The replica process is currently the commercial process for producing porous ceramics or glasses over a wide range of porosity, usually specified in PPI (pore per inch) for foams. One challenge with foams is the need for very small cell sizes to ensure a homogeneous coating without blocking the pores. In the case of composites with multiple coatings of different materials, e.g. to increase bioactivity (fast conversion on the outside, slow conversion on the inside), the compatibility of the physical properties places special demands on the selection and processing of the materials. The feasibility and limits of the replication process are demonstrated using a composite of Bioglass 45S5 and P45K9. 45 ppi foams were coated up to X times with Bioglass 45S5, and after drying, coated with the phosphate glass P45K9. Both glasses have a similar CTE (X-value), which should at least prevent thermal delamination. The TG temperature for the 45S5 is Y and for the P45K9 is Z, the softening point T is X,Z. This gives a maximum sintering temperature of ZXY °C under the dimensional stability specification. Although no delamination occurs at this temperature, the full potential of 45S5 cannot be utilized due to the low temperature, resulting in very low strength. In addition, the polymer is not completely debonded, resulting in polymer residues in the webs that further reduce strength.