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Argh! Airbrush woes!

Argh! Airbrush woes!

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9 replies

PreacherTim

Member since
January 2004
From: Ponce, Puerto Rico

Argh! Airbrush woes!

Posted by PreacherTim on Wednesday, August 11, 2004 11:13 PM

Hey all;
I really enjoy reading the forum!
I recently bought a Badger 150 (my first airbrush) and I really like it Big Smile [:D]

. However, I have been having difficulty with a powdery residue or "dust" that appears on my model (1/48 Monogram F-14D) when I try to apply a matt finish paint such as mm light grey (underside) and mm dark ghost grey (on the upper.) The conditions I am spraying under are as follows: I mix my paints at a 4/1 ratio (as suggested in another thread) using a "general purpose" acrylic thinner that is readilly available here in Peru (cannot purchase a good quality thinner such as laquer thinner or similar 'cause they just aren't used here); I have experimented with setting my air pressure as low as about 15psi and as high as 35psi; have tried light coats, medium and heavy coats as well; all with the same results. Namely, that pesky "dust" Banged Head [banghead]

. I have used 4-aut (0000) steel wool to remove the dust and smooth out the finish, with some interesting results Thumbs Up [tup]

, but would prefer to have a good coat the first try. WHAT AM I Dunce [D)]

DOING WRONG? I looked, but did not find a previous thread on this. I'd appreciate any help/suggestions. My 2 cents [2c]

Tim Schmidt

MikeV

Member since
April 2003
From: Hayward, CA

Posted by MikeV on Wednesday, August 11, 2004 11:28 PM

Tim,

Let me get this straight, you are using Model Master enamels with a "general purpose" acrylic thinner? Maybe I misunderstood you and you meant you were using MM Acryl paints instead. Let's get that clarified first. Wink [;)]

I would also say that 4:1 is much too thick if that is a paint to thinner ratio.
I would prefer 2:1 to start and possibly 1:1 if that doesn't work.

Mike

“Wisdom is the right use of knowledge. To know is not to be wise. Many men know a great deal, and are all the greater fools for it. There is no fool so great a fool as a knowing fool. But to know how to use knowledge is to have wisdom. " Charles Spurgeon

Anonymous

Member since
November 2005

Posted by Anonymous on Wednesday, August 11, 2004 11:40 PM

Whoa, hold on there: you are using Model Master Acrylics or Acryl (new formula), right? I had to ask because you mentioned you were previously looking for "lacquer thinner" which is totally incompatible with acrylic paints, so please clarify. Anyway, assuming you're using acrylics thinned with acrylic thinner, it appears that your paint is drying before it reaches the model, which is what you see as grainy "dust". 15 psi is just right considering okay temp and humidity, so I assume you're spraying too far from the model. Spray no more than 1 foot from the model, 4-6 inches distance would be ideal. If the paint still dries too fast, you may need to buy and add a few drops of acrylic retarder (see your local art store if they have it) to prevent your paints from doing so. You can also try thinning your paint more to a 2:1 consistency. In any case, notify us of your progress. Hope this helps.

Cheers,
onyan

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jdavidb

Member since
August 2004
From: Kennesaw, GA

Posted by jdavidb on Thursday, August 12, 2004 12:49 AM

Acryl has its own thinner. So, wherever Tim is getting MM Acryl from (if that's what it is), they should also have the Acryl thinner. I'd first try no thinning at all if it is MM Acryl new formula. 70% Isopropyl alcohol will do as a thinner, but that is almost an accelerator. So, try to find out if it's a "drying before it hits the model" problem before trying alcohol as the thinner.

I'm wondering if it is bleaching pigment stuck to the thinner which is not compatible with the paint. The thinner could be in the paint, not mixed, just beading inside. Any pigment stuck to the beads of an overly powerful acrylic thinner might be getting whitened.

PreacherTim

Member since
January 2004
From: Ponce, Puerto Rico

Posted by PreacherTim on Thursday, August 12, 2004 10:51 AM

QUOTE: Originally posted by jdavidb
wherever Tim is getting MM Acryl from (if that's what it is), they should also have the Acryl thinner.

It is really lucky that the one "hobby shop" in Arequipa had Dark Ghost Grey...among the 11 other bottles of paint they had in stock. I cannot get the correct form of thinner, it simply is not stocked. Business thinking here is vastly diffrent than in the Good 'Ol USA. Modeling supplies can be a challenge (at best) to obtain. Black Eye [B)]

Ok; let's see if I can get this right this time. Smile [:)]

I am using Testor Model Master enamel paint and thinning it with a generic - or - general purpose enamel thinner. I know I wrote acrylic in my original post, Dunce [D)]

but I got the types confused (thinking enamel, typing acryl). Clown [:o)]

Oh yea, I forgot to ask this in my original post: The humidity here is practically non-existent. (>20% most days) Dead [xx(]

. I live approx. 8,000 ft. asl in what is regularly refered to as an high altitude desert. Temps are very mild never getting below 45 at night nor above 78 in the daytime. Wink [;)]

Do I still need a water seperator? I have never detected any moisture in any of the compressed air when I opene up the pitcock. ?? Question [?]

Tim Schmidt

Anonymous

Member since
November 2005

Posted by Anonymous on Thursday, August 12, 2004 11:01 AM

That sounds weird for enamels but it sounds like it is drying before it hits the Tomcat. Change your thinner ratio to 2:1 and hold your airbrush about 4-6 inches away from the model with your psi at about 12. If ya get the same Texture in your paint slowly drop the psi and see if that helps.

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jdavidb

Member since
August 2004
From: Kennesaw, GA

Posted by jdavidb on Thursday, August 12, 2004 11:43 AM

QUOTE: Originally posted by PreacherTim

It is really lucky that the one "hobby shop" in Arequipa had Dark Ghost Grey...among the 11 other bottles of paint they had in stock. I cannot get the correct form of thinner, it 8simply is not stocked. Business thinking here is vastly diffrent than in the Good 'Ol USA. Modeling supplies can be a challenge (at best) to obtain.

Ok; let's see if I can get this right this time. I am using Testor Model Master enamel paint and thinning it with a generic - or - general purpose enamel thinner.

If the thinner you're using is mineral spirits, that is the correct thinner for Model Master enamel. I've used 4 different brands, and they all worked. You could see if you get better results with a product labeled "mineral spirits" rather than general purpose thinner.

I have also tried Klean Strip TurpAtine, which is a turpentine substitute. It works, but it is too brutal once it hits common model plastic. It says on the bottle "thins oil based paint". It does do that, but go ahead & keep looking for a milder variety of mineral spirits instead.

PreacherTim

Member since
January 2004
From: Ponce, Puerto Rico

Posted by PreacherTim on Thursday, August 12, 2004 6:23 PM

If the thinner you're using is mineral spirits, that is the correct thinner for Model Master enamel.

Unfortunately, when I ask (even speaking in Spanish) for "mineral spirits" here, I get a glazed over look from the proprietor who thinks I'm looking for something religious. So far, no luck finding MS...just "teener" as it's called here. Confused [%-)]

I'm beginning to believe that it is the thinner that's the problem. Sigh [sigh]

Today, I tried painting a piece of plastic w/ the paint thinned 2/1, and then 1/1, at 15 psi, holding the ab between 2 and 3 inches from the subject...both with the same resultsthat "durn dust" Tongue [:P]

. I think the paint is drying too before it gets to the plastic. I'm at a loss, but determined to keep trying. Wink [;)]

Any more input would be appreciated. Big Smile [:D]

Tim Schmidt

MikeV

Member since
April 2003
From: Hayward, CA

Posted by MikeV on Thursday, August 12, 2004 7:24 PM

Tim,

It sounds like that thinner is too "hot" and is drying in the air.
Can you get any linseed oil in your area?
A few drops of it mixed into the cup with the paint and thinner can slow down the drying time similar to what retarder does for acrylics.

Mike

PreacherTim

Member since
January 2004
From: Ponce, Puerto Rico

Posted by PreacherTim on Thursday, August 12, 2004 8:33 PM

Thanks for the great idea, Mike! Since there is alot of woodworking/craftmanship here, I might be able to locate some linseed oil. I was told just tonight, that there might be a new artisan supply store i.e., painting supplies, open near "El Centro de Arequipa". I am going to check it out...with high hopes.

Tim Schmidt

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Argh! Airbrush woes!