Time between base and clear

B

bobmeyer58

What is the maximum time to let the base coat flash before applying the clear? I will probably be using Pro Spray base and SPI Universal clear coat. I might need 12 hours is this acceptable or will I have problems? I am a pest asking a bunch of questions
 

El_Duderino

Promoted Users
Here's a bit of info Id like Jim, Barry and the others opinion on. I went to the PPG resto class and envirobase class last year. That topic was discussed. The teacher said to apply a coat of intercoat first because it has more solvent than clear to better reactivate the base(not ENV, totally different animal).
 

Jim C

Oldtimer
well if your going to clear coat a base that has been sitting for days or weeks what you dont want to do is use fast activator in a hot temp or spray your clear on the dry side. you want the clear to stay wet a little longer so it bites in. what i have always recommended is slow activator and reduce 10% with slow reducer if you feel adhesion is going to be an issue. while the instructor is correct that the intercoat solvents are stronger and will reactivate the base somewhat, a clear coat still sticks better that base does. i have seen fresh base peel off cured base that was weeks old but i have never had clear coat peel off or had adhesion issues.
 

jcmeyer5

Having fun learning!
How about an ACTIVATED basecoat? Is that any different? Or are you assuming the base is activated?
 

Barry

Paint Fanatic
Staff member
Here's a bit of info Id like Jim, Barry and the others opinion on. I went to the PPG resto class and envirobase class last year. That topic was discussed. The teacher said to apply a coat of intercoat first because it has more solvent than clear to better reactivate the base(not ENV, totally different animal).
Those who can do, those who cant teach!
Formulating 101, if your relying on solvent for adhesion your formula is bad, redo.
Clear adhesion is based on resin in the clear and the iOS's, in the hardener, more solids more adhesion especially true with water bases.
 

roger1

Member
Question.
If my wait time between activated base and clear is only 3 days, should I still reduce the first coat of clear 10%? Or is that not long enough to worry about.

I'm finally ready to start the first paint session on my '69 GTO convertible. Tomorrow possibly. It's going to be SPI Dark Red and Universal Clear. I am panel painting it and will start off with the body:

KtKT6s1.jpg


Ki0uyXC.jpg


jDlPSFy.jpg
 

roger1

Member
Thanks for the compliments guys!
So I sprayed sealer and 3 coats of base today. I reduced the red epoxy about 35% and waited over an hour before the first coat of base.
It went pretty well but not perfect.

UXTwrT1.jpg


K69IDHZ.jpg


It's relatively smooth and didn't get any runs but I do have several dust nibs. Not horrible but more than I hoped for with my filtration setup and steps I used. Most seem to be on the top surfaces and not large. I called Barry for advice after the second coat of base. After discussing a few things he advised me to ground the body and spray a 3rd coat then do a bit of sanding out of the nibs tomorrow and then spray some more base. He said I can spot spray if I want to and feather the spray out around the areas.
I had pounded in a length of rebar several years ago for grounding to many years ago and I luckily found it, hooked up a wire and then sprayed the 3 coat.
Here's a close-up of some of the nibs:

LDejIUW.jpg
 
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rdransman

Promoted Users
You're lookin' GOOD! I wet the floor down completely at least an hour before shooting, and wet it down again just before using the tack rag. It seems to help getting the dust out of the air. Of course, be sure not to get any "spritzes" of water on the body. If you do, just dry 'em off with a micro fiber towel.
 

Chris_Hamilton

Trying to be the best me, I can be
I used to wet the floor down, but stopped doing so. My paint work got cleaner and better because of it. 99% of trash comes from the car or yourself not the floor. Wetting the floor and the resulting humidity affects how base lays out and dries and also affect the clearcoat to a very large degree. Sweep it or vacuum it good and leave it at that.
Roger even the cleanest paint booths will have some trash. Yours looks great. A few nibs are to be expected and can be easily dealt with. Like I said most trash comes from the car, the second largest source is the person spraying.
 
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