Why risk personal injury of that sort, when you could just ask me, and I could make you some improvised claymore and bouncing betty mines instead?
Those can't be directed. Also, home made boom sticks can be wired up with string. Or socks. Imagine those in weapon traps. Plus detonating explosives underground... Doesn't seem particularly fun to me.
Or rather, it does, which is why I don't want to be underground when someone drops the match
Oh you silly man.
A claymore mine is a *directional* cluster mine. A suitable simulant can be fabricated similarly to a shaped charge explosive housing, with a purposefully weakened side, and a honeycomb filled with small metal bb's. A combination of case hardened steel, a high quality zirconium-aluminum oxide ceramic plate, and a kinetic detonator filled with a high explosive, like nitroglycerine, and you have yourself a real treat for goblin christmas.
Don't waste your time with little boom sticks. Go for the real fireworks on guy fawkes day.
Bouncing betties are good for elves and irritating little kobolds. But trolls, forgotten beasts, and the goblin menace? Play with the bigboy toys.
Also, don't waste time with black powder boomsticks. Not enough energy in the detonation for real fun. Go for nitrocellulose. Very easy to make. Probably could be made from dead pigtail socks even. All you need is really good cellulose dryer lint and some nitric and sulfuric acids.
Makes fine gun cotton. it packs 6 times the punch of black powder.
(Much longer post concerning synthesis of primer caps, suggestions for base gunbarrel steel alloys, and the like redacted, pending consideration of google indexer, and that it was even more scary than above.)
Just pointing out that claymore mines are very much directional, and will very much turn several people into ground beef, very very quickly.