Headache Airbrushing Metallics

[DAL3001]

Hi all, 

 

I've had my Airbrush around 6 months and have done a fair bit of painting with it. It's a Harder & Steenbeck Evolution with the 0.4mm Needle/Nozzle. In this first 6 months I've been doing my best to learn the ins and outs of airbrushing, including good practice for cleaning/maintenance, paint consistencies, consistency in relation to pressure etc... I've only really had one issue before this one, which was related to tip dry, which I've now largely managed to work around. All of the work I've done so far has been using water based acrylics from various brands.

 

I've been spraying some metallic paints recently and I've noticed that I get an inconsistent spray. The best way I can describe it is as "bursty". It's not like a pulsation because it doesn't happen in any particular pattern. As an example for possibly better context: I'll push the trigger down to a certain point to start the flow of air. I'll retract the trigger to release the paint. I'll then maintain the trigger in the same position (both air and paint) but the flow will then be inconsistent. If and when it completely stops, I can only start it again by pulling the trigger all the way back. It feels almost like I'm blasting out a blockage. Then I can use it again for a little while before the same thing happens. I can usually only manage a few seconds of flow before it stops again.

 

This is happening to a degree with all of the metallic paints I'm using although it's definitely way worse when I use some brands. Vallejo Game Color for example are giving me the biggest headache. They're pretty much unusable for me right now as the bursting makes it really hard to control. Thinning further doesn't seem to make a difference, it just makes the paint harder to use at my preferred pressure of around 25 PSI. 

 

I've done my usual routine of fully stripping and cleaning the brush and that hasn't helped. I'm pretty sure that it's not just a dirty brush problem as I can load in a different non-metallic colour and spray normally, then switch back to a metallic and see this behaviour. 

 

If I was guessing, I'd say that it's the metallic flake in the paint interfering with flow (and that's why the thinning doesn't make a difference?). I'd thought about moving up to a 0.6mm setup maybe? Thing is, seems some other people have had no issues at all spraying these paints with the same needle size... 

 

Anyone have any ideas or similar experiences, still quite new to airbrushing so would be great to get some more opinions. 

 

 

Thanks!

[bmwh548]

I use the 0.4 in my Ultra and that's about as big as you need to go. Try some good quality metallic paints (AK, Gunze's Super Metallics, MRP - careful with this one as it's very strong). My air pressure is 10-15psi.

Water based paints are hard to airbrush and metallics are even worse. If you have no choice and need to stick to these for health reasons try adding a drop of retarder to the mix and remember to move fast, the flake settles on the bottom if the mix stays in the cup for too long.

[Stef N.]

I think Game Color are better for brushing and not specifically designed for airbrushing. Vallejo's Metal Color are for airbrush and thinned ready to spray.

 

The paints @bmwh548 suggests are my preference too and excellent quality but you will need a good ventilation system.

[DAL3001]

Thanks for the replies.

 

I think ideally I'd be sticking to water-based stuff just because of the circumstances of where I have to use my airbrush currently. The ventilation isn't terrible and I always wear a mask anyway but I've got pets and other members of the household who would probably find it a bit disagreeable - is the odour fairly bad? If this changes I'd love to switch over and try something that isn't water based. I've got some flow improver (which I think has retarder in it as a primary ingredient) so I'll try and add some of that too, thanks for the tip.

 

I've got a Metal Color gold on the way as it happens, so will test that out. The Metal Color range just seems a bit limited in choice, some other ranges seem to have better choices on hue/warmth of gold. 

 

I did also have better luck with Scale75 metallics and Darkstar metallics, I can report that they do work a lot better than the Game Color.

[bmwh548]

Enamels and lacquers stink to high heaven, so I guess they're a big no-no for you. Try the specialized metallic range from Vallejo, haven't used them myself, but I've heard good things about them. You could give Tamiya's acrylics a go (with retarder), but their metallics are a bit flakey.

[Graham Boak]

Lacquers smell strongly, but enamels don't smell that much.  What does smell is using white spirit/turpentine substitute to thin them.  Try Colourcoats naptha-based thinners.  None of the cats I've had have been too bothered by the paints I use even with white spirit (rarely lacquers, to be fair).  But by all means do it by an open window not in the kitchen.

 

As an old fogey, I honestly do not remember any complaints about the smell of enamels/ws until very recent years.  Certainly in my opinion, dogs smell worse.

[DAL3001]

If it's feasible to use enamels indoors in a room with decent ventilation (Large window, fairly small room) then I'd certainly be willing to try. 

 

In the end I just gave up with the Vallejo Game Color metallics - the golds were especially problematic to get flowing correctly. Some flow improver certainly helped by delaying the dry time a little bit but it was still far from perfect, definitely still too unpredictable to want to do any detail work with! 

 

I did however have a much better time with Scale75 and Darkstar metallic paints, so if anyone is in a similar situation to myself of needing to use water based acrylics, then I'd just suggest starting with these. The Vallejo Air gold works nicely too but that range only has a single gold as far as I can tell and I needed a slightly different hue. 

 

Thanks for all the responses!

[bmwh548]

It really depends on the enamels. The old school ones like Revell and Humbrol stink up the place. I can still smell Revell residue on my booth's fan days after spraying them, which is why I tend to avoid them. AK's metallics on the other hand are also enamels, but they're alcohol based, the smell is much more tolerable for my nose (and this is a nose that is used to automotive paint).

I strongly suggest buying or making a spray booth, it will allow you to use whatever paints you want without intoxicating yourself or the household members.

[kiseca]

On 4/24/2021 at 12:49 PM, DAL3001 said:

If it's feasible to use enamels indoors in a room with decent ventilation (Large window, fairly small room) then I'd certainly be willing to try. 

 

In the end I just gave up with the Vallejo Game Color metallics - the golds were especially problematic to get flowing correctly. Some flow improver certainly helped by delaying the dry time a little bit but it was still far from perfect, definitely still too unpredictable to want to do any detail work with! 

 

I did however have a much better time with Scale75 and Darkstar metallic paints, so if anyone is in a similar situation to myself of needing to use water based acrylics, then I'd just suggest starting with these. The Vallejo Air gold works nicely too but that range only has a single gold as far as I can tell and I needed a slightly different hue. 

 

Thanks for all the responses!

I use the Vallejo Metal Colors mostly, easy to use, no odour problems and easy to clean. They generally also seem consistent quality though I've had one out of 8 that doesn't spray well. it pools, like it's too thin. (a gunmetal one).

 

I have some of the AK Xtreme Metal range too. They are also nice and easy to use, with good colours and better durability than the Vallejos which can chip quite easily (not surprising, enamel vs acrylic) but the thinners they use are really strong. Much stronger than Humbrol for instance, and strong enough to melt off any undercoat I've applied except for AK's own brand primers. Plus the thinners has a smell to match. Seems like potent stuff, so I use it less often because you really need the room well ventilated.

 

I'm using an Iwata Revolution with a 0.5 needle but my budget airbrush has a 0.3 and coped fine with them, so I'd say your conclusion is correct - the problem is the paints you were using. I've also come across some acrylics that I just couldn't make work through the airbrush (AK in my case). I usually have my pressure very low because of the big needle, probably around 10psi. I only bump it up to 20 when cleaning out the brush.

 

I haven't yet bothered with flow retarders and flow improvers and whatnot so can't say if the key is in there somewhere... instead I've chosen to stick with paint brands that I can make work easily. For me, that's Humbrol enamels - their quality is shockingly variable though, Tamiya acrylics, and then Vallejo Model Air which is prethinned so should be good to go straight out of the tin. It is to be honest a bit thick straight out of the tub, but I manage with a higher pressure. Many do recommend using Flow Improver with it. I've not yet found that necessary but I can see how it could help.

[JamesP]

I’m having exactly the same issue as the original poster. I used to be able to spray metallics through my Iwata Revolution CR(0.5mm) but over the last year I constantly have problems with spray stop/starting or just needing the needle fully retracted to get anything out. This includes Alclads, Vallejo Metal Color through to enamels. I can spray all kinds of non metallics absolutely fine. 
 

Unfortunately this thread quickly got off topic as I don’t see buying even more paint a solution as what I have should work fine. Could I have worn out/ caromed the airbrush tip, which is stopping the metallics particles from following for example. 

[Greg B]

3 hours ago, JamesP said:

I’m having exactly the same issue as the original poster. I used to be able to spray metallics through my Iwata Revolution CR(0.5mm) but over the last year I constantly have problems with spray stop/starting or just needing the needle fully retracted to get anything out. This includes Alclads, Vallejo Metal Color through to enamels. I can spray all kinds of non metallics absolutely fine. 
 

Unfortunately this thread quickly got off topic as I don’t see buying even more paint a solution as what I have should work fine. Could I have worn out/ caromed the airbrush tip, which is stopping the metallics particles from following for example. 

I have a feeling its more of a cleaning and/or thinning issue for both rather than a paint issue. 0.4 and 0.5mm are on the upper end of needle sizes. Alclad is very thin straight out of the bottle but it uses lacquer type thinners as a base. That would suggest that they are making any residue left in the brush or nozzle softer and therefore this residue is able to move and effectively gum up. I have a 0.2 nozzle with no issue whatsoever for those paint types. The metal flakes are pretty fine in the vast majority of metallics to discount the nozzle size issue.

[Bertie McBoatface]

This is rather a late reply for the op but I only read this today so I guess I'm not the only one.

 

On 4/21/2021 at 5:31 PM, bmwh548 said:

remember to move fast, the flake settles on the bottom if the mix stays in the cup for too long.

 

That's a very good point. I've experienced the problem exactly as the op describes and flake settling seems to be the problem. I occasionally stir up the paint in my paint cup by inserting a pipette and sucking the paint up from the bottom of the cup and pumping it back in several times

 

On 4/22/2021 at 10:40 AM, DAL3001 said:

The Metal Color range just seems a bit limited in choice, some other ranges seem to have better choices on hue/warmth of gold. 

 

Remember that MetalColour paints (Vallejo) can be tinted with acrylic paint or inks to whatever hue you want. (Start with the lighter ones like chrome or aluminium and add yellows and oranges for a good range of golds.)

[JamesP]

7 hours ago, Greg B said:

I have a feeling its more of a cleaning and/or thinning issue for both rather than a paint issue. 0.4 and 0.5mm are on the upper end of needle sizes. Alclad is very thin straight out of the bottle but it uses lacquer type thinners as a base. That would suggest that they are making any residue left in the brush or nozzle softer and therefore this residue is able to move and effectively gum up. I have a 0.2 nozzle with no issue whatsoever for those paint types. The metal flakes are pretty fine in the vast majority of metallics to discount the nozzle size issue.

Thanks Greg these are very good points. I agree needle size is a misnomer. However I do attempt a thorough cleaning of the airbrush including the tip with a twist of tissue paper soaked in cellulose thinners. As to thinning, I’ve tried over thinning the paint to no avail. Also the issue occurs start away so it’s not the particles settling out. 
 

I may look at alternate methods of cleaning the tip. 

Edited March 12, 2022 by JamesP

[Greg B]

No problems. I had a similar issue and it was a tiny bit of gummy/sticky residue in the tip of the nozzle. It took a couple of attempts with dentists’ paper points to tease it out.

[kiseca]

On 3/12/2022 at 10:25 AM, JamesP said:

Thanks Greg these are very good points. I agree needle size is a misnomer. However I do attempt a thorough cleaning of the airbrush including the tip with a twist of tissue paper soaked in cellulose thinners. As to thinning, I’ve tried over thinning the paint to no avail. Also the issue occurs start away so it’s not the particles settling out. 
 

I may look at alternate methods of cleaning the tip. 

 

Is it worth also checking the tip / nozzle for damage? If the result has changed and the paints have not changed, it must be something about the airbrush. Cracked nozzle, maybe a worn seal somewhere? Is it OK with everything that is not metallic?

[senux]

On 4/22/2021 at 12:40 PM, DAL3001 said:

I did also have better luck with Scale75 metallics

 

i did not have any luck with metallic Scale75 and airbrushing. It is terrible annoying result. I did tried various and many thinners (their original, Tamiya, Mr. Hobby, IPA, water, vodka, AMO Mig..)  - no secured result. One metallic with the same thinner acts better, while the other their metallic with the same thinner, gives some creamy consistency and clog the airbrush completely. I was about to bin Scale75 metallic, but left just for cases when i can do them just by brush. But not airbrush anymore. My airbrush Iwata Eclipse with 0.35mm needle.