⬇️⬇️ (English translation of the Italian text with timestamps) ⬇️⬇️
0:00 - Mastic and Turpentine from start to finish
0:11 - Mastic and turpentine is a refractive ground useful for assisting the insulation of wood and for enhancing its natural brightness and brilliance.
Recipe:
Raw Greek mastic 25g - Turpentine essence 50g
Resin:Essence ratio 1:2 (33% concentration).
After cooking, add 25g of turpentine essence bringing the dilution to a resin:essence ratio of 1:3 (1 part of Mastic and 3 parts of Essence, concentration of 25%) ideal for the application
At the end add 1g of Pumice powder, equal to 20% of the actual Mastic content (5g)
1:34 - Maintain for 15 minutes between 155° and 165°C until a clear reduction of the foam
2:08 - Mastic at 110°/120°C - Turpentine essence at 120°C
2:46 - Bring the temperature up to 140°C
3:30 - Once cooled, add the turpentine essence lost through evaporation during cooking. Dilute further with another 25g of turpentine essence to bring the resin:essence ratio to 1:3 (25% concentration), ideal for the application. Filter through quick filter paper, or leave to decant for a few days until the liquid is perfectly clear.
3:46 - After adding the lost essence - Mastic:Essence ratio 1:2 - Concentration 33%
3:53 - Added 25g of Turpentine Essence - Mastic:Essence ratio 1:3 - Concentration 25%
4:01 - Filtering in filter paper
4:18 - Adding a mineral filler to Mastic and Turpentine has the aim of increasing its hardness and consistency, improving its pore-filling properties. The light abrasive effect will also be useful for eliminating any raised roughness and giving a touch of softness to excessively sharp edges. I use Pumice, which is a volcanic rock composed mainly of Silica and smaller quantities of various metal oxides (Aluminium, Potassium, Iron, Calcium, Titanium, Magnesium), but other mineral powders with a refractive index similar to that of Mastic ( 1,536) could be used.
5:00 - Mastic and Turpentine 20g of 25% solution (1:3)
5:20 - 1g of Pumice
5:50 - Transparency test on glass - with Pumice - without Pumice
6:05 - Application
The Mastic and Turpentine must not form a shiny layer on top of the surface, but remain just inside the surface of the wood. The protein insulation (Casein) applied previously will guarantee the necessary insulation to avoid too deep penetration, which would be harmful to the sound.
Mix the Mastic and Turpentine well with the Pumice to keep it in suspension, continuing to mix it regularly with the brush during application. Use a 12mm nylon brush, a 6mm bristle brush for the pegbox and scroll and a small round bristle brush for the inside of the f-holes. Apply it evenly and insistently until there are no more absorption areas. Start with the ribs and edges, then make the back, the top, the scroll, and lastly the neck.
10:25 - After brush application, wait a few hours before proceeding to eliminate the excess on the surface. Use a cotton rag moistened with alcohol to remove excess and allow it to penetrate well into the pores. The abrasive effect of Pumice will help eliminate any surface roughness and give a little softness to sharp edges. Be careful to control the pressure so as not to cause deep scratches, this is not sanding but only very superficial smoothing. Use the small round bristle brush moistened with alcohol to remove build-up from the corners of the ribs and scroll.
15:09 - At the end of the application, let it dry for about 24 hours in the UV box (recommended), or leave it to dry for a week before continuing with the application of the actual varnish.
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