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G-Man

Humidity and Painting

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Last night I was trying to prime some pieces of my Ju87, but the paint kept splattering. I was using Mr. Surfacer 1200, mixed with Gunze Leveling thinner at 1:1. Airbrush was set around 12-15 psi. It would spray smooth, then splat. I then checked the weather and humidity was at 93%. Am I right in assuming the high humidity was causing my issues? I stripped my brush down completely and cleaned it just to make sure nothing was clogging it up.

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Well, to put it this way, they don't make extra moisture traps, etc., for the airbrush compressors for no reason.

 

For that reason, I bought the Paasche in-line moisture trap they sell at Hobby Lobby.

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If the "splat" is water, then yes, humidity is your issue. To solve that issue an in-line water trap is advised. If the "splat" is not water, then you have some other issues. It's hard to diagnose your problem without knowing what the "splat" actually consists of. 

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Posted (edited)

It's from the leveling thinner. 1:1 sound pretty thin. Try adjusting the amount of leveling thinner until you nail it between splattering and web effect. I always eyeball it, but could say the Surf is something like 55-60-65 % ... Just a drop more than the 50/50 ;)

Edited by F`s are my favs

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Well, to put it this way, they don't make extra moisture traps, etc., for the airbrush compressors for no reason.

 

For that reason, I bought the Paasche in-line moisture trap they sell at Hobby Lobby.

I was considering getting one of these. I have a moister trap on the compressor, it was empty though. I checked it a few times during spray outs. I have read that an in-line trap is better to have.

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It's from the leveling thinner. 1:1 sound pretty thin. Try adjusting the amount of leveling thinner until you nail it between splattering and web effect. I always eyeball it, but could say the Surf is something like 55-60-65 % ... Just a drop more than the 50/50 ;)

I will add more Mr. Surfacer to the mix tonight to thicken it out some.

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Generally humidity is a good thing unless its in your airlines. I have found my best finishes come when the humidity is high and the paint is thinned properly, although my moisture trap definitely is working. From what I understand, humidity slows down evaporation and drying time, but you will need to compensate with dry time.

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If your "spiting water" and in line water trap might be needed. But let me ask:

When was the last time the tank on your compressors was drained and cleaned out? I'm willing to bet it's loaded with water.

Nope, never really had a problem with moisture and high humidity and painting - just seems to effect drying times a bit.

Peter

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If your "spiting water" and in line water trap might be needed. But let me ask:

When was the last time the tank on your compressors was drained and cleaned out? I'm willing to bet it's loaded with water.

Nope, never really had a problem with moisture and high humidity and painting - just seems to effect drying times a bit.

Peter

There's no tank, just a small Master compressor with a moisture trap.

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Posted (edited)

I was considering getting one of these. I have a moister trap on the compressor, it was empty though. I checked it a few times during spray outs. I have read that an in-line trap is better to have.

 

The reason is that the problem with compressor mounted moisture traps is that the heat from the compressor keeps them from really trapping the moisture effectively.

 

The compressor's heat keep the moisture as vapor (steam) instead of letting it condenser into water and be drained out of the cup.

 

By having the trap away from the compressor's heat, it works much better.

 

That was one reason I bought the Sparmax 2000 from Hobby Lobby (@ 40% off, of course), where the filter/regulator/trap is mounted independently hosed from the compressor.

Edited by Gigant

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Ok guys, I got it spraying right with the 60:40 mixture. Humidity was lower today also. I will also still purchase an in-line trap as well to avoid future issues. But I'm very happy to finally have my nose and landing gear primed up, this build has been a chore.

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Guest Paul Budzik

Your airline carrying hot air from the compressor to your airbrush works like a condensing coil ... so the moisture trap should be as close to the airbrush as possible ...

 

Airbush-Manifold.jpg

 

Like this ...

 

Paul

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