Ok, so this is what it looks like. You take your foam piece that is sanded well for surface defects. Apply a generous layer of WBPU (water based polyurethane for those just tuning in) and apply the class cloth over top. Once on the glass will be generally tacked in place. THen go over with your brush and apply WBPU on the top to really get it soaked in and sticking solid. You will want to avoid making the cloth go over or around sharp edges. It just will not go. Once dry trim the excess and BAM!... do the other side. THEN it will be done. Its really not hard. Do another layer or two to MAKE SURE YOU FILL ALL OF THE WEAVE!!! If you dont and you use an acetone-based rattle can paint... you are done. It will melt the foam. You have been warned. The picture shows just the first side application. Both sides are done now and the whole thing needs at least another sealer coat or two before paint. Once I get the wing to this point I will join the two and cut the hatch off.
The nice thing about this process on warbirds is that it adds next to no weight. and prevents the hangar rash and car dings that plague so many foam models. In addition you get this ever so slightly wavy surface area that looks just like the real surface area of metal sheeted warbirds. Now, you can apply several layers of WBPU and sand it back smooth. Thats fine. Some models will require this in areas. Just plan ahead to use this effect where you can. Also, at this point you can lightly sand the area and apply small drops of glue for rivets. The roughed area will allow the rivets to stick and not pop off. Further, the slightly raised bumps from where the sections of the fuselage meet will provide great reference points for panel lines. Sanding smooth will eliminate most of it but you may have some more prevalent than others. Use it to your advantage.
You should know me better. I'm never one to do overly popular models.
