I did an absorbency test with 2 samples of cotton flannel.
This test demonstrates the difference in absorbency between high quality flannel and low quality flannel.
I put 4 layers of flannel down on a piece of fleece and then I placed an average topper material over top.
Then I poured 2 tablespoons of water on the fabric. I let it set undisturbed for 1 minute to allow the water to soak in.
This is what I found on with the cheap cotton flannel:
This was cheap cotton flannel from a pair of Faded Glory brand (Walmart's generic) pajama pants.
This is how the high quality flannel preformed:
I used the same amount of water (it was the same temperature, too) and let it set for 1 minute, undisturbed.
The high quality flannel was from a JC Penney brand cotton flannel pillow case.
I could tell that the JC Penney flannel would be more absorbent just by feeling it. It was very thick and lush. The Faded Glory flannel was much thinner and lighter.
The cheap flannel can still be used to make good cloth pads. Knowing that it is less absorbent is very important, though, because you will have to use more layers to achieve the right absorbency. Or, you could do what I did, and combine some high quality flannel and low quality flannel and use them together in a pad.
Here is the general rule of thumb for how many layers to use:
(The smaller number would be for high quality flannel and the larger number would be for less absorbent flannel. )
1-2 layers of flannel = light absorbency
2-3 layers of flannel = medium absorbency
3-4 layers of flannel = heavy absorbency
4-5 layers of flannel = postpartum absorbency
These numbers are just a general rule of thumb. I recommend that you get to know the materials that you are working with and use your senses to determine how many layers of flannel you should use.
Another thing to keep in mind is that flannel's peak absorbency is reached after multiple washings and dryings. If you are using new flannel fabric it may not be as absorbent, yet, as flannel fabric that has been washed and dried countless times.
I want to also add, that you should not be using softener on your cloth pads or the material you will be making your cloth pads out of. Softener will make your fabrics less absorbent and possibly make them water repellent.