Materials: Ikea Kvart, Antonius (mold), threaded rod, washers, wing nuts, double sided tape, silicone, concrete
Description: This is 90% NOT my hack. Most of the credit goes to Minni.
What I changed was to use Kvart lamp instead of Fas (Fas no longer available here and also I had 2 Kvarts lying around) and change the metal mounting for wooden one (didn't know where to start looking for one and you can use the same wood you are using for the rest of the lamp).
You take the Antonius basket, cut out a hole for the wood. Secure the wood with two other pieces of wood using the threaded rod and bolts. You have to also secure the two supporting pieces to the mold as it will be upside down. Pour the concrete (I used only cement and water mixture. It creates smooth surface and is hard enough to support the lamp). Cover with plastic and spray with water few times a day. After 2-3 days you can take it out and assemble the lamp.
Easy and very cheap.
Thanks again Minni.
~ Petr, Spain