Odorless Mineral Spirits Changing the Color of Paint....

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Thomas E. Johnson
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Odorless Mineral Spirits Changing the Color of Paint....

Post by Thomas E. Johnson » Thu Sep 08, 2016 4:29 am

I'm using enamel paints (MM) for the most part on my 1/200 Missouri. It has been about 20 years since I've used and airbrushed them. I thinned the Deck Blue with odorless mineral spirits for airbrushing, but it appears to have changed the color of the paint. More correctly, it seems to have lightened the color up by several shades, making it look more like Ocean Grey than Deck Blue.

Anyone else experience this when thinning with odorless spirits?
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NCC1966
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Post by NCC1966 » Thu Sep 08, 2016 7:34 am

I paint with enamels and never have seen it before, although I use regularly hardware store spirit (but used odorless spirit once). If it happened to only one paint is more likely to me that the paint may be spoiled. I don't see how a paint thinner could lighten the color. Maybe an expired date (old) paint?

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Post by geck » Thu Sep 08, 2016 8:31 am

"It has been about 20 years since I've used and airbrushed them"

That is probably your answer right there. Your lucky you even could use a 20 year old bottle of enamel!

Get some fresh paint and try again. I am also a big advocate for using the manufacturer's thinners. I know it costs more...but they are formulated for their paints and usually have a few extra chemicals in them to assist with thinning/airbrushing.

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Post by naoto » Thu Sep 08, 2016 9:33 am

Oh darn... So paints aren't like fine wines that get better with age?
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NCC1966
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Post by NCC1966 » Thu Sep 08, 2016 4:16 pm

So far the only enamel paint that I have seen to endure for a long time without a problem are rattle cans. The other day I picked an 8 years old can that I used when I bought it and then forgot in my garage with less than 1/3 of white paint inside. Surprisingly it was like new.

I have some small Humbrol cans purchased 8 years ago that are still good though. However 20 years is really a LOT of time!

:P

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Post by Thomas E. Johnson » Thu Sep 08, 2016 6:33 pm

geck wrote:"It has been about 20 years since I've used and airbrushed them"

That is probably your answer right there. Your lucky you even could use a 20 year old bottle of enamel!

Get some fresh paint and try again. I am also a big advocate for using the manufacturer's thinners. I know it costs more...but they are formulated for their paints and usually have a few extra chemicals in them to assist with thinning/airbrushing.
These are brand new! I bought them especially for the project!!!
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Post by SpaceRanger1 » Thu Sep 08, 2016 8:56 pm

naoto wrote:Oh darn... So paints aren't like fine wines that get better with age?
No, but Humbrol enamels seem not to age. I've got some 50+ year-old Humbrol tins, and the paint in them is as good as the day it left the factory.
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Post by geck » Fri Sep 09, 2016 8:26 am

Thomas E. Johnson wrote:
geck wrote:"It has been about 20 years since I've used and airbrushed them"

That is probably your answer right there. Your lucky you even could use a 20 year old bottle of enamel!

Get some fresh paint and try again. I am also a big advocate for using the manufacturer's thinners. I know it costs more...but they are formulated for their paints and usually have a few extra chemicals in them to assist with thinning/airbrushing.
These are brand new! I bought them especially for the project!!!
Ahh...my mistake. Your post made it sound like the paints were quite old. :)

I'd try the manufacturers thinner and see what happens.

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Post by NCC1966 » Fri Sep 09, 2016 4:04 pm

I should disagree that the "manufacturer's thinner" will work better. It doesn't make any sense. Enamels, differently from other types of paint, follows a standard formulation. Till the date I couldn't find ANY enamel that won't work with hardware store general use spirit. Really, an enamel that only work with its own thinner is a crap that cannot be called enamel. Contact the manufacturer of the paint and tell them what happened. If they come with this BS about to use their thinner, trust me, the best thing to do is to change manufacturer.

:?

I have here in my collection enamels bottled for modelling from Humbrol, Revell, Testors and Model Master. Beside these I have some cans purchased in hardware stores (general use enamels to paint gates and fences). I thin all of them with the very same general use standard spirit that I buy in quarter gallon cans:

Image

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Post by Thomas E. Johnson » Sun Sep 11, 2016 6:18 pm

It only did it with the Deck Blue (very dark blue). Tried several bottles of it also. It didn't do it with the other two colors.
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Post by karim » Mon Sep 12, 2016 4:57 pm

I'm not familiar with this particular paint, so take this with a grain of salt, but is it possible that the pigment for this color has some transparency and the action of thinning this particular paint increased its translucency, resulting in an effective lightening?

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NCC1966
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Post by NCC1966 » Mon Sep 12, 2016 5:53 pm

Certain pigmentation have more coverage power than others. One of the characteristics that make it happens is the amount of solid particles the paint has (that's why metallic paints has an excellent coverage). Enamel paints are made out of a base clear with pigment added to it. It means that the quality of the pigment will have a big impact. What I mean is that a weak pigment may cause the paint to lose its power when thinned (as Karim said).

Enamel is one of more antique synthetic paint types and it is not big deal for industries to produce it so theoretically enamel should behave always the same. But you know how some companies can really spoil a product when they try to reduce cost...

Finally (and I think that you are aware of it) but it won't hurt to mention... several dark paints will look less "deep" (or more clear) after to be applied over a surface and dry than when in liquid state. Wouldn't it be the case?

Anyway, as per you are saying I don't think that the culprit there is the spirit thinner you are using. Seems to me more like a characteristic of the paint.

By the way... what's the paint brand you are using?

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Post by Thomas E. Johnson » Tue Sep 13, 2016 12:35 am

NCC1966 wrote:Certain pigmentation have more coverage power than others. One of the characteristics that make it happens is the amount of solid particles the paint has (that's why metallic paints has an excellent coverage). Enamel paints are made out of a base clear with pigment added to it. It means that the quality of the pigment will have a big impact. What I mean is that a weak pigment may cause the paint to lose its power when thinned (as Karim said).

Enamel is one of more antique synthetic paint types and it is not big deal for industries to produce it so theoretically enamel should behave always the same. But you know how some companies can really spoil a product when they try to reduce cost...

Finally (and I think that you are aware of it) but it won't hurt to mention... several dark paints will look less "deep" (or more clear) after to be applied over a surface and dry than when in liquid state. Wouldn't it be the case?

Anyway, as per you are saying I don't think that the culprit there is the spirit thinner you are using. Seems to me more like a characteristic of the paint.

By the way... what's the paint brand you are using?
I'm using Model Master Enamels.

I'm wondering if the color will restore itself once it is clear coated, like I have observed with some acrylic (Tamiya) paints, which airbrush out to a lighter (faded) color than applied by brush, but restore themselves to the correct color once given a clear coat.
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NCC1966
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Post by NCC1966 » Tue Sep 13, 2016 7:13 am

Model Master is an excellent brand. I love it and currently is my favorite. Now it's possible that a clear coat give the darkening effect (specially the glossy) but actually it will be acting over all colors and not only this blue. It does mean that the balance of colors will be altered. In any case I wouldn't count on it to "fix" your bad paint.

Another important point that I forgot to mention is that the quality control of paint tones is something relative. Although there are standards it's not so rare that production batches have variations. What I mean is that a paint from a batch may have difference from other and it may happen for several reasons, from a change of the formulation to a miscalibration of the machines that do the mix. In any case after to bottle thousands of jars the factory won't dispose it. Unless there is an scandalous difference they will just [put it in the shelves for sale and IF someone complain about they just replace the defective product for another one. Normally most of people won't even notice that and if so rarely will complain about and ask for a replacement. That's how things works...

So it's possible that you were just a "victim" of an eventual bad batch...

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Post by Thomas E. Johnson » Thu Sep 15, 2016 10:45 pm

NCC1966 wrote:Model Master is an excellent brand. I love it and currently is my favorite. Now it's possible that a clear coat give the darkening effect (specially the glossy) but actually it will be acting over all colors and not only this blue. It does mean that the balance of colors will be altered. In any case I wouldn't count on it to "fix" your bad paint.

Another important point that I forgot to mention is that the quality control of paint tones is something relative. Although there are standards it's not so rare that production batches have variations. What I mean is that a paint from a batch may have difference from other and it may happen for several reasons, from a change of the formulation to a miscalibration of the machines that do the mix. In any case after to bottle thousands of jars the factory won't dispose it. Unless there is an scandalous difference they will just [put it in the shelves for sale and IF someone complain about they just replace the defective product for another one. Normally most of people won't even notice that and if so rarely will complain about and ask for a replacement. That's how things works...

So it's possible that you were just a "victim" of an eventual bad batch...
I thought about that. I ordered 4 bottles of the same color. They all are behaving the same way.

I experimented with the clear coat. It did re-darken the color and reverse the fading that occurred, so it is closer to the precolored wooden deck I laid on the model. It didn't effect the other colors, but then they didn't have a fading issue. Only the Deck Blue 20-B (ultra dark blue) had this issue.
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Post by Thomas E. Johnson » Thu Sep 15, 2016 10:46 pm

Double post
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Post by NCC1966 » Fri Sep 16, 2016 7:48 am

Very weird! However, seems that you have your issue solved!

:D

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Post by Thomas E. Johnson » Fri Sep 16, 2016 7:53 pm

NCC1966 wrote:Very weird! However, seems that you have your issue solved!

:D
Well the colors are now close enough to where I can accept that the difference is the result of the surfaces being steel, and the other painted wood.
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