Varnish won’t dry

[Shelly]

Hi we have sanded and varnished our floorboards with yacht varnish and after 10days it is dry to touch and walk on but not dry enough to put table and chairs on .
It’s sort of dry but soft each coat had to be left 16 to 24 hrs to dry which we have the maximum 24 hrs so anyone any advice please

 

[Retired]

Hi,

Welcome to the forum Shelly.

Is the varnish oil based that is does it thin with white spirit? If it is then depending where in the UK you live the humidity and the temperature of the room it could be causing the varnish to dry so slowly. I once varnished five coffee table tops using polyurethane varnish when the temperature was low; the varnish eventually dried but it did take a lot of time. If you've sanded the floorboards this will have opened up the grain allowing the varnish to penetrate deeper so this too could result in slower drying; if you've added more coats before the first coat has fully hardened it too can cause problems.

You say each coat; how many coats of varnish did you apply; it will eventually dry so don't worry but it's frustrating having to wait.

Kind regards, Colin.

 

[Shelly]

Hi,

Welcome to the forum Shelly.

Is the varnish oil based that is does it thin with white spirit? If it is then depending where in the UK you live the humidity and the temperature of the room it could be causing the varnish to dry so slowly. I once varnished five coffee table tops using polyurethane varnish when the temperature was low; the varnish eventually dried but it did take a lot of time. If you've sanded the floorboards this will have opened up the grain allowing the varnish to penetrate deeper so this too could result in slower drying; if you've added more coats before the first coat has fully hardened it too can cause problems.

You say each coat; how many coats of varnish did you apply; it will eventually dry so don't worry but it's frustrating having to wait.

Kind regards, Colin.

Hi Colin,
Thank you for your reply and advise,
The floor has had 3 fairly thickish coats.

Thanks
Shelly

 

[Shelly]

Hi Colin,
Thank you for your reply and advise,
The floor has had 3 fairly thickish coats.

Thanks
Shelly

Yes the varnish is oil based

 

[Retired]

Hi,

Thanks for the update Shelly. The good news is give it more time and it will dry but treat it gently in case its only skinned over in places.

Water based varnish dries much more quickly and modern water based varnishes are greatly improved.

https://www.valentiflooring.com/blog/oil-based-vs-water-based-polyurethane

A bit late to know this but might be useful in future.

Kind regards, Colin.

 

[piglet11]

Ronseal used to do a water based varnish called Diamond or similar.
Personally, unless there is a good reason to use varnish at all, I now use Osmo Polyx on all my projects. Expensive but very good, lovely finish on oak etc. Outstanding resistance to water, dries to a smooth finish in 24-hrs depending on temperature.
Yacht varnish is a very old finish and I can't think why I would use it in preference to more modern finishes. Most commercial furniture will be polyurethane finished.
As it sounds as though you have finished the floor, you will have to give it time. Solvent based finishes "cure" by a combination of evaporation and oils air curing. Three thick coats is maybe overkill and the reason why it is taking a time to harden. There may also have been wax in the wood that won't be removed by sanding.
What I would have done is sand it, scrub it with methylated spirit (windows open!!), give it one thin coat by adding about 25% white spirit, or by dipping your brush into a pot of white spirit, then a light "denibbing" with a non-woven abrasive or green pan scourer. The thin coat allows more soaking into the fibres. I would allow at least 48-hrs between coats