pressure

[Guest]

How does pressure effect the finish? What will to high or to low a pressure result in?

[stona]

It depends on a lot of factors. Most airbrushes (meaning those which mix internally) require a certain pressure to properly create the aerosol to spray. How low a pressure will spray at all depends very much on the medium.


I see a lot of people spraying at what seem to me very low pressures and getting an over spray, almost a splatter, around the line they are spraying. For me higher pressure avoids this and allows fine demarcations to be cleanly painted.


Here are some examples of free hand sprayed camouflage demarcations on Theo Nibel's Fw 190 D-9.








I just took the model out of a cabinet to photograph it, and it could do with a dust


Cheers


Steve

[Guest]

Best is to experiment Alan. With the same paint no thinners on the same plastic same distance from the target.. Try 15PSI 20 PSI 25 PSI and 30 PSI.


The higher the pressure the more paint you will spew out and vice versa at the same placement of the trigger. For intricate parts I use low pressure as that enables you to get into small areas which with a lot of paint darting about you are very liable to get curtains or runs. But I get in close as otherwise the paint is drying before it reaches its destination.


Low pressure is particularly good for airbrushing effects as you have complete control (well nearly ability also has its turn).


In the end it is a combination of paint, thinners, airbrush needle/nozzle size , temperature, humidity, experimentation and finally that elusive experience and finding what best all detailed before..


This  gives an interesting look at the subject.http://www.craigcentral.com/models/pressure.asp


Stewart

[Guest]

It depends on a lot of factors. Most airbrushes (meaning those which mix internally) require a certain pressure to properly create the aerosol to spray. How low a pressure will spray at all depends very much on the medium.


I see a lot of people spraying at what seem to me very low pressures and getting an overs pray, almost a splatter, around the line they are spraying. For me higher pressure avoids this and allows fine demarcations to be cleanly painted.


Here are some examples of free hand sprayed camouflage demarcations on Theo Nibel's Fw 190 D-9.


[ATTACH]264101.IPB[/ATTACH]


[ATTACH]264102.IPB[/ATTACH]


I just took the model out of a cabinet to photograph it, and it could do with a dust


Cheers


Steve

Thank you Steve, the main reason I ask is because my finish is Often dry powdery looking almost a very heavy matt finish if this


makes any sense. Im wondering if it is my pressure or distance that I spray or indeed a combination if the two. Just cant seem to achieve a smooth finish. Im spraying at 20 psi using an Evolution with Tamiya Acrylics. Any thoughts Steve. 

[stona]

Thank you Steve, the main reason I ask is because my finish is Often dry powdery looking almost a very heavy matt finish if this


makes any sense. Im wondering if it is my pressure or distance that I spray or indeed a combination if the two. Just cant seem to achieve a smooth finish. Im spraying at 20 psi using an Evolution with Tamiya Acrylics. Any thoughts Steve. 

That does sound like your paint is drying as or before it hits the surface. This does happen with some fast drying paints, though I am not familiar with Tamiya acrylics. It might be that you need to decrease the distance from which you are spraying, or you might look at addng a retarder to the paint to slow the drying down.


Just to show how different the techniques of different people can be, I spray everything at around 35-40 psi. This includes fine lines and mottle.


1/32 'Natter'





1/72 Mistel, mottle on Bf 109.





Cheers


Steve

[Guest]

That does sound like your paint is drying as or before it hits the surface. This does happen with some fast drying paints, though I am not familiar with Tamiya acrylics. It might be that you need to decrease the distance from which you are spraying, or you might look at addng a retarder to the paint to slow the drying down.


Just to show how different the techniques of different people can be, I spray everything at around 35-40 psi. This includes fine lines and mottle.


1/32 'Natter'


[ATTACH]264103.IPB[/ATTACH]


1/72 Mistel, mottle on Bf 109.


[ATTACH]264104.IPB[/ATTACH]


Cheers


Steve

Thanks again Steve. I will try getting closer think its a confidence issue for fear of runs, also I have bought some retarder now.


I seem to have got away with it in the past building armour and heavy weathering but my recent aircraft builds have been less forgiving.


Cheers

[yak face]

Hi alan , like steve i spray just about everything at around 30-40 psi , ive found lower pressures need thinner paint and this can cause coverage and running /spidering issues not to mention the splattering that steve referred to. I used to use tamiya acrylics alot and always found them beautiful to spray . Are you using Tamiyas thinners ? Maybe try a bit higher pressure and experiment with the distance youre spraying from- the further away you are the more time the paint has to dry in the air before it hits the model , causing the dusty dry finish. 

[Gern]

So what are you using now Tony if you've changed from Tamiya - and why did you change?

[yak face]

I started using vallejo dave simply because the tamiya range of colours was very limited ,and vallejo have a lot of specific FS and RLM colours and more of a range of basic shades .Ive still got loads of tamiya and still use them but ive built up a large collection of vallejo colours too. I always found the  tamiya paints trouble free ( apart from difficult coverage with problem colours like red and yellow, which is common to most brands) 

[stona]

It's important to o note that what works for one doesn't for another. I am aware that lots of people, even most people, spray detail, mottle etc. at low pressures and with thinned paints. That just doesn't work for me, but it doesn't make them wrong!


Everyone comes up with the thinning and pressure values that work for them.


As an enamel user I don't really have to worry about paint drying on the way to the model surface, it's going to take hours to dry anyway


Cheers


Steve