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

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