How to Finish Wood with Tru-Oil

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Tru-Oil from Birchwood Casey is my absolute favorite wood finish. Not only does it enhance the natural beauty of wood, but it is also extremely easy to apply. This is what has made it my go-to finish for a very long time. Everything from smaller projects to medium sized applications like guitars, Tru-Oil delivers.

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How to Finish Wood with Tru-Oil

tru-oil finish

This finish is inexpensive, and can be used on any wooden surface with success.  Tru-Oil has been my finish of choice for acoustic guitars for years, because it is the perfect blend of beauty and protection for wood projects.  

It goes on easily with a clean cloth, and dries quickly enough to apply several coats in one day.

Tru-Oil will make an expert finisher out of anyone in a very short time, and the resulting finish will look professional.

In the beginning, it’s important to find a finish that you can work with, and learn quickly. True Oil is that finish, and in a very short time you can become an expert.

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The product is manufactured as a gun stock finish that can be hand rubbed like tung oil or linseed oil. If it’s good enough to protect a collectible firearm from a lifetime of use, it’s definitely good enough for your project!

In this Article I will Explain:

  1. How to finish wood with Tru-Oil

  2. A step by step finishing schedule

  3. Curing times and drying

sapele guitar tru-oil

Tru-Oil is a polymerized oil, which is a fancy term for an oil that has been cooked to cross link the molecules and help it dry faster when exposed to air.

The trick to helping that drying process is to apply very thin coats.

Thinner coats dry faster, leave a smoother surface, and prevent situations where the finish looks blotchy or uneven. For more about thin coats, take a look at The Secret to Wood Finishing. I bet you guessed what it is already, but it’s worth a read anyway.

Easy Tru Oil Applicator Pads

sapele guitar maple binding

The best applicator for Tru-Oil is a clean cotton cloth like an undershirt.  I typically take older undershirts that have been laundered and cut out 4″ x 4″ squares from the chest and back area, avoiding the armpits and neck portions of the shirt.

These areas tend to have debris, deodorant residue, and other chemicals that you don’t want in your finish.

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I fold these in half twice and that becomes my finish applicator pad. Press the pad tightly on the mouth of the open bottle and tip it over briefly to get some of the finish on the pad.

The pad is then used to transfer the finish to the piece, and whenever you need more finish all you have to do is repeat the process on the mouth of the bottle again.

Wood Surface Preparation Before Finishing

It’s important to prepare the surface really well before you apply your tru-oil. The finish will not improve a poorly made surface, it will only magnify the problems.

This is largely a process of sanding the wood to remove any defects, and making the surface as smooth as possible. As you more through the grits, end with finer sandpaper like 220 or 320.

Clean the project of all dust, examine the surfaces for scratches, and go back and remove them if necessary. Once all the scratches are gone, you are ready to finish.

Applying Birchwood Casey Tru Oil

sapele acoustic guitar tru-oil

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Work in small areas applying the finish, and spread it around until it is very thin. You should not see any thickness in the finish on the surface, is should almost look like you got the wood wet, but it all soaked into the surface.

Once the pad will not go any farther, dab more finish from the bottle and repeat, expanding the part of the wood that has finish on it. When the whole piece has a uniform coat, it can be set aside to dry before the next coat.

book matched sapele acoustic guitar

When I say thin coats, I mean extremely thin coats that just look like you got the surface wet. There should be no liquid residue on the surface that looks like a layer of water, it should all look like it has soaked into the wood.

Apply the finish thinly. It will dry faster, and you can coat it again quicker. It will also self level, which is the real secret.

If you have to spend half a day smoothing out the finish you just applied, then you are doing double the work, and adding unnecessary time. If you want an expert look, apply those coats very thinly.

Finishing Schedule For Tru-Oil

  1. Prep the guitar or wooden project by sanding to 220 grit and removing all scratches.  Wipe the piece down with a clean cloth or blow it with an air nozzle to remove all dust from the surface.
  2. Apply the first coat on the surface very thinly and evenly.
  3. Allow the coat to dry completely and apply another coat just as thinly as the first coat.  (More on drying times later)
  4. Tru-Oil will amber slightly with multiple coats, which gives a warm look.  Keep on applying coats until you have the look you are after (at least three-four).
  5. Allow the piece to dry for a whole day, then lightly steel wool with 0000 grade wool. Afterwards, wipe off the dust.
  6. Apply one final very thin coat to restore the gloss, and allow the piece to remain untouched for a few days to a week.

Drying Times and Curing

The finish companies want you to buy their products. They have actually found that people will buy one finish over another because it dries faster.  They have creative ways of getting their products to dry quicker than normal, like a controlled temperature room that is warm with very low humidity.  

Both of these factors encourage a finish to dry quicker.

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Tru-Oil takes about 2-4 hours to dry enough for a second coat.  This is longer in humid and cold places, and shorter in warm dry places.  After a couple hours, lightly touch the piece. You should be able to slide a finger around without sticking.

If there is still a strong smell from the piece, the finish is still too wet. Put the piece somewhere with ventilation. A small fan to circulate air helps too. Don’t blow it around too much though. You do not want dust getting on the still wet finish.

A basic rule is that if you can still smell the solvent, the finish is still curing. Let the piece cure. It will be worth it to have a strong finish for many years to come.

The curing time will vary depending on environment as well, however a few days to a week is typically enough time.  If you can still smell the finish, it has not cured yet.

Any questions about Tru-Oil finishing, please feel free to add them in the comments and I will answer them.

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brian forbes westfarthing woodworks llc owner

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