I have a pine desk which I have had for 20 years or so. It was flat pack but I assumed it had some kind of matt varnish as it was not shiny. Over the years I realised it must have been bare wood as parts would get grubby looking. I finally got round to dismantling it, sanding off stains etc and applying varnish. I live in Croatia now but am from UK. I found an old tin of Ronseal polyurethane varnish that contained enough for 1 coat. For additional coats I had to buy a locally available product, Kemolux Lak za Čamce (yacht varnish). This is an oil finish based on alkyd resins and uses white spirit for thinners. The Ronseal was fully dry before I applied a coat of the Kemolux but 4 days later the surfaces are still tacky. Do you think this is due to a reaction between the different varnishes? I have used the Kemolux product before on oak window frames and other items without any problem. The Ronseal stuff was for interior use so I didn't find a job for it until I did the desk.