_GOTOBOTTOM
AFV Painting & Weathering
Answers to questions about the right paint scheme or tips for the right effect.
Hosted by Darren Baker, Matthew Toms
A possibly stupid question :)
Hisham
Visit this Community
Al Qahirah, Egypt / لعربية
Joined: July 23, 2004
KitMaker: 6,856 posts
Armorama: 6,363 posts
Posted: Saturday, August 29, 2015 - 05:16 AM UTC
I was wondering if the temperature in the room I'm spraying in has any real effect on the performance of the AB and how quickly acrylic paints dry causing dry tip and a coarse surface? These days in summer I always have the AC on and the temperature in the room is always between 18-20 Celsius or 65-68 Fahrenheit.. Is this better for spraying, or is warmer, more humid weather better? Or does this have no effect on spraying acrylics?

Hisham
Tojo72
Visit this Community
North Carolina, United States
Joined: June 06, 2006
KitMaker: 4,691 posts
Armorama: 3,509 posts
Posted: Saturday, August 29, 2015 - 05:26 AM UTC
I think the humidity has more of an effect,unless your talking drastic temperatures either way.
Robbd01
#323
Visit this Community
Arizona, United States
Joined: February 13, 2013
KitMaker: 791 posts
Armorama: 344 posts
Posted: Saturday, August 29, 2015 - 07:50 AM UTC
Hisham, we both might have the same issue. I live in the desert southwest US and when I am spraying acrylics, the stuff is almost dry as it leaves the airbrush. I think humidity has a lot to do with it more than temperature. I think a little more humidity does help but not too much. In my house in the summer time when it hits (hang on I need to convert to Celsius) 42ish Celsius, my inside temp is around 26C. Some of the things I have done is 1) early morning, take a shower and after the shower paint in the bathroom (a real pain). 2) I have taken a medium size pot of boiling water and put it in my modeling room for a bit before I paint (not too bad). But lastly with acrylics I add a retarder which seems to be the most consistent. This seems to keep down the surface looking like an 'Orange Skin'. I have also taken to painting in the middle of the night. In the end if I can do it with enamels I will. Hope this helps but just remember, you are not alone

Cheers
panzerbob01
Visit this Community
Louisiana, United States
Joined: March 06, 2010
KitMaker: 3,128 posts
Armorama: 2,959 posts
Posted: Saturday, August 29, 2015 - 08:44 AM UTC
Guys;

It's the humidity, or lack thereof. And AC units (NOT evaporative "swamp-coolers") suck moisture from the air.

Dry air at any temp will speed up your drying. Warmer dry air will of course dry stuff faster.

IF you suffer low humidity and too-fast drying as you spray, you can really help things out by getting one of those cheap table-top vaporizer units people buy to add humidity in their bedrooms, or get a room humidifier if your spray-booth is in a larger space. Added humidity plus some retardant will slow drying down a LOT.

I currently live in soggy south coastal Louisiana... But I'm an old 'zonie (Prescott and Flagstaff) and know by withering experience the dryness! And I'm returning to Prescott in a few months for retirement... A humidifier for the hobby-space is on my to-buy list!

Cheers!

Bob
retiredyank
Visit this Community
Arkansas, United States
Joined: June 29, 2009
KitMaker: 11,610 posts
Armorama: 7,843 posts
Posted: Saturday, August 29, 2015 - 11:42 AM UTC
There is no such thing as a stupid question.
gaborka
Visit this Community
Borsod-Abauj-Zemblen, Hungary
Joined: October 09, 2005
KitMaker: 626 posts
Armorama: 250 posts
Posted: Sunday, August 30, 2015 - 01:01 PM UTC

Quoted Text

I was wondering if the temperature in the room I'm spraying in has any real effect on the performance of the AB and how quickly acrylic paints dry causing dry tip and a coarse surface? These days in summer I always have the AC on and the temperature in the room is always between 18-20 Celsius or 65-68 Fahrenheit.. Is this better for spraying, or is warmer, more humid weather better? Or does this have no effect on spraying acrylics?

Hisham


Humidity will not directly affect the airbrush, but it will indeed influence the performance of your compressor and also the quality of the paint coats. Humid air has higher density so the compressor must work harder to compress it so it will produce the required pressure slower, again contributing to compressor overheating. Also wet condensate is produced in a higher rate, that might get into the airflow and thus into the paint, which is unwelcome - it will cause a rough surface with acrylics and a completely distorted texture with enamels. Keep your air filter dry, if necessar add a secondary mini filter directly to the airbrush intake valve.

panzerbob01
Visit this Community
Louisiana, United States
Joined: March 06, 2010
KitMaker: 3,128 posts
Armorama: 2,959 posts
Posted: Sunday, August 30, 2015 - 06:56 PM UTC

Quoted Text


Quoted Text

I was wondering if the temperature in the room I'm spraying in has any real effect on the performance of the AB and how quickly acrylic paints dry causing dry tip and a coarse surface? These days in summer I always have the AC on and the temperature in the room is always between 18-20 Celsius or 65-68 Fahrenheit.. Is this better for spraying, or is warmer, more humid weather better? Or does this have no effect on spraying acrylics?

Hisham


Humidity will not directly affect the airbrush, but it will indeed influence the performance of your compressor and also the quality of the paint coats. Humid air has higher density so the compressor must work harder to compress it so it will produce the required pressure slower, again contributing to compressor overheating. Also wet condensate is produced in a higher rate, that might get into the airflow and thus into the paint, which is unwelcome - it will cause a rough surface with acrylics and a completely distorted texture with enamels. Keep your air filter dry, if necessar add a secondary mini filter directly to the airbrush intake valve.



Absolutely correct - regarding the compressor and supply of air to the AB. You want the air supply to the AB to be as dry as possible, and one or more moisture-traps are the way to go to keep water from getting into the AB. Water condenses and collects in your compressor tank (if you have a tank compressor) and needs to be drained from time to time. And whether you have a tank or not, water will blow through into your air-line - so get a moisture trap right at the compressor outlet to keep water out of your hose. IF you are in a more-humid environment, and additional moisture-trap at the AB end of the hose is a good idea.

But the problem of water in the AB line and its impact on AB performance and painting is distinctly separate from the effects of very dry room air on the rate at which paint dries as it leaves the AB. Water in the AB can cause all kinds of sputtering and water-gapping in paint-flow - always ruinous to the finish, whether you are using oil enamels or acrylics - and regardless of the air humidity in the spray room. Very dry air in the room accelerates drying, and in extreme cases the paint can actually partially dry right when it atomizes off the AB nozzle... leading to sandy and rough finishes and leading to paint-build-up on the nozzle and needle-tip. Treat BOTH issues!

Bob
TopSmith
Visit this Community
Washington, United States
Joined: August 09, 2002
KitMaker: 1,742 posts
Armorama: 1,658 posts
Posted: Sunday, August 30, 2015 - 08:34 PM UTC
Most paint is designed to work best at "standard temp/pressure" meaning about 70 degreed F and sea level. Like others have said humidity plays a big part. If the air is dryer in your location you might benifit from some paint retarder for your acrylics. It slows the drying time to compensate for atmospheric issues.This would allow fewer problems with paint drying before it hits the surface and allow a smooth coat of paint although it would extend drying time some.
Hisham
Visit this Community
Al Qahirah, Egypt / لعربية
Joined: July 23, 2004
KitMaker: 6,856 posts
Armorama: 6,363 posts
Posted: Sunday, August 30, 2015 - 11:51 PM UTC
Thanks for all your advice, guys.. I ordered some paint retarder, but it takes at least three weeks for things to get here.. and of course Tamiya paints are now only sent by surface mail in HK where I buy all my stuff, which means three months

Anyway, I just hope the retarder will make a noticeable difference because I've tried everything, including buying a good Iwata AB (and that's another story ).. and now I'm at mu wit's end regarding getting a decent coat of paint using true acrylics!

Hisham
 _GOTOTOP