Can I Paint Over Dry Acrylic Paint?
Acrylic paints can be painted over if they've dried completely, although you may need to apply several layers before achieving full coverage with an even color and no drips or runs in between coats (this should only happen once every few hours).
How Long Should I Wait To Varnish an Acrylic Painting?
It takes about 24-48 hours for the paint to dry completely before varnishing and it's important not to apply the sealant until the paint is fully cured, otherwise you'll get a cloudy finish. If there's any risk of rain or other inclement weather conditions in your forecast, wait to varnish your painting as this will help protect it from moisture damage.
What Is The Best Way To Prevent Cracking In Acrylic Paintings?
The best way to avoid cracking is to work in thin layers, allow each layer plenty of time to dry before adding the next and avoid working in humid environments. You can also add an accelerant to help the paint dry faster.