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Vallejo varnish blocking my airbrush.


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11 hours ago, GrahamCC said:

 

For thinning or reducing I use Liquitex airbrush medium, Golden is another brand name.

Just been looking into this Liquitex product. I'm not entirely sure what it is! Is it a varnish in its own right? It says that it can be thinned by diluting with water...yet I thought one of the main points of this product was that it was a thinner itself. So now, we're thinning the thinners?!

 

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I am often confused by the general use of the word varnish to describe a variety of different types of clear matt, satin, or gloss finishes.

 

The term varnish seems to be used in the UK as meaning that clear top coat regardless of it's chemistry.  To me varnish is an oil based amber coloured finish applied over fine wood work and to water proof wooden boats.

 

We, generally speaking of model builders, use the term thinner when what we really mean or want is a reducer. Thinners and reducers are similar in function but are different and which one you should use depends on your need - you would use a thinner for lacquer based paints and a reducer for urethanes and enamels

 

Winsor & Newton, Liquitex, and other art suppliers generally use the term medium to describe a wide variety of products. For example Liquitex airbrush medium we ( model builders ) would tend to think of as a thinner, likewise there are matt, satin, gloss mediums which we tend to think of as clear coats or varnishes. These mediums are in many ways like the acrylic paints except that they do not have the pigments. We can reduce the viscosity and also their sheen and transparency of the acrylic paints using these mediums while maintaining the integrity of paint. Using a thinner or reducer can reduce the viscosity of the paint but over thinning make impact the integrity of said paint. 

 

More to the point, Liquitex Matte Medium  https://www.liquitex.com/us/products/professional/gessoes-mediums-varnishes/matte-medium/ could be used as a matte varnish or could be mixed with an acrylic paint to reduce that paints viscosity as well as make that paint more matte in finish.  I think Winsor & Newton refers to their similar Galeria product in the same way, as a matte medium.  You could even mix the matte medium with the gloss medium to create your own satin. In fact, I don't recall seeing a Liquitex satin medium and in fact in the descriiption of the matte medium suggest mixing with gloss medium to create your own satin. 

 

Using the matte medium to thin or reduce your paint in order to airbrush may work but is not the same thing as using the airbrush medium to reduce or thin you paint so that your could airbrush it. The matte medium would make you paint more translucent. 

 

All of these different products and generic use of terms like varnish can be confusing especially to newcomers trying to make sense of it all.

 

I hope that helps and isn't just adding more to the confusion.

 

cheers, Graham

 

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Forgot to add, 

 

And just to confuse the subject, Liquitex also sells products which are described as Varnishes:

 

https://www.liquitex.com/us/products/professional/gessoes-mediums-varnishes/?tab=varnishes

 

which are not the same as the mediums.  The Winsor & Newton product line is just as confusing.

 

I am not an expert by any means but I have it found it quite interesting and informative to spend some time reading through the Liquitex and Winsor & Newton web sites product information and other information as well web sites and youtube videos aimed at artists and crafts persons and their use of these products. This has helped me better understand some of the nuances of these products and their use.

 

Incidentally, if you have not already had a loo, Vallejo has a fantastic web site with lots of good information and you may be surprised to learn that Vallejo is primarily a supplier to art world and that their hobby products are a secondary but important focus for them. 

 

cheers, Graham 

 

 

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Graham you may be correct but you have made things more confusing!

 

In the UK all those final finish coats by W&N such as Galleria are labelled "Varnish".

 

If you buy "Matt Medium" or "Matte Medium" (in the US) you will get a pot of thick gloop that you are suppose to mix into your acrylic paint to make a stiffer more textured surface!

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Not quite so but I see how what I wrote could be confusing.

 

I added a bit more with my second posting to try and add a bit more clarity.

 

There are matt and gloss mediums which are not the same thing as those labelled varnishes and both Liquitex and Winsor & Newton products reflect this. 

 

And, while the Liquitex web page describes or suggests that their matt medium could be used as a thinner or reducer or as an over coat, their matt varnish is a very different product.

 

The mediums can be used to change the properties ( viscosoty, transparancey, texture ) of the base paint; the varnish is final clear top protective coating.

 

Does that any more sense? It is clear in my head but I am not sure the connection between the grey cells and my fingers are helping me to articulate.

 

cheers, Graham 

 

 

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18 hours ago, keiron99 said:

I guess I've been spraying about 6 inches away. Does that sound about right?

That sounds a little far. Airbrushing is a very personal thing and varies depending on what you are using and the effect you want. I would suggest playing around with dilution, pressure and distance to try and get a little closer. The more the clear coat is thinned the more coats you will have to apply. When I am using the W and N matt I can barely see the coverage but as I persist it gradually becomes less gloss until it is eventually very matt. Don't give up - it is used successfully by many of us on Britmodeller.

 

Airbrushing requires practice and experience to get right. I can shoot most acrylics these days to reasonable effect but when I switch to enamel it is always a disaster as I am not used to the dilution/distance/pressure triangle. 

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1 hour ago, Pete F said:

When I am using the W and N matt I can barely see the coverage but as I persist it gradually becomes less gloss until it is eventually very matt. 

 

 

How long do you wait between coats?

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3 hours ago, keiron99 said:

How long do you wait between coats?

I just do it as a continuous process. Shoot the coats so thin that they dry very quickly, so after you have covered and paused you should be good to go. The main thing is to keep it very thin/fine and watch out for signs of over spraying. Don't think about the airbrush as a spray can but as a much more subtle tool. You will be fine.

 

Remember all us airbrush users are in an endless learning process.

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On 24/02/2021 at 19:53, keiron99 said:

I guess I've been spraying about 6 inches away. Does that sound about right?

Keiron, I put on a matt clear coat yesterday and deliberately looked at how far away I was from the model (a 1/72 aircraft). I was spraying at about one inch for most of the time. Perhaps getting a little closer for difficult to reach spots. The mix was just below 50/50 possibly 60 W and N and 40 water. I don't think the exact mix is too important. I only put a small amount of liquid into the airstream at first. So little that you could barely see it hit. It dries instantly and you can quickly start to see the matt effect. As I progress I put a little more liquid in but never that much. Thick matt coats don't tend to dry very matt.

 

I don't know what sort of airbrush you have. For this sort of work I use a Iwata Revolution single action but either way you should be able to adjust the air mix by the trigger or a dial. It sounds to me like you are spraying too far away and using the brush like a spray can with possibly too much liquid in the mix. I did that when I first stared airbrushing and it can cause the effects you mention.

 

I hope that this is helpful and it all goes well.

 

Pete

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So I have been testing. Even at 60 water, 40 W&N, it stops spraying after about 3 seconds. At that ratio, it's very watery, and pools on the model. Yet despite its apparent wateriness, it is still blocking the airbrush.

 

I tried thinning it with both distilled water and Vallejo thinners, both with the same results.

 

I'm in a situation where I'm unable to varnish my models! At a total loss as to what to do.

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Sorry I missed one critical bit of info on the above - I added recently acquired Flow Improver too. 

 

But now that I research what "flow improver" actually is - it's not about improving the flow through the airbrush, it's about the way the paint flows on the material onto which you are putting it.

 

But here's something that seems to be working for me and I don't know why. I just use the mixture as above (about 50/50 Galleria/Water or thinners) but before pouring it into the cup on the airbrush, I squirt a couple of drops of just the bog standard Vallejo thinners. Give it a quick blast. Then pour in the mixture. Give another blast to test all is OK...and it seems to not clog up. Even if a put the airbrush down for a minute. I saw it done on a Youtube video. I have no idea why it is working for me, but it is.

 

I need to experiment with the rations though because as I said, I'm finding at 50/50 or even 60% W&N varnish it is watery and pooling a bit. Maybe that's my technique and I'm not moving the airbrush quickly enough?

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good day,

 

Some of your issues have caused to me think some more on what may be happening.

 

First off, "flow improver" does indeed help your media, in this case acrylic paint ( i.e. Winsor & Newton Galleria varnish ), level out and flow on the surface onto which it was sprayed BUT it also will help the media flow better through your airbrush. 

 

To quote Winsor & Newton:

 

Quote

Winsor & Newton Galeria Acrylic Medium, Flow Improver is an additive that loosens the surface tension of water within the acrylic film

 

Another name for this is a surfactant or wetting agent.

 

To quote Wikipedia:

 

Quote

Surfactants are compounds that lower the surface tension between two liquids, between a gas and a liquid, or between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agents, or dispersants. The word "surfactant" is a blend of surface-active agent, coined c. 1950

 

So, adding flow improver will help the media "flow" through the airbrush more easily.

 

I do not have any first hand experience with one of these quite common battery powered airbrush kits but there are many videos on Youtube and around the internet to be found and show that these devices can and do work. Trouble is that you are having issues with yours that you are struggling with.

 

A bit of poking around on Amazon and elsewhere leads me to think that the model making is a secondary target market for these devices where the primary market appears to the beauty and food markets, that is for applying some types of makeup and for food decoration.  Typically for these the media is very thin and often in the form of inks and food colouring. Consequently the most common tip size I see advertised is 0.3mm and 0.2mm is also common enough. 

 

On re-reading many of your comments it seems to me that symptoms indicate the use of too thick a media ( Winsor & Newton Galeria varnish ) and too small a tip. Not having any experience with one of the battery powered airbrushes I am uncertain if you can in any way adjust the air pressure. If not, then you only have media viscosity and tip size to play around with in order to get the thing spraying your chosen media.  

 

You have already discovered that you are over thinning and over thinning is never a good thing as it can cause issues with compromising the integrity of the paints binders and pigments and adhesion of the paint on the surface onto which it has been applied. 

 

The only remaining variable then is tip size.  Do you know what tip size has been supplied with your airbrush?  I suspect 0.3mm as that seems the most common.

 

At this point I would suggest that you see if you can find a 0.5mm size needle and tip replacement for your airbrush.  Many of these inexpensive Chinese airbrushes seem to be copies based on the Iwata style of airbrushes and have similar tips and needles.  I am not suggesting you try an Iwata tip and needle but only use that as a visual reference and that the tips and needles of the various offerings on Amazon are quite likely interchangeable. You will find sets of three that include 0.2, 0.3, and 0.5 but you may be lucky and find a listing that is for 0.5mm only. In either case these replacement parts are not over expensive.

 

A couple of links that you may find interesting:

 

https://sites.google.com/site/donsairbrushtips/home

 

https://modelpaintsol.com/guides/basic-airbrushing-tips-tricks

 

https://modelpaintsol.com/guides/spraying-acrylic-paints-airbrushing-tips

 

https://modelpaintsol.com/guides/acrylic-paint-airbrush-nozzle-problems-clogging

 

I remember when I first started trying to use an airbrush. It was an inexpensive Badger 350 single action that I was using with Propel "canned air" and trying to spray model airplane dope. It took me a long time to figure out that I was trying to use too small a tip and the model airplane dope was "too hot" i.e. dried too quickly. Adding a retarder to the dope help but it wasn't until I started to use a larger tip size that I finally managed to have some success. 

 

I hope you can get it sorted out. There is nothing more frustrating and discouraging than to have to struggle with something like this. Our hobby after all is supposed to fun and relaxing.

 

cheers, Graham 

 

 

 

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@GrahamCC this is fantastic information and interesting reading, many thanks.

 

After another evening of experimenting, I am now getting better results. A couple of drops of thinner in the cup and a single blast before putting the varnish mixture in the cup does help. I don't know why.

 

I think I was also applying coats too heavily. I seem to have sorted that now. More passes, but lighter coats.

 

I managed to get a decent finish using the above technique with a mixture of about 50/50 varnish/thinners.

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