Using "batting" in pads (don't!)
It comes up from time to time.. so I thought we probably should have a full post about it.
Batting (sometimes called "wadding") is a felt-like fabric designed to be used for inside quits and other things that need to be "poofy". It's designed to trap air.... if you trap air in something like a quilt, it traps warm air which keeps you warm. That is its function. It's very good at doing that. It is not appropriate for using in pads. Not even bamboo batting. Bamboo batting is not like bamboo fleece. It may look somewhat similar, but it's not the same in function.
Batting is made from thin fibres, felted together to include a lot of air. It's thick and bulky because it is very fluffy and full of air. You want a poofy thick quilt so it can trap a lot of warm air and keep you warm underneath it. You don't want a poofy air-filled cloth pad. Batting is designed to trap air, not liquid. It is simply not absorbent enough. A poly batting (just like using polarfleece as a pad core) is not "absorbent" as such and should never be used. It will hold some liquid if there is nowhere else for it to go, but it's not absorbent in the same way a natural fibre is. Bamboo batting will be absorbent because it's made from bamboo, but it will not be as absorbent as using something that is designed to absorb liquid. Fabrics designed for absorption are thicker, denser and made in a way that will trap and hold liquid, and will be durable through repeated washes.
Batting is designed for making things like quilts and craft things that are not frequently washed and not frequently worn. Cloth pads are subjected to frequent washing and wear. Pads may need to be scrubbed and soaked and are not washed gently. The fibrous way batting is made is not particularly durable through frequent washing or wear. You can usually pull batting apart with your hands. When the batting is subjected to wear, it can tear apart within a pad, and your pad is going to end up with a weirdly lumpy core.
Look at the care instructions for batting, they talk about setting the machine on gentle or even not agitating at all. :
http://www.backtobackalpaca.com/SearchResults.asp?Cat=13
http://www.fiberco.com/care/bamboo_blend/bamboo_blend.htm
A cotton terry in contrast is manufactured for the sole purpose of absorbing liquid. It has thicker fibres, more densely knit/woven together. It doesn't have a lot of air included to poof it up. It is heavier which means there is more actual absorbent component per square inch. It is made for frequently laundering and frequent use.
Bamboo and hemp terry/fleece has been made to be used in applications like cloth diapers, where high absorbency, frequent washing and trimness (non bulkyness) are essential to the items being made from it. That's what makes those fabrics the best choice for cloth pads. They may cost more to buy and be harder to source than things like batting or cotton terry, but you get what you pay for.