Wednesday, June 25, 2014

Poor Man's Airbrush Setup


After painting the RG freedom, I realized that my old airbrush setup (a Tamiya Sprayworks Basic set I share with my bro-in-law) was probably at it's limits - I wanted to do some tight shading around the edges of this tiny part - but even shooting as close as possible and trying several thinning ratios, I just couldn't get the results I wanted. This may have been lack of skill on my part, but I decided to bite the bullet and go hunting for a dual-action airbrush. Being my usual stingy self, of course I opted for a slightly used, unbranded brush akin to the HD-130s I see flying around. Php800 ($18) for a brush used only once seemed ideal for what I was going to attempt anyway. <evil grin>


Hit the read more link for the rest of this post!



A bit of background - The Sprayworks compressor broke down on us last year - and while it was an easy repair, we started to look for alternative ways to power the trigger-type gun that came with the kit. Before I got into plamo, I kept fish. Monster fish to be exact. At the peak of my fish keeping days I had an Arowana, two Snakeheads, a Dragonfin, a Red-tail cat, and a couple of Tigers - but I digress. The point is, all my fishies needed air...and they got it from these...


Aquarium air pumps. These pumps are what power the air stones that make the tiny bubbles you see in your common fish tank. When I took apart the Sprayworks compressor, I found that it shared the same basic design as a regular aquarium air pump - just a motor driving the diaphragms that pushed air out. Now I know you're thinking, "Aquarium pumps couldn't be as powerful as the Tamiya compressor.." Let's talk about that for a bit.


Tamiya's website states their compressor does 0.11Mpa, or about 15.9psi unburdened. If I understand correctly, "unburdened" means that this is the output if the air hose is unobstructed. Aquarium pumps are rated much lower, at around 7psi even for the larger ones, but this is the rating against water pressure. If you've ever tried blowing into an air hose going down to the bottom of a 100 gallon tank, you'd know it isn't easy, and you're more than likely going to get a mouthful of fishy water, not to mention Amoebiasis. That water pressure is what these aquarium pumps go up against, and they are designed to do it 24 hours a day, 7 days a week, otherwise your fish go belly up. Also, they are about as noisy as a refrigerator. Meanwhile, Sprayworks basic users know they have to let the compressor rest every 30 minutes to prolong it's lifespan...and it sounds like a helicopter.

If these bigger aquarium pumps can do 7psi against water pressure, would it add up to 14psi if I combined two? Maybe not - I don't really care about the numbers. What matters is if it actually works. These guys were painted using the Sprayworks gun, powered by the double aquarium pumps shown above...


So we've proven it works with a single-action, gravity fed, trigger-type brush. What about a double-action airbrush? Enter el-cheapo for the test run!



I made a couple of videos to show this contraption in action.. (YouTube Channel..woot!)



(*Don't forget to subscribe to my YouTube Channel - more demo videos coming soon!)

Not too shabby! The new airbrush atomizes the paint quite well. The paint flow is nice and smooth, and I can shoot close range without blowing paint everywhere except where I want it. The twin aquarium pumps seem to do a decent job of powering a double-action airbrush. I'm not the first person to attempt this kind of hack. A quick search on google shows a lot of fellow cheapskates trying crazy ways to power an airbrush - from nebulizers to tire pumps to tires themselves. There's even a design for using your own breath.

post-shading (orange on tan) dual action AB + aquarium pumps
pre-shading (orange over dark blue) dual action AB + aquarium pumps
One possible issue with the aquarium pump setup (or any setup that does not have an air tank) is getting a pulsating airflow. I've never actually experienced it myself, but apparently tank-less setups may sputter from time to time, making your paint shoot out in bursts instead of a constant stream. To counter this, I'll be trying out something else I found online:

*Image used with permission from https://sites.google.com/site/donsairbrushtips/

See the water bottle? It's supposed to smooth out the air coming from the pump. In theory, the air has to fill up the bottle before it gets to the airbrush, eliminating any hiccups in the airflow. My guess is that the air hose diameter is much larger than the nozzle on the airbrush anyway, so that alone should be enough to even out the flow. In any case, I'll update this post after I've added the bottle bit so I can let you know if it made a difference.

Now let's talk about cost. Air pumps like these can go for as low as Php700. You'll want a pair at least, so that brings it up to Php1400. A new HD-130 airbrush costs around Php1000, bringing the total to Php2400 ($55). You'd be hard pressed to find a cheaper double-action setup than that! For those who like to paint indoors, you can build a Portable Spray Booth for less than Php2500 - and you've only spent a little under Php5000 ($114) for the whole shebang.

A few notes before you run off to the nearest petshop:

  • Bring your airbrush if you intend to go aquarium pump shopping, so you can test the air flow. 
  • Aquarium air pumps are readily available and probably cheapest at Cartimar (for those in the PH), but any decent pet or fish store will have them in stock. 
  • Not all airbrushes are the same. From what I've read, siphon feed types need more air than gravity fed brushes. Check if your airbrush needs any special fittings for this to work.
  • I've only tested it with this brand/size of aquarium pump, and I use two of them, so your mileage may vary if you try anything else. Sure, you can try 7 smaller air pumps, but then you'd need 7 power outlets.
  • If you have a double-action brush, I'd recommend switching the pumps off when not using the brush for extended periods. These pumps don't have an auto-stop feature, so letting it push air against a closed door may stress out the motor in the long run.
  • I use only acrylics, so you'll have to test with enamels or lacquers yourself. Primers are thicker, so they might need more air to spray properly.

While this setup is cheap, quiet and portable, there must be some reason most modelers still prefer a proper compressor. I'll probably understand it sooner or later, but until then, I'm happy with the poor man's airbrush set. At least I can actually hear my speakers while painting. 



*some references for your own research:

https://sites.google.com/site/donsairbrushtips/work-around
http://gunplahero.blogspot.com/2007/01/lifetech-p-125.html
http://nelman.blogspot.com/2009/07/poor-mans-modeling-neb-kit-hose-hack.html


15 comments:

  1. Don't cry, man up.

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    1. This comment has been removed by the author.

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    2. Says "man up", comments as Anonymous. Pfft.

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  2. nice setup. have you ever tried to attach one of those attachment to the Airbrush that allows you to see and adjust the PSI? if you are saying that the water pump is rated at 7psi in a burdened scenario, then it might even capable of going beyond 14psi.

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    1. Thanks! I'm looking for a cheap pressure gauge/regulator at the moment. I'll update the post as soon as I get to experiment with it some more.

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  3. the tutorial it's very help me, thanks

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  4. Have you tried using only 1 aquarium air pump?

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    1. yes but the airflow wasn't smooth and the paint had to be extremely thin to even flow out of the airbrush.

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    2. Last question.. can you spray primers with it? I'm planning to use mr surfacer1000, any ratio rwcommention for thinning. Thnx

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    3. I didn't even attempt primers as the air output is low compared to an actual airbrush compressor, but I guess if you add more pumps and thin properly you can pull it off.

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  5. Hi. Thanks for this guide. Will definitely try it.

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  6. Hi! I really want to do airbrushing however, I also want to buy a cheap compressor for now. I came across shopee and found this, will it work? or do I need to get additional "tools" or "gear" to make it work for gunpla. Would appreciate an opinion :)

    https://shopee.ph/Total-Auto-Mini-Air-Compressor-140PSI-Heavy-Duty-(Green)-i.22568331.264882482

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    1. No it will not. That compressor is designed to inflate tires, and as such the PSI output is too high, cannot be controlled, has no auto stop feature built in, and is meant to run for a short period of time only. You're better off with a couple of aquarium pumps paired with a single-action airbrush.

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    2. Thanks for the reply! Good thing I didn't buy this :D Are you still using this setup? (probably not), but how long did you use this setup? :)

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    3. I used it for over a year I think, then I upgraded to a Hobbiworkz compressor with a tank.

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