Gloss paint dull finish?

Could be that the distance between the can / airbrush & the subject is too great, this will cause the paint to partially dry on it's way to the subject & prevent it from being able to create a smooth film (excessive pressure with an airbrush can also cause this problem).

It may be that other colours of the same paint will work fine with the same pressures / distances, but different colours will spray in slightly different ways due to the different pigments they contain & black can sometime be more problematic.

Gloss can also be more difficult to work with than flat, with flats you can lay down fine coat after fine coat to get the desired result, but good gloss finishes rely on a good wet / heavy coat to achieve a decent gloss.

Ditto on what Milairjunkie says but also a rough primer coat can be a problem.

Interesting. I thought the distance being too far will only give you orange peel. Could the outside temperature/humidity play a factor?

Resident Eric

Interesting. I thought the distance being too far will only give you orange peel. Could the outside temperature/humidity play a factor?

I use Humbrol enamel and I don't have any issues when its humid here (north coast NSW which rarely gets dripping wet humid just sticky), I tend to not spray if there's rain or excess humidity around especially when it comes to lacquers.

I don't recall any instance of a spray gloss (of any color) coming out flat.

I've have had the opposite happen.

Maybe a bad batch of paint? How well did you shake it before spraying?

Gloss paint needs to be applied with a wet coat. If you put it on too dry, it will look flat or semi-gloss.  Likewise, too wet of a coat of flat paint will take on a semi-matt finish.

I consider getting a good gloss finish an exercise in brinkmanship. You must put it on so wet that it reaches a point just before it runs.  How do you time it to get to that point without it actually running?  Experience.  The best way to do this is practice, working on a scrap plastic and doing it a number of times, so that you know what it looks like just before it runs.  Multiple coats by themselves are not enough.  The last coat itself must go on wet.  I use low pressure, about 15 psi, and get the airbrush or can close to the surface, and go slowly.  I do put on multiple passes for the last coat.

I make a distinction between passes and coats.  Each coat involves letting it dry between coats, passes is when I paint, say, a wing, and as soon as I get the whole wing done I go back to where I started and do it again.

What type of paint / thinner are you using?

Are you using TS14?

Heh - I'm thinking you're using SEMI-gloss, not gloss.

Yes it's ts14 which is GLOSS. This isn't my first time using it lol Pretty sure it's the paint because I notice sometimes when the can is near empty, the paint starts to shoot out in poor quality.

I found that thinning Tamiya  gloss paint with Tamiya lacquer thinner not the X20a will produce a very high gloss and will self level. Also you need a very thinned paint around  30% paint to 70% thinner to achieve  a very high gloss and keep the pressure down to about 15 to 20 psi and only a few inches away from the model. Hope this helps you.

I think I figured out the cause. The outside humidity in the air dulls the glossy finish. I tested 3 different cans of the gloss black. The paint goes on wet and then 30 seconds later, it turns flat. Tried it again inside the house, no issue at all.

That is called "Blush".  It can also, in extreme cases turn the surface whitish.  Lacquers, dope, and other fast drying stuff are very susceptible, because the rapid evaporation of the thinner lowers the surface temp below dewpoint, causing moisture to condense on surface. Sort of like spraying the surface with a fine spray of water.

Coming late to this game... have a question though.. I am refinishing an old Topping resin aircraft model F-104, and I want it to be extremely bright, almost mirror chrome. I have been spraying with Krylon gloss black enamel for a base coat (I ordered Mr. Color glass black but Amazon sent me mis-labeled paint that was actually flat naval grey!), after sanding with 6000 grit paper. I have done two coats that have dried dull, so I will do a final coat holding the airbrush about 1" from the surface, because the only places that have dried glossy have been almost pooled spots. How long would you wait between black base coats, and then, assuing I can actually get a decent gloss on the base coat, how long to spray on the mirror chrome?