AndyG
Established Member
The subject title may be a little misguiding. This isn't (yet) a complete howto on oil finishing, but it's getting there slowly.
I'm hoping that with everyones guidance the list of points below can be built-up into a real 'Oil finishing For Dummies'. BTW, if this already exists somewhere in the forum, any chance of a link :wink:
So here goes:
True Oils
- Natural substances that harden (slowly) with exposure to oxygen.
- True oils are linseed and tung, these change from a liquid to a solid through polymerization.
- Must remove excess to stop 'film wrinkling', that produces a goo
- Also known as 'Drying Oil'.
Warnings: Rags used to apply oils can combust. Be careful what you do with then when you are finished. Hang up to dry, or lay flat away from things that burn!
Linseed Oil:
- From the seeds of the flax plant.
- Leaves a soft finish.
Raw Linseed Oil:
- This is unrefined linseed oil.
- Takes a very long time (weeks) to cure so is rarely used.
Boiled Linseed Oil:
- Has driers added, cures in about a day (with excess removed).
- Hard wearing.
- Boiled linseed oil is generally more appropriate for use than raw linseed oil.
Tung Oil:
- From Tung Tree nuts
- Originally from China, therefore it is also known as Chinese Wood Oil.
- Slow to Dry
- OK for outdoor use
- Require sanding between coats
- Need to be careful that what you are using is actually 'Pure Tung Oil'
- Tung oil is paler in color and has better moisture resistance than linseed oil.
Boiled Tung Oil:
- Boiled Tung oil is also available, this dries quicker and harder, and is less likely to suffer from 'frosting', drying to a matte white finish.
Oil Blends
- True oil is often blended with driers and varnish (normally a long varnish).
- Oil and varnish blends dry a bit harder than true oils, and the finishes will build quicker with fewer applications.
- The blend ratios are varying depending on manufacturer.
Danish Oil:
- It's not danish!
- The name seems to come from the effect the oil produces. Apparently it originated as a way to achieve a finish similar to furniture originating from Denmark.
Teak Oil:
- Outside Only
- Contains a drier
Varnish
- Varnish is a mixture of resin and an oil that has been reacted with heat. The amount of oil in a varnish alters its characteristics.
- "Long oil" varnishes remain relatively soft and flexible.
- "Short oil" varnishes dry harder and less flexible.
Commercial Oils
Liberon
Liberon manufacture a number of oils, two of which are 'Finishing Oil' and 'Superior Danish Oil'. Not knowing what the difference would be I bought a tin of each. After 3 coats on oak and cherry, they look identical. The only difference seems to be that the Danish Oil may be used externally as well as internally.
Sources of Info
http://www.woodzone.com/articles/wood_finishes.htm
http://www.woodcentral.com/russ/finish7.shtml
http://www.popularwoodworking.com/features/finish2.html
http://www.taunton.com/finewoodworking/pages/w00060.asp
Questions
Q: I read that Boiled Linseed contains a metallic drier. Does this make it unsuitable for oak?
A: Boiled linseed can be used on oak without any problems (apart from the long drying time)
Q: Can a filler be used before Oil?
A: Filler can be used before oil
Q: Do open grained timbers need filling before an oil is applied, or does the process of rubbing down between oil coats help fill gaps?
Q: What is Teak Oil?
Q: Do oils release fumes? What ventilation precautions need to be taken?
Thanks
Andy
I'm hoping that with everyones guidance the list of points below can be built-up into a real 'Oil finishing For Dummies'. BTW, if this already exists somewhere in the forum, any chance of a link :wink:
So here goes:
True Oils
- Natural substances that harden (slowly) with exposure to oxygen.
- True oils are linseed and tung, these change from a liquid to a solid through polymerization.
- Must remove excess to stop 'film wrinkling', that produces a goo
- Also known as 'Drying Oil'.
Warnings: Rags used to apply oils can combust. Be careful what you do with then when you are finished. Hang up to dry, or lay flat away from things that burn!
Linseed Oil:
- From the seeds of the flax plant.
- Leaves a soft finish.
Raw Linseed Oil:
- This is unrefined linseed oil.
- Takes a very long time (weeks) to cure so is rarely used.
Boiled Linseed Oil:
- Has driers added, cures in about a day (with excess removed).
- Hard wearing.
- Boiled linseed oil is generally more appropriate for use than raw linseed oil.
Tung Oil:
- From Tung Tree nuts
- Originally from China, therefore it is also known as Chinese Wood Oil.
- Slow to Dry
- OK for outdoor use
- Require sanding between coats
- Need to be careful that what you are using is actually 'Pure Tung Oil'
- Tung oil is paler in color and has better moisture resistance than linseed oil.
Boiled Tung Oil:
- Boiled Tung oil is also available, this dries quicker and harder, and is less likely to suffer from 'frosting', drying to a matte white finish.
Oil Blends
- True oil is often blended with driers and varnish (normally a long varnish).
- Oil and varnish blends dry a bit harder than true oils, and the finishes will build quicker with fewer applications.
- The blend ratios are varying depending on manufacturer.
Danish Oil:
- It's not danish!
- The name seems to come from the effect the oil produces. Apparently it originated as a way to achieve a finish similar to furniture originating from Denmark.
Teak Oil:
- Outside Only
- Contains a drier
Varnish
- Varnish is a mixture of resin and an oil that has been reacted with heat. The amount of oil in a varnish alters its characteristics.
- "Long oil" varnishes remain relatively soft and flexible.
- "Short oil" varnishes dry harder and less flexible.
Commercial Oils
Liberon
Liberon manufacture a number of oils, two of which are 'Finishing Oil' and 'Superior Danish Oil'. Not knowing what the difference would be I bought a tin of each. After 3 coats on oak and cherry, they look identical. The only difference seems to be that the Danish Oil may be used externally as well as internally.
Sources of Info
http://www.woodzone.com/articles/wood_finishes.htm
http://www.woodcentral.com/russ/finish7.shtml
http://www.popularwoodworking.com/features/finish2.html
http://www.taunton.com/finewoodworking/pages/w00060.asp
Questions
Q: I read that Boiled Linseed contains a metallic drier. Does this make it unsuitable for oak?
A: Boiled linseed can be used on oak without any problems (apart from the long drying time)
Q: Can a filler be used before Oil?
A: Filler can be used before oil
Q: Do open grained timbers need filling before an oil is applied, or does the process of rubbing down between oil coats help fill gaps?
Q: What is Teak Oil?
Q: Do oils release fumes? What ventilation precautions need to be taken?
Thanks
Andy