Clogged Spray Nozzles

[JAL3]

Most of my paint has been sitting around for a few years without being used. Now that I am back to building, I am having trouble with paint comming out of rattle cans. Sometimes it seems like the nozzle is clogged and sometimes, even a new nozzle does not work. Could that be a problem with the can itself?

Also, is there a safe solvent that I could just store all my nozzles in so that they are fresh and ready to use?

 

[rstaff3]

I've resurrected the nozzles by soaking them in paint thinner and poking around with strands of wire. I also have had cans that clogged and wouldn't even work with new nozzles. Those went to the recycling center.

 

[JAL3]

It looks then like I am going to have a fair number of cans, some brand new, that are going to get tossed.

For the future, is storing the nozzles in a jar of paint thinner a viable option? Spray the project, pull the nozzle, drop it in the jar and store until next time; repeat as needed.

 

[rstaff3]

I'd wait for others to chime in. I don't know if what I did was the best advice. Just one data point. I don't know the long term effects of soaking the plastic nozzles in thinner nor do I know if that is better for the can. As side story, the tips on the cans can go crazy. I had one spray uncontrollably even when the nozzle was pulled.

The best advice is probably to have multiple painting projects and use up most of the paint. Like that's gonna happen with me.

 

[G_T]

Some nozzles at least can be stored indefinitely in mineral spirits in a tiny jar.

When finished spraying, invert the can and spray until the paint clears from the line. That may keep the can usable for moderate periods. But eventually paint will thicken in the internal siphon line (or whatever that tube is called).

I prefer just to buy the paint I need for a project, and use it up. I think fresh cans do better. I think a fresh can warmed up with some hot water before spraying does better still as it ups the pressure a little and the mist comes out finer and smoother.

Gerald

 

[hornet driver]

Old spray paint is like an old girlfriend--looks like a good idea but later you think--"Man I wish I had'nt done that"---Toss the old can and get a new one---That said--saving the nozzles in thinner is a great idea-- can't think how many times all I needed was a good nozzle--even with a new can!!

 

[JAL3]

Now I'm really going to show my ignorance.

So far this thread has used three terms, one of which I can properly define. That would be "solvent".

The 2 other terms that caught my notice were "mineral spirits" and "thinner". To that list I would add "brush cleaner".

I see all three (and others) in similar but different cans at the hardware store. Can somebody compare and contrast them for me?

Feel free to add similar vocabulary that I am sure I'm forgetting.

 

[luke strawwalker]

It looks then like I am going to have a fair number of cans, some brand new, that are going to get tossed.

For the future, is storing the nozzles in a jar of paint thinner a viable option? Spray the project, pull the nozzle, drop it in the jar and store until next time; repeat as needed.

Yeah, I've done this... make sure they're submerged and stay submerged in thinner... Heck I even pull off the old nozzles if they were performing well when the can ran out and toss them into the jar for "backups"... works well so long as they match the can you're trying to use that has nozzle problems (some are male, some are female, etc.)

As for older cans of paint, they can be problematical... I've seen some work great after years of storage, some not work that are relatively new. Sort of a crapshoot.

Here's two things that should help... 1) make sure that cans that have been sitting around awhile, you shake, and shake, and shake, and shake, and then SHAKE SOME MORE... you can't shake them too much, but you SURE CAN shake them too little! I personally think it also helps to store them on their side or something to prevent the paint solids from gunking up the end of the suction tube, but since you really don't know where or how it's pointed inside the can, this is problematical. The main thing is SHAKE SHAKE SHAKE!! 2) warm the cans up in hot tap water... the warmer you get the cans, the more latent heat you put into the pressurant (propellant) and therefore you raise the "head pressure" in the can. Old cans that have sat around awhile seem to behave like they've lost a lot of their propellant, or at least a lot of "oomf" from them. Warming the can up thoroughly should help with this by raising the pressure in the can, even if part of the propellant has leaked down or whatever... The other thing warming it up does is it LOWERS THE VISCOSITY of the paint, making it flow easier, and therefore more effectively and easily atomized by the nozzle, and demanding less pressure to push it out of the can...

If that doesn't work, rather than throw away a nearly full can, I'll usually bleed the pressure off and puncture the can and use a brush with it... but of course you're on your own on this... not exactly "recommended procedure"... plenty of other projects around that can use paint that doesn't have to be as pretty as a rocket does...

Later and hope this helps! OL JR

 

[rstaff3]

Now I'm really going to show my ignorance.

So far this thread has used three terms, one of which I can properly define. That would be "solvent".

The 2 other terms that caught my notice were "mineral spirits" and "thinner". To that list I would add "brush cleaner".

I see all three (and others) in similar but different cans at the hardware store. Can somebody compare and contrast them for me?

Feel free to add similar vocabulary that I am sure I'm forgetting.

I apologize for the terminology. I meant 'mineral spirits' when I mentioned 'paint thinner'

 

[luke strawwalker]

Now I'm really going to show my ignorance.

So far this thread has used three terms, one of which I can properly define. That would be "solvent".

The 2 other terms that caught my notice were "mineral spirits" and "thinner". To that list I would add "brush cleaner".

I see all three (and others) in similar but different cans at the hardware store. Can somebody compare and contrast them for me?

Feel free to add similar vocabulary that I am sure I'm forgetting.

"Mineral Spirits" is the typical thinner used with enamel paints... common at the hardware store. Also used to clean paint guns and stuff like that. Put some in a jar and toss your nozzles in there, should work fine. "Paint thinner" is usually mineral spirits. Turpentine is more for varnish and stuff like that, so stick with paint thinner or mineral spirits.

"Lacquer thinner" is a lot "hotter" solvent than mineral spirits or paint thinner... I keep some around just for tough jobs, but don't use it to reduce any paint other than lacquer! Don't let it get onto painted surfaces, because unless they're lacquer, it will soften and craze the finish and take it right off. If you have some stubborn stuck on gunk on a nozzle that pretty much has it sealed off completely (or nearly so anyway) toss the nozzle into some lacquer thinner and it should soften it up and get rid of it with some brushing or prodding with a needle... just wash the lacquer thinner off with mineral spirits before you use it to spray enamel!

Hope this helps! OL JR

 

[JAL3]

Thanks for the terminology lesson.

In my blissful ignorance, all of the terms mentioned above have been lumped in my mind into the single category of "paint solvents". Right or wrong, I used the products interchangably... with predicable results. I knew that differences had to exist but I never pursued the knowledge.

I guess an atitude of: any paint project of mine is doomed so why bother getting fancy was something of a self fulfilling prophecy.

 

[G_T]

Let's say you pick up some Duplicolor? spray at an auto store. It recommends using a mineral spirits wipedown to clean the surface before spraying. Instead, you use denatured alcohol - another good solvent to have around. You notice that the denatured alcohol removes a tiny bit of paint, but figure that is just your sanding dust. The surface looks decent anyway. You paint it, it paints pretty decently. You build up the paint in layers and get it nice.

Later on, you find that your paint chips off easily. Turns out denatured alcohol is a mild stripper for the paint. Mineral spirits is a thinner for the paint. The action is a little bit different...

Which solvent you choose for each application matters.

Mineral spirits is effectively an oil. Some paints like a little oil. Some cannot tolerate it. For those that can't tolerate it, surface prep might consist of sanding, cleaning with acetone (strong degreaser), followed by cleaning with denatured alcohol (cleans up residue).

Different tasks, different solutions.

Gerald

 

[luke strawwalker]

Let's say you pick up some Duplicolor? spray at an auto store. It recommends using a mineral spirits wipedown to clean the surface before spraying. Instead, you use denatured alcohol - another good solvent to have around. You notice that the denatured alcohol removes a tiny bit of paint, but figure that is just your sanding dust. The surface looks decent anyway. You paint it, it paints pretty decently. You build up the paint in layers and get it nice.

Later on, you find that your paint chips off easily. Turns out denatured alcohol is a mild stripper for the paint. Mineral spirits is a thinner for the paint. The action is a little bit different...

Which solvent you choose for each application matters.

Mineral spirits is effectively an oil. Some paints like a little oil. Some cannot tolerate it. For those that can't tolerate it, surface prep might consist of sanding, cleaning with acetone (strong degreaser), followed by cleaning with denatured alcohol (cleans up residue).

Different tasks, different solutions.

Gerald

Yep, what he said... if there wasn't a need for different materials, they wouldn't be around... folks would have settled on whatever's cheapest or works best a LONG time ago...

Later! OL JR