My experience with thinning paint for use with the airbrush

I'm working on a commission project for Beautiful Warfare Studio of some really cool Forge World Pre Heresy Night Lords raptors and a couple vehicles.

For the main blue cote of these figures I want to save time by airbrushing it instead of hand brushing.  The biggest problem I've found with doing this is that after using my Vallejo Model Air paints to base a figure I have difficulty blending via hand brushing afterwards.  Sometimes the jump between airbrush to hand brush blending is too obvious for my liking or sometimes I want to go back to that base color to find that VMA blends in a completely different way than the normal P3 paints I tend to like using.

I want to use P3 blue colors for the Night Lords because, as I've said in the past, P3 just works for me and my method of feathering.  These paints are so silky smooth and, to be honest, have a little wiggle room for mistakes or imperfections here and there.  It's just their nature.

In order to avoid past problems with VMA-P3 / airbrush-hand brush situations, I decided to do something I'm a little nervous about: thinning the P3 paint and pumping it through the airbrush in the first place.  I've never had much success with this kind of thing yet (probably thinning the paint down TOO much to avoid dreaded airbrush clog) so naturally it's not something I'm confident in.  I HATE having to take my airbrush apart and it happens all too often with me.  I even keep the air flow continuous such that my index finger often hurts after a decent airbrush session but the brush STILL ends up clogging somehow.  I really need someone who knows their shit about airbrushing to sit beside me and give me some pointers about what I'm doing wrong.  I've kind of learnt everything on my own thus far...

At any rate, I took the P3 Exile Blue, added some Vallejo airbrush thinner and then by accident dropped a whole bunch of water in the mix.. So then I added more paint and a little more thinner and got something akin to what I expected: a not too thin but not too thick mixture that covers well and doesn't clog the brush.

I used the Vallejo polyurethane white primer to first coat these figures.  This is a strange primer and I'm not sure if it's ideal for use outside, or maybe just not for the climate of Vancouver?  It tends to spray on to the figure messily with easy to identify "drops" all over the model.  After a couple of these cotes the problem fixes itself I guess but I'm still not sure if I'm using it correctly.

I added some of my Exile Blue mix and it went on poorly at first but after a second cote really saved me a lot of time.  I still clogged the airbrush, however, though this might have been due to some primer getting stuck (the primer is a tad on the thicker side itself).  I really get frustrated airbrushing.  I sometimes wonder exactly how much time I'm saving when it seems at least twice a session I'm taking the needle out of the brush and wiping it down... sigh...

The 5 raptors are all very blue now and quite solidly at that.  All the detail has been retained (though I don't usually have a problem with this in the first place).  For the vehicles I plan on going even further with my airbrush experimentation and doing something I've always seen done but have never experienced myself: extreme blending with the airbrush.  To be precise, I mean starting with a light color in the 1st quarter, corner of a panel, then using a few mid tones with the airbrush in the 2nd and 3rd quarters of a panel, and finally using the darkest color (in this case Exile Blue) in the 4th quarter of the panel.

I will have some pictures of the project when I deem them suitable for photography... Until then, let the trail and error commence!