How to use indoor paint on exterior

[jyl]

We have some special “copper” house paint that I want to use as an accent color on the exterior. Is there a clear coat I can use so that interior paints can survive outside?

[Evans, Marv]

If were me, I think I'd just get a color match on a quality outdoor paint.

[otto_kretschmer]

I don't think the sun is the problem. I think the difference between interior and exterior paints the differences in temperature and moisture. Outdoor paint has to deal with Minnesota winters and Death Valley summers with rain and extremely dry. Using outdoor paint indoors shouldn't be as much of a problem as using indoor paints outdoors.

[Dantilla]

I've heard the only difference is exterior paint has a touch of mildewcide added.
Other than that, the paint is the same.

[flatbutt]

https://prudentreviews.com/interior-vs-exterior-paint/#Can-You-Use-Interior-Paint-Outside

[Dantilla]

Definitely some bad information there^

"Lastly, it takes longer for interior paint to dry since it’s not designed to dry in outdoor elements."
Hogwash. Baloney. Malarkey.
A blanket statement like that casts doubt on the rest of the article.

Sure, the old oil-based exterior paints were not optimal inside, but current exterior latex paints are not "extremely dangerous" inside.

[Zeke]

What gloss is this paint? Generally you don't use dead flat paints outside. The added resins for durability will give exterior paint some side sheen that is more or less undetectable on textured surfaces. Almost all trim paint has some sheen except for solid color stains. Even some of them shine just a little.

But yes, you can fortify inferior paint and make it more suitable for exterior. Anything with a high acrylic content will help. It will never be exterior paint.

AFA the linked article is concerned, it didn't bother me so much but it was over generalized and short on technicalities. I didn't see any bad info. The exterior /interior drying thing was just poorly worded. I think they were referring to cold weather and didn't mention any conditions. Interior paints have a narrower temp zone from my experience. I've had some interior paints fail to dry well when cold and in especially humid conditions.