Thinning latex paint

I've noticed the Sherwin Williams paint I'm using is very thick which is nice as far as not running or dripping, but, it's not very good at leveling either. Even with a quality brush and primed baseboard I have more brush strokes than I prefer.

Decided to thin it and noticed on the can they recommended a 8:1 thinning ration for touching up so I gave that a try.

Seems to be much smoother result but maybe the coverage is down a bit which doesn't matter since I'll be doing a second coat.

My question is, do today's paints need thinned more than in the past? I never had this issue before but then again I never used SWP.

Thanks.

 

A lot depends on the particular paint along with the conditions it's being applied. It's often beneficial to thin if the temps are hot/dry or if the substrate is thirsty. Often the cheaper coatings don't need thinning because they are often kind of thin to start with. Traditionally paint manufactures have advised against thinning their coatings by more than 10% so a 8:1 ratio tells me they know that particular line of paint is thick and thinning it more than 10% won't be an issue. Anytime paint is thinned you will loose some coverage properties and of course the dried film will be thinner.

 

Thanks for the info. In my particular case, I think thinning the trim SW paint (and in hindsight maybe the wall and ceiling paint) improves the application and the finish. I know most times you ask about thinning at a paint store they don't recommend it. Perhaps they are worried about void the 'warranty' which clearly states 2 coats are required. Not sure I understand a paint warranty tho?

 

Paint warranty is more a guide than actual fact IF the paint store wants to they can find an application reason not to stand by the warranty. [poor prep, wrong primer, temp, problems with the substrate, etc] The only times I've seen paint stores stand by the warranty was for big companies that bought a lot of paint. Probably more as good will than anything else.

 

I hear you. I never even gave any thought to a paint warranty until I read it on the car. My first attempt at 8:1 worked ok but seemed a bit thin so I went with 16:1. Painted a bunch of base all afternoon and seemed to work well!

No matter how hard I tried, I still got some paint 'blobs' on the back edges so next will be some quick sanding.

 

The more you use any particular coating the more you understand that coating's idiosyncrasies. That is one benefit of being a pro painter and using the same line of coating - after 100s of gallons you know as much as possible as to how a certain paint acts/reacts to any given job.