Thinning clear more than the recommend amount is never OK. Most manufactures allow you to thin 10% or more under some circumstances.

However, I agree that it is a crutch for improper gun adjustment. If your gun is adjusted properly, you really don't need to adjust your viscosity (thinning). One final coat of thinned clear is not the end of the world, as long as you aren't abusing it.

So in closing we can say that if mfg. allow thinning of their product then it's okay IF you think you need it. My clear does not allow thinning with any kind of mineral spirits.
I thought I would consult here first to pick the brains of experience. I can see applying a thinned final clear if you see that your clear is a little up and down. But if people here find that thinning comprimises the clarity or durability and longevity of the cc then there is not point unless your in a hurry to finish a vehicle that your not concerned with.
Thanks all

Hopefully you misspoke when you said "mineral spirits" since they have no place in automotive paint mixing/thinning.

Jayson m wrote:Do you honestly think you can do better playing junior chemist than a multi billion $$ paint company .

It is all technique and proper selection that determines what kind of finish you get,not changing the mix against the manufacturers recommendation.

It might look good on a computer screen but might look like in person,and most importantly how will it look in 1-5 years?That is the true test ...

They spend millions of dollars on producing the products legally and advertising them. The directions are designed to generate generally good results and maximum consumption of the product. So as a person who has done massive amounts of "junior chemist" experiments I can honestly say that there is no better way to gain real knowledge than to find out through experimentation. Sure you can "hop on the band wagon" of people who some how think and interact with others like you and simply follow the directions but some people want actual knowledge rather than simple common sense.

What he is failing to explain is the product is formulated to have a very long shelf life and when used as directed without thinning will cure and last for as long as the product possibly can (with profits and in mind).

He is obviously not concerned about the cost of the product and he obviously doesn't care about the problems people might face when attempting to use the product normally.

It may be possible to thin the clear coat without affecting the life span of the cured paint, however, thinning it may also reduce the life span of the clear coat paint and cause other problems. Life span and coverage may be affected based on the amount of thinner or reducer used up to a point where it completely ruins the paint (life span reaches null). I think that adding a little thinner can make a big difference in the amount of clear coat you actually get onto the vehicle but it may also affect the way the clear coat cures or in other words it may reduce its life span and when it comes to chemicals there is a sweet spot and there is a grey area and then there is the point when properties tart to dramatically change with only small additions of the chemical that was previously producing acceptable results.

If you really want to do some experiments with lacquers and thinning in addition to your car experiment then I recommend nitrocellulose lacquer since it's similar and I learned a lot from messing around with it.

Personally I'm planning to thin some ready-to-spray dupli color clear coat tomorrow along with some metal flake .004 and in my mind i believe it is possible to thin it out a little. Maybe I will post some pictures of the plain clear coat with metal flake and the thinned clear with metal flake and then leave it out in the sun and take pictures periodically to update those who are curious.

actually all the above posts are wrong... no offense

the correct way to reduce any paint is with a viscosity cup, should tell you on your TDS what size and how long you should time it. there is a limit to reducer you can put in depending on the temp of your paint, try to keep your paint around 75-80 degrees

Why wake up a 4 year old post.Comments on over reducing duplicolor Lacquer clear are in no way shape or form comparable to a urethane clear.Either follow manufacturers guidelines or check flow with a viscosity cup according to what the manufacture says. Being a junior chemist in your back yard is one thing but when you paint a few hundred cars a month in a large production shop you dont take chances.Just sayin....