stain removal on oak

[mpooley]

Hi
Im making some oak french doors and the oak has blackish stripe marks on it.

It looks like marks left from the sticking.

how can i get rid of these please?

Mike

 

[mpooley]

no one know?

 

[Jeff Gorman]

Try a solution of oxalic acid crystals, but remember to keep it away from others since it is a poison with irrecoverable damage to the kidneys.

However, I suspect that it ain't like cyanide!

 

[Timmo]

I used some the other day (Oxalic acid) and it works a treat....But the correct safety procedures need to be followed....I wore gloves and full face visor and worked in the front of my garage with the garage door open for ventilation...
If you look up oxalic acid on google you will find lots of links to safety data sheets etc....You are supposed to get some hot (I used warm) water and dissolve the crystals in it...I didn't make a very strong solution myself as I only needed to get rid of a small stain but you just slapit on with a brush and leave it to work its magic....Some say to then neautralise it with bicarb of soda..others say just rinse it off with plety of water....
I was only using it on a little pipe rack and it worked very well..although after reading all the hype I was more worried about using it than I am about using my table saw..although that was probably the correct way to feel....
Hope that helps
Cheers
Timmo

 

[Lord Nibbo]

I've used oxalic acid a lot. Can I offer everyone a little tip

After dissolving it mix in some wall paper paste and make it a gel rather than a liquid, as a gel it can be painted to an area where it will stay put rather than run down if used on anything vertical and because it's in a concentrated form (i.e. THICKER LAYER) it works better.

 

[mpooley]

Thanks all

I will give it a try and see how it goes.

one question though - I googled oxalic acid and found some instruction which mention it dont work on oiled wood.

is this true? My wood is not oiled yet but will be soon and it looks like i will need to revitalise the colour again after a few years - should i not oil the oak?

mike

 

[Ironballs]

Try a test piece first and see if you can oil that, can't see why the oil wouldn't adhere though.

I assume that you don't have enough thickness in the timber to remove the offending stains? As that would be simplest

 

[mpooley]

Try a test piece first and see if you can oil that, can't see why the oil wouldn't adhere though.

I assume that you don't have enough thickness in the timber to remove the offending stains? As that would be simplest

Ive tried sanding it down but i think the stains go deep.

I think you misunderstood about the oil- let me explain

I have made a green oak conservatory and the french doors are kiln dried.

I am assuming that the colour of the oak on the inside will fade as there is so much light in a conservatory and im thinking i could uise the acid in a few years to restore the colour? but not(?) if i oil it - do you see what i mean?
the exterior will be oiled but i know that will turn silver pretty soon and i dont mind that but i would like to keep the nice colour i have now on the inside.

the stains as such are the marks left in the oak that i am using for the french doors caused by the way timber is stacked with the sticks leaving the mark.

I hope that is clear

 

[Simon]

hey Mike it would be great to see some pictures of the conservatory, sounds like you have been busy.

You will also find that the oxalic acid will clean up the brown stains on untreated oak that are left once it gets wet, The blueing stains are the reaction between the tannins and ferrous metal contact with the wood.

 

[mpooley]

hey Mike it would be great to see some pictures of the conservatory, sounds like you have been busy.

You will also find that the oxalic acid will clean up the brown stains on untreated oak that are left once it gets wet, The blueing stains are the reaction between the tannins and ferrous metal contact with the wood.

Thanks I will get some asap

also been meaning to post some pics of the conservatory,
I am very pleased with it and its nearly finished now

have not took to many pics as im always too busy to stop work lol

will post in the projects forum soon

Mike

 

[RogerS]

Mike, there is also my thread here. I managed to get the oxalic crystals from my local small chemist and also the borax to neutralise it.

I'm told that the oxalic acid effectively bleaches the oak and you can get left with a halo around the edges of the mark.

In my case, oak beams...a coarse sander has worked very well.

 

[RogerS]

I am assuming that the colour of the oak on the inside will fade as there is so much light in a conservatory and im thinking i could uise the acid in a few years to restore the colour? ......

You're right....untreated oak will change from that pale honey(?)colour to a nice silvery grey in sunlight but I'm not sure that oxalic acid will restore the original colour as my understanding is that it acts as a bleach.

I don't like oiling oak for outside use...seems to me that you always think you need to keep on oiling it....year after year after year...personally I like the silvery colour. Wood stain if it gets to much for you?