Chas, I'm interested in knowing what is in the Deks Olje D1 product. Is it in part linseed oil? any other particular oils? I also prefer oils to varnish not just because of the natural aesthetic but because it seems to let wood live longer and perhaps be - and I am not sure of this - more 'supple' than if quasi hermetically sealed. important too when non-skid surfaces are involved. the tradition here is to use linseed oil - often thinned with turpentine (and sometimes another oil in furniture) - for much of the exposed wood on boats. so am interested to know what research and maybe technology has come up with as being the most 'wood friendly'.
appreciated the helpful description of application and the making of a swan.

Hi David, Im almost certian that Deks olje is based opon tung oil. Tung oil is far more water resistant than linseed oil, the Chinese have been using it on their boats for over 2000 years. Linseed oil however is better for furniture and gun stocks etc, things that dont get the constsant exposure to water and moisture you would get on boats.

A boat is often subject to extremes of temperature and humidity, particularly here in the UK when the interior can vary between fridge and oven. in those extreme conditions, wood expands and contracts a lot and eventually, any surface finish on the wood, varnish, resin etc is almost certian to crack somewhere. Cracks in he surface will allow salt atmosphere to enter the now unprotected wood and then the deradation starts. The surrounding finish starts to flake and the wood gradually becomes discoloured.

Oil finish penitrates deep into the wood and would be less affected by movement in the wood as the wood is deeply impregnated rather than coated. If the oiled finish starts to become tired it is easy to just clean and recoat as there is no old finish to have to strip and make good.

I wouldn't use any sort of finish oil or otherwise on teak decks though, just leave them natural for maximum non-slip. Oil could be used on floors inside the boat providing that they were proper wood and not that teak and holly flooring as the veneer on that is far too thin and that must be coated rather than impregnated.

Hope this helps.

All the best

Thanks Chas, that's very helpful. I knew I'd forgotten something and that was 'tung'. Have certainly heard about it but dont know what tree[?] it is from. Interested to hear that linseed is not so good for the exposed bits. wonder why they use so much here.. perhaps tung is very expensive. don't have teak decks on the Sigma but also have a 'Seabird' - 21 foot gaff rigged dayboat designed in early 1900s by an admiralty architect specifically for bombay harbour [thogh they've been sailed across to Muscat, down to Mangalore, up to karachi etc - a little foolhardy perhaps] which has teak seats coamings etc and one does need to protect these. will look out for tung now.
Aye, David

David, just type in tung oil on a search engine like Google. There is stacks of info on it.