Making a Hollow Mast with West System Epoxy

In this episode of Nomad Boat Building, Mark walks through the full process of building a bird’s mouth hollow wooden mast using traditional spar-making techniques and modern epoxy methods. Starting from the sail plan, we break down how to determine mast diameters, lay out an elliptical spar taper, and calculate stave dimensions. Then it’s into the shop to mill Douglas fir staves, cut precise bird’s mouth joints, plane accurate tapers, and glue everything together using West System 105 epoxy and 207 hardener. This hollow spar construction method creates a lightweight, strong wooden mast that’s easier to handle and step than a solid spar. Whether you’re building a small boat mast, boom, or yard, these techniques apply to traditional wooden spars of all kinds. Big thanks to West System Epoxy for supporting this video. https://www.westsystem.com/ 👉 Bird’s Mouth Spar Calculator & Resources https://www.chase-small-craft.com/birdsmouth-sparmaking  #Boatbuilding #WoodenMast #SparMaking #BirdsmouthJoint #Woodworking #Epoxy #TraditionalCraft #WestSystem00:00 Intro & Finished Mast Tease 00:41 What Is a Bird’s Mouth Mast? 00:47 Reading the Sail Plan for Mast Dimensions 01:32 Understanding Elliptical Spar Tapers 02:42 Simple Method for Laying Out a Mast Taper 05:44 Calculating and Tapering the Staves 06:28 Keeping One Side of the Mast Flat 07:30 Milling Douglas Fir Staves 08:52 Cutting the Bird’s Mouth Joint 09:25 Planing Stave Tapers by Hand 10:41 Preparing for Glue-Up & End Blocking 11:07 Making Octagonal Blocking for Mast Ends 13:26 Setting Up for the Epoxy Glue-Up 14:47 Keeping the Mast Flat During Assembly 17:14 Wetting Out Joints with Epoxy 19:13 Avoiding Glue Starvation 20:01 Installing Internal Mast Blocking 21:24 Coating the Inside of the Hollow Mast 22:37 Thickened Epoxy in the Bird’s Mouth Joints 24:17 Assembling the Staves in Saddles 26:22 Closing the Final Stave 27:31 Clamping with Hose Clamps 29:48 Laying the Mast Flat to Set Shape 30:45 Using a Laser to Keep the Mast Straight 31:44 Glue-Up Complete 34:18 Knocking Off Corners – Octagon Shaping 35:10 The 7-10-7 Rule (Octagon to 16 Sides) 38:53 Sanding the Mast Round 39:38 Why Hollow Masts Are Worth It 39:56 Final Thoughts & Resources My website: https://www.nomadboatbuilding.com Instagram: https://www.instagram.com/nomadboatbuilding/ Support these videos with monthly or annual pledges at Patreon: https://www.patreon.com/nomadboatbuilding Or make a one time donation: https://www.paypal.com/paypalme/nomadboatbuilding