Refilling Empty Aerosol Paint Cans With Car Paint and Compressed Air—Is It Possible?

Hello.
Recently, in the garage I found an old aerosol with WD-40 and unfortunately the preparation was in a can, but you couldn't spray it with it - no pressure.
I had to dispose of this can, but I had an idea to use the contents in some way - for an insignificant undertaking. The idea was to squeeze compressed air and for this I put the tip of the pistol on the compressor and squeezed compressed air through the valve.
It worked !!!!!!!!!!!
I pissed out all the way to the end of WD-40 :idea:

However, my question is of the same nature, however, regarding aerosol paints.
Is it possible to squeeze new paint (car paint) into the can (after the old paint) and top it up with compressed air? Here I also have a question about a possible hardener - it is about drying the paint after it is removed from the can.
Does it make sense and will it work - maybe someone has done such experiments.

Why not, I guess? You just have to be careful that it does not explode. The problem may be some difference in the old and new paint, or the dried up remnants of old paint in a can, valve, etc. And above all, the question is, is it profitable at all? Do the spray paint and the same in a regular can differ in price so much that it will pay off? Besides, I understand that it is a one-off or occasional adventure. Anyone who paints seriously does not use spray paints, but a gun anyway.

With WD-40 there was no need to force air in, you could just cut the can open and use the liquid without the possibility of spraying. Sometimes it's a much more sensible method - you can buy WD-40 in this form.

Yes - a one-off adventure, although it may or may not be left for later painting.
The gun you say - yes, yes. Only this washing brings me despair. Using the can is faster and there is not always access to a compressor at home. My wife would go crazy if I was still keeping the compressor at home. :|

Regarding WD-40, it was possible to cut the can, but I would deprive myself of the possibility of using the preparation after some time and, of course, spraying (spraying).

I wonder what this paint is in the aerosol and what to use (car paint with a hardener or ordinary enamel like all cars used to be painted - probably enamel or acrylic - I don't remember what it was called).

I usually use car paint with a hardener, but it goes to the gun.

When it comes to profitability, there is nothing to talk about, an example.

Primer paint in a can 0.75l - cost about PLN 18
0.75l acrylic paint (the same as used in old cars - varnish) - cost about PLN 20.

An aerosol can of any color, 450 ml - costs about PLN 12

Filling a 300 ml can - cost PLN 6 (half the price of an aerosol)
The spray can does not have 450 ml anyway - I checked only about 100-250 ml or even less (only varnish, paint with a solvent, of which a solvent is a significant amount). I checked it by evaporating the solvent. It follows that the paint substance itself is only a small amount.
So - I think this fun pays off.

However, one more question - is there compressed air in the aerosol or some gas (it is about maintaining the pressure and paint flowing out of the can).

Let me mention that I stuff all the solvents into the aerosol and fill it with air, and then it's great for cleaning difficult places. I am not interested in the pressure either, because when it is going poorly, I refill the air and I can continue to work. I press 6 bar (I have this designation on the compressor) - that is, the maximum that will be enough and the solvent is poured into me.

I don't know much about paints and painting, so I can't discuss comfort or such matters :P

HONDACX wrote:

Regarding WD-40, it was possible to cut the can, but I would not be able to use the preparation after some time

You can make a hole with a nail and pour the contents into another, closed container.

HONDACX wrote:

The spray can does not have 450 ml anyway - I checked only about 100-250 ml or even less (only varnish, paint with a solvent, of which a solvent is a significant amount). I checked it by evaporating the solvent. It follows that the paint substance itself is only a small amount.

Well, I guess every paint has a solvent, right? It doesn't matter if it's a regular can or a spray. Anyway, it would be tough. Maybe the spray has a little more solvent because the paint has to be thinner to spray it this way (the compressor gun works differently than the can spray).

HONDACX wrote:

However, one more question - is there compressed air in the aerosol or some gas (it is about maintaining the pressure and paint flowing out of the can).

Probably some gas. When you use gas, you can be sure that it is cleaner than air, more reproducible, and the lack of oxygen in the mixture will at least not bother you.

c4r0 wrote:

You can make a hole with a nail and pour the contents into another, closed container.

Preferably in the mouth and then sprinkle on the element. Also way. hahahahaha

c4r0 wrote:

Well, I guess every paint has a solvent, right? It doesn't matter if it's a regular can or a spray. Anyway, it would be tough. Maybe the spray has a little more solvent because the paint has to be thinner to spray it this way (the compressor gun works differently than the can spray).

The paint has several ingredients including all kinds, solvents, extenders, pigments, oily compositions, fasteners etc. So ????

c4r0 wrote:

Probably some gas. When you use gas, you can be sure that it is cleaner than air, more reproducible, and the lack of oxygen in the mixture will at least not bother you.

This is the most substantive answer on this forum. Way to go ! Farting in 3-City is the best. hahahahahahahahah


Maybe I'll wait for more constructive suggestions.

Okay, then I don't speak anymore And will I get a diploma for the most substantive answer?

Yes - the president's hug. :)

I came up with an idea - I am implementing it now - as I will describe it. Of course, in the subject as befits.

With that air in the can, a nice bomb could come out, especially at the end when the paint is running out.
Let something catch fire while painting, you would have to look for the fingers holding the can on the walls.

Jerzykowski wrote:

As far as I know the sprays are filled with butane so I don't know why the can filled with air should explode.

Because it has a flammable mixture inside, air (oxygen) and volatile hydrocarbons, so it will propagate to the inside of such a can with a known effect.
Do you know why you cannot, for example, weld fuel tanks without rinsing them thoroughly and filling them with, for example, nitrogen or CO2?

The paint (solvents) or butane will only burn on the outside of the can, but if there is air (oxygen) in the can, the flame propagation will not stop on the sprayer, but will go inside.

But nobody here will weld the paint can.
Welding the fuel tanks - I have already done this - I covered them with sand and welded them - the handles are still in place. :)

I am just wondering about the can explosiveness - as far as I know, there are 3 factors to meet for a fire or explosion to appear.
In this case, rupturing the can under (air) pressure will not give an explosion effect, but only rupturing the can from excess pressure.
From my experience - 6 bar - the can withstand calmly. I checked on an industrial compressor - up to 40 bar. The paint can began to change its shape - at 16 bar.
So there is no danger - tearing the can.
Muse to do one more experiment - how many "bars" has a factory filled can of paint. I just don't know how to do it yet - I have no connections.

HONDACX wrote:

But nobody here will weld the paint can.
Welding the fuel tanks - I have already done this - I covered them with sand and welded them - the handles are still in place. :)

I am just wondering about the can explosiveness - as far as I know, there are 3 factors to meet for a fire or explosion to appear.
In this case, rupturing the can under (air) pressure will not give an explosion effect, but only rupturing the can from excess pressure.
From my experience - 6 bar - the can withstand calmly. I checked on an industrial compressor - up to 40 bar. The paint can began to change its shape - at 16 bar.
So there is no danger - tearing the can.
Muse to do one more experiment - how many "bars" has a factory filled can of paint. I just don't know how to do it yet - I have no connections.

Have you heard anything about static charges?
If not, read on.

HONDACX wrote:

Muse to do one more experiment - how many "bars" has a factory filled can of paint. I just don't know how to do it yet - I don't have connections.

It is very easy.
1 - go to the website http://isap.sejm.gov.pl/
2 - We turn on the search engine and look for:
"Regulation of the Minister of Economy on detailed requirements for aerosol products.

And there we are looking to what pressure the can should be filled.

Depending on the capacity, this pressure cannot be higher than 8-9 bar at a temperature of + 50 ° C, and the can is to withstand a test pressure of 12 bar without changing the parameters.
Knowing the pressure at 50 ° C and the capacity, you can easily calculate the pressure at room temperature.

And air is not used for punching, because the oxygen contained in the mixture under pressure poses certain risks. Therefore it must be an inert gas. And propane-butane is used because it is the cheapest of the inert gases. It is post-production waste and the excess would have to be burned. And that's just how you use it for cans. The effect is the same, but some cash still falls into your pocket.

Concrete gas as a propellant is used in aerosols so that at the pressure in the can it is in a liquid state with all its consequences.

The cans suitable for filling from the compressor are ready.


It's nice how much you paint with different paints and washing the gun every time is not worth it ... Or you need to have 10 guns and worry that sometimes one of them does not dry out.

Most often, non-odorizing propane-butane is used as a propellant in aerosols. in exceptional cases there are other gases, e.g. DME or dimethyl ether which is very well miscible with most paints and varnishes. When answering the question whether it is possible to charge at home and how much pressure, I answer - that you cannot inject gas into an aerosol in a home-grown way. An exception to this rule are paints which, in most car paint mixing plants, can be stuck to a previously gassed aerosol can using a special razor through the valve to the center of the paint. The important thing here is that you cannot "squeeze" into this package, for example, grease or shaving foam. Why? and because, apart from the gas itself, there is a special solvent mixture inside with a hardener that will allow you to paint with 1K paint in such a way that a durable coating is created. The quantity and pressure that the aerosol container is able to take is specified by the packaging manufacturer.