Oil Finishing for Dummies

[AndyG]

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

 

[Anonymous]

Questions:
- I read that Boiled Linseed contains a metallic drier. Does this make it unsuitable for oak?
- Do open grained timbers need filling before an oil is applied, or does the process of rubbing down between oil coats help fill gaps?

Thanks
Andy

The answer to question 1 is no, many finishes (most?) contain a mettalic drier. I have used boiled linseed on oak many times without any problems other than it takes ages to dry. It is one of my favourite finishes and leaves a lovely golden glow on the wood.
My other favourite slow drying oil is pure Tung (careful as many 'pure Tung oils' are not what they claim to be).

For the second question, I tried a grain filler from Axmonster about 9 months ago for the first time and on oak and Ash. Now I prefer to use it before applying the finish and have use dit on about 70% of my projects since first trying it.

If you're interested, my favourite finishes in order of most used are:
Danish Oil
Patina
Shellac (Blonde dewaxed hand-cut)
Pure Tung oil (the smell is gorgeous
Boiled Linseed oil (used this on my bench last time I flattened it and it has been great - hard wearing and tough)

I often use Chestnut Products' Wax over any of the top three but not the bottom two.

 

[AndyG]

Great, cheers Tony, I'll update the original post with these new nuggets of info
I have to admit, I started this thread with a bit of an ulterior motive. I'm trying to work out the best way to finish my competition entry (Pure Tung Oil is my current plan). Hopefully though, if we gather enough info, this thread can become a good starting point for finishing novices, like me
Andy

 

[Anonymous]

Great, cheers Tony, I'll update the original post with these new nuggets of info
I have to admit, I started this thread with a bit of an ulterior motive. I'm trying to work out the best way to finish my competition entry (Pure Tung Oil is my current plan). Hopefully though, if we gather enough info, this thread can become a good starting point for finishing novices, like me
Andy

Andy, whilst pure Tung is a good choice, which gives a beautiful finish and smells lovley, it takes longer to dry than any other finish I have ever tried - think in terms of several days for a coat to fully dry :roll:

 

[Neomorph]

Q: What actually is Danish Oil?

Thanks
Andy

Danish Oil is actually Tung Oil with hardeners and driers added. When I bought my first lot of this I swore when I read the caution on the back of the can...

Warning: Application cloths may self ignite without warning

:shock:

OMG... another dangerous task in the wonderful world of woodworking. It's not just power tools it's even applying finishes!!!!!

 

[AndyG]

John,
Aha, right, will add that too.
RE the fire warning. I've read that a lot. Seems to be a common warning given when people are discussing oils.

Keep the info rolling

Cheers
Andy

 

[Chris Knight]

Danish oil is actually a bit more complicated. It varies between manufacturers but it generally consists of a drying oil (eg Linseed or Tung), a varnish and driers. Varnish itself is a resin and an oil that have been reacted with heat. The amount of oil in a varnish alters its characteristics. "Long oil" varnishes like spar varnish remain relatively soft and flexible. "Short oil" varnishes dry harder and less flexible. Danish oil is usually blended using a long oil varnish.

 

[AndyG]

Chris,
It was going so well :wink:
Thanks though. Shall try to add that in
Andy

 

[dedee]

Andy,
FWIW I'm using a Liberon Finishing Oil (which is, I guess, a Danish Oil :?: )on my oak piece at the moment and I will finish with Adam's No1 Beeswax.
I have not used a grain filler as (and I am prepared to be wrong on this) I like to feel the grain of the wood though the finish rather than have it super smooth.

I have been using the oil in the kitchen, over the hob in fact, with the extractor fan on which gets rid of the smell. As advised elsewhere I then lay the oil soaked rag flat in the garage after use.

Andy

 

[AndyG]

Andy,
You mean your garage floor isn't covered in wood shavings
Shall give Liberon Oils a look.
Cheers for the tip
Andy

 

[Neomorph]

Danish oil is actually a bit more complicated. It varies between manufacturers but it generally consists of a drying oil (eg Linseed or Tung), a varnish and driers. Varnish itself is a resin and an oil that have been reacted with heat. The amount of oil in a varnish alters its characteristics. "Long oil" varnishes like spar varnish remain relatively soft and flexible. "Short oil" varnishes dry harder and less flexible. Danish oil is usually blended using a long oil varnish.

I got this off the Rustins info...

Danish Oil is a special formulation developed by Rustins Ltd. based on Tung Oil, also known as Chinese Wood Oil. The oil is extracted from nuts, similar in size to a Brazil nut, growing on species of trees found mainly in China and some areas of South America.

After processing the oil is blended with synthetic resins to improve hardness, and other vegetable oils. Driers and solvents are added to improve the performance and application properties, so that Danish Oil may be applied with a rag or brush.

lol... it sounds like it's a vegetarian woodworkers finish. :lol:

 

[tim]

This may be useful:

http://www.taunton.com/finewoodworking/pages/w00060.asp

Cheers

Tim

 

[George_N]

If you're interested, my favourite finishes in order of most used are:
Danish Oil
Patina
Shellac (Blonde dewaxed hand-cut)
Pure Tung oil (the smell is gorgeous
Boiled Linseed oil (used this on my bench last time I flattened it and it has been great - hard wearing and tough)

I often use Chestnut Products' Wax over any of the top three but not the bottom two.

Is there a reason for not using wax on top of boiled linseed oil?

cheers

George

 

[AndyG]

I've added a section on Commercial Oils, including a bit on Liberon Oil.
Has anyone got any more info to add?
Cheers
Andy

 

[johnelliott]

We've nearly finished a kitchen in American Ash. It's looking pretty good and the customers are pleased. Our finishing technique is this-

Sand the wood to 120
Apply a coat of danish oil, probably by brush, rub of excess with rag
Allow a few hours to dry
Quick rub down with grey scotchbrite, or sometimes just draw a stanley knife blade held vertically over the surface to denib (we do this with our painted kitchens as well, lots cheaper and much quicker than sandpaper)
Apply a second coat
Rub down as before
Stop

The essential point here is that we are NOT reying to acheive a shine. Shine is something we remove with scotchbrite if we find any. The danish oil brings out the grain magnificently and the matt surface we achieve feels and looks right.

We have experimented with different makes, and find that Liberon suits us best

I'm not for a moment saying that one shouldn't aim to produce a shiny surface, just saying that it isn't necessary in order to bring out the beauty of the wood, and will increase your workload considerably due the the way the shine will highlight the smallest imperfections

John