ModelFlex, what primer?

[central.vermont]

I had this same problem and I found out is was the humidity in the air that was giving me problems. I put an air drier in my system and the problem went away for me.

Jon

[learmoia]

To clarify, you mean humidity in the compressed air moving through the airbrush....

~Ian

[central.vermont]

Yes. When the humid air is compressed it will form micron sized water droplets that move with the air through the brush and is expelled under pressure causing a splatter effect of the paint when it contacts the subject being painted.

Jon

[peteski]

Yes. When the humid air is compressed it will form micron sized water droplets that move with the air through the brush and is expelled under pressure causing a splatter effect of the paint when it contacts the subject being painted.

Jon

Yes, that is a big problem with the "stinky" organic-solvent-based paints.  As the air decompresses and cools down when coming out of the airbrush nozzle it causes the water vapor in the in the air to condense into microscopic droplets.  Those can end trapped in the paint, ruining the paint job.  Also when the volatile solvents (like acetone) evaporate from the paint freshly applied to a model, that cooling effect can cause moisture from the air to condense on the paint surface causing blushing

But I thought that with water-based paints this would not be a big problem (since water is one of the ingredients in the paint's solvent).

[Big Train]

While water is part of the acrylic paint formula, the problem with water in the air line is that it is insufficiently atomized. Sometimes after air brushing, the water trap will have anywhere from a 1/4 to 1/2 a teaspoon of water pulled from the compressed air. That amount left inside an air line will sputter out eventually. Usually after you almost finish laying down a perfect coat of paint.
 

[amato1969]

As far as primers are concerned, I tried everything before using Badger's Stynylrez (weird name, I know) but it works. Easily the best acrylic primer I've every used through an airbrush. That is my go-to primer now.

Truth!  This is also the primer I use exclusively; goes on smooth every time, and provides a great base for airbrushing or brush painting.

  Frank

[thomasjmdavis]

I have one of these
https://www.paascheairbrush.com/product/r-75/
attached to my airbrush hose.  I have found the ideal set up for me is - compressor- water filter- regulator set to 70-90 lbs - airline hose- quick connect- Paasche filter/regulator set to 22 lbs- 6' hose- airbrush.  Lets me keep the compressor in another room so the noise is not so bothersome, have pressure control at the workbench, and the second filter catches anything that condenses in the 25-50 hose run or any gunk that made it through the first filter.  If I need to fill up a tire, just disconnect from the Paasche regulator, and when I reconnect, the pressure to the airbrush will be exactly the same.

[diezmon]

yeah, i should probably try the moisture trap next. I don't have one.  I'd never had problems before without one, but I'm in a new house with new humidity and using my same nail gun compressor.    I guess I'd be surprised if there's not moisture in there.

I'll try that next

[Lemosteam]

It would be a good idea to drain the compressor tank to if you have not done so already.

[MK]

yeah, i should probably try the moisture trap next. I don't have one.  I'd never had problems before without one, but I'm in a new house with new humidity and using my same nail gun compressor.    I guess I'd be surprised if there's not moisture in there.

I'll try that next

I hope it's an oil less compressor as most nail guns require oil.

[diezmon]

I hope it's an oil less compressor as most nail guns require oil.

it is indeed.

[peteski]

It would be a good idea to drain the compressor tank to if you have not done so already.

My compressor (with 4 gal. storage tank) directs the user to drain the tank daily.

[wazzou]

It is such a pain in the a$$ though.

[peteski]

It is such a pain in the a$$ though.

But a bursting tank, due to corrosion, could be even bigger pain in the a$$.
Mine is not that difficult to drain.  I have my compressor sitting on a piece of plywood with casters. To drain it I simply tilt the compressor so the drain cock is on the bottom of the tank and open it.  I just make it a routine task after using the compressor, before putting it away.

[diezmon]

But a bursting tank, due to corrosion, could be even bigger pain in the a$$.
Mine is not that difficult to drain.  I have my compressor sitting on a piece of plywood with casters. To drain it I simply tilt the compressor so the drain cock is on the bottom of the tank and open it.  I just make it a routine task after using the compressor, before putting it away.

Yep, mine's right on the side/bottom too.  It's a small tank, and i can't remember the last time I drained it.  heh.