1. Is kintsugi food safe
2. What are the differences between the types of lacquer?
3. Can I use basic lacquer for all the processes?
4. Why is middle lacquer black and top lacquer red?
5. Is it possible to fill a crack with just lacquer?
6. Why use a middle and top lacquer?
7. Can I skip filling a chip on a cup and just coat it with silver? Below is the original question.
8. What is the difference between togidashi polished gold and gold polished with a burnishing tool.
9. Is this a hopeless project? How to clean old material, shelf life of lacquer.
10.Do the different choices of lacquer make a difference in the time taken for it to dry? Does it take hours or days for the lacquer to set?
B How long does it normally take to fix one piece from start to finish?

1 Is Kintsugi food safe?

Yes, all the lacquers I sell are food safe.

2 What are the differences between the types of lacquer?

This question is usually asked in relation to the 3 types of lacquer I sell.
Shinurushi is a synthetic lacquer.
Cashew lacquer is derived from cashew nut shells.
Real lacquer is made from lacquer tree sap.

Reactivity
Synthetic lacquer isn’t very reactive to skin.
Cashew lacquer is a little more reactive.
Real lacquer will sometimes cause reactions to skin.

Curing
There are big differences in the way each of them cure and how to use them. Both synthetic and cashew derived lacquer will cure in a room environment. Real lacquer needs to be cured in a warm, humid
place so it is usually dried in a cooler box with a heat source like a light bulb and a bowl of water for moisture.

Cashew has a much stronger smell when using it although it dries to a state without smell. It also will cure at room temperature and at regular humidity.
Real lacquer causes much more of a reaction to skin. It doesn’t have a strong smell when using as such like cashew lacquer. It also requires a temperature of 25 +C and a humidity level of more than 70%.

3 Can I use basic lacquer for all the processes?
Yes you can. It is better to use basic for the first steps such as mixing mugiurushi(flour/water/lacquer) or sabi(jinoko/water/lacquer) and then red for the middle and upper lacquers. Basic will work, it is a less refined lacquer so won’t give you the results that red will.

4 Why is middle lacquer black and top lacquer red?

The functional aspect of using different colors is that when you are applying your top red lacquer as a substrate for your metal, gold, silver, brass, etc., it is very easy to see what area has been applied to and what has not if you have a good contrast in color. If you were to apply red as your working middle lacquer and then use the same red as your substrate lacquer it would be very difficult to tell what has been covered and what hasn’t.

5 Is it possible to fill a crack with just lacquer?
Usually it isn’t. The only types of cracks that can be ‘filled’ are those where you can’t fill them if you run your fingernail across then. Stand your finger up and rub the crack perpendicular to the line. If you sense a crack then it is probably too wide to fill with just plain lacquer. If you don’t feel any bump or sense the crack then it should be able to be filled with just lacquer.

6 Why use a middle and top lacquer?
Quality, hardness, and price are the main reasons. You can use a top lacquer for doing middle work but it is a waste of money since top lacquers are more expensive than middle, sometimes significantly more. Middle and top lacquers can differ in many ways but one of the main differences is in how hard they cure and therefore their durability. As lacquer is refined from a basic lacquer on up to a refined top lacquer the main process is the driving off of water and the subsequent concentration of the urushiol. Urushiol is what makes the lacquer form natural polymer bonds through curing. It is too simple to say you are paying more for just the increased urushiol in the lacquer since top quality lacquers also have oils and other qualities in their finish not related to just urushiol but all top lacquers contain a very high percentage of urushiol.

7 Can I skip filling a chip on a cup and just coat it with silver? Below is the original question.

I have a cup with a chip on the rim. I do not have the chipped off piece, and I wish to simply coat the chipped spot in silver. Can I use the top layer lacquer to do this? Would I need to cure a preliminary application of the lacquer and then add another layer and the silver dust? Or is it better to do this all in one application?

If you just want to coat the chip then use a top lacquer. You don’t have to cure it. If you want to fill the chip before your coat of silver then use jinoko/water/basic lacquer which is called sabi.

8 What is the difference between togidashi polished gold and gold polished with a burnishing tool.

Togidashi is a word used in the maki-e world that can be translated to mean finishing by polishing using specialized whet stones, It is a long and detailed process wherein gold or silver is applied to a surface, hardened through applications of lacquer which also results in the surface being a layer of lacquer with the silver or gold beneath, and then polishing that surface down to reveal a layer of metal. There are several layers of lacquer after exposing the metal after polishing but they are to realize depth in the surface.
The second, fourth and fifth photos show #3 gold polished with a burnishing tool, the first, third, and sixth photos show #3 gold that was properly hardened and polished with polishing stones.
There is a lot of depth to the gold that was polished with the traditional method of togidashi. The surface is also far more robust in the properly done togidashi surface.

9 Is this a hopeless project? How to clean old material, shelf life of lacquer.

A few years back I was working on a project and became discouraged when I mis-mixed a batch of lacquer, flour and water with disastrous results. I was attempting to fill in joints after cementing the parts and the mixture was spread all over the bottom and the sides.

I have a couple of questions:
a) is this hopeless and should I start over?
b) If still viable what is the best way to clean?
c) I seem to remember you saying that lacquer has a limited shelf life. Is the material I have had since 2016 still viable for anything or do I need to replenish?

A, No, it isn’t hopeless, it will just take time to clean up. Starting over would mean scraping off the mugiurushi which never works well.

B. Hardwood charcoal that has had the tip soaked in water will usually take most materials off of a ceramic surface with some consideration given to the firing temperature of the body. The higher the firing temperature the more likelihood of success, the lower fired bodies tend to be softer than the charcoal. Store bought briquettes won’t work.

C. The shelf life of lacquer is usually about 12 months, I have only gotten 16 months at the longest. There are enzymes in the lacquer that die and render it useless.

10 Do the different choices of lacquer make a difference in the time taken for it to dry? Does it take hours or days for the lacquer to set?
B How long does it normally take to fix one piece from start to finish?

Shinurushi (synthetic), and cashew lacquer will dry in a normal room environment and dry within a day or two. Natural lacquer needs a warm and humid environment and takes between 2-4 days to dry, sometimes longer depending on the quality of the lacquer, the temperature and humidity. Generally speaking the higher the quality of the lacquer the longer it can take to dry.
B It depends on the complexity of the break but it can take between 2 weeks to 2 months to do a repair. A very complex break can take a year or so depending on your skill level.