Newbie airbrush painting issue

[wavodavo]

For the first time properly, I have started to use an airbrush for painting. I got a RDG tools airbrush and compressor for a Christmas present. I have done some practices on scrap models to try and get the right paint/thinner mixture. I've also been using Alclad 2 Aluminium which doesn't need to be thinned and went on well on a test model but now have a problem with an actual model. First the primer went on very rough, so rubbed down so it was smooth again and re-primer. Now the Aluminium has gone on but seems to still show where the primer was still rough, how do I solve this? I only have only ever used a Badger airbrush with the old canister type.

Also, being quite dumb and all but is Vellejo surface primer actually go on quite thin?

 

[Chrissy_J]

I've never used Alclad but I understand that, because it's so thin, it really needs as smooth and perfect a primer surface as you can provide. Any blemish in the primer, as you describe, will be magnified by the Alclad. You'll need to rub down the rough surfaces and re-prime them, then get it smooth.

I can't comment on Vallejo's primer as I've never used it.

[dnl42]

Alclad is a lacquer, and is indeed quite thin. It will show everything beneath it, including the surface color. If the primer went on rough, I wonder if you had thinned it sufficiently, the air pressure was right, or you were spraying too far away. For Alclad, I use my airbrush with a 0.5mm nozzle at 1 atm pressure and about 25-40mm distance. For priming, I thin Mr Surfacer 1200 or 1500 to about 1% milk consistency and the same airbrush parameters. My primed surface is perfectly smooth. Before that, though, I carefully file and sand the surface, ending up at 6 cut files and 12000 grit abrasive pads.

[Corsairfoxfouruncle]

I agree the best thing you can do is to use some polishing pads in the 2000-12000 grit ranges. Then Re-prime and re-spray you should get a much better finish if you polish the model. Ive also sprayed multiple coats and wet sanded between coats. Just like they do with a custom car paint job to get that smooth glassy finish.  

Edited January 31, 2019 by Corsairfoxfouruncle

[bmwh548]

Clean up the model back to bare plastic, polish the surface if needed. I strongly recommend Mr. Surfacer (1200 or 1500) as primer, if you apply it correctly the result will be very smooth. You can cheat and use the black version if you want (metallic colors should be on black basecoat anyway). Never used Alclad, not a fan of their products, I would use AK Interactive's enamel metallics. They dry up beautifully, very forgiving and you can actually clearcoat them with the GX range from Mr. Color. I've used GX112 over Gunmetal and it didn't change the sheen at all. Since you already have the Alclad paint: apply very, very thin layers and allow to dry between them. The solvent is very strong and it will easily eat into a waterbased primer (and it will even etch the plastic if the coat is too thick).

[wavodavo]

Thanks for the hints and tips guys, I didn't realise Alclad would be that thin. That was my only thought for rubber right back to the plastic.