Airbrush blockage

[Lord Raven 19]

I was trying to get my new(ish) airbrush working today. However, I encountered a problem that I have seen before but have no idea how to fix. The airbrush doesn't spray any paint except when depressing the needle to return to the default position. Does anyone know why this occurs or how to fix it?

[Astral Arcane]

Clean the unit then try to run regular water through it. If it sprays okay then you know it's an issue with your paint consistency or nozzle clogging. If it doesn't then it's a mechanical issue with assembly or in general with your airbrush. 

[Lord Raven 19]

Thanks, it was unused so I will go through and make sure all seals are tight and all valves work.

[Bat33.1]

If your new to airbrushing one of the things that will be a steep learning curve is how much you really need to thin your paint. It still catches me out sometimes and I've been airbrushing for years, any clumps in the paint will immediately block your brush.

 

Are you thinning with medium (Liquitex or similar) or just plain water? 

 

Add your water or thinner/medium to the airbrush cup before adding paint works for me and I then use an old brush to stir the paint/medium in the airbrush cup to mix it well before starting to test spray on paper or whatever. If you have any issues with the mix it's best not to find out by spraying straight onto your nice new kit.

[Lord Raven 19]

Using Vallejo airbrush thinner to try to spray their airbrush primer.

[Bat33.1]

Vallejo primer I find best at 50/50 thinner to paint but I also up my pressure to about 35psi as the primer is a heavy medium. This is using an Iwata Revolution with a 0.5 needle.

 

I wouldn't try to put vallejo primer through my Iwata Eclipse which has a 0.35 needle it's just too prone to clogging with the primer and I usually run about 14psi or less for fine control with the eclipse.

 

A drop or two of Vallejo flow aid will help to stop tip drying and clogging too.

[Magos Takatus]

This goes some way to explain the woes I've been having lately. I have been trying to push some Vallejo primer through my 0.35 needle Iwata airbrush and I just keep getting clogs. It's a lot more prone to clogging than it used to be. I've tried thinning the paint with Liquitex airbrush medium, eventually the airbrush either dried at the tip or clogs in the needle and I find I'm increasing the pressure to compensate, which is just the brute force way of trying to deal with the problem. Several times during use I have to unclog and clean the parts, lubricate the needle and test with water before I resume painting. I will try some flow improver to see if that helps. failing that, I might have to invest in a 0.5 neelde airbrush. I don't really want to open my wallet again if I can help it. 

 

Just to add some additional information, I tend to find my gloss black Stynylrez primer seems to be a lot more co-operative. Is that a general trend? I might get a flat black primer from them and just relegate the Vallejo one to hand-brush touching up at this rate.

 

Can primer go bad in the bottle? I sometimes find the Vallejo paint bottle clogs from time to time. Could the paint be too old in general?

[infyrana]

Check out some of Angel Giraldez youtube videos, he had some interesting tips on using Vallejo primer which I intend to try next time I'm at it. From a much lower psi to pouring it from the bottle into a blister plastic and giving it a good stir to check consistency and removing dried pieces.

 

But yeah, vallejo primer takes some getting used to and probably a horrible first airbrush experience. After you clean the brush, just try some normal very thinned acrylic paint and play around.

[Axineton]

I had a new badger airbrush last year and it was blocked with like some petroleum jelly so I used a sonic cleaner for 10mins with some dettol surface cleanser and it was fine afterwards. If you have a sonic cleaner I’d suggest using that mate.

[Firedrake Cordova]

I have been trying to push some Vallejo primer through my 0.35 needle Iwata airbrush and I just keep getting clogs. 

Have you tried adding any Vallejo Airbrush Flow Improver?  Also, don't take this the wrong way, but are you sure your airbrush is fully clean internally (around the nozzle), as opposed to "looking clean"?  Which colour primer are you using?  I've found black to be the best-behaved, grey (near white in reality) to be well-behaved, and we probably shouldn't mention white.

 

I've found that I can kinda spray the black Vallejo Surface Primer neat through my H&S Evolution with a 0.4mm needle @ 1.8 bar (~25psi), but for prolonged use (i.e. more than 1 model), I'll want to add Aibrush Thinner and Airbrush Flow Improver.  If I want to use the 0.2mm needle, I'll need to add a lot of thinner, but it does then behave itself (the 0.2mm needle is prone to clogging/tip dry - even Daler-Rowney FW inks need thinning a bit).

 

You can thin out the polyurethane primer a lot - I'm sure I saw Angel Giraldez using it with an Infinity with a 0.15mm needle, and Rob Ferreira (author of Vallejo's "Airbrushing and Weathering Techniques" book) thins it to the point of being mostly thinners, applying it at about 10psi in "dust coats".

 

Can primer go bad in the bottle? I sometimes find the Vallejo paint bottle clogs from time to time. Could the paint be too old in general?

My 200ml bottle of black polyurethane primer is about 10 years old. As long as you don't leave it open, or let it freeze, you should be good.

Edited January 7, 2021 by Firedrake Cordova

[Magos Takatus]

Check out some of Angel Giraldez youtube videos, he had some interesting tips on using Vallejo primer which I intend to try next time I'm at it. From a much lower psi to pouring it from the bottle into a blister plastic and giving it a good stir to check consistency and removing dried pieces.

 

But yeah, vallejo primer takes some getting used to and probably a horrible first airbrush experience. After you clean the brush, just try some normal very thinned acrylic paint and play around.

That's a good suggestion. I've watch a couple of his videos before and it amazes me that he seems to use a 0.2 airbrush to spray on primer. I have been mixing my paint and thinner in small metal dishes. Not quite the same but it's better than mixing in the brushes' cup I suppose.

 

I had a new badger airbrush last year and it was blocked with like some petroleum jelly so I used a sonic cleaner for 10mins with some dettol surface cleanser and it was fine afterwards. If you have a sonic cleaner I’d suggest using that mate.

Again, good advice. I do have an ultrasonic cleaner and it gets a lot of use on the smaller parts. I haven't done a deep clean on the main body of the airbrush yet. Kind scared of dismantling it fully.

 

 

I have been trying to push some Vallejo primer through my 0.35 needle Iwata airbrush and I just keep getting clogs. 

Have you tried adding any Vallejo Airbrush Flow Improver?  Also, don't take this the wrong way, but are you sure your airbrush is fully clean internally (around the nozzle), as opposed to "looking clean"?  Which colour primer are you using?  I've found black to be the best-behaved, grey (near white in reality) to be well-behaved, and we probably shouldn't mention white.

 

I've found that I can kinda spray the black Vallejo Surface Primer neat through my H&S Evolution with a 0.4mm needle @ 1.8 bar (~25psi), but for prolonged use (i.e. more than 1 model), I'll want to add Aibrush Thinner and Airbrush Flow Improver.  If I want to use the 0.2mm needle, I'll need to add a lot of thinner, but it does then behave itself (the 0.2mm needle is prone to clogging/tip dry - even Daler-Rowney FW inks need thinning a bit).

 

You can thin out the polyurethane primer a lot - I'm sure I saw Angel Giraldez using it with an Infinity with a 0.15mm needle, and Rob Ferreira (author of Vallejo's "Airbrushing and Weathering Techniques" book) thins it to the point of being mostly thinners, applying it at about 10psi in "dust coats".

 

Can primer go bad in the bottle? I sometimes find the Vallejo paint bottle clogs from time to time. Could the paint be too old in general?

My 200ml bottle of black polyurethane primer is about 10 years old. As long as you don't leave it open, or let it freeze, you should be good.

 

I haven't been using flow improver but I have a large quantity of it from... Daler Rowney I think? I can decant some into a bottle and keep it by my airbrushing area.

Secondly, I'm not going to take the advice the wrong way, this advice is useful for anyone, not just myself. I am pretty fussy about keeping the airbrush clean but it doesn't hurt to check. I was using black primer and I also own the grey primer your mentioned as well. I also got some white ink so I can practice zenithal basecoats.

 

Thanks for the advice all. I put the offending pieces through the ultrasonic cleaner several times and thinned the paint even more and it eventually started playing ball, but the paint was very fluid at that point. I think at that point I should turn the pressure down to prevent it spidering?

 

Please forgive my stream of questions but I am not great with my airbrush. I've had it a while and made some progress with it but getting primer to play nice seems to be a big weakness at the moment. It is frustrating when I could have undercoated the model by hand in less time today but when I've got the airbrush working properly it's been  real time saver.

[Firedrake Cordova]

I haven't been using flow improver but I have a large quantity of it from... Daler Rowney I think? 

I don't know if regular flow improver is different from the airbrush variety, or if it's the same stuff and I effectively bought it twice, but it does help delay tip dry, so I'd say give it a go (generally, if your paint sprays fine at the start and becomes problematic whilst you're spraying, paint is drying in the nozzle area or on the needle tip).

 

the paint was very fluid at that point. I think at that point I should turn the pressure down to prevent it spidering?

Yup, drop the pressure down, or spray from a bit further away.

 

I don't know if this helps (it's Tamiya's alcohol-based acrylic paint, but the principal is the same): 

 

Please forgive my stream of questions but I am not great with my airbrush ... It is frustrating when I could have undercoated the model by hand in less time today but when I've got the airbrush working properly it's been  real time saver.

There's a very definite learning curve with them, and every question you ask and get answered is potentially saving someone in the future from having to ask as it becomes searchable.

Edited January 8, 2021 by Firedrake Cordova

[Bat33.1]

I think there is a difference with the vallejo heavy thinner technique and how we use finished models and guys like Angel Giraldez as we expect our models to be handled for gaming. His are going in a display case and nowhere near random pick up your models without asking in a gaming store types so we need a more durable primer coat.

 

I find if it's heavily thinned past 50/50 then it rubs off with little effort. Flow improver might be they way forward instead of thinner and 2 or even 3 coats as I know with the Daler FW inks I can have more flow improver than ink in the cup and that might help durability, or a good varnish once completed. I want to try the metal color gloss black primer to see if that is better to work with as the metal color paint airbrushes incredibly well.

[Firedrake Cordova]

I think there is a difference with the vallejo heavy thinner technique and how we use finished models and guys like Angel Giraldez as we expect our models to be handled for gaming. His are going in a display case and nowhere near random pick up your models without asking in a gaming store types so we need a more durable primer coat.

Honestly, I've not noticed any difference between multiple thin coats and one thick one, as long as you end up reaching a sensible thickness of paint in the end (this includes traditionally problematic pointy bits like the corners of Chaos Warrior cloaks, and I also handle my models a lot whilst painting because I have no discipline ).  One thing with the Vallejo primers is that they have a 24 hour curing period before they reach maximum durability, which isn't highlighted much, so often isn't respected.

 

 or a good varnish once completed

Varnishing is highly recommended for gaming pieces.

 

I want to try the metal color gloss black primer to see if that is better to work with as the metal color paint airbrushes incredibly well.

Try the Mecha Colour primer - it's supposed to be the most durable of the lot, as it's designed to be applied to the movable surfaces of Gundams.   Some people also say Badger Stynylrez (also sold under the Ultimate Modelling Products brand) is better (I can't comment as I've not tried it)

Edited January 9, 2021 by Firedrake Cordova