Expert: Ellen Choate - 8/1/2010

Question
QUESTION: Hi, I'm using colored, melted cocoa butter as 'paint' with my Iwata Eclipse. The cocoa butter must be at a very specific temperature when I spray or the end result is ruined. When melted properly the cocoa butter is a bit thicker than average paint thickness. I use an Iwata Studio Series Sprint Jet compressor that starts at about 60psi and then drops to 20 - 30psi when I start to spray. My problem is the spray usually takes awhile before it kicks in and then is very sporadic. The 20-30psi delivers a very mild spray while I'm looking for a quick, smooth, relatively high-volume spray to protect my temperature. I know it's a unique circumstance but do you have any suggestions? Also how do I best clean the airbrush after use with food-safe products?
Any help is greatly appreciated.
Thanks,
Mark

ANSWER: Hi, Mark!  I don't have specific experience with cocoa butter airbrushing, but I think everything is analogous enough to what I know.  Let us explore:

It sounds to me like a pressure problem, alas.  For higher volume spraying, you really need a working pressure of at least 45psi, and since your material is thicker and probably more viscous, you should probably go a bit higher, 55-60.  I work at 60 on absorbent materials, 40 or less on hard surfaces where the paint will bounce off and just produce more overspray. Set your pressure gauge while spraying air; that will give you a more accurate working setting. Truly, the best long term fix is a larger compressor with a tank, not a diaphragm compressor. You can find them that are less noisy.

If your compressor won't give you more pressure, the only things to do besides getting a bigger, tank compressor are thin your medium or try a bigger airbrush tip (cone) and needle.  If you change the tip you must also change to the corresponding size needle.  If you can thin the cocoa butter with maybe oil or ghee (clarified, liquid butter), that would fix the issue, I'm sure. If not, you'll have to find a way to get more pressure.
The sporadic spraying you mention is most likely due to the diaphragm compressor; these do tend to give you a pulsing effect, especially at lower pressures.

As far as cleaning, since your medium is greasy, I think it would work to spray hot soapy water through, then plain water if you need to clean while working.  For an end of the day cleaning, I would first spray through with hot soapy water to remove most of the cocoa butter, then disassemble and give Mr. Airbrush a good soak in hot soapy water for a couple hours.  Overnight will not hurt it contrary to what you may have heard.  I do it frequently.  Rinse thoroughly before reassembling and make sure it's dry since you are using an oil based medium.

There ya go!  If you have any other questions or need help with compressor recommendations, please contact me again.  I know sometimes you need a quick fix for a project, other times it's a permanent fix for a recurring problem.  I hope this helps!
Ellen

---------- FOLLOW-UP ----------

QUESTION: Hi Ellen, Great advice. I started looking for compressors with tanks and quickly became overwhelmed. Can you advise? I'd like something as quiet and inexpensive as possible but that can handle your recommended psi settings.
Thanks very much.
Mark

Answer
Mark, the last compressor I bought was a 2hp Ranger, but they don't make these anymore :(  Too bad, too, because it's relatively quiet and has been reliable.  Craftsman used to be good, but the newer ones are really noisy.  Check out a smaller horsepower--3/4 to 2 HP-- with as big a tank as you can get. Consider the CFM at your desired pressure, cubic feet per minute.  Mine is 7.0 CFM @ 90psi, 2HP with a 10 gal tank. This helps keep it from coming on as often and ensures that it will handle the use you're going to give it. You can get something like this for 200--300 bucks and it should last you five or 10 years, even with daily use. For food usage, I think an oilless one would be better, and put a water trap on your airbrush hose if you don't already have one.  This keeps moisture from the condensation in the tank from traveling through the hose and splatting onto your almost finished wedding cake. Drain the water from the tank daily to prevent rust.

As far as the noise levels, the specs don't usually tell you the decibel output, but sometimes you can find out from customer service.  Of course, you can also just go to the store and plug them in.  Think about putting it in a vented (for needed airflow) cabinet or box to dampen the sound if you find one you like at a good price but it's noisier than you want.

I wish I could tell you to go and get X compressor! It's perfect! Unfortunately, what you get will depend on your noise tolerance, budget and local availability. Do ya some Internet research.  This website I just found looks very helpful, has customer reviews, lists the CFM and some have decibel levels.  This compressor looks like a  real possibility to me:  http://www.northerntool.com/shop/tools/product_200419182_200419182  Customer review says it's quiet and sturdy, it runs 5.5 CFM at 40 psi which is decent and you can't beat the price!
Once again, thanks, and let me know what happens.
Ellen