Round Coaster Base is 100mm Round and 4mm Thick.
 
MDF - Interior Use Only.
 
We recommend that you seal your MDF Coaster Base before starting to Mosaic.  Use one part PVA to 2 parts water and brush over both sides of the base allowing to dry.  Recommend 2 coats.
 
After completing your mosaic paint the back of the coaster with a standard paint.