Exterior finish for oak

[AjB]

Does anyone know if Danish oil is suitable for an exterior oak door?
Thanks

 

[ED65]

I don't think Danish oils are generally meant for exterior applications, teak oil (which is very similar) is however.

You can easily make your own versions of this type of thing. Do you have any exterior varnish, spar varnish or yacht varnish already?

 

[deema]

I wouldn't use teak oil on oak, it can turn it black! The traditional coatings are Tung or raw linsead oil, however, personally I prefer Osmo oil with an added UV filter.

 

[Phil Pascoe]

Liberon advised me that finishing oil is for interior work and Danish is recommended for external. They also advised me it wasn't suitable for use on oak, but I didn't get a reply when I inquired why.

 

[RobinBHM]

I believe that Danish oil is a mixture of linseed oil, varnish and mineral spirits. Teak oil and Tung oil are all similar. I know pure Tung oil is an oil in its own right, but the products marketed are usually tung oil finishes containing a % of tung oil.

I tend to advise customers not to use these finishes externally. They may work for a short period, but they offer no protection from UV and have limited water resistance so frequent reapplication will be necessary.

Osmo may be a bit better, or sikkens / sadolin -gernally only finishes which are coloured have any useful degree of UV protection.

Ive not tried it but if you are happy for the door to go grey then you could try Sioo

 

[Making Shavings]

I'd never seen this stuff, or heard of the brand before, but at the UKIWS event in Coventry a couple of weeks ago, I had a good look around their display and demo's, bought a tin of Woodoc 50 matt sealer for some oak table tops to be used outdoors. So far, it's been great... 3 coats, de-nib between the first 2.

 

[custard]

There is no transparent outdoor wood finish that is apply and forget. They all need sanding back and refinishing every two or three years.

A guy on this forum (Richard?) once said something very smart, he commented that if you leave timber to weather it goes silver grey. But if you apply an oil or oil related finish, then get fed up with the maintenance, instead of a uniform silvery grey you get horrible greeny black patches. His hypothesis was that microscopic bugs start eating the oil which looks carp. It then takes several years before all their food is consumed and they die off, at which point the silvery grey colour comes back.

If that's true, and it certainly fits with my experience, you have to be aware that when you first slap on your finish you're actually signing up to a lifetimes worth of maintenance. If you ever stop the timber will look much worse for a few years than if you'd never applied a finish in the first place.

My take out from that is follow one of three routes with outdoor timber. Do nothing and learn to love that natural silvery grey. Varnish or oil, but only on things like a beautiful wooden boat that you cherish and will be happy to maintain indefinitely. Or thirdly, paint it!

Good luck!

 

[Making Shavings]

That all makes sense to me Custard.

 

[skipdiver]

I just use Osmo for everything now.

 

[AJB Temple]

I agree with Custard. I do not put a finish on the external oak work I am doing. I embrace the natural silver grey colour that it quickly takes on.