Working in metal clay you will often read or hear people talking about rolling their clay out to 4 or 2 cards thick ect. Where did this all come about? Well to keep costs down, people were using playing card thus came the "cards thick" terminology. Yes you can still use playing cards if you like, but I found that not all cards are the same thickness and so did other "clayers"
From thickest to thinnest
(Slat sets by Pam East which we carry represent the colors)
Purple - 0.08” or 2mm or 8 cards thick
Red - 0.06” or 1.5mm or 6 cards thick
Blue - 0.04” or 1 mm or 4 cards thick
Green - 0.03” or .75mm or 3 cards thick
Yellow - 0.02” or .5 mm or 2 cards thick
Black. - 0.01” or .25 mm or 1 card thick
But heck playing cards work too
*Pictured are the cool metal clay rolling frames.