I've built a few by now, out of PVC. PVC will break sooner or later, so fixing it til its unfixable and building a new one is what I've been doing. The one I'm using now has lasted that longest. The thing about the new IKCA plan PVC dummy is that it has metal flanges going into Iron pipe which is screwed onto the plywood. You stick the PVC legs onto the iron pipes. Eventually you will make a good dummy that will take a punch and so of course you will knock the flanges loose. I have the legs come down, attach to 3ways and then have pipes going back, which then attach to each other with elbows or 3ways. Moves kind of like a rocking chair. Old IKCA was mounted on metal straps to plywood, which I've never tried. Metal dummy would be great, maybe someday, or I'd love to buy the ultraman. As far as sinking into the ground, that sounds great, but I would make it more like a mook jong as it sounds like that is more what you want anyway IKCA type dummy gives you targeting, esp. groin, legs, face, but no arms to simulate blocking or trapping. I've always wanted a metal dummy with a spring arm to practice trapping on. Hope this helps. building a dummy is worth it. One more thing, if you're building one for outside use only, look at using tires, I've done this and it's fun to practice escrima sticks and other weapons on.
