Hera are Japanese bamboo spatulas. There can be made in a wide variety of sizes for numerous purposes; lifting, stirring, folding, smoothing, mechanical removal of backing material, marking for wet tearing, etc…. They are typically owner made, and can easily be customized with a knife or chisel– ie. making the blade slightly more flexible (by thinning) or less flexible (by shortening), making it smaller to fit a specific purpose, and making it sharper or duller. In fact, since the edge is very delicate, it is almost necessary that the owner be able to repair or reshape them. Recently, I became interested in them thanks to Robert Minte, conservator at the Bodeleian Library in Oxford, UK, who showed me some examples he made when he was studying scroll mounting in Japan.
Fig. I. Examples of several hera I have made.
Fig. II. Close up of a single hera, showing the flexible curved blade, transition from the handle, and the typical placement of a growth node near the end of the handle, on the right.
Hera are quite easy to make and another useful tool in a conservators arsenal. Small, thin ones as pictured above are useful for backing removal. I’ve even used some stout ones for lifting weak, deteriorated book cloth. Some conservators find them useful when removing pressure sensitive tape. Thicker pieces, with more of a knife shape, after soaking in water, are an effective tool for wet tearing, since they slightly abrade the tissue as well as wetting it. The strength, flexibility, and smoothness of bamboo is unique among materials. They are also very fun and highly addictive to make.
Bamboo. I found some bamboo at a local hardware store/ garden center. Larger diameter bamboo permits making a wider tool- a 3 inch diameter piece yields about a maximum .5 inch wide tool. There are over 1200 kinds of bamboo, but traditionally the best for hera is susu dake, or soot bamboo, which is very hard. According to Thompson, “Soot bamboo is so called because it was reclaimed from the roof beams of old Japanese houses. Other bamboos are perfectly acceptable but the slower grown (the hearly growth nodes should be as close together as possible) will produce more durable tools as the structure of the wood is more compact.” (1)
I cut the bamboo to the desired length with a coping saw. It is best to cut the pieces longer than required, then adjust the length after preliminary shaping. After cutting to length, it is easy to split into desired widths with chisel, then to pare them into rough square of rectangular shapes.
Fig. III. Splitting the bamboo with a chisel.
Working on a small block of wood to protect one’s work surface, the chisel was then used to square up the sides to the desired width, clean off any of the thin, soft inner lining of the bamboo, and smooth any rough corners. Mainly the soft interior of the bamboo is shaped– the cutting edge (the outside of the tool) is the outside of the bamboo.
To shape the blade, I found it easiest to clamp the handle of the tool and working with the bevel of the chisel, gradually shape a graceful transition. Bamboo is very easy to split and shape.
Fig. IV. Shaping the blade
Once the blade is at the desired thickness, it can be chopped to length with a quick chisel blow. At this point the bamboo is fairly brittle (2) so it is safest to continue to shape and refine the edge with sandpaper or scrape it. Caution: as it gets thinner, it can get sharp enough to easily puncture flesh. A progression of 150 US grit followed by 400 US grit worked well for the initial shaping. Final polishing consisted of a using 3M Tri-M-Ite polishing paper of 1200 then 6000 grit. A thin coat of Renaissance wax gave it a nice look and feel.
(1) Thompson, Andrew. ‘Japanese tools for conservation’ in The Paper Conservator, Vol. 30, 2006. (Pp. 65-72) There is a picture of a variety of sizes and shapes of hera in the article.
(2) In fact, it occurred to me that bamboo is much like the structure of a Japanese chisel– there is an extremely hard cutting edge (the outside of the bamboo), supported by a softer backing material (the inner pith) that adds flexibility and strength.