Fast/ slow reducer
Does the air temperature determine if fast or slow reducer is used?
I heard the slower reducer will have more gloss but if you are painting in the temperature in the low 60....don't you have to use fast reducer??
It's very simple. The temperature of the part, which is normally the air temperature in the place the part is residing, determines the selection of the reducer. Normally I go one up from the recomendation to get better flow out. For example if the temperature calls for fast I'll use normal. This is also dependent upon what size of object you're painting.
HERE IS THE FIRST AND ONLY RULE OF SPRAY PAINTING.
The entire surface that you're painting should be wet simultaneously. Whatever you need to do to achieve that is what you do.
Therefore, Fast reducer on a side view mirror works fine in summer.
Extra Slow for a complete paint job in winter, if you've got a clean booth, could be the cat's ass.
Dennis, you posted - "Extra Slow for a complete paint job in winter, if you've got a clean booth, could be the cat's ass." (end quote).
If the vehicle and the paint area is properly heated in the winter time to around 75 deg.F. then the same mid temp reducer would be used then as in the middle of the summer time with temps in the mid seventies. In the average homeowners garage where cars are painted in the winter time where the heat recovery is extra slow during painting then you sure wouldn't want to be using a slow reducer and an extra slow reducer would have the piant sliding down the sides of the car and ending up on the floor with runs the size of a tsunami.
I personally use fast reducer and fast hardener just about all the time, unless the temps are in the 90s (then I go to mid temp reducer). The slower the reducer the longer the paint stays wet. The longer the paint stays wet the more the odds are of runs in the paint. More of a mottling problem, more dirt sticks in the paint. more problems all the way around. If the paint is applied correctly with mid temp or fast reducer then the gloss will be just as shiny as if slow reducer was used.
Choppersrule - with temps in the lower 60s I would definately use a fast reducer.
I use the slowest I can get away with on larger jobs. Dennis is right, in that a mirror in summer can be sprayed with fast reducer and be fine.
If its a complete, or a large portion of a vehicle, at 60 degrees, I'll use mid temp, or reducers made for 85 degrees. Im not that worried about the dust free time. Especially if the dust is ON TOP of the last coat of clear.
For novice, its probably better to use a fast reducer at 60 medium at 70-75 and a slow reducer at 80-85 etc.
Guys, it gets more complex than simple reducers, how about if it is a "fast" clear, or how about the hardener "speed"?
There are many clears that if you were shooting it on a 90 degree day with med reducer you it would end up looking like gravel guard.
Generally speaking you are on the money, Dennis' "The entire surface that you're painting should be wet simultaneously. Whatever you need to do to achieve that is what you do" is the basics in a nutshell. This can be achieved in a number of different mixes of fast or slow clears, hardeners and reducers.