For anyone wanting to try their hand at grafting, this video from Johnny's will be a great help. I cannot emphasize enough that you should use a dome-covered tray, keep the inside humid and away from sunlight/high heat until the grafts have taken.
You can find inexpensive double edge razor blades at Wal-Mart; Wilkinson Sword. $1.76 for a ten pack. The major drug store chains also sell them, but at up to 3X the price - or higher!
http://www.walmart.com/ip/20926177?a...l5=pla&veh=sem
Two things you don't want to do:
Do not bury the tomato seedlings below the grafted section of the stem. This defeats the purpose of using rootstock, since the top-grafted scion will send out roots of its' own.
Don't cut yourself! These blades are literally razor sharp. If you feel uncomfortable handling a thin bare blade, you can pick up an inexpensive razor that is designed to hold 1/2 a blade, after you split it in two. This is what I use. I also keep a glass of 90% isopropyl alcohol on the bench, to sterilize the blade as needed. (Give it a few minutes to dry before you start making your cuts) Sally Beauty stocks this razor in their stores and I'm sure you can find one at other beauty/barber suppliers.
http://www.sallybeauty.com/Magic-Raz...l?cm_vc=SEARCH
Video credit:
Produced by Vern Grubinger, University of Vermont Extension
http://www.johnnyseeds.com/t-video_tomato_grafting.aspx