Airbrushing larger areas to a gloss finish

Recently through a project at work, I had the opportunity to have them buy an Iwata HP-CS airbrush, compressor and associated things for my team. Once that project ended, I was able to bring these things home and I’ve been building some 1/24 scale auto and 1/12 scale motorcycle models.

Although I’m sure there is a learning curve to airbrushing, I’m not feeling fully satisfied with the results I’m getting with the Iwata HP-CS airbrush that I’m using.

For painting smaller parts, the HP-CS is great; my issue with the HP-CS is for larger parts, like vehicle bodies. I feel like I’m finding that the spray pattern is too narrow, making it quite difficult to achieve an even ‘wet’ coat of paint, particularly on bonnets (hoods), roofs and boot (trunk) areas. I believe that another issue might be in the maximum amount of paint that can be sprayed out when the trigger is pulled fully back. Obviously if the amount of paint sprayed is low, this will also make it difficult to achieve a ‘wet’ coat necessary for a glossy finish.

I have already spent the money to get the 0.5mm needle and nozzle set (from the HP-BCS), but didn’t find any significant difference in spray pattern and when I measured it, the amount of paint sprayed is less than the 0.35mm set! (As a test, 2ml of 91% IPA took 42 seconds to spray with the 0.35mm set vs 63 seconds with the 0.5mm set)

Now that I’m enjoying the hobby again, and I’ve built up some experience with the Iwata Air-brush, I’m not against spending some of my own money this time on an alternative airbrush if that’s going to improve my models, and that’s why I’m posting.

Several scale auto builders on YouTube seem to favour the Harder & Steenbeck range of airbrushes, and I’ve seen a comparison review on YouTube that seems to indicate that the 0.4mm needle on the Evolution / Infinity air brushes produces a large spray pattern and flows a lot of point. My understanding is that Harder & Steenbeck airbrushes have not been available in the US as long as other brands, and that might be a reason whey they seem to be used more by Europeans.

Could my issues be improved with practice and technique, or might trying a different airbrush help?

What paint are you using ( brand and type of paint) ?

I can only tell you what I do for broader coverage and good full wet coats. It starts with proper thinning ( this is key, very important). In the case of acrylic paint I use a .5 needle/nozzle in my Badger 200. I have retarder in my thinner and up the pressure to the mid 20psi range. This allows me to back away from the work and the natural result of that is a wider pattern. If you don’t have the retarder in there the paint will go on dry, even rough. Some people put in some flow aid as well, I do that only in the Liquitex line of soft body fine art paints. But Model Master and Tamiya I have not found to require that. Both flow out nice with my thinner blend I make…

On another note, don’t they make a fan cap for your existing airbrush ? Those will generally give a 3" pattern or so.

Model Master enamels will flow out nice with their own enamel thinner. Also with a combo of lacquer thinner and mineral spirits as the thinner, or lacquer thinner and paint thinner as well. The hardware store variety. I mix enamels in a way that I basically fog the paint onto a body from 6-8 inches away. If I go in too close it will run.

A Paasche H with the number 3 tip will do well too. I have one but prefer my Badger for body finishing personally. Actually in general. I mostly use the Paasche on my wife’s ceramics for varnish coats. But world champion model builders have used and advocate the H and #3 for their custom paint jobs on car models. some even use the 5 but you have to have a compressor that will keep up. I personally find the #5 over kill, it’s 1.05 tip. The 3 is a .77 as I recall. But there are other options too and what you have should work as well.

Hmmm… when I’m doing auto bodies, I use a rattle can by spraying in several light coats.

I used to do that, it works great. But, well never mind.

Ahoy Nezil,

Your initial observation is right on the money. The Iwata is super at smaller parts (but not exclusively). There are people who can make an Iwata stand up and talk…very talented people.

However, I’ve got to throw-in with oldermodelguy. When I have a car body to do, I break out my Paashe H with a #3 tip. It covers the larger area very well. That’s what its made to do.

Since you guys are willing to provide such great info, I’m going to press my (and Nezil’s) luck…

You mentioned a #3 tip… is that the same as a “size 3 (.66mm)”?

I found a brush on the amazons that says the spray pattern is hairline to 1". It comes with the “size 3”.

Thanks for the help and sorry for a noob question.

T e d

Well first what model airbrush was it ? Paasche has the Talon series where the size or what I call number 3 is .66. The H is a different airbrush sytem though, single action and the “3” tip is .77.

If it was the Talon ( tg or ts) you can put on the fan air cap, that gives a 3" wide straight line pattern like an automotive spray gun has. In other words vs oval or round pattern.

Thanks everyone for the responses so far…

Since working my original post, I’ve now ordered an H&S Infinity 2 in 1 set with 0.2 and 0.4 needles. This may not meet my needs 100%, but it’s a beautiful airbrush and since my HP-CS technically belongs to my employer, I wanted to have something that covers it’s capabilities as well in case I have to give it back!

The Talon series looks REALLY interesting, particularly with its fan head. Having said that, scale Auto bodies, whilst larger, aren’t only large flat sections, and I’m not sure how good a fan shape would be, but I’d love to try it out.

The price of the Talon set isn’t high though, so it’s very tempting to give it a go.

I’m going to try my H&S Infinity 0.4 first, comparing it to the HP-CS 0.35 (the 0.5mm in the HP-CS, as I said earlier flows less paint and had no wider spray pattern, and is therefore pointless as far as I can tell). I know what I’m like though, and think I see a Talon in my future…

To answer the question regarding paint type, I’m typically using decanted Tamiya spray can lacquer, thinned with Mr. Colour leveling thinner, or what I understand to be automotive based lacquers from Splash paints, Gravity colors or Zero paints, which are pre thinned.

Depending on the era of the model I’m building, I’d either aim for gloss from the colour coat (only possible with decanted Tamiya), or apply a clear coat which would be either decanted Tamiya lacquer clear (TS-13 I believe), or some brand of 2K urethane clear; I’ve used Zero and Splash paints in the past.

I have found that spraying neat leveling thinner as a last coat over decanted Tamiya lacquer works quite well, improving gloss, but not as much as I’d like.

Finally, of the colour is right, I’ve used Tamiya acrylics thinned with either X20a or Mr Color Leveling Thinner as a base coat. Coverage is good, but I’m rarely happy with the level of gloss this produces.

2K urethane gets the closest to what I’m looking for, but I’m still getting noticable orange peel because I think I’m not getting enough paint down between passes, hence my post .

Wow 3 inch.

The description reads “Paasche Airbrush RG-4SA Airbrush Raptors”.

Thanks for the response.

T e d

Ted the fan aircap for the Talon series AB is about $9 and fits the .66 nozzle only. That’s at Amazon .

I think it’s a Petty nascar paint job that MC Model Works did up on youtube using the fan cap on a Raptor ( glorified Talon ab is what the Raptor is if my brain cells are all firing today). If I find a link I’ll post it up.

Edit: I was wrong he uses a Paasche Vision, .66 and fan aircap. Here is the video but I warn you this guy drags it out and he isn’t right about 100% everything:

https://www.youtube.com/watch?v=gBQmymyM7X8&t=1141s

Watch this video on the Paasche H and spraying plain Testors enamel and see why I like enamels, but I us MM myself and a bit different thinner mix. My Paasche H came with little 3/4oz bottles actually. anyway have a look see: https://www.youtube.com/watch?v=lCKZ_fo4eW0

When you replaced the nozzle and needle, did you also replace the nozzle cap? It’'s a different part.

The eclipse is a great airbrush. I doubt whether the H&S will do any better at broad coverage.

Don

Though it seems uneeded to back up the advice of our resident airbrush expert, Don, I’d just like to chime in that I own and use both the Iwata HP-CS and H&S Evolution 2-in-1 and you should not expect much difference in spray pattern.

I do have the .7mm needle/nozzle for the Iwata and though I’d love to have a fan pattern mini airgun, the .7mm is probably as close as I’m going to get.

Don, it is always appreciated when you take the time to comment here.

Thanks both Greg and Don. I was going on the basis of this YouTube video that the H&S might flow more paint, even if the spray pattern isn’t significantly wider:

I now have the H&S Infinity, with the 0.2 and 0.4mm needle sets. I’ll be giving it a try at some point either tonight or over the weekend and I’ll report back here on my finding.

I have to say that I am worried since I discovered that my HP-CS had a trumpetted nozzle and was therefore flowing a lot more paint that it should have been as it was… The H&S Infinity 0.4mm might flow more than the HP-CS 0.35mm, but it probably will flow less than the old 0.35mm damaged nozzle did anyway!

Greg, you mentioned that you have a 0.7mm needle set for your Iwata; which one is that? As far as I knew, only a 0.35mm and 0.5mm were available, and I found based on object and subjective testing that the 0.5mm was pointless (no larger spray pattern, and less paint flow than the 0.35mm). If there is a 0.7mm option for the HP-CS, I’d like to give that a go too.

Over the last few days I’ve been taking a look at Paasche airbrushes with the fan head, and also the Paasche H external mix mentioned above. The H looks like it’s capable of flowing a LOT of paint, and might be a good option for me. It’s also an older design, and therefore cheaper and perhaps better quality than the newer Paasche products. I’ve read on several forums people complaining about the Vision / Talon / Raptor quality control.

Greg, how does that .7 do, does it fill the gap pretty well ? I have one for my Badger 200 and would just say if you open it up it guzzles paint more than the Paasche H and .77 needle I think. I rarely use it, I find the .5 sufficient for my needs and my go to needle/nozzle for car bodies.

I agree with both you guys on the H&S, though the op may be buying because he just likes the idea.

So my H&S Infinity 2 in 1 arrived last night, and having just got home from work, I’ve had a chance to run the same experiment that I ran with my HP-CS earlier in the week for an objective understanding of maximum paint flow. I really don’t understand why this isn’t a specification mentioned by airbrush manufacturers, or discussed by users on forums like this, because I’d have thought that this would be a key buying factor.

My test involved putting 2ml of 91% IPA in the colour cup, then timing how long this took until empty under full trigger when running with ~15psi of pressure. Results are:

  • 42 seconds - Iwata HP-CS brand new 0.35mm needle & nozzle (~0.05ml / s)
  • 50 seconds - Iwata HP-CS almost new 0.5mm needle & nozzle (~0.04ml / s)
  • 20.5 seconds - Iwata HP-CS old, trumpetted nozzle & nozzle which still sprays fine (~0.10ml / s)
  • 19.2 seconds - Harder & Steenbeck brand new 0.4mm needle & nozzle (~0.10ml / s)
  • 55.3 seconds - Harder & Steenbeck brand new 0.2mm needle & nozzle (~0.04ml / s)

@oldermodelguy - You’re somewhat correct; I did buy the H&S partly because the design and good reviews appealed to me, but as I’ve stated in my original post, I was hopeful that its 0.4mm needle would flow more paint than the 0.35mm needle in the HP-CS. This YouTube video suggested that it might, an the H&S air-brushes seem to be favoured by most of the modellers on YouTube making 1/24 scale autos.

As you can see from my tests above, I was correct! The H&S 0.4mm flows about twice as much paint as a new HP-CS 0.35mm needle and nozzle, and about 2.5 times as much paint as the HP-CS 0.5mm needle and nozzle.

Having said all of that, I’ve not actually painted with it yet, so it remains to be seen how I get on with it and its other performance characteristics. Flow though… should be great!

So this post should be short…

The H&S airbrush is incredible… The additional flow with the 0.4mm needle & nozzle really makes a difference for larger areas. The flow to trigger control is very linear, the spray pattern is nice and large, and clean up is even easier than the HP-CS, which is renowned for it’s easy of assembly etc.

I guess the best part about all of this is that all of the H&S airbrushes use the same nozzle & needle set, so should all have similar performance from the Ultra, right up to the Infinity CRplus!

I’m still shocked that flow rate and spray pattern size aren’t standard specifications, and with that in mind, I’ve created a Google Sheet with my results that hopefully others can add to. I was considering buying the 0.6mm and 0.15mm needle & nozzle sets for my H&S, but I can’t justify the cost right now having emptied my wallet on the Infinity… The publicly editable document can be found here:

https://docs.google.com/spreadsheets/d/1c-4cmwrlagSfVg84IWSIO9MQPuh_ESpdP_6nSO7ZNiU/edit?usp=sharing

Painting gloss finishes is a completely different animal than doing flat colors. I have done several 1/48 Blue Angel planes that have a high gloss finish. Thru experimentation my gloss finishes came out glass mirror smooth. I use MM gloss enamels heavily thinned which spray very smooth and glossy using a Neo ab with a .35 tip, no fancy ab here but works very well.

To further enhance the gloss I shot several thinned coats of MM clear enamel then set aside for a week to cure. After curing, a soft rag with a little Novus polish was used to rub the clear coat to a glass smooth finish.

I’m not a car modeler but I’m guessing the car guys follow a similar method to obtain that wet look.

I think you will love that airbrush. I have the 2 in 1 Silverline. I go back and forth using it or the HP-CS as my primary. Like them both, the H&S “feels” better and I find it easier to strip and clean, but for reasons unknown I tend to default to the Iwata often.

Ok, this is embarrassing. I am away from home so I cannot verify anything, but you are correct, I cannot find anything about a .7mm nozzle/needle for the Iwata either. I would have sworn I had a .7mm, but now I think my memory might be failing me. Unfortunately, by the time I return home, I doubt I’ll remember to post a follow up.

It really bothers me when I post bad info, sorry about the confusion.

The test you did is very interesting, and I would never had guessed that the H&S .4mm has more flow than the Iwata .5mm. Good to know, and enjoy that H&S.

Please see my reply to Nezil above, omg. I think I may have made a typo or some other senior moment boo-boo about the .7mm nozzle, and I won’t be able to confirm same for quite a while.

Sorry!