While the foam is still wet or sticky, shape it gently using gloved hands or a putty knife, generally during the first five minutes after spraying. Step 6: Creating a Shape for the Wet Foam Create rounded edges and angles to mimic river rock, or sharper edges and angles to imitate crushed granite.

As required, spray additional onto the structure once the expansion has stopped. To allow the foam to expand, stop spraying long before it reaches the required rock size. Continue spraying gently to form a rock-shaped mound, taking note of the expansion as it happens. Spray the foam in a tiny spiral on the cardboard or top, similar to how you would a can-based whipped topping on a dessert. Allow the foam to expand and cure as directed by the manufacturer. To make a foam mound, move the nozzle around. Remove the top from a can of spray foam insulation and spray the foam onto the waxed paper on the cardboard using the provided spray nozzle.

The rubber gloves will protect your hands while wearing safety glasses can protect your eyes. Often such spray foams can be harmful or toxic to your skin. This also brings up and mixes all the residue in the spray bottle if your can has been sitting around for a while. This may differ depending on the type of spray foam you are using. Shake the expanding foam container for 30 seconds or as directed on the label. If you’re going to make a rock out of cardboard, make sure it’s bigger than the rock you produce. You will need ventilation with all those fumes from the sprays. Process Using Expandable Spray Foam Step 1: Ensure that the work area is secure and safe.Ĭover the work area with a sheet of cardboard or a plastic tarp in a well-ventilated room, ideally outside.

Step 6: Creating a Shape for the Wet Foamīefore starting off to make the foam rocks, check off a few things you will need:.

Step 1: Ensure that the work area is secure and safe.

Small fake landscape rocks