Water Stains In Hardwood

[halfcut]

Re-doing window sills and surrounds in bathroom and laundry. Water stains have turned some of the wood dark. Tried sanding but it will not go away. I am using a clear finish. Don't want to paint with solid colours. Any hints?:C

[elanjacobs]

If you keep sanding for long enough you'll get fresh timber, but you might have to take a mm or 2 off.

[auscab]

Do some test spots with Oxalic acid and see if that works . look for it at Bunnings .
Its real good at removing some water staining due to iron oxide staining and some types of dirt and grime staining . I like to apply and dry it off fast with a heat gun . Or just apply and wait for it to dry . Some types of staining just dissapear before your eyes with Oxalic acid as soon as it goes on .

[halfcut]

Thanks for your advice.