[nova69]

Since we can't have the sun cook the clear in the winter time, should cure temps be extended or steps added to get the same result? Shop temp will be pretty close to 70*. And -- Does adding hardener to the basecoat plus having the hardener in the Universal Clear make the finish TOO hard? I don't want to be overly concerned about little rock chips turning into big ones. Thanks.

[BarryK]

Originally Posted by nova69

Since we can't have the sun cook the clear in the winter time, should cure temps be extended or steps added to get the same result? Shop temp will be pretty close to 70*. And -- Does adding hardener to the basecoat plus having the hardener in the Universal Clear make the finish TOO hard? I don't want to be overly concerned about little rock chips turning into big ones. Thanks.

------------------------------------------------------------------

The sun helps as well as warm outside temperatures however those two items are not as important as the UV's. It can be 30 outside and cloudy and the UV's will cause the solvents to move.
The darker the color the more effective the UV's are as for example the carbon in black is a natural UV inhibitor so it turns the UV's into heat and dissipates the heat. ( that is how UV inhibitors work)
So it could be 30 and cloudy and the hood of a black or dark blue car might reach 50-70 degrees.

Adding activator in the right amounts to the base be it 1 ounce to 2 ounces per quart will not make the paint job brittle, it will give the paint more flexibility and stronger adhesion and of course resist stone chips better.

[jcclark]

Electric blanket!!!!

[a440plus6®]

It's the Reducer you use that will speed up or slow down curing time......any knowledgeable auto paint shop such as PPG or DuPont in your area should be able to answer your questions.

[baddbob]

Reducer speed is only one factor, but oftentimes fast reducer causes a slow cure-think open time, listen to what Barry says

Evaporation of solvents is only part of what takes place when a urethane clear cures, it's the crosslinking that's the big thing, a slow solvent tacks up later but the extended open time lets the clear purge more solvent for a complete cure that happens sooner.

[a440plus6®]

Slow cure in cold weather insures sags...ie runs.

[BarryK]

Originally Posted by a440plus6®

Slow cure in cold weather insures sags...ie runs.

----------------------------------------------------------------------

Sorry but cure has nothing to do with runs.

You must mean flash time??
you would know I guess -- so you tell us AND answer the guys question while your at it or you just here to be a jerk?

You either know or you don't so if you know write the answer to the guys question so we can all learn.

[a440plus6®]

Sorry, 1 finger typer and been busier than a 3 legged cat burying s**t.....so I'll bow out. I was not questioning your reply ....you are correct....I was just pointing out one potentiol problem.

[shine]

i use the slowest reducers and hardeners year round. i learned many years ago if you go for the fast kick your gonna have a die back problem in a few weeks. sags are just an indicator that your getting enough on dry to touch is the worst way to judge anything dealing with paint. trapped solvents ruin more paint jobs than sags. at least you can fix a sag easily.

[jcclark]

Shine-me too! I always use the slower stuff.
(And I thought I was the only one.)
It really helps on a lot of different problems, including
solvent pop.
It just test my patience so much, it's so hard to wait longer
when you want to put another coat on.
I don't do waiting very well

[nova69]

Thanks to all. I'm on the right track. Great info on the UV.

[BarryK]

Also I may have overlooked the main question, yes 70 is great!