Burnt Chestnut wood
I often see "burnt chestnut" handles on Japanese knives (I also just ordered one). I browsed the web a bit, and knife handles seem the only object where this wood is mentioned; chestnut wood used by woodworkers is paler and, well, not burnt.
So is it, like the name implies, chestnut wood that has been burnt, or is it just a reference to the color? If burnt, is it only the outer layer? What is the process? Is it a traditional material for Japanese knives?
Also, how should someone care for that wood? Can tung oil (or similar) be used to protect the finish? Would it damage its "still grippy when wet" natural attributes?
It is exactly as the name implies ... burnt, just on the surface.
Toasting or burning the outer layer of the wood changes the color but more importantly, it alters the texture and improves the grip. As the wood chars, the texture will become more rough from the thermal expansion on the surface. At the same time, the carbon residue from the burn fills wood pores which helps to seal the grain. The combination has both waterproofing impact and adds texture which mproves the grip, particularly when wet.
To make the handle more waterproof you can oil with tung oil or linseed oil. That shouldn't have much impact on the "grippyness" ...
Is it traditional? .... not sure, but it's not a new technique. Shou Sugi Ban is the name of another method of burning wood that been used in Japanese woodworking for hundreds of years as a means of weatherproofing. I don't know if that had any influence on charring chestnut handles for knives, or when charred chestnut started to become more common, but it is a frequent option on Japanese knives.
You sir, are a gentleman and a scholar, thank you!
If I wanted to replicate the process, would a simple blowtorch do the trick, or there are more steps involved?
Glad to help.
Originally Posted by Brett_M
A blow torch should work fine. Couple things to be aware of. 1. If you're doing this to an already assembled handle with a horn or plastic ferrule wrap the ferrule with tape, cloth or something to make sure you don't accidentally hit it with the flame. You don't want to crack it, or otherwise damage it. 2. Keep the flame moving and don't sit in one place for too long. You don't want to go from light charring to burning.
The torch will raise the grain of the wood. If you like it very textured, you can leave as is. Alternatively, you can knock it down a little with steel wool by rubbing with the grain after the scorching. Once done, you can oil the handle if you want.
Another method ( specially If the handle is octogonal) is heating up a flat piece of steel with the torch and then " iron " each side of the handle; this way the sharp edges will not burn leaving more crispy angles.
Also no problem raising the fibers or grain of the wood (pass the iron with the grain), than just gently brush-clean until almost all the black is gone then oil or you favorite wood finish.
This process was used in ancient Korea specially in cabinetry to replicate mountains using flatsawn wood.
Sorry for my lack of grammar and Typos , just wanted to help
I simply find it amazing how helpful & cooperative people are on this forum. Props to all the "willing" to help!