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Hi all,

I had a frustrating night last night attempting to prime Vallejo white surface primer on some plastic and resin model parts.

I used about 12 to 15 drops with 2 to 3 drops of thinner. no flow improver though.

I am painting at 17 to 20 psi with an Iwata hpcs eclipse. I am using the optional .50mm nozzle and needle for the first time rather than the stockk .35mm nozzle and needle.

the first few parts were no problem though as i needed more primer is when I had issues. splattering or misting, constantly cleaning the tip. My technique probably needs work as it tends to pool, perhaps i keep the gun in one spot to long or totally misjudged where the paint will land.

I cleaned the gun 2 to 3 times though had to stop when the spring for the trigger went down the drain. A new one is arriving on Tues so I will give it another go though I am finding airbrush priming more difficult than airbrush painting. Same with varnish.

I am thinking i need to put less primer in the bowl to keep a ring from drying and causing clogs and increasing my ratio of thinner and using flow improver. Also being more mindful of sweeping my hand and not leaving it too long in place to pool. I was priming 5 infantry but they were all umassembled and mounted on wire and wine corks. Is that too much to airbrush in one sitting?

I think my psi is about right though will take any help I can get. Almost wants to make me go back to rattle can do to lost time but the airbrush results are so smooth.

What am I missing?

I have a 0.3mm needle on an Iwata copy. The air supply is a cheap 12 psi tankless compressor. Because of my combination of air supply and airbrush, I had a lot of problems with Vallejo surface primer drying on the tip of the needle or in the cup. I finally figured out how to get very good results on plastic models by using a wet mix.

Whatever you do, combination of needle size, air pressure and paint viscosity has to be balanced to make sure the paint doesn't dry on your needle. Because of my cheap airbrush/compressor setup I'm forced to use a very wet mix, but it works for me. Because I add a lot of water to the mix, I have a large volume of liquid in the airbrush that gets sprayed very quickly. It doesn't have time to dry inside the airbrush.

I primed 30 infantry in one sitting last week using this method:

1) Make sure the primer is very well mixed. I use an agitator in the bottle and a cheap nail varnish shaker mixer.
2) Mix the primer 2:1 with water before putting it in the airbrush. I typically do 20 drops of paint, with 10 drops of water from a pipette in an old shot glass.
3) Use the pipette to transfer the watered down primer from the shot glass to the airbrush.
4) Spray from a good distance, low PSI, it's a very wet mix so you want it going on a large area in very thin coats. Do short blasts of full spray, never holding the airbrush still for a moment.

It can be a bit too wet at first, so you might think maybe the ratio should be 3:2 or something, but it gets better as you use it. (I don't know if this is because the paint is starting to dry a bit in the cup).
If I need more, I mix it up in the shot glass with water and keep going. Occasionally I need to wipe the tip of the needle with a cloth or sponge.
Two coats is normally enough. Three at the most.

I might start thinning my primer now that you guys have mentioned it.

I did try it once, quite a while back, but I got really odd results and and because of that, haven't tried it since.

The other day, I managed to prime all of the Mythic Battles: Pantheon core set (40 or so minis of various sizes) in one go with a 0.5 needle at 20 psi, but it was hard going. I managed to bull my way through it, but if thinning the primer makes life easier, maybe I should revisit it.

 Skerr wrote:

I am painting at 17 to 20 psi with an Iwata hpcs eclipse. I am using the optional .50mm nozzle and needle for the first time rather than the stockk .35mm nozzle and needle.

Although it's not vallejo, I've been running Stynlrez at a much higher PSI (per instructions) than I generally paint at, 25-30 PSI through a .50mm nozzle.

Vallejo (in their FAQ) recommends minimizing how much you thin their primer, but doesn't recommend a specific pressure to operate at. You may want to experiment with a higher pressure first, rather than a thinner mix.


Re: Quantities of models, no 5 models is not too many at once assuming you're not spending minutes moving parts around.

Thanks guys, going to just experiment seems the key is watch drying on the tip.

I use a cheap knock-off airbrush for priming and varnishing. It takes a lot of punishment in the cleaning after a session.

Anyway, I use the Vallejo PU primers and I don't water them down. I stick the PSI up though (30-35 PSI), pull the airbrush further back and do short bursts with a couple of coats. Airbrush is 0.35, I believe. I will get tip dry after a while and once it starts I find I will need to keep cleaning the needle every few models. At that point I have taken off the front nozzle so I can access the needle quickly. However, it doesn't usually set in until I have done a fair few models (maybe 12-15 infantry or a few large Tyranid monsters)