I've been making faux armor using the foam and vinyl technique since 2005, and here is what I learned after years of practice. You can find large rolls (36" x 60") or sheets (9" x 12" or 12" x 18") of craft foam under the brand name Darice or Foamies. The thicknesses run from 2mm up to 6mm (which is very stiff and does not bend easily). I usually buy my craft foam from www.createforless.com
. For the vinyl, be sure to use the type that is suitable for clothing, not "marine vinyl" or "upholstery vinyl" (both of which are too thick for faux armor purposes). Also be sure the vinyl has a fabric backing (otherwise the vinyl by itself will be too thin and any imperfections, marks or colors on the foam will clearly show through). Nearly all clothing vinyl has a fabric backing, but sometimes it doesn't, so just double check to be sure. It really doesn't matter if you use 2-way or 4-way stretch vinyl. It all works pretty much the same way when using it for faux armor. I prefer to use a spray adhesive to attach the vinyl to the foam instead of any type of liquid or paste glue. Spray adhesive goes on smoothly, it covers the entire foam piece, and you can re-position the vinyl if necessary. I would also recommend any part of the armor that is curved or round that you bend it into shape first before apply the vinyl. If you apply the vinyl first and then try to bend the piece into shape, it may not work correctly. The vinyl actually makes the foam stiffer, so you may end up with wrinkles or the foam not bending exactly the way you want it to. Most vinyl vendors will send you sample swatches for a dollar or less each if you want to see the actual colors of a fabric since it can be difficult to judge onscreen. Comparison shop online for the vinyl. I check ebay first then expand my search to other fabric sites. It can be tough finding everything you need from one vendor, so you may end up having to buy from a few different sources to gather all the colors you need. Recently I had to order some vinyl on ebay that came all the way from South Korea. Measure, measure, measure! There is nothing worse than running out of foam or vinyl in the middle of your project.
Foam and vinyl armor is a great option as long as you plan your design very carefully and purchase your supplies wisely.