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PSI for airbrush and House of Kolor


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I spray at 23 to 25 psi for everything, and have had zero problems to date.

That's about what I use, too. Although I go by what feels right and/or works, and don't pay all that much attention to the actual numbers.

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There is no fixed rules for airbrushing (like paint viscosity, pressure, nozzle size, distance from the surface being painted, etc., etc.).  There are too many variables (including the model of the airbrush).  Some people use 40psi, others use 16psi (and many other pressures in between). It can even change depending on a particular paint job or paint.  Sometimes I even change the paint pressure during a painting session (lower the pressure to get the paint in some tight corners, then go back to higher pressure for the larger flat areas). To me every airbrushing session is different.  That is what makes the task of airbrushing so flexible (unlike using a spray can).

The way I see it, in order to become good with airbrushing you need to practice and determine what works best for you. Sure, you can pick up some tips from other modelers, but in the end it is really you who will choose the technique which works best for you.

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first let me say thank you all for the replies. I was really pumped up to get started airbrushing. Thinking with knowledge of painting full sized cars that it would help. Gotta think small now! time this past weekend was a disaster turned learning lesson. Used spray can duplicolor  grey primer earlier in the week. Paint day was maybe too cool to started too early at 63 degrees. Sprayed house of kolor orion silver that was ready to spray for an airbrush. It sprayed beautifully at 30psi. Let it sit about an hour and it felt dry. Then topped it with some autoair candy 2.0 blood red, same psi. Wow it was like red chromed finish. It started to wrinkle up so I moved it into the sun, had turned to about 72 degrees now. Photo looks better than actual model. Still had slight wrinkles but figured it was a learning lesson. Cleared with can tamily ts13. It sort of looks like old dried alligator skin now. Guess I need to slow down and allow more time between colors, coats, etc. Did learn to clean my airbrush really well. Getting another donor model ready to try again. Any ideas or any step by step tutorials? thanks!

IMGP4439.JPG

Edited by DrewCfromSC
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I tried rushing things when I started airbrushing and got some weird results to say the least. I now let everything dry at least a week before I move on to the next step. Results are more consistent now.

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Ray mentioned the "holy trinity" of painting as viscosity, pressure and distance.  Add temperature and humidity to the equation and you have all the factors that affect airbrushing.  Unfortunately if you are looking for a single answer to each of these, that doesn't exist.  They all interact and a change in one requires adjustments in the others.  This is the one piece of advise that I give to all beginners:

START A JOURNAL!  Get a notebook(or your could use a computer with a spread sheet if you want to get all geeky on us) and make a column for each of these and one for comments.  Each time you paint do the following.  Measure(and I don't mean eyeball it.) the ratio of paint to thinner(viscosity), and spray with a fixed pressure.  See the result and comment on it.  Then try the same thing but change the pressure and see what happens.  Do this multiple times and you will find a sweet spot for pressure at a given viscosity, temp and humidity.  If you do this every time and write it down, you will have a guide for painting that you can follow.  Since you can't generally control the temp and humidity, you need to do this over time to get a feel for what happens.  Never change more than one variable at a time.  Otherwise you will just get confused.  

I know a lot of builders use the back of plastic spoons to test paint and that is good and cheap.  However you can go online to different paint shops and they have a thing called a speed form.  It is about the size of a small model car and is great for testing paints.  If you have been in a paint shop, you may have see them mounted on a board showing off a manufactures paint.    You can often find them on sale for less than ten cents each.  I buy them in packs of 100.  That many will last you for a long time and they give you a good view of what your paint will look like on model. 

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Pete is right on!!!! Their would be fewer trips to the pond if any! IMO if more builders would prepare like 1:1 you wouldn't see as many paint problems on the forum.

Mix the paint as per recommended instructions... They really do print the directions for a reason..... It works! 

Little adjustments can be made to reduction, I try not to add more than 10% more reducer than recommended....The only exception to that rule I break is when doing fine detail Airbrush work with White, However that is 1:1.

Pete, Thanks for sharing your knowledge! Great post!

Jimmy "RASS" 

 

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A post script on my prior posting. 

 I have been experimenting with HOK urethane automotive clear with mixed results.  I mentioned it the last time I was a Coast Airbrush in Anaheim and they said they absolutely mix that with equal parts reducer and paint instead of the 3:2:1 that is used for full sized guns.  You have to keep the hardener the same ratio to the paint.  I have not tried it yet, but they are definitely experts on the stuff.

Edited by Pete J.
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thank you all for the information. Don't know how to reply to individual posts?  Got to do a little with create acrylic airbrush paint this weekend. Like the easy clean up and low low fumes. Not much done between rain showers. Did try a chart of booth temp and humidity. any ideas how to lower humidity? Its been about 60% with the rain were getting.

IMGP4437.JPG

Edited by DrewCfromSC
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Ok, this is going to be a little wierd science here.  The humidity that we are all familiar with is "relative" humidity.  It is a percentage of moisture saturation at a given temperature and pressure.  Since you can not do anything about the pressure, I will not bother discussing it.  So that means that with local humidity, you can lower the relative humidity by raising the tempurature, or put a heater in your space.   You can also buy dehumidifiers, but the room needs to be close and that is not a good thing when you are painting. Sears sells them but they are not cheap.  The other option is to use an air conditioner and a heater(which is what a dehumidifiers is).  You cool the air off and the moisture condenses on the coils of the AC unit, then you warm the air back up and your humidity it lower.    Frankly, none of these is a great choice when you are talking about model building and airbrushing because of the small scale of the operation.  

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  • 8 months later...

IMG_3875.thumb.PNG.50cd28181b43d823cc6ecHowdy, 

i recently switched from building military aircraft to Hotrod type Vehicle builds. Painting aircraft was very forgiving compared to that of the A/B finishes I'm now doing on cars. It became obvious that I needed to get into a better  more CONSISTENT AB PAINT SET, & ive been looking at HOK - ZERO  & GRAVITY. I've made a recent friend with a local longtime builder & paint expert that uses Exclusively HOK! I'm curious what your recommendations would be for a starter kit for me. My next several kit builds will be color schemes that aren't too crazy.... (as in no flames-heavy metallic flake-) but mostly looking for the DEEP GLOSSY Purple-Red-Metallic Blues & in that arena.... ALSO the CLEAR COAT U would recommend with this system.

much thanks!

Lee

**the photo attached was my 1st FC & 1st ever Contest entree.

Edited by Droneoutlaw
missed photo
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I know a lot of builders use the back of plastic spoons to test paint and that is good and cheap.  However you can go online to different paint shops and they have a thing called a speed form.  It is about the size of a small model car and is great for testing paints.  If you have been in a paint shop, you may have see them mounted on a board showing off a manufactures paint.    You can often find them on sale for less than ten cents each.  I buy them in packs of 100.  That many will last you for a long time and they give you a good view of what your paint will look like on model. 

SPEED FORMS!!!! ?I've been seeing those things on every well made AB painting Demo on YouTube. In the back of my mind I always thought to myself....mmmmm??I wonder how they make those (car blanks). Thanks for that TIP!!!???

Lee

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