Argument against thinning primer

What is the argument against thinning primer? Everywhere I read says not to thin primers like badger stnylrez. After getting fed up with trying to prime, I decided I would try thinning. I add two drops of windex in with my primer and the difference was night and day!

I live in a dry climate and previously I would get constant dry tip, the airbrush itself would clog, intermittent spray. The result was I would have to stop and clean my airbrush way more than I would like to. Priming a vehicle would take hours!

After thinning I got zero tip dry, no clogging, and the primer sprayed nice and smooth and dry to nice a flat and smooth finish. So far adhesion seems to not have suffered either. It seems like thinning has turned priming from an extremely frustrating experience to an easy one, I primed a whole vehicle in about 10 mins.

However, given that everywhere says not to do this, I wanted to make sure I wasn’t missing something?

1 Like

With Styznelrez I had no problem with both super humid and extra dry weather directly from the bottle, however I tried to add thinner, with a little thinner nothing, all perfect ,but if I add a little more I noticed that it loses adhesion, rub off easily.

I believe that usually especially acrylic primers, which do not bite the plastic like lacquer, are designed not to be diluted for maximum adhesion performance,to avoid that from primer they become a simple gray paint.

1 Like

Agree with the above . Stynylrez seems to be very forgiving of varying humidity, etc . It does need a coarser needle and if I am spraying large areas I put in a drop or two of flow enhancer . I use a single action Badger 200 gravity for priming and Iwata Revolution for nearly all else - Tamiya HG superfine ( made by Iwata ) occasionally for fine detail work .

1 Like

Okay this is good to know. Looks like I got lucky by not adding too much. I only add about a drop or two of windex to 1 ml of primer. It greatly improved flow and it seems to be holding up well to light sanding. Good to know too much thinner can ruin it

Yep…i forgot,i use a Grex Tritium from 0.3 to 0.5 or a GSI Creos Mr. Procon Boy SQ 0.4,usually between 20-25psi but if i use the fan tip around 35-40psi

I’m using my Paasche VL, with the size 5 which I believe is a .5 nozzle. Around 35 psi. It sprays good for a few minutes but starts to dry and cause issues after about 5 mins. The windex seems to help a lot

35psi sound a lot to me but i never use the VL or similar with the external mix.

Sorry it’s the VLS, it’s an internal mix AB. Think the high pressure might be leading to tip dry?

Could be one of the factor,but it would be better if someone answers you with the same AB, I’m not used with suction feed only gravity feed (cup on top)

1 Like

Thanks for the help!

1 Like

I’m having a nightmare scenario with primers. I use Mig Ammo primer. The Sand/Flesh works like a dream. No thinning. Straight out of the bottle. (Are they bottles?). I also have Mig Ammo Brown Oxide primer. After many tries it’s going in the bin/trash. It dries on the tip. Clogs indiscriminately. A right proper PITA. I’ve tried it straight out of the bottle. Good for about 3-4 minutes. I’ve thinned it almost to 50/50. And everything in between. It sprays but its way too transparent. Not all primers are created equal. Just last night it took me over an hour to prime the tracks for my Tiger 1 with the Brown Oxide. If it does spray then it dries very very flat and all most gritty. Yes I’ve played with thinners. Pressure and distance.

I think I start buying rattle cans for priming.


That’s the experience I’m having with my stnylrez if I don’t think, dries almost grainy, dries very fast, after about 3 minutes of airbrushing all hell breaks loose and I have tons of problems.

Thinning seems to have cured this issue