Infusion appearance of infused laminates, four additional test laminates were manufactured. These were typical boat hull sandwich structures with a PVC foam core. The first one had no skin or barrier coat. The second one had an AME 6000 T 35 skin coat. The third one had an AME VPRO barrier coat. The fourth one had both an AME VPRO barrier coat and an AME 6000 T 35 skin coat. For comparison, a reference CSM laminate was made by hand lay-up. The laminates were aged in the same way as before and their surface quality was measured after each step. The gelcoat and barrier coat thicknesses were monitored during the manufacture, aiming at 0.8 and 0.7 mm wet thicknesses respectively. The skin coat consisted of two layers of 300 g/m2 CSM, with a targeted cured thickness of approximately 1 mm. The results showed clear differences between the laminates. The influence of the skin coat on fibre print-through can be seen as a drop in Ra. The AME VPRO barrier coat prevented fibre printthrough so well that the final Ra value of the selected laminate structure was close to that of the CSM hand laminate. Adding a skin coat to the AME VPRO barrier coat did not have a notable influence on fibre print-through. Conclusions In this project, the surface quality of infused laminates was observed and alternative ways of improving it were developed. New types of low-shrinkage resins together with special surface reinforcements were introduced. Tests showed that low-shrinkage resins combined with smooth reinforcements yielded a more satisfactory surface quality than traditional resin/reinforcement combinations. Moreover, it was noted that an AME VPRO barrier coat prevented fibre print-through more effectively than a skin coat. As a conclusion, it was shown that, in vacuum infusion, a surface quality equivalent to traditional hand lay-up can be achieved without a skin coat. Fig. 4: Both skin and barrier coats lowered fibre print-through. The final surface quality of the AME VPRO barrier laminate was close to a typical CSM hand laminate level. More information: www.miktech.fi No43 September 2008 / JEC Composites Magazine 43http://www.miktech.fi http://www.corematerials.alcancomposites.com