Try gelatine mix, its used a lot in special effects and gives a very nice translucent look, pait it with oil paints or silicone mixed paints .
heres a link I found for the formula but you can goolge more if you like
be aware that it can be hot! this may melt your wax depending on its melt temperature
You can use 2 part foams or plastics but these can be expencive.
Try smoothon products
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