I would make a habit of WARMING my airbrush paint by keeping them tightly sealed in capped squeeze bottles. I would store these in a larger container of hot water until I needed them.
Don is right... for some reason the air coming from the airbrush is cooled... I use a Binks Wren, Miller and have used a cheapy Harbor Freight.. with a Binks Compressor or Miller Compressor
my own rules of thumbs..
1. 70-90 degrees
2. humidity is less than 60%
3. Use retarder
4. warm the surface and airbrush (I use shop lights sometimes, but not too close)
5. When painting outside.. here in Washington, I don't paint before 10-11 AM and have had problems after 5 PM
6. If the surface appears "milky" stop and sand the next day carefully.. if he surface is dull, no problems.
7. I don't use an airbrush to apply clear.. just colors and put them on with light coats. It is easy to get carried away.
8. Don't spray too close to the surface, or too far away.. experiment on a practice surface first never spray on the "good" surface without testing first. Old Light Bulbs are great for tests..
9. Clean the surface well. I wash my hands and have used latex gloves.
10. I use Sig Retarder and Dave Brown Plasticizer
DOPE RETARDER - When Butyrate Dope is used in a high humidity environment, it will sometimes “blush” (meaning it will dry with a dull, milky finish). The best way to prevent blushing is to slow down the rate of drying by using Dope Retarder as a partial substitute for the regular dope thinner. Use only as much retarder as is needed, to prevent blushing, typically 25% to 100% of the normal thinner requirement. Dope Retarder should be used only in the last one or two coats of the finishing process. (I have used it all the way through but don't put 10% in .. 5 % or a little ess has worked for me..
Painting is something you have to learn... and most of us have paid our dues...
Flex-All
Flex-All is a plasticizer for lacquer, primer, and butyrate dope. In lacquer, it completely eliminates cracking and spiderwebbing. Also it aids in the gloss retention of the paint. When used with dope, it helps reduce shrinking. One bottle is enough for use on several airplanes.
Here are some other suggestions..
Hazing/Blushing
Hazing, associated with lacquers, appears as a cloudiness in the dried clear or pigmented film. This reaction is commonly found with lacquers when relative humidity conditions are high trapping moisture in the dried film.
If hazing develops, mist on a compatible lacquer over the film once the humidity level has decreased. The thinner dissolves the top layer of the lacquer film and allows the moisture to evaporate. The application of too much thinner will result in ruining the finish.
From a ship building site...
http://www.modelshipbuilding.com/buildship.htmIf hazing is experienced with Aero Gloss, once the humidity level has decreased, a compatible lacquer thinner should be applied in a fine mist to the dried film. The thinner dissolves the top layer of the lacquer film and allows the moisture to evaporate. This will eliminate the hazy appearance. The application of too much thinner will result in ruining the finish.
When hazing is experienced with Glosscote lacquer, apply mist applications of the Glosscote when the humidity level decreases. The lacquer will dissolve the initial layer of lacquer and allow the moisture to escape.
http://theairbrushforum.com/http://www.woodweb.com/knowledge_base/Avoiding_Blush.html"To fix the discoloration, you can fog on a very light application of lacquer retarder or spray another coat of lacquer that has some retarder in it. A general rule for spraying lacquer (or shellac) is don't spray if the relative humidity is above 65%.
A more accurate guide is don't spray if the dew point is within 20 degrees of the ambient temperature. For example, if the dew point is 65 degrees and it's 80 degrees in your spray area, don't spray unless you use retarder. You need more than a twenty degree difference between the dew point and temperature to be safe.
As the solvents in lacquer evaporate, they have a cooling effect on the surface they're sprayed on (put a few drops of isopropyl alcohol on the back of your hand to feel the effect). The cooling effect can be as much as twenty degrees. If you cool the surface down below the dew point, water will condense on the surface and you'll get blushing – the milky white look in the lacquer/shellac.
Also make sure the piece you're spraying is the same temperature as the environment where you're spraying. I once made the mistake of taking a piece from an air conditioned space and spraying it in the outdoor heat. The piece was a lot cooler than the outdoor temperature and the finish blushed almost instantly. In order to spray lacquer in high humidity, you'll need to add lacquer retarder. Lacquer retarder is a slowly evaporating solvent (thinner) that lets the moisture escape from the lacquer before it dries. Only use a small amount of lacquer retarder in place of the regular lacquer thinner. Use the same brand of retarder as the lacquer you're spraying and only use as much as the manufacturer recommends. For example, if you usually thin the lacquer 15% with lacquer thinner, and the manufacturer recommends 5% retarder, switch to 10% lacquer thinner and 5% lacquer retarder (15% total thinning as usual). Adding lacquer retarder causes the lacquer to dry more slowly than usual. Spray your coats a little lighter to avoid runs and sags and allow more time between coats."
Here are some fun things to view..
Airbrushing - simple flames - airbrush - learn how to airbrush
Airbrushing Bullet Holes - killer airbrush technique
Airbrush Techniques : How to Use an Airbrush, Basic Techniques
Jim
Topic: Air Brush Problem (Read 2865 times)