After my post in april, I did some pruning on the crabapples. Put the shoots in my nursery outdorors and water more or less daily. A few held on for awhile. But, when I went away for 4th of july for 2 or 3 days, the folks who watered them either missed them or didnt give them enough. Out of 30 or so I did, only about 7 or 8 were holding into june. I had 3 or 4 right before the 4th of july, then those died. I did this with the water sprouts on my old apple trees too, maybe 2 or 3 out of 20 held on for the month of may and thats it.
Wanna do a bunch of rootstocks cheap..... Well for the time, effort, and other supplies involved, a 3 or 4 dollar roostock is pretty darn cheap already in my book.
But, I did see a youtube video of a guy who took a B118, grew it to about 6ft tall or so, then put it on it's side into the soil. He buried it in woodchips and sprouts would shoot off of them. He would dig down into the chips until he has some decent bit of roots, then clipped a roostock off.