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What is Shellac?

Shellac is a natural resin, which is produced by an insect that lives in Thailand and some regions of India, which uses it to cling to the bark of trees.
Once harvested, after a first purification process, it presents itself in very brittle, thin, amber-colored scales.

The characteristics

It is easy to find in any fine arts shop and is generally sold in 1 kg bags, but it is usually possible to buy even in fractions of 100 grams.

The fundamental characteristics of shellac are its extraordinary durability and brilliance. It is no coincidence that it was already used in the nineteenth century for the finishing of fine furniture, in particular by the French from whom it was also copied the technique of application and polishing, through the use of a pad, in the past it was used mainly in casting for the production of decorations or small accessories.

Today it is mainly used in restoration and furnishing, even of value, it has been almost entirely replaced instead by synthetic paints.
Its application requires time and a lot of patience, but the final results are excellent, long-lasting and give the wood a lively and pleasantly soft appearance.

Since it is non-toxic, it is sometimes utilized also in the pharmaceutical industry for the production of the coatings of the pills or in the agri-food sector as polishing agent for fruits and vegetables.

Preparation in alcoholic solution

The most used solvent to dissolve it is ethyl alcohol, of which I personally recommend with a concentration of at least 94 degrees, so not the common alcohol that is found in the supermarket and that we often have at home.

The dilution process is very simple: what I am reporting is not an absolute rule and it is easy that there are very different opinions and techniques, but it is the result of consolidated experience and knowledge acquired by experienced professionals.

Shellac is usually applied in three stages: application or application, roughing and polishing. For each of these phases it is advisable to prepare the shellac with different dilutions.

Different dilutions

We will start with a 20% dilution, also known as the stock solution, understood as the ratio of bottle volume to shellac weight, or in a 1 litre bottle (better made of transparent plastic to preserve the release of flammable alcohol in case of breakage of the same) we will pour 200 grams of shellac and fill the bottle with alcohol until the end.

The shellac will immediately start to dissolve with a consequent drop in volume, but no more alcohol should be added. Let it rest for at least one night and, the following day, let it rest well and filter it into a new bottle using a funnel with a common women’s stocking like a tights.
Our shellac is ready to be used.

Obviously, smaller quantities can also be used, as long as the volume/weight ratio is respected.

For example, for a half-litre bottle, we will use 100 grams of shellac to obtain a 20% dilution.

On the basis of the above, we will also prepare a 10% dilution (therefore, in the case of a 1-litre bottle, use 100 grams of shellac and lots of alcohol to fill it) and a 5% dilution (50 grams of shellac for a 1-litre bottle).

Eventually, useful if we need small quantities, we can also extend the solution already prepared to 20% to obtain intermediate dilutions: if we pour in a half-litre bottle the solution to 20% up to its half and fill the rest of alcohol we will immediately get a ready dilution to 10% and so on.

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Author: Mr Wood

My name is Mark, I'm 29 and I have my own carpentry shop. About 10 years old, I like working with wood. I tried to make simple products, collected tools, read carpentry books. Nothing unusual, just a hobby. Sometimes it was even annoying. But as time passed, I came back with an even greater desire to build, assemble or learn something new.

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