1. Acrylic air brush paints are great for marbleizing, if used with a
water-based thickener such as carragean (Marblethix). The paints are
just the right consistency to float properly on the surface of the
water, and can be manipulated for swirl effects and cool designs. You
might be able to use thinned down student acrylics for this. Try
thinning and using eye droppers to drip paint in the water.
2. One solution(no pun intended) is to go down to Wal-Mart and buy a
box of Borax laundry powder and mix that in the water. I use model
enamels to drip in the water solution and swirl with a stick or other
tools. This not only makes great paper marbleling, but gives you the
added attraction of being able to do three dimensional work, as well. I
have not used acrylics with this, but I think it may work.
Hope this helps, Jerry