinder. These cartomizers with holes are ready to be filled and inserted inside of a cartotank. Each time you draw vapor, more juice enters the cartomizer from the tank. This keeps the filler material moist with juice.
carto punch tool
Un-punched cartomizers can also be used in tanks, but require the user to make their own holes. A carto punch tool can accomplish this. Use only stainless steel cartos for tanks, not the black ones, which have a sticker applied for appearance purposes. I recommend for beginners to purchase the pre-punched cartos initially. One or two holes is adequate for all but the most thick e-liquids.
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cartotank
Above is a diagram of a typical CARTOTANK setup. It is made up of a clear tube with end caps on either end. A punched cartomizer is inserted between the two endcaps. A drip tip, or mouthpiece, fits into the end of the carto. This combination is what is referred to as a cartomizer tank.
Tanks can have a capacity of between 2 - 9 ml.
Tube material can be polycarbonate or polypropylene plastic, pyrex glass, or stainless steel. Pyrex is preferred. Endcaps can be made of plastic or metal.
Tanks sizes are categorized by length: standard (using a 35mm cartomizer) or an XL size (using a 45mm cartomizer). The diameter of tanks vary greatly, but typically are between 18mm and 30mm.
Cartomizers in a cartotank can last for 1-3 weeks depending upon how heavily it is used and how dark the juice is. Darker & thicker juices will eventually cause the polyfill in the carto to become clogged, resulting in flavor loss and a stiff pull when vaping. A cartotank can be refilled multiple times with the same carto in place. Spent cartos are discarded.
