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TonyD

Basic Airbrush Questions

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I have a Paasche VL airbrush and D500 compressor that I bought probably 30 years ago and haven't used in maybe 15 years. Decided to break it out this week.

I took it apart, cleaned it and set it up to spray water. Looks like its working fine, and now to try some paint.

But first I have some questions that date back to my last sessions using the tool. I did a search for 'airbrush techniques and basics' but didn't return any relevant results.

I've read that 20 psi is a good starting point for spraying pressure. I have my regulator set to 20 psi at 'idle', but I notice that the pressure drops to approx 10 psi when flowing. Is this OK?

Typically my paint jobs are not very big so I've only used the open spray cup (1/4 oz.). In the past I would use a pipette to put a couple drops of solvent in the bottom of the cup, followed by paint from the bottle, and then finish with a few more drops of thinned paint from the pipette. (After taking paint from the bottle and delivering it to the spray cup, I put the 'dirty' pipette in a small bottle of thinner, draw some up and put that mixture in the cup.) Then I use a toothpick to mix the paint in the cup. I figure the initial drops of solvent should be the first thing to go through the spray tip if I don't mix it completely for some reason. I would love to hear your comments on this! Of course I have thought of pre-mixing the paint,  but this seems like it would waste more paint than I actually sprayed (transferring from mixing bottle to spray cup).

I bought an airbrush holder; U-shaped wire thingy, but it seems no matter how I place it in the holder, between the hose fitting on the bottom of the brush and the spray cup, it won't sit like I would like it to, i.e. ready to pick up and use. I need to keep the spray cup off the brush and insert it after taking it out of the holder. Did I just buy the wrong type? The holder that came with the airbrush is sheet metal and actually works great, but it needs to be mounted flat to the work table whereas the wire one mounts to the side and holds the brush above the table.

Finally, clean-up. I will usually pour any remaining paint from the spray cup back into the bottle. I have a jar with thinner ready that is large enough to immerse the spray cup and I put it in there to soak. I also have the 1 oz glass spray bottle ready with thinner and insert that into the airbrush and spray into a rag until clear. Paasche's instructions say I only need to remove the needle and clean it, so that takes care of the brush. But that leaves the following items to clean: spray cup, jar that it was soaking in, small thinner jar that got contaminated when I put the paint pipette into it, the pipette, and the 1 oz spray jar I used to clean the brush because inevitably when I remove it some color backflows into the bottle. Plus of course the mixing bottle if I used one.

And this needs to be done for each color change. No wonder I haven't used it in 15 years! Am I making a bigger deal out of this than needs to be?

Looking forward to your feedback.

 

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Interesting experience. I cannot answer to the air pressure thing, but I can offer a suggestion for the cleaning aspect. I too pour any remaining paint into the jar it came in. I also have two of the airbrush cleaning bottles that you can spray into to remove anything in the brush. One I use when I'm cleaning out the cup. They way I clean my cup is this: first I get a small spray bottle with an adjustable nozzle and set it to 'stream' and I fill it with Lacquer thinner. You can use any cleaning medium you wish. The small spray bottle I use can be gotten from one of those stripper kits for stripping shellac from wood surfaces. After clearing the interior of the airbrush by spraying it into one cleaning bottle; I then tip the airbrush cup over the mount of one of the cleaning bottles and spray the stream of thinner in the cup, letting it run out and into the cleaning bottle. I keep spraying until it runs clean. Then I add some more thinner/cleaning agent to the cup, cover the needle end with a paper towel and backflush the brush. I then pour out the remainder and spray the remaining interior cleaner into the other cleaning bottle. I repeat until the backflush comes clear. After that; if I still need to break it down to clean, I do.

 

Sorry I couldn't be more help with the rest of your questions. Hopefully soon, others will be here to offer more excellent advice.

 

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Pressure drop is normal to characteristics of inexpensive compressor, not a high flow one assuming it has no storage tank on it?  Should still work fine.  Good upgrade is a carbon dioxide tank or a shop compressor with tank on it.  I have an old Craftsman/Sears compressor which is bulletproof and inexpensive to maintain.

Edited by Mister300

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Thanks for your reply. Yes,  I am not using a storage tank.

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I would not worry about it the spray pressure depends on your viscosity and media etc.

 

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I usually set my pressure with the trigger depressed--it gives me more of an idea what the pressure at the gun will be when I'm spraying. 

I used to return thinned paint to the original jar, until I had several jars solidify or turn to jelly on me after a day or so.  I learned then that if I wanted to save extra paint to do so in a clean jar, that way the original won't be compromised.  I've had this happen with both enamels and acrylics, the lacquers don't seem to have this issue.

I use acrylics almost exclusively these days, so after each color I'll start by spraying cleaner through the airbrush until it comes out relatively clear.  Then the airbrush gets field stripped (head assembly comes off, needle and nozzle get pulled)--not so much because I'm afraid one color will pollute the other, but because as the acrylic dries, it can clog the gun and create additional clogs.  I wipe the parts down, reassemble the gun, and then spray airbrush cleaner through the gun again.  I use Iwata's cleaner--I used to think it and needle lube were nothing but snake oil that the airbrush manufacturers sold, but once I started using them, I won't stop.

Beware that using ammonia (or products containing ammonia like window cleaner) to clean an airbrush might void the warranty--I know Grex says this, and Badger says to flush it out with water after using ammonia.  Ammonia erodes the plating and will oxidize the brass.  Several people I know ruined their Iwata airbrushes by using WIndex--after repeated use, the nozzle froze in the body, and when they tried to remove it, it broke off at the threads.

Oh, and if you use acrylics, don't use alcohol--alcohol is a drying agent and will cause the paint to dry inside the gun.  Or that's what Badger says--and seeing as they've been in the airbrush business for many, many, years, I have little reason to doubt them.

Once a year, I will do a full strip and clean using lacquer thinner to get any residual paint out of the nooks and crannies.  At this time, I examine all seals and gaskets and replace them if they are worn.

Cheers!

Ralph

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Thanks for all the comments. It looks like what I'm calling the hassle of cleaning is 'the nature of the beast' if I'm going to use an airbrush. If you've stumbled on any of my previous posts, I'm recently retired and have accumulated a number of kits and supplies and am getting back into modelling. Unfortunately, a lot of those supplies are enamel paints - Testor's and Model Master. I haven't tried acrylics yet and maybe I should as it seems like it would be easier than handling all that laquer thinner!

Keep 'em coming! I'm still waiting for suggestions on mixing/thinning paint prior to airbrushing.

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I use the Passche H1 single action airbrush with siphon tube from “ bottom load” paint bottles. I use Model Master enamels and, now, Trucolor. I have used this airbrush exclusively since my Bink’s Wren died many years ago.

I think of the H1 as the AK 47 of airbrushes- simply, sturdy, forgiving and reliable. Spare and replacement parts are easy to find. I follow Ralph’s regimen for cleaning between colours and for periodic field stripping. I clean the MM with Mineral Spirit- it is relatively low in toxicity. Trucolor must be cleaned with acetone. I vent my spray area when cleaning with both.

With respect to spray pressure, I do not even know how accurate those gauges are. The best pressure to spray with is that which takes into consideration paint brand, paint thickness, compressor characteristics, humidity, temperature, airbrush tip size and, most importantly, what effect you are trying to achieve. In other words, the best approach is to practice  on scrap plastic until you get the result you are seeking. Experience and mistakes are the best teachers.

Regards, Nick

 

 

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