Hi Noah (@Noah)

I do not know the answer to the question "how long do oil paints take to dry?".

What I can share is my own similar experience.
I do have oil paints that after over a month (I have stopped counting the time actually, so no longer sure for how long, but in some cases I know over a month, maybe even two) haven't still not dried yet! And the pieces I painted with these oil paints, in some cases, do get Sun light on them almost all day long (window exposed to the SW, with another larger glass door to the left, hence SE) .

I just don't know for how long it will take for them to fully dry.

Being Winter now, I think the cold temperatures may have some influence and increase even more the already known (compared to enamels or acrylics) long drying time of oil paints.
I know that for keeping a oil paint or mix in good condition for a longer period of time, is keeping it on the fridge, for instance.
So that is one possible explanation.
The other one being how these oil paints mixes we do use are diluted on thinners. There are some products for using with oil paints that reduce the drying time, something that (apparently, from my limited knowledge based on my own observations) the traditional (oil) thinners don't all necessarily do.
There are what is called "drying mediums", which include different kinds of products, brands, etc.
You may want to type in your browser "drying mediums for oil paints", and you'll get a lot of info and help on how accelerating this long drying time oil paints seem to have.

Hope it's of some help.

Cheers!

Dolf

Rob (@robbo)

Mix/dilute the oils with White Spirit, right?
I use it mainly for cleaning brushes.
What I'm somehow a bit apprehensive with using White Spirit as a thinner, for mixing it with the oils, is that White Spirit is better known as a cleaner, like Acetone and Turpentine.
Mixing it whith the oils doesn't kind of "dissolve" them in time? Or render the colors like yellowish?
I've seen this suggested by other oil painters.

As a thinner I do use Green for Oils, by Sennelier (this one: https://pontodasartes.com/pt/catalogo/pintura/oleo/auxiliares/medios/diluente-sennelier-green-for-oil/ ) . I'm not sure it helps to reduce the drying time, it's just a thinner, for diluting the paint as much as we want.

Yes, I've seen those varnish/other spray options (this one for instance: https://www.pontodasartes.com/pt/catalogo/pintura/oleo/auxiliares/secativos/secativo-para-oleo-em-spray-maimeri/ ), I may have to use those. But there are a few other products for helping oils dry faster on this drying process, such as these: https://www.pontodasartes.com/pt/procurar/?q=Secativo&subm=ok

It's taking too long for my oils to properly dry. And I don't usually use oils from the tube, almost always have them diluted (on occasion heavily) with my thinner.
Still have some of an old one I had, believe it's from a local manufacturer, which I lately have often used mixed with the one from Sennelier. Not sure if I should better not mix them, and instead use one, or the other, it may even help finding one that may help the paint dry faster. If not mistaken, before I started using this thinner from Sennelier, I used the old one I already had, and if memory not wrong, the oils then used to dry a bit faster. I'll have to test this again.
But the cold/the Winter is definitely a factor, if I'm not wrong.

I found this, it looks interesting:

http://www.artpromotivate.com/2012/11/how-to-speed-up-oil-paint-drying-time.html

Cheers!

Dolf

Yes. White spirit or Artists turpentine but the latter is very strong and must be used with some caution.

Thanks Rob (@robbo) !

I'll give White Spirit a try.
There are different types I believe, some more "friendly" then others, if not mistaken.

Cheers!

Dolf

Noah (@Noah),

Yes, I've also read about the hot lamp.
Earlier this year (Summer, Autumn) on my place it used to attract tiny small mosquitoes... which would glue to the wet paint... Annoying at least!

Maybe I'll try again now that it's Winter, cold and no mosquitoes 😉

Cheers!

Dolf

Adolfo, I let my wet pieces just dry in a room with a air vent or an open widow so that way no mosquitos or other bugs can get anywhere near them. And yes that why I started drying indoors, just because of those bugs. 🙂

Well, I most of the time just use the air flowing through the room from the AC or from a portable fan but if I do use a window I normally do it during the day. My windows have pretty small grates and I don't much mosquitos indoors, but I do get gnats and thats why a spider in my widow is always welcome. 🙂