Airbrushing success (but...)

[Stevekir]

After much practice and varying settings (e.g.., pressure), confirming that water in the air was not a problem, buying a good airbrush (0.4 mm nozzle), and rigorous airbrush cleaning, I seem to have solved my problems of nozzle blocking and sputtering. The following are what suits me:

Vallejo Surface Primer "Acrylic-polyurethane". 73.6xx: 30 PSI, unthinned (but 10% and 15% thinned also worked.)

Vallejo Model Air Paint: 30 PSI, 5% or 10% thinned.

Klear (Pledge) Varnish: 15 PSI, unthinned (Klear is as thin as water).

Vallejo Gloss Varnish 70.510 30 PSI, unthinned. Another story. I had to place the nozzle very close to the model to get any buildup, the buildup of a coat required several passes before it looked like becoming wet, and the consumption of varnish was four times greater than for the primer or the paint and even then it wasn't yet glossy.

Therefore:

== Are my settings for the primer and paint more or less conventional? (I started with 20 PSI on advice from several sources but that caused spattering and often blockage in the case of the paint.)

== Why does the varnish behave so differently from the paint?

== Would Klear be a good varnish to standardise on?

== What should I use for the varnish?

Thanks for any help (I'm getting there. Airbrushing is more complicated than it appears!)

 

[Ian M]

It sounds to me young man that you are sorting out many of the "beginner" problems in a very clear and methodical way. I tip my hat to you. You have found the secret code. Try, note things down if they work and observe what is helping and what is not.

I cant help to much with psi as "over here" we are into "bar"

I am sorry to say but Pledge klear is not varnish but floor polish. You may deduce from that, that I am not a "klear is the answer to everything" camp. I have one thing I use clear for and that is dipping clear parts in. Windows, canopies, that sort of thing. I have tried it as a "cheap" varnish, but to be honest, I cant see what all the fuss is about. These days there are Acrylic varnishes ad libatum, that are made for the job. Vallejo's are some of, if not the best I have used. How the new formula ones are, I have yet to discover.

The Gloss varnish does take a while to give a good gloss, and its a far better thing to build it up slowly. Its a lot easier to add a coat or two than it is to remove sags and runs.

The fact that you are having to spray tight to the surface, would suggest to me that the varnish may just need thinning a bit. One thing I find is that the gloss varnish does clog the nozzle quite quick. A thinner helps as it also has a retarder in. I am rather pleased for the new Airbrush thinner they make as it does what it says on the bottle.

So a bit more playing with the thinners and varnish Steve. You'll get the better of it.

Ian M

 

[Danny]

Hello Steve..we are on the same journey, one of learning by trying. Can I ask have you tried metalics in your AB yet?, as Im having problems with most that Ive tried...

Regards Danny

 

[michaelm]

Hi Steve, good to hear you're getting the hang of your airbrush, like many of us I began with a cheap brush and a can of propellant, after a bit of trial and error I got pretty good results with it, but when I upgraded to a better brush and a compressor I can control everything got much easier and with much better results. I don't use vallejo paints but I'm surprised you're having to go to 30psi, I don't go that high. I spray Tamiya paints at 18-20psi and use alclad varnishes which are used at an even lower psi, 14-15.

Danny, try Alclad for your metallics, I think they are far and away the best for this finish.

 

[Danny]

Thanks Michael, i will give them a go... :smile1:

Danny

 

[rickoshea52]

Mixing your Bar and psi is an easy mistake to make, even for those trained in using pressurised gases. Someone I know did this and was fortunate to escape with his life even if he wrecked the nose gear of a Tornado F3. 1 bar = 14.5 psi or thereabouts.

 

[BarryW]

Steve

After lots of practise generally I use Vallejo Model Air at 15-20psi and thin it about 10% using a .2 needle. Sometimes I don't thin at all but have the air pressure up a bit (not to 30psi though)

I also thin the Vallejo varnishes about 20%, building it up with thin coats with a .4 needle

I am not scientific about it and the thinning is very approx.

That is what works for me.

 

[rickoshea52]

Steve,

I think that you have your psi too high so that the varnish dries before it comes into contact with your model. You may wish to reduce the psi to about 15 psi and thin your varnish a touch more.

Good luck. And remember, the man who never made a mistake learned nothing.

 

[Dave W]

I use a 0.5 nozzle and Vallejo varnish won't spray through it unthinned.I used to use Vallejo thinners.Then I read the side of the bottle.It says it can be thinned with water,so that's what I do now.About 50/50 works well for me and I usually put a couple of coats on before applying decals.Like Ian I only use Klear for canopies and don't think it's that wonderful as a gloss coat.

 

[Stevekir]

I cant help to much with psi as "over here" we are into "bar"

Ian M

30 PSI = 14.4 mBar

 

[Stevekir]

Hello Steve..we are on the same journey, one of learning by trying. Can I ask have you tried metalics in your AB yet?, as Im having problems with most that Ive tried...Regards Danny

No. I have not tried metallics. One step at a time for me.

 

[Stevekir]

Barry W, rickoshead, Dave W: I will try the varnish again, at 20 PSI, and thinned to 20% and 50%. Thanks for the help.

 

[m1ks]

Unfortunately, model paint isn't as strictly controlled as auto paint where thinning ratio is concerned, you can't just use a mixing stick and get the perfect ratio.

Some Humbrol enamels take a lot of thinners, others much less for example, tamiyas acrylics are fairly consistent but still theres no magic ratio.

Acrylics will flash off faster than enamels so if you're spraying somewhere very warm that can adversely affect your working time, if too cold it can adversely affect the paint and your fingers and trying to hold a steady flow whilst shivering is never good.

Getting back to the point!

For thinning, I aim for 'milk' consistency, I picked up a few medicinal dispensing pots from the checmist, (the little translucent cups that hold about 30ml), put in the paint and add thinners with an eye dropper mixing thoroughly then 'swiping' up the side of the pot to check consistency, what you're aiming for is the bulk of the paint to pool back to the bottom leaving a thin translucent coat of your colour on the side.

I spray enamels between 20 and 25 and acrylics between 12 and 15 typically.

 

[stona]

There's nothing wrong with spraying at a higher pressure if that works for you.

Most model/hobby sprayers seem to use 15-25 psi but many professionals go considerably higher.

Like m1ks I typically spray enamels at somewhere between 20 and 30 psi.

Cheers

Steve

 

[AVB99]

Hello

I don't want to hijack Steve's thread (apologies sir!) but it seems daft to start a new thread....

Sometimes when I airbrush I get a finish that is rough. For example I sprayed my 1/48 spit with Tamiya matt paint on top of very smooth Vallejo primed surface recently. It usually goes on as smooth as a baby's bottom. This time it has a rough surface. This only happens occassionally. Does anyone have any ideas as to why please?

Thanks

 

[BarryW]

Aidan - the paint will be drying before it hits the surface. Try a drop of retarder in the paint cup or thin it a little more. If you use Tammy's own thinner it does include some retarder.

 

[cutandfold]

As far as the model paint products and their usages, I am learning plenty from the responses!!

Thanks!

Steve I see no reference to airbrush tip /needle size.

Generally (in my painting world) primers and clearcoats are much heavier products

that require slightly higher pressures

but more importantly require larger tip/nozzle sizes.

...I even switch guns to spray clearcoats.

For better clear finishes, wider sprays are necessary.

Having a dedicated gun for clearcoats might not be a bad idea.

I would choose something with a larger tip size (maybe .5mm?) and a wide fan spray ability.

I teach airbrushing, and the most complaint is sputtering and tip clogging.

And other than the obvious paint related reasons (eg paint too thick for too small a tip size)

the usual answer is the brush and its parts need more cleaning.

My rule is "if you think its clean, go back and clean it again".

Your work saving your "settings" is what I wish I could do.

Remembering pressure settings, mix ratios, etc will always come in handy.

 

[stona]

Aidan - the paint will be drying before it hits the surface. Try a drop of retarder in the paint cup or thin it a little more. If you use Tammy's own thinner it does include some retarder.

Exactly.

Not a problem with enamel paints

Steve

 

[BarryW]

LOL Steve, but they smell......

 

[Stevekir]

Steve I see no reference to airbrush tip /needle size.

Remembering pressure settings, mix ratios, etc will always come in handy.

My original post mentioned a 0.40 mm nozzle. I chose that to minimise blocking.

On remembering settings, I am easily confused and forgetful. So I make a table and write down the settings and the results. Here is an extract:

View attachment 58550

Yes I know its obsessive, but otherwise I get into a muddle.

Today's tests, based on advice in this thread, were successful. I reduced the pressure. My standard setting (unless I get bad results in future) are now:

Vallejo Model Air Paint: 20 PSI thinned 10% with water.

Vallejo Primer "Acrylic-polyurethane" 73.600): 20 PSI thinned 10% with water.

Vallejo Gloss Varnish: 20 PSI thinned 14% (thinned 18% also worked).

I guess that using water (less volatile I suppose) rather than thinner reduces the opportunity for the varnish to dry on its way to the model.

Thanks for all the help.

View attachment 60412