you can also try rice instead of sand. i hate sand it too damb hard.
to get a Thai bag to around 150lbs it will take a ratio of 75/75lbs sand and cloth. if your going the flour route it the ratio will be higher for the flour as flour isn't as dense. you can pick up cloth from any fabric/textile distributor starting from $0.60/lb (thats Canadian) or you can hit up any textile place they will be willing to gather up there unused material and sell it to you for a bit cheaper.
hope this helps
Last edited by GFG; 03-10-2007 at 12:57 AM.