Island Forge: An Inside Look at Earthen Walls

An interesting opportunity to study the internal workings of tsuchikabe wall construction as the island kajiba series of photo essays comes to a concluson, documenting 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 utilitarian Japanese inaka naya (納屋) style of a century ago.

The kajiba project came to a close much earlier than expected which required the building, tools, and materials to be removed from the property on short notice. Several blacksmiths and friends providentially converged around the same time and helped make short work of cleaning up the area and providing new homes for most of the tools and materials. The building has been donated to a good cause and will eventually be reassembled by a young smith to launch his craft.


Yakisugi & Lath Walls

The first step was to remove all wall panels that were only wood. This was accomplished in sections by running stabilizing supports across the outside of each panel and then removing the screws holding the boards to the timberframe. This approach was then applied to the wall sections with earth plaster on the inside, keeping the clay intact as much as possible for reassembly. The amount of damage was minimal and the clay mixture surprisingly durable.

Island Blacksmith - Crossed Heart Forge
Cross section of interior earthen wall visible after removing the stabilized panel.
Island Blacksmith - Crossed Heart Forge
Bamboo lath visible along the edge where the earth meets the timber post.
Island Blacksmith - Crossed Heart Forge
Scraping away the overlap on the curved beams to prevent larger tear out.
Island Blacksmith - Crossed Heart Forge
Fairly clean removal with very little cracking or loss given the flexibility of the wood backing panels.
Island Blacksmith - Crossed Heart Forge
Outside view of yakisugi panels braced with scrap wood before removal in sections.
Island Blacksmith - Crossed Heart Forge
Inside view of panels being loosened one by one for removal, these are heavy!
Island Blacksmith - Crossed Heart Forge
Removing the angled yakisugi drip guard along the front wall.
Island Blacksmith - Crossed Heart Forge
Crisp looking strip along edge of cupboard inside front panel after removal.
Island Blacksmith - Crossed Heart Forge
Front panels removed, tied split cedar lath showing along the bottom edge of tsuchikabe infill.
Island Blacksmith - Crossed Heart Forge
The roof and upper tsuchikabe panels will be the goal for day two.

Disassembling the Roof

After the roof sheeting and framework is removed, the rafters and beams can be lifted off of the tenoned lath to allow the tsuchikabe panels to be removed.

Island Blacksmith - Crossed Heart Forge
Galvanized totan sheeting removed, purlins next.
Island Blacksmith - Crossed Heart Forge
Lifting the rafters off from the top of the wall provides an interesting look at the cross section.
Island Blacksmith - Crossed Heart Forge
Clay plaster interacting nicely with tied split cedar lath.
Island Blacksmith - Crossed Heart Forge
View showing the outside and inside of the tsuchikabe wall construction.
Island Blacksmith - Crossed Heart Forge
The smallest panels are light enough to lift out intact.
Island Blacksmith - Crossed Heart Forge
Wall is in excellent shape more than one year after installation, lovely view of the stone and brick floor.

Removing the Tsuchikabe

After the top rafters and beams are removed, the side tenons for each tsuchikabe panel can be sawed off freeing them from the timber frame. The two smallest panels can be lifted out but the larger four must be dropped to the ground for removal. A tarp catches the broken earth plaster for reconstitution at a later date. Historically old plaster has always been saved and reused as it is recognized as superior in quality to newly made material, and also cuts down the preparation time.

Island Blacksmith - Crossed Heart Forge
Side tenons sawed through allowing lath section to be lifted out or dropped to the ground onto a tarp.
Island Blacksmith - Crossed Heart Forge
A perfect drop with flat landing leaves the panel largely intact, even from 8′ off the ground.
Island Blacksmith - Crossed Heart Forge
A missed landing leaves the panel needing quite a bit of work to replace or restore.
Island Blacksmith - Crossed Heart Forge
Broken plaster is caught by a tarp and saved in buckets for future use.
Island Blacksmith - Crossed Heart Forge
The front roof beam is lifted off the top of the front panels and the same procedure repeated.

Structure

After the roof beams are removed the structure can be disassembled relatively quickly by a small crew. Once any remaining staple nails are removed, a timber hammer and a couple of extra hands keep the process moving quickly.

Island Blacksmith - Crossed Heart Forge
Once the rafters are removed the back wall panels can be swung away from the frame.
Island Blacksmith - Crossed Heart Forge
Working all the way around one post at a time in the reverse order of assembly, each wall is taken apart.
Island Blacksmith - Crossed Heart Forge
The large frame parts are labeled already but each and every piece of wood is given a label by the new owner during the disassembly.
Island Blacksmith - Crossed Heart Forge
The largest and heaviest panels are the last remaining pieces on the site.
Island Blacksmith - Crossed Heart Forge
Beautiful combination of green and gold Bamboo with earthen plaster.
Island Blacksmith - Crossed Heart Forge
Shadows of Bamboo leaves on the cracked earth surface.
Island Blacksmith - Crossed Heart Forge
The panels and timbers are loaded up carefully for transportation to their new home.

Floor

The floor was laid with reclaimed clay bricks from the backlot of the Bethlehem Walk set, along with some river stones. The bricks will be relocated to the museum forge and the stones are going to a good home.

Island Blacksmith - Crossed Heart Forge
Boiler or furnace brick, melted and warped from heat, with a character almost like cobblestone.
Island Blacksmith - Crossed Heart Forge
Naturally smooth river stones formed an undulating work area in front of the anvil, allowing strikers to develop a consistent location and foot placement by feel.
Island Blacksmith - Crossed Heart Forge
Post foundation stones, large retaining wall stones, and the sand and gravel base are all that was left the evening the large anvil was picked up to go to its new home, reunited with a former owner.
Island Blacksmith - Crossed Heart Forge
The number one encourager on the scene, who helped keep this project going during its most difficult days, here bidding a last farewell to a rusty old friend after almost a decade of work in the forge.

Special thanks also to Steve and Josh for helping with the takedown process in the middle of a busy hay season. Thanks to Michael and Kevin who assisted with moving brick and stone and to the many who offered encouragement, support, and help along the way.

see the whole process of construction in the island kajiba series

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