Question about GW white primer

[Antonio J Carrasco]

Lately I have been using GW white primer for my miniatures. Usually it doesn't give me any trouble, but I have noticed that sometimes it gives me a somewhat 'grainy' surface, which is a pain in the ass for painting because paint doesn't flow but it is "absorbed" by the primer. It is not always that I have the "grainy" surface problem, but only in a few figures. It happens especially when the primer can is new.

I haven't met that problem with black primer.

Has anyone had a problem like that? And if so, how did you solve it?   

[cram]

Bought a can of this myself the other week. Test sprayed it on a piece of scrap plastic to see what it came out like and it had a that grainy texture you refer too. It was a fairly warm day, so I figured the paint was drying before it reached the plastic. Waited for a cooler day to have another go, yesterday evening it was a little on the cold side so I had another go in that temperature, this time the paint was still wet when it hit the plastic.....but when dry it still had the grainy texture! Haven't got a solution other than to try a different brand.

[Ahistorian]

My solution to funky GW spray paint is using Hycote spray paint. It's been eight years now and I've never been let down - at half the price of the posh stuff.

[tomek917]

I've had the same problem with the GW spray, no matter the weather.

I've had the same problem with a lot of different sprays and varnishes so now I've switched completely to using my airbrush when basecoating.

[Antonio J Carrasco]

I've tried this morning and results have been better. Shook the can for three straight minutes and then primed at a range of 20cms, in small bursts. It has made the trick. At least it looks like the surface is smooth. The figures with more grainy basecoat first I have brushed them with an old toothbrush and then I have varnish them with gloss varnish; it has partially corrected the problem -at least the worst of it- but it is far from ideal. 

[Antonio J Carrasco]

Confirmed. It is the "shaking" time what counts most.

I have made a small experiment.

I primed figures at the same time, in order to have the same weather conditions (dry, with a temperature of about 30ºC). Also, as control group, I primed three figures with Black Primer.

First figures were primed after one minute shaking, using controlled bursts at a distance of 20 cms, approx. The result was a grainy surface, both in plastic and in metal figures. The figure primed in black (plastic) didn't show any grain.

Second figures were primed after two minutes of energic shaking of the can, again using controlled bursts at 20 cms. The result was again grainy, without any noticeable difference with the one-minute figures. Figure primed in black didn't show any grain.

Third batch were primed after three straight minutes of energically shaking the can, with controlled bursts of paint at 20 cms. That made the trick and the resultant primed surfaces were smooth, without any noticeable "grain".

So, in conditions of dry, hot weather, apparently three minutes of energic shaking will get the best possible results.

[cram]

Interesting! I'll give the 3 min shake a go, on a bit of scrap plastic first as not to ruin any figures.

many thanks.

[Antonio J Carrasco]

Hope it works for you too! Let me know how it went.

[Hammers]

I tough a slightly grainy surface is what we are looking for in our primers. Does it become excessively so when using GW primers. I use a generic brand spray on white primer. When I use brush-on white gesso (Liquitex) the surface also become noticeably grainy, which I like.

[Westfalia Chris]

I tough a slightly grainy surface is what we are looking for in our primers. Does it become excessively so when using GW primers. I use a generic brand spray on white primer. When I use brush-on white gesso (Liquitex) the surface also become noticeably grainy, which I like.

I've had similar issues with almost all white primers (regardless of manufacturer) I used in the past, to an extent that it was one of the major factors in my decision to switch to greys. Strangely enough, where their white tended to "dust", the uniform grey Army Painter spray I use these days never gave me trouble. I wonder if the different pigments can actually have such an effect, or if it is psychological or pure luck.

[Kommando_J]

I have found that GW's black primer to be awful in pot form(just a heads up) will not adhere but makes for a great wash .

[Antonio J Carrasco]

I've had similar issues with almost all white primers (regardless of manufacturer) I used in the past, to an extent that it was one of the major factors in my decision to switch to greys. Strangely enough, where their white tended to "dust", the uniform grey Army Painter spray I use these days never gave me trouble. I wonder if the different pigments can actually have such an effect, or if it is psychological or pure luck.

Without empirical evidence is hard to say, but I believe it is not too far off from the mark the idea that it is how pigment reacts with solvents in certain conditions of humidity and heat what gives us smooth or grainy surfaces. That would explain why longer times of shaking makes for a smoother surface, as the solvent and the pigment are more integrated and therefore less affected, I guess, by the humidity or the heat. Of course, that means that different pigments and different solvents react also differently. I don't believe it is psychological, nor luck, just chemistry. Wish I understood it better! Why didn't I pay attention at Chemistry classes in school?

[cram]

I'v used brush on black gesso up until now. Never spray primed before, the texture is only slightly grainy, but I expected it should be dead smooth??

whether its been wet or dry, hot or cool, its been very humid in my neck of the woods at the moment.