Wooden Wayfarer sailboat mast restoration
This 23-foot long hollow Sitka Spruce mast belongs to a 1963 Wayfarer sailboat built in the U.K. It had been glued together in two halves, likely with Aerolite 306, a urea-formaldehyde adhesive developed for building wooden aircraft during WWII. Over the 55 years since it was built, the adhesive began to deteriorate in the luff groove, where it wasn't protected by varnish. Eventually, when the mast was wet, the glue joint and the luff groove would open up to the point where the luff rope would fall out.
At some point in the mast's life, the original Tufnol and bronze halyard sheaves had been removed and the mortices for them had been enlarged to take modern sheave inserts. Luckily, the original sheaves and axles had been kept. When the mast came in for repair, the owner asked for the sheaves to be put back as original.
Here's how it was repaired:
1. The mast was measured and a scale drawing produced. The scale drawing was used to lay out a set of supports for a jig that would be built to hold the mast in alignment during re-gluing.
2. Steam was directed at the glue joint using a 10-gallon steam boiler on a propane burner.
3. The glue slowly softened and released the two halves of the mast from each other. The released joint faces were as smooth and clean as the day they had been glued up. The builders' pencilled reference lines looked like they had just been drawn. No glue residue or squeeze-out was visible.
4. Damaged areas and previous repairs were made good. The mortices for the halyard sheaves were repaired to take their original sheaves.
5. The mating faces of the two halves were lightly skimmed with a sharp jointer plane to clean off any glue residue and ensure a good fit of the mating surfaces.
6. The gluing jig was set up using a laser level shot through multiple reference points. The extra width of the gluing supports provides a work surface to support the mast during gluing.
7. The mast halves were masked to save cleanup time. The mating surfaces were wet out with WEST 105 resin and slow hardener, then brushed with a thin coat of 105 resin thickened with microfibers.
8. The two halves were clamped together with zip ties and then slid into the jig to cure overnight. Light clamping pressure was applied with c-clamps.
9. New axles to replace the worn out sheave axles were turned from a silicon bronze bolt on a drill press.
10. After gluing, the mast was lightly planed and sanded and a sealer coat of spar varnish applied. Messenger lines for future halyards were fed through the mast with a vacuum cleaner prior to installing the original sheaves.
11. With the cleats re-installed, the mast is ready to be picked up by the owner who will complete the varnishing and re-rigging. Ready for another 55 years.