applied to the magnesium band 64 in some cases operation of only one of the heads 68 and 78 may be sufficient band 72 is preheated at heated roll 80 and then bonded to band 64 in rolling mill 82 to form a clad sheet product 84 composed as indicated in the detail view fig4 u2032 of a magnesium band 64 and an aluminum cladding 72 the caster in fig5 differs from that in fig4 in the provision of means for feeding another band of aluminum cladding 86 into the other side of the rolling mill 82 surface preparation is provided on both sides of band 64 by the provision an additional mia cleaning head 88 and thermal spray station 91 band 86 is fed from a coil 90 and cleaned by mia cleaning head 92 the clad sheet product is composed as indicated in the detail view fig6 u2032 of a magnesium band 64 and two aluminum cladding bands 72 and 86 fig6 shows an embodiment of applying cladding to a core by a thermal spray process for instance arc spray a magnesium band 64 emerges from the twin roll caster 22 and is given a surface preparation treatment in this case by scratch brush 94 the band is then pre heated at 70 and from there moves over thermal spray deposition heads 96 where the first head applies a coating to prevent inter diffusion between the magnesium and the aluminum that will.