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Do It Yourself UK/caustic soda damaged oak worktop


My kitchen sink worktop has splatters of caustic soda stains from tipping a caustic soda mix down the sink to clear a blockage (!). The top is 40mm thick, only a year old and was pretty perfect, finished with Danish oil. Can it be sorted out or is it ruined for ever?

Hi Sue

There is good news. Overall the oak should be ok but it could take quite a bit of sanding to sort it out and you are going to have to redo all the worktop otherwise it won't look right. The caustic soda will react with the oak but it depends how long it was left before it was dealt with. In my experience the finish itself is usual ruined and doesn't usually  penetrate beyond a 1mm.. I would recommend you to use a random orbital sander as these are good for removing more than you would using an orbital sander. You will need to start off with 120grit abrasive. A lot depends on the finished you are going to use to how many grits. Usually I use a 120, then 180 then 240grit depending upon the manufacturer's wood finish guidance. The dust generated is really bad for your health so you need a sander with bag filter, personally I use a Hoover with my sanders. Make sure your room is well ventilated but keep the doors shut from the kitchen otherwise you will find the dust spreads.

Danish oil...whilst there is nothing wrong with it, in my opinion  it not the best product for kitchen worktops. I would prefer using Liberon finishing oil and more recent I have been using another product called Treatex on all my woodwork. Further information can be obtained at;

Hope this helps you.


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Stuart Mawle


I can give advice / help on carpentry & joinery, health & safety, woodworking machinery, power tools, suppliers, timber and timber related products e.g. adhesives, finishes.


Carpentry & Joinery;I have served an indentured carpentry apprenticeship with a medium sized building contractor doing a wide range of domestic and commercial work. This has included office buildings, barn conversions, building extensions and renovations. During my career, I spent over three years as a wood trades technician at a college. My job involved joinery work, wood machining and helping CITB carpentry & joinery students' practical projects.I am all ready an voluteer expert in the wood working category.

I am a member of Institute of Carpenters

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