What wadding/padding to use for DIY active carbon filters?

[frankvw]

I've been making activated carbon filters for quite a while, using the ubiquitous upside-down soda bottle principle. I drilled a small hole in the cap to achieve a low flow rate; I put about 4 inches of cotton wool in the neck of the bottle, I put my active carbon powder (obtained from a local pharmacy) on top of that, and this worked fine. I filtered large amounts of alcohol through these things without any problem whatsoever. Life was good.

Now I've moved to another part of the country, and I decided in my wisdom not to take the existing filter with me (having visions of carbon powder going everywhere during the move) but instead to make news ones after having settled in our new home. Which I did, but now the results are terrible! Carbon comes through the cotton wool no matter what I do, and whatever comes out of the filter is black as sin. I've bought new active carbon but used the same cotton wool, so the consistency of the active carbon is most likely the culprit; the new product is from a different local supplier. What I used previously was a powder, but this is a small granule which obviously comes with very tiny particles in the mix that are small enough to go straight through the cotton wool.

Since I have no control over the consistency of the active carbon (I have to use what I can get, here in South Africa) I'm having a look at the padding/wadding that's supposed (but fails) to prevent the carbon from ending up in the filtered product. Based on what I see now, cotton wool may not be the best. I've tried coffee filter paper in a funnel, but that either passes a lot of carbon powder as well OR simply clogs up.

So I'm open to suggestions. What else can I use? Or, alternatively, what better way is there to build a good active carbon filter apart from the upside down soda bottle approach?? There is a lot of content here and I haven't managed to wade through it all, so I can use some pointers on good active carbon filter designs. I'm filtering small batches; we're talking a couple of gallons here at most. Specifically, what is a good material to use as wadding/padding in order to keep the carbon inside the filter and out of the product, given that what I have here obviously contains tiny particles mixed in with the granules?

Tnx!

// FvW