Home Contact Tru-oil Varnish Finish Mandolin Hospital Finishing

 

What is it?   Tru-Oil is a polymerized linseed oil with other natural oils added.  This formulation will actually build-up as a finish unlike the raw or boiled linseed oils. Although this finish lacks the depth and gloss of lacquers or French polished shellac, the thin rubbed oil finish provides an appealing low luster sheen that enhances the natural beauty of the woods. The fact that it is thin and flexible, allows maximum vibration in the wood of musical instruments.
Ease of use?  The real strength of this oil finish is that it is extraordinarily easy and safe to use.  No special equipment or ventilation is required during finishing.  Only clean cloths are needed for application with minimal sanding between coats.  This finish is also much easier to repair and maintain than either lacquers or shellac.
Fill pores or not?   Multiple thin coats can be applied directly to the raw wood for a very natural, open pore finish. The pores in hardwoods like rosewood can be filled first, so that the finish can be made to approach a factory lacquer finish. 
How is it applied?   The application is very simple.  Just wipe the oil over the surface with a cloth. Wipe off any excess material leaving a very thin coating.  This thin coat will harden enough in several hours to apply the next coat.  Several coats are applied over several days to achieve the desired depth or thickness, with light sanding between coats.

 

Applying Tru-oil varnish

   What you will need: 

  • Tru-oil varnish. (a  bottle will easily finish a mandolin)

  • White cotton cloth (an old sheet works well)

  • Gloves (optional)

  • Wet and dry 600, 1000, 1200, 1500, 2000 (or similar)

  • Cork sanding block

  • 0000 wire wool

 Preparation:  Before beginning, it is imperative to make the surface of the wood as smooth as possible, as the finish is very thin. Any blemishes will show in the finish if left.  Bear in mind also, that preparation will differ between untreated and pore-filled surfaces.  Check the Wood Preparation page.

   The Process:

  • I wear light disposable rubber gloves when applying, mainly to protect the wood from the oils in my hands.

  • Use a folded, lint-free, white cotton cloth (about 4" square is big enough) to apply the oil. Use a fresh cloth for each application session. 

  •  Choose which part of the instrument to work on first. I generally start on the top, then the back, then the sides, and finally the neck and head. (In order to hold the instrument for the neck and head, I insert fingers in through the sound-hole, and place my thumb on the fingerboard.)

  • Wipe a thin coat quickly over the working area. I tend to pour a small pool of oil onto the top/back, and spread it rapidly with circular movements. If I do not have sufficient to cover, I add more to the cloth, by placing it over the bottle mouth, and up-ending.

  • If you work too slowly, the oil will begin to dry and will smear if contacted by the cloth.

  • Before moving on to another surface, I finish off by wiping the surface with the same cloth (as long as it is not over-charged with oil) in the direction of the grain.

  • It is important not to cover too thickly, as it will run whilst hung to dry, and also take much longer to dry.

  • Move to another area and repeat.

  • For the sides, neck and head, I do not pool oil, as surfaces are curved, but work from the cloth

  • It will only take 10 to 15 minutes to coat the entire instrument.

  •  Hang the instrument to dry overnight.

  • To store the Tru-oil,, wipe the neck of the bottle thoroughly, screw on the top, and stand upside-down. This helps to stop a thick film forming over the oil inside the bottle. If it does form, the oil is on top.

   Building up the finish:

  • After each oil coating has dried, it is smoothed before another is applied. I use a fine wet and dry paper (600+) or 0000 steel wool.

  • After each coat, I use a finer paper than the the previous one.

  • Rub over the surface very lightly to remove any minor roughness.  This is not a leveling process like with other harder, thicker finishes.

  • Apply more Tru-oil as above.

  • Only three or four coatings can result in very beautiful sheen over the entire instrument.  However different woods, conditions, and varying techniques may require additional coatings to reach this level. 

  • After the final coat, leave the finish to set. Time will depend on temperature and humidity, but certainly leave for a week.

   Polishing/buffing the final finish:

  • Tru-oil does not seem to respond too well to buffing.

  • I tend to rub vigorously with a rough natural fibre like burlap or net.

  • Rubbing with Lem-oil helps to keep the finish grease free.

   Problems and Solutions:

  • Smearing: If you work too slowly on larger instruments, the thin finish will begin to dry quickly. If you cross this drying finish with the cloth, you can roughen/smear the surface. If this happens, allow to dry and then sand smooth again before recommencing.

  • WARNING - This oil product, like others, may not cure over Cocobolo. Avoid oil finishing over this oily wood. I once had problems on rosewood too. The wood may need sealing if this occurs.