Yakisugi (grilled cedar) 焼き杉 - Charring Wood as a Finishing Modality

Jay, et. al.

Wanting to use wood from giant aspen we need cut down.
Since this wood prone to deteriorating, I would like to preserve it well for exterior applications, using whole or split logs and boards. Here are my steps with questions:

- remove bark from logs
        Essential?
- apply Tim-bor (borate product)
       Is this alot better than just using borax and water?
       Is borate important to preserve, even if charring?
       Does this serve as a flame stop alternative, or do I
        also need flame stop (or other fire retardant) ?  
- apply boiled linseed oil
        If I apply oil and borate product, do I still need a
        flame stop?
- char and scrape
- apply Natural Heritage or homemade oil/wax finish.
- keep wood above ground (scribing posts to stone, etc).

Thanks,
Drew in CO

Hello there, interesting twist. What are the benefits of only doing the first 3 feet?

I just want to share this video I found of the technique being done with means other than a propane torch.

Thanks for sharing this Lew.  Seems like a nice low tech approach.

L. Johnson wrote:I just want to share this video I found of the technique being done with means other than a propane torch.

This was fascinating to watch! I love the idea of doing this without propane. We have a bunch of red pine that I may try some charring on to make siding. I thought about just running boards through a bonfire, which, after watching his method, actually seems less risky than building a fire underneath them like he did!

Also, anyone know what that noisy machine is that he was cranking and burning boards with?

The author of the above video, Mr Chickadee, recently posted another video on the topic. In this he states that you can simply light a fire inside the box that you form if you'd rather not use the blowtorch.

Edit: d'oh, I just read the messages. That is literally what you were talking about and what is shown in the video. Ignore me. Leaving the video as it is related content.

I’m really curious how this stuff holds up. It seems like everyone is toting the traditional Japanese name and benefits of the method, but most people seem to be doing it their own way. I mean using propane torches, various species of wood, various char depths, scraping and brushing or not, oiling and sealing the wood or not...

And so much online information is so new that they would have no idea about the longevity of the finished work.

We have a bunch of freshly milled red pine and I’m considering charring some for a variety of applications. Chicken coop siding, fence posts, picnic table, benches... My thoughts are to either get a big propane torch or try running the wood through a bonfire. Maybe trying the flue idea, but it seems that it would be very easy to overcook the ends of the wood that are directly on the fire. Then I think I’ll try brushing off the excess char and adding either linseed oil or tung oil.

Who knows though, maybe I’ll get new information before getting started and change my plans!

Well, first hand I have seen a few buildings and structures with these boards. I can't say how old they are, but they certainly don't weather the same way as raw wood does. Japanese builders use a lot of raw cedar, permies would be happy. It ages and discolors pretty quickly, even if it lasts a long time. The burnt stuff doesn't change...

I don't see charred cedar a whole lot, probably because it's time consuming, energy intensive, and most buildings are made around here with the intention of being rebuilt in 15-20 years anyway.