Home>Discussions>PAINTING & FINISHING>Linseed oil vs. tung oil (in S. FL)
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Linseed oil vs. tung oil (in S. FL)

Hello, my front exterior door is wood and was coated with polyurethane (no paint) about six years ago. It is time to refinish/protect again. A friend of mine from Germany recommends treating with raw linseed oil because he said he has seen 300 year old windows (in Germany) in GREAT condition that had been treated solely with linseed oil. I live in South Florida, so not only does the extreme humidity take a toll, but the door also faces west so has blazing sunlight on it for a good part of the day. Thoughts/advice about linseed oil or tung oil or something else in this application? Thanks.

Re: Linseed oil vs. tung oil (in S. FL)

While I see the suggestion has merit, I wouldn't think that you would want to re apply the oils every year where you could skip a few years with poly urethane.

You could always experiment this year, see how it does then correct any problems you encounter next year.

Re: Linseed oil vs. tung oil (in S. FL)


In terms of work involved, the polyurethane will probably give longer life without period maintenance. However, if you let the finish deteriorate you will have to do a complete stripping of the door. Tung oil requires periodic maintenance coats, usually yearly, but these are relatively simple - just clean and wipe on more oil.

If you like a high gloss look, you will never get it with tung or linseed oil. You can get a lustrous sheen, but not gloss. Many woodworkers feel that a polyurethane gives a somewhat plasticy look.

If you go the "varnish" route, consider a spar varnish such as McCloskey's. A true spar varnish is made from natural resins. It forms a durable, flexible coating. If you have a panel door, the flexiblity is important. The panels in entry and garage doors move with the variations of humidity with the seasons. The panels are purposely not glued into their slots. If they were not given room to expand, they would crack. Polyurethanes are very hard and brittle. As the panels move, the bead of coating where the panel meets the rail or stile breaks, allowing water to work its way into the wood. Then the sun beats on the door and vapor pressure is created in the wood. Peeling results. Pay attention to the seam at the bottom of the panel where it meets the rail. This is where water damage will first become evident.

Over the years, I have finished many new fine garage doors of redwood, hemlock etc. Often the manufacturer would put a label on the door stating that if polyurethane was used on the door, the company would void its warranty

If you decide of tung oil, make sure you are using real tung oil. Many products labeled as "tung oil finish" actually don't even contain tung oil.

Many people do not like linseed oil as it can blacken the wood. Some manufacturers have stopped using linseed oil as the base for their stains for this reason. Linseed oil has nutriant value for mildew.

However you decide to treat your door, do not forget the top and bottom edges of the door, especially the bottom! The cross grain cut of the door rails will wick water up into the door leading to failure of the finish and warping of the door.

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