danish oil on garden furniture?

number9

My newish garden furniture got a bit weathered by the recent rain. I wiped on some rustin's danish oil and the furniture looked great and then, after the oil had dried, it rained again. The water sat on the table - waterproof, I thought - good job.

The next day blak water marks appeared on the table. I don't know why nor do I know how to get rid of them. Any tips (other than sanding the lot down and restain!) ?

leveller2911

number9 wrote: »

My newish garden furniture got a bit weathered by the recent rain. I wiped on some rustin's danish oil and the furniture looked great and then, after the oil had dried, it rained again. The water sat on the table - waterproof, I thought - good job.

The next day blak water marks appeared on the table. I don't know why nor do I know how to get rid of them. Any tips (other than sanding the lot down and restain!) ?

Its probably Tanic acid which is present in Oak,Iroko and also some teaks. You can sand them away but they will appear again.If the table is Oak then you have no chance of keeping it at bay.The only thing you can do is either keep the table under cover when it rains .

Giving it a few coats of oil will help "feed" the timber but you won't stop black patches appearing and after a few months exposed to the weather it will go a uniformed silvery grey which many people like.

number9

thanks for your quick response. The black spots only appeared after I oiled the table. I've used this many times on my beech worktops without any problems and only applied a very light/thin coverage with a rag, then wiped off any excess.

leveller2911

number9 wrote: »

thanks for your quick response. The black spots only appeared after I oiled the table. I've used this many times on my beech worktops without any problems and only applied a very light/thin coverage with a rag, then wiped off any excess.

Beech doesn't contain tanin (tanic acid) so it wouldn't go black from acids.It could go black from mould in time but thats not linked to the problem with the table. Do you know what timber the table is made from?. Is it possible that the area where the black stain has appeared had any water on it previous to you oiling it? if it had then I would still say its tanic acid.