oddworxs wrote:I mainly use shopline's clear. the mixing ratio is 4:1, i have never thinned out the clear, simply because it just a 4:1 ratio... and also my paint sales lady told me that i shouldn't, but yet some people do. I'm confused....

Dont be confused. look at it this way, thinning clear is a crutch that people use when they dont know how to properly apply the clear to get the results they want.

i did come to think that as well, this other guy i work with thins his clear but we get the same look, like i mentioned beforehand, i dont thin mine. i only add reducer when the mixing ratio states it. THANKS!

All spray guns spray best when the viscosity is matched to the gun, period!!!!
The gun does not know what you're spraying, it only knows the viscosity.
The tip size will change that, a bigger tip can spray thicker materials.
All clears vary on their viscosity, some are much thicker than others.
Even temp's affect the viscosity.
That's why mfg's give thinning instructions.
So to say all clears should be sprayed full strength
to spray best is not common sense, to many variables.

No. Clears should be mixed and sprayed per the TDS from the manufacturer.

JCCLARK wrote:All spray guns spray best when the viscosity is matched to the gun, period!!!!
The gun does not know what you're spraying, it only knows the viscosity.
The tip size will change that, a bigger tip can spray thicker materials.
All clears vary on their viscosity, some are much thicker than others.
Even temp's affect the viscosity.
That's why mfg's give thinning instructions.
So to say all clears should be sprayed full strength
to spray best is not common sense, to many variables.

I tend to agree here.

Where do I get the data for the ideal viscosity for my gun and the tip size I'm using? Is that data commonly published?

ding wrote:No. Clears should be mixed and sprayed per the TDS from the manufacturer.

I agree.
Reading the tech sheet for your particular clear will tell you all you need to know. A tip size is recommended, spray gun settings, proper application techniques, etc.
Some will require reducer when mixing, others will allow thinning if necessary to a certain percentage and yet others do not.
Most of the problems I have encountered with spraying clear and getting it to lay flat have been in my technique. Moving too fast, holding the gun too far away, too much air, not enough air, and so on.
I think this is why people tend to stick with a clear they find works for them.

Tech sheets tell you how much you can thin it.

If it had a negative affect, the mfg. wouldn't tell you how much
you can use. Follow the directions and you can't go wrong.
Everything else is B.S.

Ya, tech sheets tell if you can or how much you can. if you didnt notice this thread is talking about thinning clears that dont call for it or over thinning clears that do call for it.
Bottom line is adding more thinner than called for can have a negative effect

The only problems I've seen with thinning clear is "burning" it or some are incompatible with urethane reducer.
"Burning" is when the clear looks cloudy/hazy and sometimes has a grainy texture/finish. Too much reducer.

Example of "incompatible" clear would be: S-W/NAPA Finish 1 FC720. The manufacture states that you can use their compatible Acetone, NOT urethane reducer. This is something to be aware of and take note on any product data sheets!

Lets see. Solvent pop, Die Back and Delamination are just a few negative effects of thinning clear more than the TDS calls for. Do you guys that seem to know better than the manufacture of the product, spray extra coats of this over reduced clear to make up for the lack of required film build needed to keep the product from failing ?