Hi @lis!
Liquefied styrene is some kind of "filler". You take small pieces of styrene, put them in a small vase and add some very thin liquid glue. Leave it overnight and the next morning it has become a homogenous liquid. You can make it thinner or thicker by adding styrene pieces or thin glue.
You may apply it in places needing filler carefully, with a toothpick or so. Leave to dry and sand it as you sand normal filler. Use small amounts, as too much will deform the surrounding plastic.
It's a very good filler and it bonds nicely, as it is, indeed, styrene!
It's very good for filling difficult spots, or weak joints, as it strengthens them. Practice on some scrap plastic first. I think you'll find it interesting and helpful.
I sometimes use it as glue, as well.
Best is to start using it and slowly take advantage of its benefits, as you will adapt it to your personal style of modeling!
Here are two relevant videos, the first shows how to make it, the second also shows how to apply and sand it:
Hope you find all abaove informative; I did not want to overflood you with information, so I stop here, please write ANY question/comment you might have! I will be happy to answer!
