What's wrong with my paint?

[jonwinn]

I just bought this about a month ago. A small square bottle of

Testors enamel gloss red paint. I used it a week or so ago and it

was fine. I went to mix it up and the brush handle came out covered

with thinner and little bits of pigment. It looks like the paint in the bottle

is coagulating and morphing into little chunks of rubber stuff. Are there

any chemists in the house that can explain this? I tossed a bottle last year

that completely turned into a glob of rubbery like substance. Looks like

it's time to switch brands after a mere 50 years.  jon

Edited October 3, 2020 by jonwinn

[jonwinn]

Image 2  jon

 

Edited October 3, 2020 by jonwinn

[Mstor]

You didn't by chance add any thinned paint back into the jar?  That can often upset the balance of the components necessary to maintain the pigments in suspension, or something like that. Suffice it say it will mess the paint up.

[jonwinn]

Yup, that's it! So once it thickens you can't thin it! So much for

Testors. I really don't remember this happening years ago. Oh well.  jon

[ElectroSoldier]

Im not sure if its going to help knowing whats wrong with it but your carrier has separated almost completely from the medium which is what carries the pigment.
A small amount of a quality enamel thinner and a really really good mix might fix it for you. But I doubt it. Having read the last two posts now I would say it now depends on the thinner you used, I would say it works to help use it but once added to the bottle it separated the medium from the carrier...

I never pour thinned paint back into the bottle because of this problem.

Edited October 3, 2020 by ElectroSoldier

[WymanV]

 I've had that happen with all brands of enamels I've used over the years. Saving thinned paint is a crapshoot-usually it survives but from time to time this happens. Considering how seldom it happens and how relatively inexpensive it is, I just dispose of the offending paint and buy another.

[jonwinn]

I did NOT pour thinned paint back in. I THINNED pea soup thick paint

with TESTORS enamel thinner. I will never do that again.   jon

[habu2]

1 hour ago, WymanV said:

...Saving thinned paint is a crapshoot...

 

this - only thin as much as you will use

[Joe Hegedus]

23 minutes ago, jonwinn said:

I did NOT pour thinned paint back in. I THINNED pea soup thick paint

with TESTORS enamel thinner. I will never do that again.   jon

I've noticed that thinning  Testors enamels with mineral spirits (i.e. paint thinner) will cause them to react in this way.  I've also found that using a decent quality lacquer thinner (thinner, not paint stripper) to thin them does not result in them separating and coagulating for some reason.  The lacquer thinner thins the paint, but if it evaporates and the paint thickens up again adding more lacquer thinner restores it.  Gunze Mr Color thinner works a treat with Testors and MM enamels, as does their leveling thinner.

[jonwinn]

Ok, I thinned the paint in the bottle with what made sense to me.

Testors thinner for Testors paint. I know know that's wrong. So if

I want to thin paint I should have taken some of the thick sludge

Testors sold me and mix a small amount with their thinner in a pallet

or paint cup to use brushing. I DON'T airbrush, I use small bottles to

do cockpits and detail painting. So I could use Testors thinner in a

cup or pallet to thin the amount need?  jon

 

Edited October 4, 2020 by jonwinn

[jonwinn]

Now you say I can thin the bottle with lacquer thinner? This won't turn

it into a toxic rubbery mess? This is what I have for lacquer thinner, is

this acceptable to use in a thick bottle of Testors paint?  jon

 

Edited October 4, 2020 by jonwinn

[Joe Hegedus]

1 hour ago, jonwinn said:

Now you say I can thin the bottle with lacquer thinner? This won't turn

it into a toxic rubbery mess? This is what I have for lacquer thinner, is

this acceptable to use in a thick bottle of Testors paint?---John

 

That's one that I've used successfully.

[Steve N]

I've had that happen occasionally with Testor's paints since the 1970s.

 

SN

[Scott Smith]

Every once in a while I would get the same result.  Not sure why it happened, but I mix my paint and dump what I don't use now. 

[Stan in YUL]

The components of the enamel are clearly contaminated.  Sometimes it’s what’s on the stir tool or a brush, and yes poring thinned paint back in the bottle will do it.  Scrap it and get some more.

[jonwinn]

Thanks for the answers and just to be clear again I DON'T thin paint for airbrushing and pour it back in the

bottle! I will state it one more time, I GOOFED, common sense told me to thin Testors enamel paint with Testors

enamel paint thinner. So much for common sense.   jon

[breadneck]

Corona got it.

[ElectroSoldier]

Its more to do with why the paint was pea soup thick than adding the enamel thinners to the paint.

[jonwinn]

Thanks, I am tempted to buy another bottle of Testors red enamel and IF it is

thick and unbrushable I will try as Joe suggested and try my Mr Color 110 lacquer

thinner. I like enamel paint  and have been using Testors for over 50 years. I really

don't remember this many problems way back so I am wondering if it is a new

eco friendly formula that is easily tossed out of balance by thinning. If that doesn't

work I will consider getting some 2 inch brushes and a putty knife at Home Depot

and give up on plastic models and try painting "happy little clouds".   jon

Edited October 6, 2020 by jonwinn

[Stan in YUL]

 

22 hours ago, jonwinn said:

Thanks, I am tempted to buy another bottle of Testors red enamel and IF it is

thick and unbrushable I will try as Joe suggested and try my Mr Color 110 lacquer

thinner. I like enamel paint  and have been using Testors for over 50 years. I really

don't remember this many problems way back so I am wondering if it is a new

eco friendly formula that is easily tossed out of balance by thinning. If that doesn't

work I will consider getting some 2 inch brushes and a putty knife at Home Depot

and give up on plastic models and try painting "happy little clouds".   jon

Unfortunately, I don’t expect that any lacquer thinner will have the desired affect.  The resin binder in the enamel has been affected.  It’s like trying to un-bake a cake.

[jonwinn]

Something like this?  jon

Edited October 7, 2020 by jonwinn

[ElectroSoldier]

Paints are made of 3 things not 2.

Pigment

Binder

carrier

The pigment is in the binder and gives the colour, the binder is what makes the pigment stick to the surface of what you are painting, the carrier is usually but not always like a thinner. It is what makes it easier to spread the binder over the surface of what you are painting.

It is the carrier that causes peoples confusion with acrylic paints, in that it doesnt have to be a water based carrier to be an acrylic paint. The acrylic part is the binder not the carrier.

 

In your case the problem is the fact that the binder has had an adverse reaction with the carrier and the carrier has damaged the binder, that the the red goop, its red because of the pigment, its goopy because of the binder. the liquid around is is almost certainly the carrier, in your case its mixed with enamel thinners.

The problem with the paint existed before you added the thinner, it manifested itself as thick paint, you added the thinner which highlighted the problem to you because it thinned it down so you could see it was separated.

[jonwinn]

OK so the paint had problems before I tried to fix the problem? So my main concern is why the Hell

does Testors sell enamel thinner which can't be used with enamel paint. So what the Hell am I suppose

to do to thin paint? I am no chemist and all of this is just making me more confused!!!! Everything I

learned years ago has to be thrown out? Or do I need to send my paint to a lab to have it  analyzed in

order to know how to thin it? Or is this Testors' problem caused by lack of QC?  jon

[ElectroSoldier]

Im not 100% sure it did what you think it did.

I think the thinner you used just highlighted a problem you already had and made it a bit more liquid...

 

My first port of call for any paint is the thinners of the same brand that states its for that paint.
I cant get hold of that particular thinner but if I could then its what I would use too. a Lacquer thinner like Mr hobby leveling thinner or the Mr Hobby Thinner wouldnt be my first choice. It might work but then so would many other things.

 

It might be that the paint had a problem. It might be that the thinner has a problem, that thinner is on its way out but that paint is too and they bounced off each other so it might work on in another paint but not that one.

 

Personally I would try another pot of paint as the thinner of the same brand should always work. Other thinners are always a second choice.

[Mstor]

On 10/3/2020 at 3:27 PM, jonwinn said:

Ok, I thinned the paint in the bottle with what made sense to me.

Testors thinner for Testors paint.

 

This. Did you actually thin the pain IN the bottle, i.e. add thinner INTO the bottle? If so, this could cause your problem. It is essentially the same as returning thinned paint back into the bottle.

If this is not what you did, then I have miss construed what you wrote and you can ignore this post.