Hi there, when we have trialled Artbars at the SAA, we actually used Bristol Board and the thickness of the card meant that you could use as much water as you liked and the surface did not ripple. I used the Artbars much like pastels to do the background and used several colours, then used a large wash brush to blend it with water. The effect was beautiful. If you didn't want to use Bristol Board, you could try a heavy watercolour paper such as Saunders Waterford 640gsm. This would probably work much the same as the Bristol Board. I hope that helps.