Sodium Alginate is a seaweed derivative that is used to thicken dyes for painting, stamping or screen printing. Instructions Mix 1 quart water with 1/4 cup Urea. Note: Use approximately 2 tsp Sodium Alginate for hand painting and 4 tsp Sodium Alginate for screen printing. Slowly sprinkle Sodium Alginate over water/Urea mixture, stirring constantly, for 10 minutes (or mix in blender until smooth). Let stand for 1 hour and then stir again. Solution may be stored in refrigerator for months.