Rattle can "glop" leakage

[plasticprime]

Does anyone know what this glop is that appears to be leaking out from the seams of some of my rattle can spray paints? It's somewhat sticky, but fairly odorless. The age of the can doesn't seem to matter and it's happening with both Testors and Tamiya paints (enamels and lacquers). Some ae exhibiting just a bit, and some are like the one in the photo. They're all being stored inside, upright, at room temp. Are they still good to use?

[dragstk]

Ive never had this happen on a Tamiya can, but I have with several Testors cans. I believe this is the propellant. There may still be paint in the can. I can feel it when I shake the can. I just havent figured out a safe way to puncture the can. Then it could be air brushed

[Straightliner59]

5 minutes ago, dragstk said:

I just havent figured out a safe way to puncture the can. Then it could be air brushed

Just turn it upside down, as if you're clearing the nozzle, until no more propellant is escaping. Then, you can carefully punch a hole, however you choose!

[1972coronet]

Testors cans have been doing that for - in my experiences - at least 15 years. I've never had a Tamiya aerosol can leak, and I've been using their aerosols for more than 20 years (one can was "bad", but that was my fault).

The shelf-life of Testors paints have always been quite short, bottles and cans. However, at one time, if the can wasn't used-then-stored, its contents were fine for a while. But, once used - even for a spritz - they turned to garbage in short order.

[dragstk]

Thanks Daniel. Ill give it a try cause I few cans like this. But if it doesnt work, just look out for the guy with 1/2 a blue face.....??

[Straightliner59]

1 minute ago, dragstk said:

Thanks Daniel. Ill give it a try cause I few cans like this. But if it doesnt work, just look out for the guy with 1/2 a blue face.....??

I have a few, too! I'll be all kinds of colors!?

[1972coronet]

1 hour ago, dragstk said:

But if it doesnt work, just look out for the guy with 1/2 a blue face.

He was on Dragnet 1967 !

[Ace-Garageguy]

1 hour ago, dragstk said:

I believe this is the propellant...

Nope. The "propellant" is a gas, both dissolved in the paint and above it.

What's escaping is the clear liquid "carrier" that the pigment is normally suspended in to make "paint".

In this case, it's essentially clear lacquer, and this gooey ooze is very common with Testors products.

It happens because the bottom seam of the can isn't rolled quite tightly enough to retain its seal over time.

"Pigment" in paint is a very finely ground solid, and the pigment particles are too big to leak out of the microscopic seam failure, but the clear lacquer can escape.

The cans will often continue to spray kinda normally for a while, sometimes for years.

Edited March 28, 2023 by Ace-Garageguy

[Miatatom]

Well, I wish I'd known this about a month ago. Tossed 2 cans of black cherry pearl. Like the OP, I should have asked here.

[yh70]

i just throw them away. who knows one day one may blow up on you. be smart be safe. ether let the air out and spray in a airbrush or toss it..

[NOBLNG]

It won’t blow up because it is slowly losing pressure. If it loses enough it just won’t spray. I have one Testors can that is leaking like that. Whether the remaining paint is viable to use in an airbrush with the diminished amount of carrier I won’t know for sure till I try it.? Maybe someone on here has tried airbrushing some leakers?

Edited March 28, 2023 by NOBLNG

[plasticprime]

5 hours ago, Ace-Garageguy said:

Nope. The "propellant" is a gas, both dissolved in the paint and above it.

What's escaping is the clear liquid "carrier" that the pigment is normally suspended in to make "paint".

In this case, it's essentially clear lacquer, and this gooey ooze is very common with Testors products.

It happens because the bottom seam of the can isn't rolled quite tightly enough to retain its seal over time.

"Pigment" in paint is a very finely ground solid, and the pigment particles are too big to leak out of the microscopic seam failure, but the clear lacquer can escape.

The cans will often continue to spray kinda normally for a while, sometimes for years.

Thanks! This is very informative! I assume the "pea" (or "rattle") is contained in the blue area of the diagram and helps mix the liquid and propellant mixture prior to spraying. Despite what others have experienced, I currently have 3 cans of Tamiya exhibiting the same leakage and one of those is 2-3 years old and still in the original shrink wrap. I also have a few ancient cans of Testors enamel that are 45+ years old that have no leakage at all. So go figure.

[64SS350]

My first experience with this is when I came home to find a can of caboose red leaked heavily ( maybe entirely) and ran down the wall from a high shelf .

Yes, decant them or pitch them!

[Ace-Garageguy]

6 hours ago, plasticprime said:

I assume the "pea" (or "rattle") is contained in the blue area of the diagram and helps mix the liquid and propellant mixture prior to spraying. 

The "pea" is to mix the pigment with the clear carrier.

Pigment is usually a very finely ground solid, and can settle out of the clear carrier over time.

You've probably noticed the "pea" sometimes doesn't rattle when you first shake the can. That's because it's stuck in the gooey pigment mass that's formed at the bottom. Shaking eventually loosens it, and then its movement helps to remix the pigment and carrier.

NOTE: You may have also noticed that clear often has no "pea" in the can to rattle when you shake it. That's because there's no pigment material to settle out, so there's no need for a "pea" to remix it.

The propellant is a gas, and some is always dissolved in the liquid, but all of it can't be absorbed, so some remains in pure gaseous state (orange arrows in the diagram above). Decanted paint will often bubble after it's been decanted, as dissolved gaseous propellant literally boils out of it.

I've never seen or heard of leaking cans exploding (unless they get heated), so if you want to keep them around until you get time to decant, there's really no danger...other than the goop getting on the shelf.

One thing to remember though: sometimes you may have to add a little clear lacquer to paint decanted from a gloopy container to return it to its original consistency. Paint won't dry properly if there's not enough carrier in the mixture.

[NOBLNG]

2 hours ago, Ace-Garageguy said:

One thing to remember though: sometimes you may have to add a little clear lacquer to paint decanted from a gloopy container to return it to its original consistency. Paint won't dry properly if there's not enough carrier in the mixture.

That’s what I was wondering about. How do you know if you need to add clear? Make a judgment call on consistency or do a test spray I guess??

[Ace-Garageguy]

20 minutes ago, NOBLNG said:

That’s what I was wondering about. How do you know if you need to add clear? Make a judgment call on consistency or do a test spray I guess??

Yes.

You have a very rough idea of the volume of clear to add by looking at the volume of the blobs that have leaked out.

[dragstk]

16 hours ago, 1972coronet said:

He was on Dragnet 1967 !

I was hoping that no one saw my previous TV experience....?

@Bill- Thanks for clearing up what is really happening with leaking paint cans

[Bills72sj]

I have had only one of my Testors cans ooze out like that. It was a bare minimum 10 years old but more likely 15. I simply decanted it and sprayed it through my airbrush. Like mentioned above, you MAY need to thin it with lacquer thinner depending on its consistency once you have it out.

[Reegs]

On 3/28/2023 at 11:50 AM, dragstk said:

I was hoping that no one saw my previous TV experience....?

@Bill- Thanks for clearing up what is really happening with leaking paint cans

Benjie "Blue Boy" Carver.

Edited April 3, 2023 by Reegs

[Rick L]

On 3/27/2023 at 6:23 PM, Straightliner59 said:

Just turn it upside down, as if you're clearing the nozzle, until no more propellant is escaping. Then, you can carefully punch a hole, however you choose!

I agree with this method and I would shake it before decanting. That way, you may not have to add anything to the mix. 

[Dave G.]

 

[Dave G.]

 

[Ace-Garageguy]

On 3/27/2023 at 6:23 PM, Straightliner59 said:

Just turn it upside down, as if you're clearing the nozzle, until no more propellant is escaping. Then, you can carefully punch a hole, however you choose!

You might want to repeat this at least a couple of times prior to punching the hole.

Propellant gas is dissolved in the paint too, and when you release all the pressure from the free gas in the can, more will boil out of the paint.

Decanted paint will very often bubble and boil...and sometimes even spray out the hole...even after "all" the propellant has been bled off.

 

[Dave G.]

And this is how I also have been doing it for the last couple of years if not decanting the entire content of the can. Works for me.

 

[Rick L]

Go outside, shake the can, empty the air, place a nail to the bottom of can and cover with a rag. While holding the rag over the nail, puncture side of can at the bottom, repeat at side top of the can. The leakage is minimal. Drain vented can into glass jar.