What is the best solvent/cement to paint onto HIPS styrene for a really good, smooth finish?

Hello

If you paint a solvent/cement onto your styrene (HIPS/Plasticard) model, it briefly dissolves the outer surface and when it evapourates it leaves a nice smooth finish.

Do you have any tips about how to do this?

I have tried Slaters MEK-PAK but it's pretty agressive and doesn't smooth itselve out very well as it dries. I also tried Tamiya Extra Thin Cement, but that seems almost weak and doesn't do a particularly good job of smoothing. I tried pure acetone but rather surprisingly, as I was led to believe that it was the strongest solvent out there, but that doesn't dissolvethe styrene at all!

Cheers

J

PS Also what happens if you paint your solvent/cement onto your styrene model TWICE? It seems that the new deposit of smooth styrene that forms after the solvent evapourates is slightly different from the original, virgin styrene. For one thing it seems to be slightly harder than the virgin styrene when you are sanding it. Also, one of my test samples seems to have formed an outside layer that then cracked and ended up looking like a surface of old paint(!). I've not been able to replicate this, so I don't quite know how that happened...