Individual results will vary based on
1 quality of playpit balls used
2 quality of glue used
3 temperature of glue gun
4 weight, and type of filling used
5 your personal craftsmanship
Note: This video was originally posted on youtube. At the end of the video, it says to read the description box for more info. JTV doesn't allow very many characters in their video description boxes, so read the youtube description box at the following link for more info including alternate sealing methods, alternate filling options, and notes on fixing common problems you may have with home-made russian balls.
Video by Steve, November 2009