Quote:

... so here is my question. I'm on page 25 of this thread and have read the origional and have not seen this addressed. My spray paint mentor once told me to watch the temp vs. due point when painting. If the temp is falling fast..don't paint. If the due point and the temp are too close together..don't paint. My mentor said when the concrete is sweating they are definitely close together. I see some experienced painters on here and would like to read their comments on this, and whether or not it has any effect on a single stage paint like the tremclad/rustoleum.





When spraying or rolling... the temperature and the humidity both play a factor in how things will go....

The temperature will affect how fast (too hot) or how slow ( too cold ) the paint will cure. If the temperature is too hot then the paint will not 'self-level' itself out properly because it has dried too rapidly. If the paint dries too rapidly the skin will dry quicker than say the paint that is in contact with the body of the car. This can lead to the wrinking effect ( which is worst than dealing with orange peel ).

When it is toooooo cold.... well the problem is that the paint does not cure within the time frames that the manufacturer says the paint will cure. You again may end up in a situation where the surface skin 'appears' to have 'dried' - but in fact the paint below the skin is still attempting to cure. This may result in the 'carrier' of the paint trying to evaporate through a sealed skin surface. I think this tends to give the paint a foggy appearance - which you can't simply compound out.

The thing about humidity is that if it is too humid then the paint will not have as nice a gloss or shine on its skin ( the outer most surface - the one that is visible ). The higher the humidity the less gloss and shine.

If it is too humid you may find that the coat of paint you apply might take on a bit of a foggy appearance, along with the lack of gloss. I am not a chemical engineer... but I think when the paint is drying, and the carrier solvent is evaporating from the paint.. there might be some molecular chemical reaction happening between the evaporant and the moisture in the air. This is something similar to what people have experienced with 'water spots' - where it has rained on their curing paint.

So ideally you want to do the spraying or rolling on days where the temperatures are within specifications of the paint manufacturer. If it is comfortable enough to work without breaking into a sweat then that is probably a good day.

As for humidity... well you can usually tell when there is too much moisture in the air ( after a rain, prior to a rain, first thing in the morning when there is a temperature transition from warm to cold or cold to warm - where condensation might form ).

In my case I had to wait five days to put the final coat of paint on my car because we were in the middle of a heat wave.... up past 100 ferenheit.. Then we got hit by two massive rain days. Rather than take a gamble on the how the weather might affect the final quality of my last coat of paint I waited until the temperature and humidity were optimal.

I should mention that I was quite pleased that I waited it out before laying on the last coat of paint because that final coat had the best appearance of all the previous coats that I had put on... ( it was road worthy shiny ).
.

Last edited by Marq; 08/23/06 09:20 PM.