A) Painting over Acrylic paint – Difficulty level Low
1) If the canvas has raised texture, sand the canvas with 120-grit sandpaper in a firm circular motion. There’s no need to sand if your canvas has no raised texture.
3) Once dry, apply a second coat with brushstrokes in a vertical direction. Focus on any areas where the original painting is showing through. Keep layering the gesso and letting it dry between coats until you have a fresh, white surface. Et voila!
B) Removing Acrylic paint – Difficulty level Medium/High
1) Using a container large enough to hold the canvas, fill the bottom with 1/4 of an inch of rubbing alcohol, turps or ammonia (solvent). If you dont have a container large enough, you can spray the canvas with your solvent however this won’t be as effective. Put the canvas into the container face down to soak for minimum 1hr.
2) Wearing a mask and gloves, place the canvas on a flat surface and moving in long strokes from the edge, gently scrape a putty knife across the surface of the canvas to remove paint. Keep working until you have a flat surface. You may need to resoak the canvas for stubborn areas.
3) Using warm water and dishwashing detergent, gently scrub the canvas with a soft brush to remove any residual paint and rubbing alcohol.
4) Rinse the canvas in clean water and leave to completely dry.
5) Once dry, gesso as normal.
C) Removing Oil Paint – Difficulty level High
1) Using a razor blade, scrape as much paint off the canvas as you can. Be very careful as you may slip and cut yourself or tear the canvas.
2) Sand the canvas with 120-grit sandpaper (as per previous).
3) Dip a cloth in isopropyl alcohol and rub the canvas to remove residual paint. The canvas may be stained. Allow to completely dry.
4) Gesso the canvas as above but use OIL based gesso. Acrylic based gesso over oil paint residue will not adhere and will cause new paints to crumble and chip off.
Sources. Info: Wikihow. Pic: Steve Johnson – Unsplash.