H-Series beds are typically covered in Kapton. We find that urethanes adhere well to scuffed, cleaned Kapton. TPU also releases readily when acetone is applied at the seam. When we print in other materials, we often put a raft layer of TPU down as an adhesion layer. This is a simple solution to a complicated problem, and one advantage of multi-material printing. The TPU not only sticks well, but is also mechanically compliant, so it allows rigid parts that want to shrink and warp a tiny amount of room to move, thus preventing and peel points from initiating. Since the adhesion layer is consumable, the Kapton lasts virtually forever. The Kapton we provide is 0.2mm thick, which is incredibly durable and also much easier to install.
Many people use glass print surfaces, generally treated with a polymer (think hairspray). The threaded holes on the H-Series Bed are intended for this purpose (such as toe clamps to hold down the bed). Remember, when adding material to the bed, remeasure the Z-axis so the machine knows where the new bed surface should be.
We also like Geckotek material for all-around adhesion to PLA, PVA, TPU (be careful because it sticks extremely well), and others. Please take part in the forums to share your experience with adhesion and material combinations. If something works well for everyone, we will include it here.