The folks at Hot Wire Foam Factory are fantastic people, excellent customer service, and very generous when things don't go well with their products. I have several of their products, and some are better than others. The product you are referring to, I do have, but use very sparingly now, due to the same reason you noted, and for other reasons. I have had to come up with alternatives, and a drill press, a large hole cutter, and radial arm saw are now my tools of preference. Must be very cautious though, foam is not like wood, it can be in your hand one second, and airborne the next. The radial arm saw is safer, as it allows one to see both blade and fingers at the same time, using a table saw is very unsafe, and I absolutely do not recommend it.|
I make bridges now out of other things too, more conventional materials, plastics, wood, real stone, and foam.
I enjoy incorporating things that are really made for other uses into my bridges, as can be seen from some of my experiments in my blog.