Sunday, February 12, 2017

Project #17 - Mounting Shiro-suita from Ohira-yama on a wooden support

Again - another non-knifemaking project. Somewhat similar to what I did in Project #14, but this time a bit more complicated - with a shaped base. After all - we are talking $500 stone which deserves to be mounted properly :)

This project proved considerably more involved that I expected - partially because after 2 hours of work I realised that I needed to start from scratch.

Disclaimer: I am even less of a woodworker than I am a knifemaker. Those who have experience with woodworking will probably shake their head when reading this I assume. Those, who like me do not have that experience should consider this article to be at most an inspiration, not a How To instruction.


  • Wood No. 1: Peruvian nutmeg
  • Wood No.2:  Brazilian tulipwood (Dalbergia decipularis).
  • G/flex epoxy (lot's of it)
  • Shellac (1:5 weight parts with ethanol)
  • water-based lacquer from 330mate_com (apparently not available since several months), but it is really great and 100% water resistant once dry.

The design

I wanted to do something a little nicer that just a rectangular piece of wood and then I got a very nice (about 100 years old) mounted on a nicely shaped (but otherwise very simple and roughly finished) base that I took for inspiration. So after working on the design ... for about 10 minutes, I came up with the following:

The profile of the holder
Nothing fancy. What is not shown is that I decided to embed the stone some 2-3 mm into the wood for a more secure attachment.

The process

The basic idea was:
  • cut the board to shape
  • shape the board with rasps and files 
  • remove about 3 mm of material (with a chisel) so that the stone can 'sink in'
  • finish the board with sand paper, coat with Shellac
  • coat the bottom and sides of the stone with a lacquer
  • fill-in low spot on the bottom side of the stone with epoxy
  • glue the stone to the board
Simple and easy, right?  Nope :)

Attempt No.1

The first step was to cut out a pice of board that had the right dimensions. It turned out to be a rather decent upper body training to make one long (28 cm) and one shorter (9 cm) cut into a 4 cm thick hard wood.

Note-to-self: get a bandsaw
 Once the board was cut to shape and sides evened out with a coarse sandpaper, I proceeded to shape the base with rasps - the Japanese one is really great.

It is all straight forward.

About to start shaping (rounding) one of the ends
 I first shaped the ends of the stone with the rasp (and took first notice that wood seems to chip too easily) and than started to work on the 'arches'. My hands were already aching and there was a lot of material to be removed which on top of everything kept chipping. At this stage I should mention that I have never did any kind of work like this with a rasp, so making errors is not really surprising here.

Well, not quite finished yet
For a reason not known to me, until this moment I competely forgot that I have a little 1x30" belt grinder. I felt so stupid that I started to laugh. I've put on a fresh #40 grit ceramic belt and 15 minutes later the rough shaping was finished.

After about 5 minutes on belt sander.
I then switched to #120 belt to smooth out the arches.

Before doing any more finishing work I turned to the next task - cutting /chiseling out the groove for the stone. The idea was:

  • Draw the profile (from the top of course) of the stone on the wood
  • Cut along the profile line with some thin blade (to keep chipping the wood outside the area in check)
  • Use a special 'curved upwards' chisel (also known as Saya Nomi) made by Robin Dalmann to slowly remove the material.
Already trying to make a deep enough cut along the line proved pretty much impossible as the wood was, well - hard, but after struggling with the chisel for about 15 minutes I realised that it will take me many, many hours to get the work done, and, that the wood is very chippy along the grain.

At this stage I abandoned this piece of wood.
Yep, the wood chipped very easily. In retrospect it was not maybe quite
as bad, but I did not come to think about the Proxxon.
So I stopped, went to local hardware store and bought a proxxon with cutting discs and a milling bit. Yep, I chickened out.

Attempt No.2

Since I was not too impressed by the behaviour of the wood, I have decided - before doing any more work - to switch to the board which I originally bought for the purpose - a lovely piece of Brazilwood. The reason I did not use it in the first place was that the surface was very rough and about 2 - 3 mm of material needed to be removed to flatten it and since I did not have an idea how to get that done, I just put it aside.

But since the brilliant idea of using the belt grinder (which I have for about a year and use for all possible tasks) I now had the means to do it in a reasonable time.
Board that I originally bought for the purpose

But first of course the board had to be cut to shape, so ....

Anyone finding this familiar?
But once the cutting was done and I cleaned the sides quickly on the grinder so I could proceed to form the board.

This time much faster.
It took me about 30 minutes to carefully grind the board to shape with a #40 belt and clean it up to #120 belt. It was very easy to make 'facets' into the arches, but not easy to remove them.

Rough shaping finished, the wood has a lovely figure.
The wood is really lovely.
 I then quickly sanded the wood with #240 sandpaper and worked on the arches a little more and followed with #400. Then it was time to get digging.

Did I say to wood looks lovely?
After #400 grit.

First step as already mentioned was to draw the shape of the stone on top of the board. Just before I did that I noticed that the board did not have the same thickness on the long sides (say left-and-right). I felt stupid for not noticing sooner, so I wend to check the stone and ... found out that it was also tilted to one side - lucky me :) So I only needed to orient the stone such that the two tilts would mostly cancel. You need to have a lucky day from time to time.

Yes, this is the stone. The feel does not compare to synthetic stones.
Just fantastic :)
 Next - cutting along the line - this time with a cutting disc at 10.000 rpms (as 20.000 proved too much). This time I tested it first on an off-cut piece. Once I got a feel how to proceed I cut the grove.

Cutting the groove - the blue line indicates the depth I was after.
Just a few minutes later. The little Proxxon is definitely worth the cash.
At this stage I still wanted to try it with the chisel ...

Yep, the chisel is really is "bent".
And again, this is a hard wood ...

... and I was not getting nowhere. The fact that I basically did not work before with a chisel was not of much help either. So I turned to Proxxon and a milling bit and decided to do it the crude way.

Now this seems to work.
I first carefully milled a groove just along the cut-out line and them moved inwards. Eventually I had to swap to a longer mill bit. It took me about an hour of work and I had the depression where the stone would fit.

About half-way done.
I then proceeded with more sanding (and trying to cover-up the few places where my hand slipped with the Proxxon). I went through #400, #600 and #1000 grits. I used a sandpaper holder to make the work easier and keep flat parts more-less flat.

Sanded to #1000 grit and ready for Shellac.
Once I was happy with the result (and tested the stone would fit in) I proceeded to surface finish with Shellac. I use the 'clean' one (light amber color) mixed with ethanol about 1:5 or 1:6 and one could thin it even more for a more even result. Applying the first layer made the already strong figure even stronger.

About to start coating the base with Shellac
First coat of Shellac is drying.
Even though it is rather chilly in my workshop at the moment, the Shellac dried in about 15 minues. Within an hour I have applied 3 coats and decided to let it cure until the next day for first sanding with 0000 steel wool (that would be the finest grade). I would then repeat the process with applying 3 more layers, allowing them to fully cure and subsequently sand lightly with a steel wool.

The steel wool makes the overly glossy and not to even (in particular around edges) looking finish more even and less 'flashy'. See below.

After second round of 3 Shellac coats but BEFORE
sanding with a steel wool
After second round of 3 Shellac coats and AFTER
sanding with steel wool

The stone

In the mean time I needed to test the following:
  • water-based stone lacquer on a piece of natural stone I had lying around from making fingerstones
  • Once cured a bit see whether G/flex epoxy actually attaches to it
  • Test whether the G/flex could be removed from the sticky part of 2 different scotch tapes - this was necessary as I needed to fill-in one corner of the stone and wanted to use the tape to outline the shape

Coating the testing piece of stone with the stone lacquer.
Here I would s inforhort mention the lacquer from 300mate_com (an eBay seller who specializes in sharpening stones and knives). Concetrated the lacquer has a consistency of 'thick milk'. According to information provided with it it can be thined from 1:2 to 1:5 with water. I used 1:2 as that was plenty thin with the stone. Thinned lacquer looks exactly like milk and has practically no smell - so make sure you mark the container properly so someone does not drink it (!) as I guess it is not too healthy to do so.

I would use a simple hair brus to apply a thin coat to the stone surface. On places which are uneven (and thus a more lacquer would collect there) one could see 'white spots', but after drying you are left with nearly perfectly transparend, slightly glossy surface. Even after 5+coats you do not change the look of the stone. I really like that.

G/flex on both tapes and stone (after coating). Right - the
bottom side of the stone getting the lacquer.

So - on epoce it turned out that the lacquer works well, epoxy holds on it and the epoxy can indeed be removed from the tapes, I applied about 4 coats on the stone and once it all dried over night (I wanted to be sure that even the local fractures and inclusions were all dry) I moved to the next step - evening out the bottom side of the stone with epoxy. I did cover the complete top (working) surface of the stone with the orange Tesa tape to protect it before starting with the lacquer.

The reason to do this was to have the complete bottom part of the stone having contact with the wooden support and not to have one corner 'sticking out' and asking for trouble.

The top-left corner has a depression going down to the edge
that I wanted to fill with epoxy
Since the stone does not have equal thickness ove the whole area but has one long side thicker than the othjer, I taped wooden sticks to the thinner side to level the surface I was about to pour epoxy onto.

Working side of the stone - covered with Tesa tape
with 'leveling sticks' attached to it.
I then used the orange Tesa tape to make a barrier around the stone so the expoxy would stay where it should - yes this is why I tested whether it will be possible to remove the tape after the epoxy dried.

I have mixed 15g of G/flex and filled the corner and a few low spots along a strong, but shallow iron line. I took my time to do this as well as I could. G/flegavex was great for this job as it gave me enough working time plus its lower viscosity made it easier to spread it evenly.

The top-left corner and all the low spots filled with G/flex
Epoxe-filled corner
Low spots filled with epoxy
Checking the stone after the epoxy cured revealed that I indeed pretty much managed to level the bottom side side of the stone.

The repaired corner of the stone.
Seems that I actually managed to get it level rather well.

Once the re-modeling of the bottom part of the stone was done I have carefully removed the tape. Still - on several places it managed to remove the applied lacquer, so I had to re-apply it. This was however rather quick job.

Remnants of the lacquer on the tape.
Applying first layer of the lacquer after the tape was removed - the darker places
are where the stone absorbed the lacquer.

Finished base:

Bellow are a few photos of the finished base before the stone was glued on it. It can be clearly seen that my hand slipped a few times when working with the Proxxon. I will be more careful next time.

Bottom side - the curves show the grain of the wood
really nicely.
Detail of the milled depression.

Next to off-cut piece - shows the difference with and without
surface finish.
Next to off-cut piece - shows the difference with and without
surface finish.

Mounting the stone

Since I had to model one corne of the stone I needed to to some light adjustment to it so that it would fit will the base. I used a sharp knife to do that. Also the edges of the stone needed slight sanding to get a proper fit. This also meant that I had to apply a few coats of the stone lacquer to cover them

Once I was happy with the fit I have prepared 30g of G/flex epoxy, spread it evenly on the base and attached the stone. I would mention here that for this kind of job you do NOT want to use a 5 minutes epoxy - as it takes some time to spread it over the base, put in the stone, if necessary do some adjustments and finally wipe the excess - while the epoxy is still flowing. I have spent about 30 minutes wiping out the excess glue MANY single movement wipes. You can not cheap out using acetone as you would probably damage the Shellac, so just dry wiping. 

About to get started with gluing.
Stone is in place - now is the wiping time!
Filling in the corner was probably a good idea, it would otherwise been
in a risk of breaking off.

And done! :) Lets have a look how it looks in a kitchen environment

Lessons learned

This was a new kind of project for me, so naturally it was a lot of discovering and making mistakes. But here it comes:
  • If you have never worked with a high quality chisel (means hard and easy to chip), than starting with a hard wood is not going to be too successful and in particular - do not expect removing material fast.
  • If you want Shellac not to be uneven (mean uneven thickness after applying), than you need to make it thin (at least 1:5 if not thinner). Still - you can improve a lot with 0000 steel wool.
  • Do not sand after first coat of Shellac - the layer is too thin and you will just remove what you applied (though that may depend on what kind of finish you want). Applying around 3 layers will give you enough thickness so you will not go down to bare wood while sanding (lightly!) with the steel wool.
  • Once you turn to powered tools like Proxxon (or Dremel or similar), you need to be careful as you can very quickly dent or chip your work. I tried to be fast and the result shows this.
  • Always test new materials (glue, lacquer, wood, etc) or processes (sanding, filing, rasping, polishing, gluing of different materials, etc.) before you start to work on the actual piece. It can save you a lot of trouble.
  • That little 1x30" belt sander is really very helpful when working around wood :)

Finished stone

Let's splash some water on the stone to see the Aka Renge pattern


  1. really impressive work and a very nice idea the leveling of the stone using epoxy...

  2. Hi ,
    Nice article.Thank you for sharing the information.I really glad enjoy read that topic.I appreciate post for your.
    Knife making