Oxalic Acid, when to use, how pedantic do I need to be?

[Nigelb]

To be clear, I have no black stains but the wood is weathered in places, as the timber was exposed over lockdown.

My intention was a light sand P80 prior to staining with primer and the Coelan. However I don’t want to aggressively sand to remove stains etc.

So should I be using Oxalic Acid, or is this too aggressive and will only raise the grain and lead to more sanding etc.

The surface is very good so I am wondering if a light sand with P80 will suffice and the primer stain will cover any areas of discolouration?

 

[Caraway]

I would think P80 too coarse. I tend to use P120 or P180.
Oxalic acid can be a bit hit and miss. I would only use it for heavily stained areas. (On dinghies, not large areas)
I have had mixed success with it and still have half a tub left.

 

[Tranona]

Ordinary bleach is a good place to start rather than going straight to oxalid acid. Also try a cabinet scraper before sanding. agree with 120 or 180 rather than 80.

 

[arcot]

I would think P80 too coarse. I tend to use P120 or P180.
Oxalic acid can be a bit hit and miss. I would only use it for heavily stained a
reas. (On dinghies, not large areas)
I have had mixed success with it and still have half a tub left.

I use peroxide to lighten and gently bleach wood.

 

[mullet]

Not relevant in this case if the wood will be sealed, but any general thoughts about bathing teak in a biological washing powder solution, letting it soak a bit, then giving it a good scrub? It’s what we occasionally did to revitalise teak decks on a superyacht I crewed on (no 2-pack acid cleaner, which was used on most of the boats, because of the amount of varnish we had). It softened the very top layer of the wood enough that it could be scrubbed away, then it needed a very good rinse afterwards though. Not something to do often because it slightly reduced the deck thickness each time, but handy and easy for occasional use. I’d be interested if others have strong views about pros/cons of this.