Is there any difference between the activator used for an Acrylic Urethane Enamel paint and an Acrylic Urethane clear coat? I am shooting Kirker paint and I need some more activator, they carry two separate activators one for the ProFlo and another for the paint. Can I activate the paint and clear using just the Acrylic Urethane Enamel? Or should I be using both? Kirker states all their products are compatible with each other so I was hoping one product could be used.

I wouldn't mix them, the clear is a 4 to 1 mix,
the paint is a 3 to 1 mix.

You can go here and ask them

http://www.kirkerautomotive.com/html/our_products.html

Axalta (and others) are making moves to reduce the number of activators in order for paint shops to be able to reduce inventory costs. Already, in Dupont's time there were a range of different activators that could be used with most 2K and clearcoat finishes, not to mention primers.

I seem to recall a post on here about the different types of clear and the activators that would, and those that wouldn't work. I now have a single activator that I can use in primer, base, clear and 2K. In different ratios, of course, but it works just fine. Or I can use different activators for faster clear or high solids or even a really slow clear.

You have to know for sure though and that is where JC's suggestion to contact the manufacturer above is very important. Check with the paint company, rather than your distributor.

Well kirker also states you can mix their clear in with the single stage paint in equal parts so I figured the activators need to be compatible with each other.

Yes, I think it will work ok but which ratio would be right.
Are the activators different so there's a different ratio
or is it the paint that's different?
Either way, probably only difference is the time it would take to harden.

I have used a activator that was labeled "universal"
it would work in any of them but the finish was never as good as
using what was recommended, it just didn't flow out very well.
It did work as far as activating the paint, but it didn't spray very well.