Island Forge: Part 6 – Interior Walls & Shutters

This series of photo essays will document the preparation, construction, and set up of a simple swordsmith style kajiba (鍛冶場, forge building) from the ground up. The main inspiration for aesthetic, form, and technique is the humble Japanese inaka naya (納屋) style of a century ago.

Earthen Walls

The interior walls are arakabe (荒壁), a traditional infill technique used extensively in Japan, and some of the lower sections are reclaimed wood. Arakabetsuchi (荒壁土) is a rough mixture of natural clay, sand, and straw applied over lath (komai/kabekomai 壁小舞).

In this case the soil was used as-found and large rocks were picked out during mixing and application. In the Kansai region (eg. Kyoto and Osaka) the mixture is sifted through a 50mm screen for consistency. For a less-utilitarian structure the arakabe would be coated with a sandy middle layer and a finer top layer of finely screened material.

Reclaimed first slabs are used to tie between the timbers in certain locations.

Reclaimed split battens are nailed over the gaps and horizontal split cedar lath is nailed to them.

A finer screened soil mixture with less/smaller stones is helpful for smoothing thinner areas above battens.

After rough application, reclaimed wooden walls visible below the tie beam.

An antique cupboard relocated from the old shop and built into the earthen wall.

Split cedar and bamboo lath at left, fresh arakabe at right.

Dried arakabe surface, project rack above, kata hanging below.

Interior walls almost dry, the lower section is thinner to allow the sliding door to pass in front.

Reclaimed antique hand-hewn first slabs make up the ventilation in the back wall as well.

Cedar Blackout Panels

In order to facilitate light control during operations such as yaki-ire, two hanging panels made from reclaimed boards can be hung in various locations in the forge. They are sized to completely block the north windows but can be used to partially block the larger windows and even the smoke louvers if necessary at certain times of day.

Made from two matching slices of a cedar tree that was once used as a counter top in a field camp.

Split Cedar Shutters

Light control on the south windows is facilitated by exterior shutters that swing upwards (shitomibame 蔀羽目) to create shade even when opened. The material is thin boards of split cedar and they can be propped open at various angles or hung from hooks above like shitomido (蔀戸).

Propped open the shutters form an awning to keep direct light from the workshop.

Inside view with shutters closed.

Inside view with shutters held partly open by shitomido tsurikanagu (蔀戸吊金具) hanging brackets for shade.

The cedar will eventually age to a lovely silver colour to match the reclaimed window sill.

A shorter hook raises the shutter closer to level but runs the rain off.

The longer hook allows air to flow through but keeps the lighting dim.

Timber Workbench

A sturdy mounting spot for the leg vise and a surface for tools. The raw materials are salvaged posts and hand sawn first slabs. A shelf below will provide much needed storage space off the floor.

Preparing the simple half lapped joinery.

In place and ready for the leg vise to be mounted.

The next steps will be to organize the tools and steel and start forging!

Timeline

Gathering materials began in Fall 2018, site preparation in December 2018, the lumber was milled in the first week of January 2019, the frame assembled February 5th, and roofed February 7th. Yakisugi siding and tsuchikabe walls installed during March, and interior wall finishing in April. The goal is to have it operational by Summer 2019 minus a few finishing details.

Thanks to all who were involved in one way or another in helping facilitate this project, providing space, time, materials, assistance, advice, and encouragement.