It's not an exact science. I don't know if this will help but I put a bunch of information on making foam swords over here (https://www.instructables.com/DIY-Foam-Weaponry...) that might give you some ideas. Let me know how it goes!
Oh, I forgot, I used two cores. I got the fiberglass from Home Depot.
Hmm, I'm not sure, it's been a while. Maybe here? I looked up "filament wound epoxy tubing" on google and found a few different options, so probably pick the one that works best for you.:D best of luck making your staff!! I'd love to see pics when you're done.
24 Carrot Cake
Pressly:DIY Almighty Smartphone Button
A rainbow of fractals in Minecraft
Crayon Melt Art
Burning Soap Bubbles
Art Against Humanity
3D Chess Board
Teen Survival Box - The Best Graduation Present EVER!
Taste the Rainbow
Hidden Computer Drawer
HOW TO: Use Old CDs for Mosaic Craft Projects - DIY Kitchen Backsplash Tips and Tricks
Build Your Own Smartphone
Electric Cigar-Box guitar w/ Built in amplifier
Pixel Minecraft Nerf
How to Make Ninja Stress Balls
Bent Wood Rings
Bentwood Rings with Stone Inlay
Woven Wire Rings
Miniature Minecraft Cubes!
Password protected sketchbook
Giant wooden Lego men
Giant Cardboard LEGO Blocks
Loading Message Card
Wooden YU-GI-OH Card (Or any card you like)
How To Recycle HDPE Plastic The Easy Way
Cat Sweater with Zipper-Mouth
Knex Ball Machine: Uprising
How To Make A Phone Wire Bracelet
Broken iPod Touch Wallet
DIY 3D Head-Mounted-Display using your smartphone
Terrarium in a Bottle Necklace! Fairy Garden Jewelry!
Periodic table of the elements blocks
Gummi Bear Surgery
PC to Portable workstation/toolbox
How To Recycle Bottle Lids into Slingshots
Make your own smart watch
LEGO Desert Eagle .50
Instructions on how to climb a staircase
Pick holder pendant
Multi key + Bike Tools + USB Drive + Bottle opener + Screwdriver (~$15 ~1hr)
Creating your First Multi-touch Table
How To Make Your Own Sugru Substitute
sugru - how to make your own DIY sugru sachet / save left over sugru
Make your own cellphone from scratch.
Glowing Color-Changing Guitar
Cyberpunk cellphone watch
Altoids Sours BBQ Grill
PONG Video Game Costume
The Ol' Squirter: A Rather Large Water Gun
Hack an RC car's unused 3rd channel!
Build a Suitcase Drum Set
Cardboard Electric Guitar
PVC AND DUCT TAPE KAYAK
Giant 100mm LED
DIY Google Glass AKA the "Beady-i"
Invisible Book Shelf
Raspberry Pi wearable computer.
Twitter Mood Light - The World's Mood in a Box
Embossing Designs Into Duct Tape
Dragon Gem K'nex Ball Machine
Steampunk Treo Smartphone Mark 1
Hex Nut Tree Topper and Ornaments
Paint Pulse: Digital Water Marbling
How to Make Chewing Gum
Cargo Scarf: Free your hands, and your mind will follow!
How to Make a Cardboard Canoe for your Kids in the Pool
magnetic silly putty
Pac-Man & "Tie Dye" Bread!
Lego Computer Case
100% Authentic Duct Tape Hoodie (110+ yards of duct tape)