Wood staining

[rwakeham]

Hopefully the attached photo shows unsightly black staining that has developed over the winter. I have tried sanding the area, but the stain is quite deep- is there another way of treating the surface to get rid of it before I varnish it (and fix the leak in the window....)

Thanks in advance for any suggestions.

 

[Simes]

Looks like water ingress, Try drying the wood out then a light sandind and / or varnish stripper then re varnish.

The timber looks like ply? possibly teak faced? if so the teak laminate will be very thin (0.3mm) fine wet and dry on a blocking pad will work better than sand paper.
It also helps if you can remove the timber to a warm place to carry out the work.

Hope that this helps

Simes

 

[tillergirl]

Oxalic acid. Strip back to bare wood (if ply be very careful not to sand away the top laminate which will be decorative and v thin) and apply repeated applications of the acid. It will also bleach the unstained parts but a very light sanding after you have finished with the acid will bring that colour back.

 

[PuffTheMagicDragon]

May I suggest that, after removing the stains and having sanded the bare wood, you should apply <u>traditional</u> varnish? Thinning the first four coats heavily will allow the varnish to soak into the wood. This will help to avoid the future ingress of water because most all of the internal microscopic voids will have been eliminated. Follow these coats with at least four more at full strength, sanding down with wet-and-dry between alternate coats.

 

[rwakeham]

Thanks very much for the above - v helpful and will try all three. Definitely water ingress - the seal in the window is not what it should be.