Here is how you make a slingshot capable of denting a metal stopsign:
Step 1: Materials
Surgical tubing; the big mamma of slingshot elastics ($17 for 10 feet at Lowe's.)
A knife; pretty obvious why I have this
An even, Y shaped stick; DUH
Leather pouch; if u want a ghetto slingshot, layered duct tape works
Cotton string; nothing to say about that
Step 2: Stick
I cut my stick with a pair of hedge clippers. I recommend hickory. The shorter the two prongs are, the easier it will be to pull back the slingshot.
Step 3: Sring
Cut 4 long pieces of string
Step 4: Tubing
Cut 2 pieces of tubing, each about a foot long. Cut vertical slits on both sides of your pouch. Run the tubing through the pouch like so.
Step 5: Finishing Bands
Double the tubing back on itself and tie it down with string. The short part of the tubing should face outwards.
Step 6: Attaching Bands
Double the ends of the bands over the end of the stick. Making sure that both sides are of equal length, tie the bands to the stick with string.
Step 7: Done!
You now have a very powerful, accurate, and reliable slingshot. You may want to experiment with different lengths of tubing and sticks.
I hope this was helpful. Comment, and tell me if it was!