Airbrush questions

[Docbritofmf]

Hey guys I could use a little assistance with my airbrush.

When I started airbrushing I messed around with a few cheap airbrushes with various success but eventually I went out and purchased a Iwata Neo CN gravity feed airbrush and a small airbrush compressor.

My over all success rate with the airbrush improved with the higher end brush and compressor however my problems started arising after few uses and cleanings.

When I started using the brush I would originally clean it out by running what ever thinner I was using for the preticular paint IE acrylic or enamel but then I started to run into feed issues were I wasn't getting a good flow from the gun tip.

I started to realize that I wasn't cleaning the gun as good as I should and found that the pipe cleaner brush kits weren't getting into the more smaller sections of it, I also found that the thinner was ruining the o rings and I was getting small leakes,

My research lead me to find out that airbrush cleaner is specifically formulated to clean and lubricate the inner components of the airbrush and prevent deteriorating o rings.

I think I'm at the point where I'm gonna have to replace some o rings and maybe some parts but I really don't know when I should be replacing things threw out the life of the airbrush aside from the obvious such as the o rings

What do you guys recommend for cleaning your airbrush when switching between colors and what do you recommend for cleaning it after your done using it for the day?

Also how often do you need to replace parts likes tips and needles? Just when they are damaged or do they eventually need replacement?

And o rings I am unfortunately not sure just how many orings and there location are in my air brush that might need replacement the store I bought the kit from seems to only sell one more two of the large o rings but I believe there were other smaller ones such as around the threaded end of the needle tip and in the crown and cap

 

[urumomo]

There is usually an O-ring where the air cap meets the AB body .
The needle gland ( on the bushing that the needle runs thru ) is usually nylon or PTFE .
I don't own an Iwata so hopefully someone here can help you with the particulars .

The O-rings wear out because they are continuously compressed and decompressed during assembly / disassembly .

I use isopropyl alcohol to clean it when using acrylics and mineral spirits or xylene when using alkyds ( enamel )
No lubricant is needed .
The needle bushing is self lubricating and the air valve is sealed ,,, although if you develop leakage past the needle bushing and onto the air valve you will need to clean it which , depending on the size of the mess , may require you to disassemble it

Often you'll miss resin in the spray tip that you can remove with a soak in solvent for acrylic or you can soak it in something like Super Clean that contains sodium hydroxide that will remove both acrylic and dried alkyd .
Your degradation in performance is most likely from dried resin in the spray tip .
Components like needles and tips only require replacement when damaged . But , over time the repeated insertion of the needle's tip into the spray tip can expand the spray tip's opening since the wall thickness is super-thin .

Tamiya's AB cleaner is the same as their Thin Cement .
1/2 acetone and 1/2 butyl acetate .
You can get ethyl acetate from Home Depot which works just as well as the butyl acetate for dissolving resin .
It's labeled " MEK Substitute " .
MEK ( butanone ) works too of course .
That Super Clean is easier on your nervous system though .

 

[Docbritofmf]

There is usually an O-ring where the air cap meets the AB body .
The needle gland ( on the bushing that the needle runs thru ) is usually nylon or PTFE .
I don't own an Iwata so hopefully someone here can help you with the particulars .

The O-rings wear out because they are continuously compressed and decompressed during assembly / disassembly .

I use isopropyl alcohol to clean it when using acrylics and mineral spirits or xylene when using alkyds ( enamel )
No lubricant is needed .
The needle bushing is self lubricating and the air valve is sealed ,,, although if you develop leakage past the needle bushing and onto the air valve you will need to clean it which , depending on the size of the mess , may require you to disassemble it

Often you'll miss resin in the spray tip that you can remove with a soak in solvent for acrylic or you can soak it in something like Super Clean that contains sodium hydroxide that will remove both acrylic and dried alkyd .
Your degradation in performance is most likely from dried resin in the spray tip .
Components like needles and tips only require replacement when damaged . But , over time the repeated insertion of the needle's tip into the spray tip can expand the spray tip's opening since the wall thickness is super-thin .

Tamiya's AB cleaner is the same as their Thin Cement .
1/2 acetone and 1/2 butyl acetate .
You can get ethyl acetate from Home Depot which works just as well as the butyl acetate for dissolving resin .
It's labeled " MEK Substitute " .
MEK ( butanone ) works too of course .
That Super Clean is easier on your nervous system though .

Man they should start paying you or you should get you self a hotline number. Thanks I think when I have a second I'll break it down and put some photographs up so maybe I can get a better understanding and ask questions it seems pretty straightforward but I could be missing things.

 

[urumomo]

LOL

Btw , I use a needle , or tiny pin , to scrape around inside the spray tip to loosen any stubborn resin .
You just need to always be careful around the tip's opening because it's delicate and easily damaged .
always use something thinner than the opening so you can't accidently expand the hole .

Looking into the backside opening of the spray tip , where the threads are , and pointing the tip into a bright light will allow you to spot any dried on paint resin .

I don't know exactly what issues you're having currently but , yes , air leaking out from the air cap via a bad O-ring will definitely cause problems .

 

[the Baron]

What brand and model brush do you use? You might want to check with the manufacturer, too, for care and maintenance tips.
I've got a Paasche VL, and an Iwata Neo; both companies are pretty good with that kind of info, and also with service for replacement parts.
I do similar to Momo-I use water or isopropyl, after spraying water-based paints, mineral spirits with enamels, lacquer thinner with lacquers. I will run SuperClean through, too, after water-based paints. But I also do a field-strip and cleaning every so often, blowing lacquer thinner through, then water to flush it. I've got a set of micro brushes to use for cleaning, too.

 

[Docbritofmf]

There is usually an O-ring where the air cap meets the AB body .
The needle gland ( on the bushing that the needle runs thru ) is usually nylon or PTFE .
I don't own an Iwata so hopefully someone here can help you with the particulars .

The O-rings wear out because they are continuously compressed and decompressed during assembly / disassembly .

I use isopropyl alcohol to clean it when using acrylics and mineral spirits or xylene when using alkyds ( enamel )
No lubricant is needed .
The needle bushing is self lubricating and the air valve is sealed ,,, although if you develop leakage past the needle bushing and onto the air valve you will need to clean it which , depending on the size of the mess , may require you to disassemble it

Often you'll miss resin in the spray tip that you can remove with a soak in solvent for acrylic or you can soak it in something like Super Clean that contains sodium hydroxide that will remove both acrylic and dried alkyd .
Your degradation in performance is most likely from dried resin in the spray tip .
Components like needles and tips only require replacement when damaged . But , over time the repeated insertion of the needle's tip into the spray tip can expand the spray tip's opening since the wall thickness is super-thin .

Tamiya's AB cleaner is the same as their Thin Cement .
1/2 acetone and 1/2 butyl acetate .
You can get ethyl acetate from Home Depot which works just as well as the butyl acetate for dissolving resin .
It's labeled " MEK Substitute " .
MEK ( butanone ) works too of course .
That Super Clean is easier on your nervous system though .

So MEK Substitute...

I went out to the Home Depot today to find some of the things you recommended and had planned on getting Xylene but unfortunately due to Covid and the work force shortage the stock in my local home Depot is limited and extremely unpredictable, you can't even get an answer on when items will be replenished or if you order them online when they will show up to the store so the only xylene they had was the big can and that's way more then I'll need nor did I want to pay the price for it.

I Have acetone, Denatured Alcohol which I like a lot for thinning acrylic though it's probably over kill but it works great in my experience, paint thinner and mineral spirits at home and while they do work they weren't getting the hard to get stuff out very great.

So what was left was MEK substitute which as you mentioned is pretty hazardous stuff. I'm used to be a part time paid fire fighter and dabbled in hazmat for a brief period of time and we used to have a Nickname for certain chemicals Methyle Ethyle Death and MEK sure fits the name.

Man that stuff cleans but holy hell that stuff will kill you if your not careful. A word of caution for those using the stuff 1. Use sparingly and in a well we'll ventilated area, 2. Wear gloves, 3. ventilation be out side if possible. 4 find another chemical lol

For those of you who don't know the recommended way to dispose of this stuff is to absorb it in paper or something else absorbent and safe to burn, then set it on fire and burn the chemical off there is even cause to add other flammable fuel to make sure your burning it off. In the fire industry we let this stuff burn at a distance because clean up of the liquid form is more dangerous in some cases.

I recommend a coffee can with sand in the bottom. Soak the left over chemical into a cotton rag or paper towels and burn it in the can on a not so windy day and make sure the smoke blows away from people it can harm.

The stuff works but it's definitely a hazard

 

[urumomo]

All solvents are hazardous .
People set themselves on fire with alcohol far too often .
That ethyl acetate evaporates super fast so if you have a can you're disposing of just leaving the cap off will clear it of vapor .
I don't know why you would need to burn large amounts of it . Sounds crazy .

Acetone and the ethyl acetate will degrade the nitrile rubber O-rings much faster than isopropyl alcohol .
Methyl and ethyl alcohol which make up denatured alcohol won't affect nitrile or butyl rubber .
The O-rings won't dissolve but will lose their elasticity .
You should remove the O-ring if you are cleaning with solvents that will damage the O-ring .
That includes sodium hydroxide for nitrile .
Butyl rubber O-rings are superior but who knows half the time what you're getting . The majority of them will most likely be nitrile rubber .

Handy Tables for chemical compatibility for solvents vs different polymers : https://www.applerubber.com/chemical-compatibility-guide/

The PTFE ( Teflon ) bushing used for the needle isn't affected by any of those solvents .
Mineral spirits is only a solvent for waxes . It won't dissolve cured acrylic or alkyd , or linseed resins .
It's only good for removing uncured alkyd ( enamel )

As far as alcohol used for acrylic thinner - it depends on the type of acrylic polymer used in the paint .
Acrylics listed as " lacquer acrylic " are fine but there are other formulations , AK's Next Gen for one , that will congeal upon exposure to alcohols .
If in doubt , it's easy to check by adding a few drops of the alcohol into some paint .

 

[Docbritofmf]

All solvents are hazardous .
People set themselves on fire with alcohol far too often .
That ethyl acetate evaporates super fast so if you have a can you're disposing of just leaving the cap off will clear it of vapor .
I don't know why you would need to burn large amounts of it . Sounds crazy .

Acetone and the ethyl acetate will degrade the nitrile rubber O-rings much faster than isopropyl alcohol .
Methyl and ethyl alcohol which make up denatured alcohol won't affect nitrile or butyl rubber .
The O-rings won't dissolve but will lose their elasticity .
You should remove the O-ring if you are cleaning with solvents that will damage the O-ring .
That includes sodium hydroxide for nitrile .
Butyl rubber O-rings are superior but who knows half the time what you're getting . The majority of them will most likely be nitrile rubber .

Handy Tables for chemical compatibility for solvents vs different polymers : https://www.applerubber.com/chemical-compatibility-guide/

The PTFE ( Teflon ) bushing used for the needle isn't affected by any of those solvents .
Mineral spirits is only a solvent for waxes . It won't dissolve cured acrylic or alkyd , or linseed resins .
It's only good for removing uncured alkyd ( enamel )

As far as alcohol used for acrylic thinner - it depends on the type of acrylic polymer used in the paint .
Acrylics listed as " lacquer acrylic " are fine but there are other formulations , AK's Next Gen for one , that will congeal upon exposure to alcohols .
If in doubt , it's easy to check by adding a few drops of the alcohol into some paint .

I'll touch base on the burning and why in a second but regarding that last part funny thing just happened..

So I'm using vellejo red brown primer acrylic and I attempted to thin it with Mr Thinner and surface leveler which in a couple of YouTube videos I watched seemed to be a recommended thinker for priming Ive used it with Mr surface leveler and it works great guy when I mixed it with the vellejo primer it turned thicker rather then thinner.. lesson learned

But regarding the leveling thinner and the surfacer what are your thoughts for use? Mixing and thinning and clean up after words?

In relation to the Burning of the MEK Substitute in regards to Methyl Ethyl Ketone the Hazmat Book first responders use called the ERG emergency response guide which is put out in a combined effect by major chemical producers and the DOT sums it up as the MEK while does evaporate does so slowly in cooler temperatures and faster at higher temps, it's considered unsafe for runoff water and the vapors in high concentration unsafe for handling with out proper protective equipment like an SCBA.

By increasing evaporation you increase the Fumes and also based on concentration the flash point of the chemical so leaving larger quantities creates I higher hazard potential, if it's burned you are eliminating both the chemical in it's fluid and vapor state and in a controlled environment this is the best way to handle clean up, MEK Burns off like a fuel and at hot enough temperatures the product is burned off completely.

When you look up disposal of the product you'll find Controlled Incineration to be consider the best way of disposal.

This of course changes if we were say fighting a fire in a residence or a building where this chemical was stored and we are trying to prevent spread but overall the object in that instance is to keep the chemical cool to prevent evap and use limited water to prevent contamination then absorb the chemical with something and ship to some place that will in the end burn it off.

 

[urumomo]

Ha ha , yeah , man , I understand all that hazmat chemistry but we're talking about the home hobbyist with a quart can of the stuff .
Fire fighting methodology concerning those solvents is sound but that's really addressing larger stores of the stuff , like drums and multiple gallon containers that would be found in industrial or retail / wholesale settings .

I don't understand what you are asking concerning the Mr Leveling Thinner .

 

[Docbritofmf]

Ha ha , yeah , man , I understand all that hazmat chemistry but we're talking about the home hobbyist with a quart can of the stuff .
Fire fighting methodology concerning those solvents is sound but that's really addressing larger stores of the stuff , like drums and multiple gallon containers that would be found in industrial or retail / wholesale settings .

I don't understand what you are asking concerning the Mr Leveling Thinner .

Sorry maybe I should clarify, Mr leveling thinner from what I found is a Laquer thinner with. Reducer and a retarder but I've seen a lot of people using it with acrylics how ever I seems to work ok with some and not with others I'm not sure whats what with it cause I'm only finding other people's work and explanations on using it.

Then the surface leveler is it acrylic or enamel or a Laquer and what should be used to thin it and clean it up after I'm done using it? I'm currently using the leveling thinner with it and it works just fine but clean up isn't working well with any of the basic stuff.

 

[urumomo]

Keep in mind that the term " lacquer thinner " is as meaningless as the word " beer "
" beer " doesn't tell you if it's a lager or ale yeast , what grain was fermented , if hops are added , what the alcohol content is etc .
You can just hope it's served cold .

Paint manufacturers formulate their lacquer thinner to work with the type of resin employed in the coating , and it's tailored to provide the best performance - evaporation rate - for the most likely environment it will be used in , temperature and humidity-wise .
Here's a brief overview of acrylic resin differences in paint : https://coatings.specialchem.com/selection-guide/acrylic-resins-for-coatings

Lacquer thinners can be only alcohols , only ketones or a combination of the two with other solvents possible .
The Mr Color utilizes both a ketone ( like acetone , but not ) which is a pentanone and more than one alcohol
You can see in this MSDS : https://manualzz.com/doc/8122791/gunze-mr-colour-thinner--t101--102--103--104-

This formulation is designed to work with the acrylic that they have selected to use in their paints .
It will not be compatible with all acrylic paints , but will be compatible with those labeled " lacquer acrylic " like AK's Real Color or Tamiya's for example .

The lacquer thinner you find in hardware stores / big-box stores is usually used for cleaning purposes and is literally the kitchen sink of solvents .
The Kleen Strip brand is mostly methyl alcohol and acetone but also toluene , ethyl acetate ( surprise ! ) and alkanes and cycloalcanes that they don't define , but pentane / cyclopentane and higher for sure . Who knows , it's the kitchen sink ...
And of course a glycol ether since it works so well though it's very toxic .
https://redwavetech.com/wp-content/uploads/2021/06/Klean-Strip-Lacquer-thinner_SDS.pdf

Can you use that in Mr Color paints ?
Yes , but it's certainly far from ideal .

So in short , the reducer must be compatible with the resin employed in the paint .
There are also modified alkyd resin paints -- the majority of enamel spray paints -- that are engineered to work with these various solvent formulations for the same reasons .

For cleaning you can use whatever solvent you want that will dissolve the cured resin at hand ,,, obviously taking into account the material you are cleaning will not be damaged by the solvent(s).

 

[urumomo]

" the surface leveler is it acrylic or enamel or a Laquer and what should be used to thin it and clean it up after I'm done using it? "

It's acrylic .
That's the type of resin used as a binder for the pigment .
The term " lacquer" refers to the type of vehicle / reducer that is used -- it's really more an indicator of the type of acrylic resin used . It's another term that causes confusion like " enamel " since it isn't wholly descriptive .
You'll see paints labelled " acrylic enamel " -It's an acrylic paint that dries to a hard , glossy surface ( maybe ? ) but again , it's a corruption of terminology .

" enamels " use alkyd resins which cure through oxidation . They actually change chemically during the cure .
Acrylic's do not .

Alcohols , acetone and other ketones , pretty much all of the solvents discussed will dissolve dried acrylic resin .
Cured alkyds are much tougher and you need solvents like xylene ,ethyl acetate , butyl acetate or a caustic solution like sodium hydroxide ( found in that Super Clean and in much higher concentrations in oven cleaners )

 

[Docbritofmf]

" the surface leveler is it acrylic or enamel or a Laquer and what should be used to thin it and clean it up after I'm done using it? "

It's acrylic .
That's the type of resin used as a binder for the pigment .
The term " lacquer" refers to the type of vehicle / reducer that is used -- it's really more an indicator of the type of acrylic resin used . It's another term that causes confusion like " enamel " since it isn't wholly descriptive .
You'll see paints labelled " acrylic enamel " -It's an acrylic paint that dries to a hard , glossy surface ( maybe ? ) but again , it's a corruption of terminology .

" enamels " use alkyd resins which cure through oxidation . They actually change chemically during the cure .
Acrylic's do not .

Alcohols , acetone and other ketones , pretty much all of the solvents discussed will dissolve dried acrylic resin .
Cured alkyds are much tougher and you need solvents like xylene ,ethyl acetate , butyl acetate or a caustic solution like sodium hydroxide ( found in that Super Clean and in much higher concentrations in oven cleaners

First thank you for explaining all that, it's a lot to take in.

Today I purchased some vellejo paint and vellejo Airbrush Thinner the kind that comes in that little dropper bottle, they had another type called thinner medium that was this cloudy milkly looking stuff but I figured the airbrush stuff was what I needed..

I'm not sure if my ratios are the issue or if it's something else but for every one drop of paint I added two drops of thinner and mixed it in my airbrush paint chamber like I do with Tamiya paint (this could be the issue prehapes it doesn't work that well for vellejo), I know vellejo makes two type of this paint one that pre thinned for airbrushing and another that's not and would need to be thinned, the type I got was the non thinned stuff.

When I tried to airbrush it was a night mare, it would sputter, splatter, clogg, then come out supper liquidy, then barely come out at all, or any variation of the above.. it was like I said a night mare. Its made double the work as I'll have to go over the model and sand it and clean it up and spray a nice clean fresh coat.

I thought it was my airbrush so I switched from my higher end Iwata to a lower end no name brush that I use for primers and less intricate work but I ran into the same problems.. what shoulda took roughly 10 mins took nearly 45. And most of that time trouble shooting the spray of my airbrush.

Vellejo products are new to me, so maybe it's a learning curve but before I spray them again I have to sort this head ache out

 

[urumomo]

First , always mix your paint in a separate container then add it to the paint cup of the airbrush .
I cut the bottom off of small pill bottles like aspirin bottles etc and use that for mixing .

Vallejo can be very inconsistent in viscosity between colors in their Model Color line of paints so you will need to adjust the thinner/ paint ratio accordingly .
Their AB ready paint is called Model Air .

2 parts thinner to 1 part paint seems really high , but I can see that being necessary with some of their colors but not all .
Make sure you mix the paint in it's bottle thoroughly .
Remove the dropper top and stir it .

These are the two thinners I would recommend for thinning Vallejo Model Color for airbrush :



What size spray tip and what air pressure are you running ?

 

[Docbritofmf]

First , always mix your paint in a separate container then add it to the paint cup of the airbrush .
I cut the bottom off of small pill bottles like aspirin bottles etc and use that for mixing .

Vallejo can be very inconsistent in viscosity between colors in their Model Color line of paints so you will need to adjust the thinner/ paint ratio accordingly .
Their AB ready paint is called Model Air .

2 parts thinner to 1 part paint seems really high , but I can see that being necessary with some of their colors but not all .
Make sure you mix the paint in it's bottle thoroughly .
Remove the dropper top and stir it .

These are the two thinners I would recommend for thinning Vallejo Model Color for airbrush :

View attachment 94299

What size spray tip and what air pressure are you running ?

.35mm is what I believe it is Iwata lists it as a N3 nozzle but no size the airbrush is a IWata Neo CN and I run it at around 15-20 psi

 

[urumomo]

That tip size and pressure should work . 20 psi being better .
Let me know if mixing it well prior to pouring it into the AB paint cup helps your situation .

Is that the Vallejo thinner you are using , in the photo above ?

 

[Docbritofmf]

That tip size and pressure should work . 20 psi being better .
Let me know if mixing it well prior to pouring it into the AB paint cup helps your situation .

Is that the Vallejo thinner you are using , in the photo above ?

Yes that's the thinner just in a smaller bottle.

Currently trying to resolve another issue now, the airvalve for my Iwata the connects to the hose and screws into the bottom of the airbrush, the piece that allows air to flow into the brush when the trigger is pressed down, seems to be getting stuck closed, I took it apart and there's nothing inside to clogg it but I am getting mositure in my air line that's making it past the moisture collection cup and into the line I believe that it's causing the o ring to slip up the rod instead of staying in place

 

[urumomo]

The air valve won't open ?
That's usually from paint getting atop it and basically gluing it shut , but it sounds like you have inspected it so I imagine you would have seen any paint on it .

I don't know exactly how that Iwata is constructed but I doubt the O-ring can move once the valve assembly is screwed into the AB body .

This is the airbrush ? :

 

[Docbritofmf]

The air valve won't open ?
That's usually from paint getting atop it and basically gluing it shut , but it sounds like you have inspected it so I imagine you would have seen any paint on it .

I don't know exactly how that Iwata is constructed but I doubt the O-ring can move once the valve assembly is screwed into the AB body .

This is the airbrush ? :


View attachment 94301

The piece labeled N-020-1 seems to be where the problem is, that brass pin slides up and down inside of it the trigger pushes the brass pin down and opens a slide valve letting air pass threw. On the bottom of the valve is a hex nut that retains that brass center pin I removed it and the pin slides out on the inside of the chamber the brass pin has a second red oring not shown in the diagram when the pin moves the o ring moves with it and it opens or closes a path for the air to flow threw.
This o ring has grove it is set into and seems to be popping out of the grove and remaining in the closed position while the pin moves freely with out it.
Originally this pin felt spring loaded except when I removed it to inspect as far as I can tell there was no spring unless it was super small and I lost it unknowingly.

When I re assembled it it still functioned for a bit and then I felt the o ring slip again and it stopped.. so right now my airbrush is outta commission untill I can find a replacement part.. modeling today has not gone very successful.

I did switch my paint over to a Tamiya color that I didn't have in the vellejo colors and a lot of the issues I was having didn't occured, which leads me to believe it's a ratio and mixing problem as far as that issue goes. I did notice that the vellejo paint was drying up into film like chunks in the tip and causing problems

 

[urumomo]

There WAS definitely a small coil spring on that valve stem .
You need to find it .