(Relative) newbie airbrushing question re: finished paint texture

[munkster]

OK - think I'm getting there as far as confidence (ie. "giving it a go") with the airbrush goes and using it to do basic coverage however I'm still concerned that when applying the paint (usually matt Tamiya acrylic over Halfrauds grey primer) the finish is very "rough", both to the touch and in appearance, in the right light. I am thinning the paint approx 1:1 and when I tried to thin more as a test it just came out like water. Any suggestions there?

Is it the primer that's causing this rough finish perhaps? Will the finish soften up with an application of a varnish maybe? Am I not thinning enough?

Any help greatly appreciated - I posted up my attempt at pre-shading recently which looked ok but that too felt very rough indeed - and yes, now I've sprayed over with a darker colour in the camo the pre-shading in those areas is obliterated!! All a learning curve I guess...

 

[stona]

I don't use Tamiya paints but I do use Halfords primer. I have sometimes noticed a slightly rough texture to the finish of the primer.

Gritty finishes are usually caused by paint drying before it hits the model but in the case of the primer I think it may be caused by the way the blast of paint/propellant flows around the shape of the model causing vortices,particularly in areas like the wing root. Also the lack of controllability of the spray can means it is always tempting to spray from too far away to minimise the chance of flooding the surface with primer.

Anyway,I give the primed model a gentle wipe over with some 1500 grit paper,though fine wire wool will work, before giving it a good wash with water to remove the dust followed by (when I'm happy) a wipe over with IPA or good old meths to remove all my greasy fingerprints etc.

Cheers

Steve

 

[munkster]

Interesting cheers. Is it "too late" to sand it with a high grit sandpaper now it's painted would you say?

 

[stona]

If the problem is indeed in the primer layer you would have to go through your Tamiya colours to get to it so I fear it would be too late for this one,unless you think it is worth a complete re-paint.

Cheers

Steve

 

[munkster]

Good god no way!! It took me so long to do all the blu tak sausages and mask it up - can't face doing that again!!!

Thanks for the help again.

 

[Dave W]

Personally i dont bother with a primer coat.Unless the kit is moulded in dark plastic like the dark brown of the old Monogram Skyraider im currently building.Or if it needs extensive filling and sanding as a couple of vacuforms i have built did.

 

[m1ks]

I'm a believer in the importance of a primer coat for several reasons.

It gives a solid base for the overlyling paint to grip to. (especially important when using Tamiya acrylics as these don't adhere well to bare styrene)

It gives a uniform colour over the entire paint base, vital when you have a kit with some parts moulded in a different colour.

It shows any blemishes, gaps, seams and so on than a bare styrene base would allowing this to be filled, smoothed, rectified etc before re-coating.

For priming I use Humbrol enamels in matte, either white, Grey or black according to what the overlying paint is destined to be, sprayed through the airbrush.

Aerosols are typically a bit too aggressive for covering models I find.

The rough finish could be the base coat of primer, it could also be the top coat, and it could be for a number of possible reasons.

Bear in mind that matte paint will have a slightly rough feel anyway, even with a good smooth coat the actual surface is not like a gloss surface so make sure you're not confusing this natural finish with a mistake you're making.I'd recommend you practise spraying with the aerosol and airbrush on scrap plastic, Old milk bottles etc, practise is the best way to get a feel for a good spray and finish

 

[munkster]

For priming I use Humbrol enamels in matte, either white, Grey or black according to what the overlying paint is destined to be, sprayed through the airbrush.

OK, understood. My only real question there then is, "don't you get through hundreds of those tiny Humbrol enamel pots then??"

Will give it some consideration; will also try the sanding method next time - enough people do seem to be happy with the Halfrauds primer I thought?

 

[Ian M]

Another very good primer are the ones from Vallejo. White, grey and black. The airbrush strait out of the bottle, so all you need to do is give it a good shake, squirt it in the air brush and go for it.

It is a self levelling acrylic so you can clean up with water IF YOU ARE QUICK!!! It dries rather fast and any residue left in the air brush will quickly form a tough plastic skin. A good airbrush cleaner is the safer bet. I use Alclads, as it is what I have at hand. I am sure any of the proprietary brands will do the job just as good. Another good thing with them is they can be toned with vallejo paints. This makes it easier if you are painting a red car or bike, a squirt of yellow in the white primer and that red paint will come alive!

Ian M

 

[Dave W]

I bow to all your greater knowledge but i have never had a problem with enamel paints adhering to bare styrene.I always wash the kit parts in washing up liquid/water before i start any build.And the model gets another wash before appling the paint finish.

 

[m1ks]

I bow to all your greater knowledge but i have never had a problem with enamel paints adhering to bare styrene.I always wash the kit parts in washing up liquid/water before i start any build.And the model gets another wash before appling the paint finish.

Neither have I, I prime with humbrol Enamel, the OP however uses Tamiya Acrylic and regardless of the prep Tamiya acryl does not stick well to styrene, it sticks well to a base primer coat though.

Theres nothing wrong with not priming if it works for you, it's not right or wrong either way as a model is built for static display and many people don't prime but I do simply because it helps me get a good base for top coats.

I don't use aerosols as they are just too unpredictable re fine control and it's so easy to flood a part.

Initially it just shows any flaws that need rectifying and having built models in the past with differing colour cast parts without primer the end result is an obvious colours shift though sprayed with the same paint.

My only real question there then is, "don't you get through hundreds of those tiny Humbrol enamel pots then??"

No, surprisingly, it only takes the same amount to lay a priming coat as your top coat would, Humbrol enamels take quite a bit of thinning so a tinlet stretches a fair way, i guess pound for pound it does work out a bit pricier than an aerosol but I'd rather the controllability of the AB.

I guess you could decant from the aerosol to spray through the brush but that adds another step to the process and you still have to clean the brush.

 

[Dave W]

m1ks,I take on board your comments about priming when using acrylics as i intend switching to these in the near future.mainly because of the health implications when not just spraying enamels (i use a mask) but cleaning the airbrush and jars afterwards.I always end up with thinners and/or paint on my hands which cant be doing me any good.

 

[m1ks]

You could try vinyl / latex gloves, I use them always when spraying Enamels as getting it off your hands is a real chore and getting the paitn and thinners all over your skin is certainly not good for you.

They're about £7 a box of 100 which I think is well worthwhile, i've used them for many things ever since I was a mechanic way back when and got sick of it taking 2 weeks to get the ingrained oil from my hands.

Re paint type, though i've not tried it a couple of people on here use the Vallejo primer and reckon it's pretty good, i've only limited experience of Acrylics beyond Tamiya so it's possible that some adhere better than others, i've heard three different people on here mention using the Valejo though so I may get some to try myself, on builds where all my topcoatings acryl, (most military, matte stuff), it would make things easier, the real benefit being i wouldn't have to wait 48 hours for it to dry fully.