If you draw a vacuum (put pressure)on a part with an 'open cell structure' core(honeycomb,etc) backing, don't you invite the skins to dimple in at each cell void?? The old problem with 'print thru' of the core structure (contour cut balsa in the beginning) would be much more promenant when utilizing polester resins as a result of their considerable shrinkage rate during curing in contrast to epoxies and vynlesters. Wouldn't this use of polesters be a problem with open cell nidacore? I realize the layer of mat is utilized to prevent some print-thru, but doesn't this now require a heavier mat to do the job. So now you have a heavier mat combined with the scrim mat that comes on the nidacore. All this mat adds up considerable in weight?? > Brian, I have never had a problem with print through with Nidacore. I > attribute this to the polyester scrim, and the fact as with most builders, a > layer of mat goes on after the gelcoat. Nidacore makes a version designed > specifically for infusion as well. > > > > ----- Original Message ----- > > But it doesn't work too well with vacuum systems (infusion, etc), does itPat? > > And there are some problems with 'print thru', particularly with > > polyester resins and its honeycomb structure?? > > > > Brian