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Finishing


Finishes for Woodworking Projects

Finishing is one of the biggest fears of many woodworkers. They are undaunted by complex joinery, intricate and precise machining, or hand-carving details, yet many woodworkers dread the thought of applying a finish to their work. The question of 'best finish' and the fear of ruining their project with the wrong finish, or applying it incorrectly, keep woodworkers from taking that last step. If you ask yourselves the same question whenever you are working on a project, you will find that overcoming that fear and developing the confidence to finish what you have started is essential to your satisfaction in a project.

The purpose of applying a finish to a project is to offer some sort of protection to the wood surface. The type of finish you select will be based upon the intended use of the project, the expected wear, special resistances desired, and finally the overall look of the project.

An important consideration for the finish you select is whether it will ever come into contact with food. If the answer is yes, please do read the following extract from the US Department of Agriculture, Forestry Services.

 

NameAppearanceSafetyProtection                     DurabilityApplicationBuffingReversabilitySolvent
WaxCreates shineSafe when solvents in paste wax evaporate
The finish is foodsafe.
Very little
Level: 1
Does not last and needs to be reapplied frequently
Level: 1
Applied with a rag. Needs buffing.
Ease: 2

Rag
Must
be buffed.
Can easily be removed with solvents
Level: 10
Turpentine, Naphtha, mineral spirits, paint thinner
ShellacSome yellow or orange tint, depending on grade usedSafe when alcohol solvent evaporates
The finish is foodsafe.
Fair against water, good on solvents except alcohol
Level: 4
Durable
Level: 6
Needs buffing/sanding to obtain a fine finish
Ease: 2

Brush Rag Spray

Can be buffed.
Excellent results
Can easily be removed with alcohol
Level: 10
Alcohol (denatured alcohol, ethanol, methanol, etc)
Nitrocellulose lacquerTransparent, good glossUses toxic solvents, including toluene. Breathing protection is needed, especially                              if sprayed
The finish is not foodsafe.
Good protection
Level: 7
Hard and durable
Level: 8
Transparent, good gloss
Ease: 6

Rag Spray

Can be buffed.
Excellent hard finish
Completely reversible using lacquer thinner
Level: 10
Toluene, lacquer thinner, acetone
Conversion lacquerTransparent, good glossUses toxic solvents, including toluene. Breathing protection is needed, especially                              if sprayed
The finish is not foodsafe.
Excellent protection against many substances
Level: 7
Hard and durable
Level: 8
Requires spray equipment. Used in professional shops
Ease: 7

Spray

Can be buffed.
Excellent hard finish
Difficult to reverse
Level: 2
Toluene
Linseed oilYellow warm glow, pops grain, darkens with ageRelatively safe, metallic driers are poisonous
The finish is foodsafe.
Very little
Level: 1
Fairly durable, depending on number of coats
Level: 4
Easy, apply with rags and wipe off. Takes relatively long time to dry
Ease: 10

Rag

Can not be buffed.
Needs sanding out as oil is absorbed
Level: 3
Mineral spirits, naptha, turpentine
Tung oilWarm glow, pops grain, lighter than linseedRelatively safe, metallic driers are poisonous
The finish is foodsafe.
Very little
Level: 2
Fairly durable, depending on number of coats
Level: 5
Easy, apply with rags and wipe off. Takes relatively long time to dry, but faster to dry than linseed oil
Ease: 10

Rag

Can not be buffed.
Needs sanding out as oil is absorbed
Level: 3
Mineral spirits, naptha, turpentine                     
Alkyd varnish                      Not as transparent as lacquer, yellowish/orange tintRelatively safe, uses petroleum based solvents
The finish is not foodsafe.
Good protection
Level: 6
Durable
Level: 7
Brush or spray. Brushing needs good technique to avoid bubbles and streaks
Ease: 5

Brush Spray

Can be buffed.
Fair results
Can be stripped using paint removers
Level: 6
paint remover
Polyurethane varnishTransparent, many coats can look like plastic                     Relatively safe, uses petroleum based solvents
The finish is not foodsafe.
Excellent protection against many substances, tough finish
Level: 10
Durable
Level: 7
Brushing needs good technique to avoid bubbles and streaks
Ease: 5

Brush

Can be buffed.
Poor results: as coats do not meld leading to white rings if rubbing out cuts                              through coat
Can be stripped with difficulty using paint removers
Level: 4
paint remover, petroleum based solvents (mineral spirits, naptha, turpentine)
Water-based polyurethane                     Transparent, may give cold bluish tinge to woodSafer than oil-based, fewer VOCs
The finish is span>not foodsafe.
Good protection
Level: 8
Durable
Level: 7
Brush or spray. Brushing needs good technique to avoid bubbles and streaks
Ease: 2

Brush Spray

Can be buffed.
Poor results: coats do not meld leading to white rings if rubbing out cuts through coat
Can be stripped with difficulty using paint removers
Level: 4
Mineral spirits, naptha, turpentine                     
Oil-varnish mixesSimilar to oils unless many coats applied, then takes on characteristics of varnishesRelatively safe, uses petroleum based solvents
The finish is not foodsafe.
Low, but more than pure oil finishes
Level: 4
Fairly durable, depending on number of coats
Level: 6
Easy, apply with rags and wipe off. Faster to dry than linseed oil
Ease: 8

Rag

Can not be buffed.
Not viable unless many coats applied
Needs sanding out since oil is absorbed
Level: 3
Petroleum based (mineral spirits, naptha, turpentine)

References

Wikipedia wood finishing chart for initial data extract