birds mouth mast

[mirage]

Does anyone know if it is possible to join a few sections together when making a hollow mast using the birds mouth construction?. If so how is it done?

[alan white]

Accuracy of the pieces and accuracy of the building table is vital. The vee cuts must be carefully done. All of the staves should be identical in dimension and taper, entailing setting up a bench as long as the mast and clamping/stacking straight-ripped pieces four or eight high and planing them down together. Pieces will no doubt be scarfed at 10:1 or so to get long pieces. No scarfs should be adjacent to other scarfs.
The vee-cuts can be done beforehand on the table saw, since only the flat face will get planed to a taper (where there is a taper).
There are eight pieces. In addition, there would be solid fillers in several places.
You need a lot of glue-time. Tropical epoxy hardener will allow a good long open time. So will air conditioning or cool seasonal temps followed by turning on a heater once all is clamped.
More people would help. A set of staves made of cheap wood, maybe a few feet long, will allow practice clamping. Staves will have corners sticking out. this will be the point where the "clamps" contact. clamps can be as simple as multiple loops of nylon twine (a selvegee) a bit larger than the mast diameter, set aside and waiting for the gluing operation. One every foot, for example. These are tightened by driving under them wooden wedges also waiting in quantity. Nylon webbing sewn into loops would be even better.
All staves were multiple coated with epoxy on the inside surface days ago.
The "clamps" can be positioned along one stave first and the remainder of the staves slid in end-wise until all eight fill the clamp-loops.
Do a dry run first, no glue, to see how it's gonna go.
Include the solid blocking in the dry run.
Use full strength epoxy to glue the staves, but use a thicked epoxy to glue in the blocking to ensure all gaps are filled.
Have lots of latex gloves on hand.

Alan

[Raggi_Thor]

Thanks Alan, that was a good description. I'll look back here when I need a wooden mast.