Saturday, April 18, 2015

Gatepost (85)

Post 85 in an ongoing series describing the design and construction of a kabukimon, a type of Japanese gate. This is a project for the Museum of Fine Arts in Boston. Post 1 in this series can be found here if you'd like to start at the beginning. Each post links to the next at the bottom of the page. Recent installments also to be found in the 'Blog archive' index to the right of the page.

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I expect this will be the second-to-last posting in this series.

After a 5-day vacation down to North Carolina, I returned to the MFA to finish up some of the remaining items from the gate installation. During the interim all sorts of interesting things happened at site....

I wanted to get to site for 7:30am, and I needed to drop by my shop on the way to pick up a couple of items which I had thought to bring along while tossing and turning the night before. I got up at 5:00, and was out the door at 5:15. I thought this would enable me to slip into the city before rush hour got going too much. Wrong. Way wrong.

I got in at 8:15. Leaving 45 minutes earlier than I might otherwise got me in at about the same time.

Anyway, the welders were coming to site at about 9:30 so the first order of business was to set up the kiosk, connecting lower framing to upper, and then to fit the shachi sen pins to the crossbeam joints and then the wedges to lock up the scarf joints: 


That went smoothly and the the joints drew up tightly. The shoes are stainless steel and are to be connected to some mild steel foundation elements in the ground. Between the two metals was a 3/8" mild steel plate which was affixed to the stainless shoes by way of six 1/2" fine thread stainless allen head bolts:


The mild steel plate was in turn to be welded to the mild steel in the ground.

The welders were also delayed in getting to site because of Boston traffic, however once there they got to work fairly quickly. The mild steel in the ground was cleaned off with a grinder, then we all lifted the kiosk up and placed it onto position. A few tack welds were made and the structure checked for level and plumb, and adjusted slightly. Then the welds were burned in:


While this process was going on a representative from the fire department was on hand to supervise the process. Apparently there was a major fire in boston a few years back caused by welding, so now they are very strict about the permitting, supervision and inspection.

The welding done, the welder told me that the joins were good for 60,000 lbs., which I reckon should be enough for this structure:


The hardware has also been refitted, in preparation for the wooden sign board which I will be rehanging next week. I think the design of metal shoes, which looks close to the original metal plates but keeps the post bottom well out of the ground instead of in the ground, and allows for the structure to be readily removed simply by unbolting, was a success.

I'm pleased with the way the kiosk rebuilding came out, and glad to have it at last standing again and its roof's delicate copper work out of harm's way.

I had worked with Port Orford Cedar many years back in Northern California, where it is sunny for 10 months of the year it seems, and it appeared to tolerate outdoor exposure fairly well. On the Ellison project, I recall some cedar-clad exterior posts developing problems with shrinkage after exposure to the sun, however it otherwise seemed well behaved. This project gave me a chance to work much more thoroughly with the material over the past year or so, and yet I wasn't entirely sure what to expect when it was put out in the weather.

In the early days of this project I argued strenuously - and ultimately unsuccessfully - for making the new gate a roofed gate, having seen the seriously bad degrade to wooden elements in the old gate. Having lost that battle, at least the new gate would have an improved foundation system which kept the post lowers and the panel sill out of the soil, along with changing the old side door's wooden sill for a granite one. Also the copper cladding would be far more extensive on the new gate, extending to post lowers, the top of the sill, the tops of the rear support posts, and, most critically, was to be properly attached with clips instead of being face-nailed on like the old copper.

I also took a lot of time and care to dry the wood slowly and carefully down to a suitable moisture content averaging 12%. The wood came down to 12% and had minimal degrade. That moisture content was thought to be about right for the installed location, however the environmental conditions in the gate's location are fairly varied. Also, being a large flat wall of material, one side of the gate would tend to get more sun than the other, and that was invariably going to affect what the wood was going to do....

All that careful preparation and design notwithstanding, I could not be certain at all with what actually would happen to the wood once in place and exposed to the weather.

Wood is a varied material, to say the least. If a wood is going to be exposed to the outdoors, then the best choice is to use species with good rot resistance and stability. That's the starting point. I have been learning about various woods in this regard through some the pieces I have installed outdoors around my house. In the front yard, for example, there is a shrine lantern made entirely of Honduran mahogany. It's on the sun-exposed side of the yard and has been beaten by the sun for two full summers, and also therefore withstood two winters as well. That piece is holding up exceptionally well. Other than the inevitable wood bleaching from the sun, and a little shrinkage in the roof panels, there is not a crack or a check to be seen anywhere. I find that wood to be very impressive in that regard.

Out in the back yard we have a garden with Black Locust planting beds directly in the soil. That wood was green when put together with joinery (since you cannot find anyone willing to dry that wood around here), and has suffered some degrade from shrinkage. The joints are holding together fine however the end grain has checked extensively. The soil has not bothered the wood at all from what I can see.

Also in that garden are some Jatoba trellises, and these have been through a summer and two winters so far. These are holding up quite well, with some bleaching and a bit of distortion. Interestingly the white paint I put on the end grain of the Jatoba has not adhered well at all.

I've been learning a lot from these small projects out in the weather.

While I was away on vacation, it rained in Boston. We don't get the monsoon-like conditions you will see in the Pacific Northwest around here. It'll rain for a day or two at most and that's about it.

The rain caused the door drawbar to swell and get stuck so they could not open the main doors of the gate. Upon return, I was anticipating having to cut out of the kannuki to remove it, and had fabricated a spare (slimmer) one in preparation for the visit to site. However when we got there we found we could pull the kannuki out without too much effort. However, it wasn't raining and had presumably shrunk back down. The new one I had made was 1mm skinnier in thickness and section height, however I held off on transferring the bronze end caps over, and simply fitted the spare in 'as is'. It's going to rain this weekend and I want to see if it swells sufficiently to bind. If so, I know to go skinnier yet with the dimensions. I want to keep the bar as fat as possible so the gate doors do not have a lot of play when they are held together with the drawbar. So I make my best guess and then wait and see.

The fence end wall caps, though dry vertical grain material and epoxied together, had developed quite a bit more checking than I had expected. These 'sins' we covered with three coats of paint, which should mitigate that issue:


The concrete fixing screw counterbores on those panels are not yet plugged. That'll happen next week.

A look at the right side end cap from the inside after paint:


Also visible in the above picture is the copper cap not fitted to the top of the kasagi beam overhead. I also fitted the two-piece copper cap to the main crossbeam, kabuki, and to the paneled section's mud sill. It was nice to have all that in place.

Ah the lock....

The side door lock was operating fine when I had left site last, however in the interim the cylinder had come a bit loose and had made the door a problem to unlock, so MFA staff had to jump the fence to open the side door's deadbolt. Then something else went on which led to the striker of the lock getting broken. By the time I arrived the entire lock box had been removed:


The locksmith, also delayed by bad traffic, showed up later that morning. His opinion was that the lock wasn't going to last well, and had a proposal for installing the deadbolt back temporarily and then seeing about getting a custom lock box made in Connecticut.

The lock had come without any mounting instructions, and I could see that I should have tightened the set screw which fixed the lock cylinder. I had not known about this, and the spinning cylinder had led to a cascade of events which rendered the lock box broken. I was dismayed at this outcome but it is what it is. I have ordered a new box lock from Japan. Once that is installed the old broken one can come out and be sent to that place in CT to see if they can make a more robust duplicate.

Another issue: when I had showed up with the new gate about 10 days ago, I learned that the MFA had wanted the gate's lock keyed alike to other locks, and this was a new piece of information for me.

I wish I had known that particular matter before ordering the lock in the first place. Water under the bridge now.

I had no idea whether the new Japanese lock could be have its cylinder recored to suit the required key, but was hopeful. According to the locksmith however, the old lock cannot be refitted with the desired cylinder core, so the only recourse is to have a custom lock box made which will fit the lock's door plate mountings. And that's not a 'for sure' thing, just a possibility to explore. At least in the short term the door is going to be lockable, which will allow the chain-link fencing to come down at the front of the gate.

A lot more hassle there with the lock than I had ever dreamed possible! About the last thing I would have imagined to be an issue.

With the kiosk set up, and the door lock issue resolved, we could attend to the remaining minor tasks on the gate itself. One of those was to trim the kusabi (wedges) on the stretchers and paint their exposed end grain:


A look at the upper stretcher connection to the rear support post with the kusabi trimmed:


The kusabi were flat to the upper edge of the stretchers when I left, and are fine-grained vertical grain material, however exposure to the weather had caused them to curl very slightly. I find this annoying, but I gotta live with it.

It was astonishing to see the degrade in some areas of the gate after just a week outdoors. The main door tops had checked quite a bit, the front panels, despite being 10% MC when installed, had shrunk. I could see that the main door stiles had sufficiently expanded after they had been rained upon so as to push tight against one another. So, we took the main doors off, I planed the stiles about 1/16" each to give a 1/8"+ gap when the doors are closed up, and painted the stile's end grain with epoxy to seal them.

I had made copper caps for the door stiles, however I later decided not to install them after worrying about swelling/movement causing them to rub on adjacent pieces and rub off their black powder coating. Also, the adjustment to the door stiles in fitting them has meant the original copper caps I had fabricated are now too large. I think I will see how the epoxy coating holds up first, and if it seems necessary down the line, and the door stile dimensions are proven to be interference-free in all conditions, I'll have new copper caps made.

I'll be back to site next week for a few final minor tasks. There is a invitation-only opening gala at the end of next week (guess who has to buy a new suit?), and after that the garden will be open to the public.

The Japanese gardener who is responsible for the Tenshin-en's garden maintenance came by and shook my hand, saying he thought the gate was terrific and that it would be "great if we could work together on projects together in the future". That was nice.

Once this job is buttoned up, I'll be turning my attentions to finishing two more Chinese wheelbarrows in teak for Jeff Koons, and then there will be some repair work to do on the Machi-ya at the Boston Children's Museum. After that, I'll be getting started on the sideboard in bubinga for my west coast client, and I'm currently engaged in the design process for that. So, lots of thrills and spills to come this year.

All for now - thanks for visiting the Carpentry Way.