I spray close up from start to finish, light coats.

Last time i used Vallejo primer was on that large test piece above, and i applied it by brush, mostly been using MIG grey primer before that(by brush mostly).

And yes the primer is grainy if i spray it, everything i spray have the same bad finish.

But those Tamiya pieces had no primer on at all so it cant really be a primer issue

I checked the temperature and humidity in my painting area today and it showed 19 degrees celcius and a humidity of 43%, doesnt seem too extreme?

And that picture i posted from my Tamiya test isnt working for some reason and i didnt find the edit button so i´ll post it again

https://imagizer.imageshack.us/v2/709x530q90/r/909/lUZPj7.jpg

That is with 1part paint to 1.5 part tamiya thinner + 20% retarder

I am assuming that you are using an XF series of paints (flat), how does the gloss type end up? The flat finish considering that there is no primer seems ok but still having a bit of a rough texture. I don't think you should attempt to go beyond the 50:50 ratio and no retarder for tamiya. Usually people stick to 50:50-70:30 paint-thinner, and I have never used a separate retarder in my mixes. Your weather conditions do not seem to pose a problem for airbrushing.

Now where else can it be going wrong. Well that's a tough one since you basically covered quite a lot. I must say that it MIGHT be the way you spray on paint. Try making a video 50:50 no retarder @ 15-20psi for 2 pieces (with and without SPRAYED primer). I know it's a chore to make but right now I find it really strange that you're are getting these results from various products using a lot of different configurations. Also you get the same result spraying vallejo primer which is not rough enough unlike the spraycan tamiya. The common factor now is the indian, not the bow and arrow, so to speak.

Last thing I would look at would be the air supply. If the regulator is really working and the trap is functioning properly. I only get a sandy finish at high air velocity and long paint travel time. Do you have a fan or the AC blowing at you while you are airbrushing? Or does it take you a long time to stop the release of air from your airbrush even after you've push the lever forward. I've seen some people have a habit of keeping the airbrush spraying air on the work piece even after the paint lever has been pushed forward.

I only have the flat version of the Tamiya paint, didnt get a glossy one.

I´m starting to think it´s the way i spray aswell since it doesnt seem to matter what paint/thinner i use or how i thin it

I can try and make a video, i dont have a great camera but i´ll make it work somehow.

The only thing that have been the same from the start is my regulator/spiral hose, not sure if they could affect anything.

I dont have a fan or anything like that nearby.

I´m not sure what you mean by keeping the air on after the lever is pushed forward? I do keep the airflow going pretty much all the time during spraying a piece if thats what you´re asking? I´ll show it in the video.

I'm not familiar with spiral hoses since I use braided hoses but some people use a water trap in between the hose and airbrush to prevent water that has accumulated in the hose. I myself have never had an issue with that even with 3 meter hoses, not spiral though.

I think typical phone cameras would be enough to give an idea on the spraying method

What I meant by keeping the airflow is the for double action brushes you press and pull the lever. I have seen at times people press for air, pull for paint and once the lever is pushed to cut off paint, the air valve is still depressed.

Basically I spray air and paint roughly the same time (air 1 second or less head start) but mostly they cut off the same time.

I think i do kinda the same, when i paint a larger area i usually keep both air and paint coming all the time and move side to side until the piece is covered.

I did some more testing with my thermometer and i have a spot with 19degrees and 49% humidity and one with 10 degrees with 65% humidity that i could try spraying in aswell to see if that makes any difference

So today i tried some spraying in a cool damp basement with 60ish% humidity and around 10-15 degrees celcius temperature.

I tried both Tamiya, vallejo and citadel again, but didnt notice any difference at all, only things is that the paint took abit longer to dry, but no better results.

So temperature and humidity doesnt seem to be the issue either.

I´ll try and get some video footage of my spraying as Jomark requested asap, just havent had the opportunity/time yet.

I am really dumbfounded by this issue. A question though. If you hand paint vallejo model color thinned with water or their thinner on a flat piece, do you get a better finish than with an airbrush?

Now this is really weird, i just painted some flat unprimed pieces with modelcolour, citadel and vallejo grey primer, all with a brush and i got similar finish to when i´ve been airbrushing?!?!

I also primed some pieces with the tamiya fine grey primer that i´ve used before and it was on closer inspection kinda grainy aswell.


Last time i used the tamiya primer and handpainted vallejo/mig primer it looked fine, but maybe i just didnt notice it then or wasnt inspecting it closely enough??


hmmm, so could the paint behave weird when painted/sprayed onto bare plastic and cause the graininess? even if its a primer?

I need to find a primer that goes on super smooth and then try spraying ontop of that since bare plastic might not be the best thing to test on

Maybe it is already because of the surface itself. Try painting on used CD/DVDs that should provide a smooth surface as a baseline

The pieces i paint on have been cleaned quite thoroughly by the cleaner i use to strip them, and it´s been the same with pieces straight out of the box so it shouldnt be a plastic issue

Have you tried Lacquer based Mr.Color paints ?

The best finish I've gotten after trying almost every brand out there.

I havent tried any laquer paints yet. I´ve been wanting to stick to acrylics but maybe i should try it out.

Do mr.color have acrylic paints aswell?

thanks for the suggestion

Gunze Sangyo has two lines of paints. Mr. Color which is lacquer, and Mr. Hobby Color aqueous which is acrylic. The acrylic line is very similar to tamiya so I don't think you'll find any difference between the two. There is a 3rd line of paint which is called Hobby Color Acrysion which based on the store, is the same as the acrylic line except for changes in components that have environmental law restrictions and such

I suggest try eliminating more culprits before further trying out new paints. You've pretty much tried most of the usual paints that everybody uses. It's more likely something else.

Just a thought. How about hand brushing one of your miniatures with vallejo and see if the finish is better. I'm curious how much different it will be compared to the first few pictures you posted in this topic.

Mr Color acrylics are hands down the best acrylics I've ever used.

But, Tamiya XF's are close behind, when thinned with their Laquer Thinner (the bottle with the yellow cap). Much less prone to dusting, than when thinned with the acrylics thinner (X-20A). I'm also in the habit of adding a bit of Clear (X-22), which improves things also.

Sure, the paint get's less flat, but then you don't want your model dead flat before decals, washes etc anyway.

Used to use Vallejo Air all the time, but after I installed a proper spray booth with a good fan, I'm not looking back.

Thanks for the information guys, some interesting stuff

I feel like i need to find a good smooth primer first before i do anything else. Testing on pure plastic doesnt seem to be the best way to go

The vallejo primers you are using is already pretty smooth. If you want to go even smoother then an option would be Mr. Surfacer 1200 which is lacquer based.

And if you want an even smother surface there's always Mr Finishing Surfacer 1500 . It even comes in black .

Looking forward to an update. Having the same issue as you, but only on models. I can spray a plastic spoons very good (not gritty).

Maybe I'll stick to building Plastic Spoon figures

Could "high" CFM in a paint booth also cause these issues?
I'm thinking the airflow could dry the paint prior to getting to the model.

Sorry for the lack of updates, i´ve just been very busy lately, will hopefully continue with the experiments this week.

Hey Ivan, sorry that you´re having problems aswell but atleast its nice to know im not alone

No problem and hopefully you can find a resolution.

Hey again

I havent really had time to do much hobbying the last few months, but i just tried some Alclad lacquer primer today and that stuff dries even faster than acrylics!, i used it right out of the bottle and my tip dry was really bad and it was hard to get a proper flow, maybe i shouldve thinned it even tho it says not to? the result was even grainier than with acrylics, and the alclad airbrush cleaner melted my plastic cups and my gloves, it must be some really strong stuff!

I´m not sure lacquer is for me, i think i´ll just continue looking for a solution with acrylics, or maybe i´ll try some enamels.

Are there any good enamel primers out there that can be airbrushed? enamel isnt as strong as lacquer and it dries way slower right?

I know there are plenty of enamel aerosol primers out there but if there´s a good bottled version that can be airbrushed i´m interested to try it out as aerosols seems really hit or miss.

I also bought some Mr.surfacer 1200 and 1500 but now i´m abit hesitant to use them. Think they would work better than the alclad? i got the leveling thinner aswell