Help wanted: Dried airbrushed paint reactivating and running

[lawnor 25939xp 0]

I’ve had my airbrush for many years and something has started happening over the past year-ish that I don’t think was happening before and seems to be getting worse.  Paint I have airbrushed on to a model and left to dry for many days is instantly turning to runny paint again when a wash or even a brush with a little water or saliva on it touches it.

About a year ago I learned that I should leave an airbrushed model overnight before applying a wash or the paint would bleed in to the wash, and this time appears to have extended a little so I’ve been giving them 24 hours.  This seems acceptable.  However I’ve just applied a wash to a model I last airbrushed 4 days ago and the paint is turning to water and mixing and running.  I tried to clean up a little paint yesterday with a wet brush and that reactivated paint that should have been dry.

Whats going on and why?  Has this always been an issue and I’m only just aware of it now?  What can I do to pevent this?  Right now I’m a little anxious to apply varnish when I’m done for fear all the paint will run.

The paints in question today are a selection of Vallejo paints applied over a Stynylrex base primer and a Vallejo Zenithal primer.  The primers were left 24 hours before any paint was applied over them.  Anything airbrushed was mixed with Vallejo Airbrush thinner.  The washes in question are GW ones, but as I said its not just washes.  Applying paint so far doesn’t appear to have done this.

[kingandcountry 3014xp 1]

Have you changed what you clean the airbrush/regular brushes with?

are you able to apply a varnish between layers? either brushed or air brushed

[lawnor 25939xp 0]

The only change I’ve made is that I picked up my first bottle of Stynylrex last year at Chillcon in September and the first model I noticed this on is in pics dated January 2019.  I could varnish between layers, but I’m not sure thats not going to start triggering this issue as its the worst its ever been right now.

Oh, I also switched from masters brush soap to Jentastics drunken unicorn goop in July.  Again after the issue first occurred.

[zorg 18801xp 1]

Is it a new paint pot that could be faulty?

[lawnor 25939xp 1]

There were 2 new pots of vallejo used in this particular paint, but this has been going on since at least Jan 2019.  It just seems a lot worse / a lot later than previous this time around.  4 days and it still reactivates seems pretty bad.  Its completely dry otherwise and i’ve painted over it with GW and vallejo paints thinned with water and lahmium medium without noticeable effect.

You made me think then.  I was using Gloss Nuln Oil when it happened, but it also happened with Non Gloss Agrax.  It also happens with water and saliva.

[zorg 18801xp 1]

What about with a brush?
Or change your paint mix to see if that works?

[Anonymous 0xp 1]

Anything airbrushed was mixed with Vallejo Airbrush thinner…

Is this the only thing you have used to thin your paints since the problem started?

Try airbrushing the same paints with only water as a thinner and rule out that you have a dodgy bottle of this.

[lawnor 25939xp 0]

Its the only thinner ive ever used and I never noticed any issues for the first few years.  I appear to have bought this bottle in Jan 2020 and have 20% left.  I didnt realise.  I need more ASAP.  The issues started long before I got this bottle.

[shingen 13941xp 2]

What also comes to mind is moist in your compressor tank (I assume you have one). Recently I learnt that you should empty your moist trap regularly but also use special valve under your tank from time to time. I did it after a year living in Ireland and amount of oily, rusty water that escaped from the tank was scary. I learnt it from this channel: https://www.youtube.com/user/florymodels/videos but I can’t find the very clip he told about it. I guess it was about a year ago.

Also when you have your airbrush for a good while you may have some leakage of lubricant inside (between triger and air duct) due to worn orings – it is also just a guess.

All in all my suspicion would be some grease mixes with your paint  and prohibits it from drying properly.

[gilbert 122xp 1]

 

Hmm, what a mystery!

I’ve a few questions after reading your post. Also do you have some pics of what’s happening?

1) Have you sure you’ve given the bottle a bloody good shake first? (I know it’s a silly question equivalent to have you turned it off and on again but it helps eliminate one variable at least)

2) What is the model made of, acrylic, resin, metal?

3) You say you are thinning the paints down. Including the undercoat? Also, how much are you thinning by?

4) Is it that the undercoat is running or just paint on top?

 

[Anonymous 0xp 1]

Its the only thinner ive ever used and I never noticed any issues for the first few years.  I appear to have bought this bottle in Jan 2020 and have 20% left.  I didnt realise.  I need more ASAP.  The issues started long before I got this bottle.

Happy days, one less thing to worry about.

 

 

[lawnor 25939xp 0]

@shingen I, mot sure when I last drained my moisture trap so I’ve just done it and pretty much nothing came out except air.  There does appear to be rust stains on the “windows” in to it though.

How would I check for leakage of lubricants?  I break it all down in to parts and run it through an ultrasonic cleaner after every prolonged use.  Would that clean up any leakage?

 

@gilbert There are no pics.  I’m usually applying a wash and I cant stop to take a pic or video or I’ll get tide marks.  I’m also usually panicing and trying to prevent the paint from mixing with the wash or exposing what I painted over.  I could theoretically go and make it happen and take a video but I’d rather not risk damaging my paint work.  Hmmm.  I have paint over the base.  Perhaps there is something I can do.  Let me think on that.

1: I give every paint a good shake (Maybe not a bloody good shake.  Not sure where the line is) to the extent I shake my dropper bottle of water every time I pick it up without thinking.

2: I am currently painting Reichbusters models.  High end board game minis.  Not sure what they are made of.  I gave them all a wash before the primer got to them.  I have painted models of every material.  I can definitely say I’ve had this issue on resin.  Not 100% sure what else I’ve seen it happen to.

3: I add thinner to everything that goes through my airbrush.  With Vallejo primer and varnish its about 50/50.  With Stynylrez its 4-6 drops of thinner and then full the cup with primer.  With the vallejo paints its 6-8 drops paint to 30 drops thinner for a solid coat, but I did try thinning it further for the highlights on these minis.  I’m not very good at thinning my airbrush paints for anything much more than a solid base coat.

4: Not 100% sure which layer is running.  I assume its all of them.  I think I exposed through the layers the other day, but i can’t say for certain right now.

[lawnor 25939xp 1]

https://drive.google.com/file/d/1AnD6-4i_PaYInwmOkrFST94Bs4IKeWYr/view?usp=sharing

Thats a link to a short video of me applying water over paint that was airbrushed 4 days ago.  if the link doesn’t work or you want something better let me know.  What I applied to my hand has like milk.  It coloured my finger prints and then faded.

 

Here’s a clip of what happens with Agrax earthshade: https://drive.google.com/file/d/1Ap_Knc40oIYb1fpaoF89x8q8mc0RMrN0/view?usp=sharing

[zorg 18801xp 0]

MMMMM could it be contamination in the gun?

[shingen 13941xp 0]

@lawnor, re. compressor I rather meant a screw you have at the bottom of the tank, I can’t described it any better, so I took picture of what I have.

Important note: before you unscrew it let all the air out using safety valve or the one your moist trap, also do it over some container and have paper towel ready. Hope this helps.

Regarding seals I meant those around your air valve, deep inside the brush. Your cleaner may clean it properly, but the valve works whole time you airbrush and may add some lube every time you push your trigger (lubricant should never be removed completly by ultrasonic cleaner). On the other hand now that I think about it, I don’t think there is enough of oil there to give you such headache. Anyway a useful video on airbrush servicing:

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