trick for refilling aerosol cans

That would save me alot of wasted wd40!

 

Very interesting! I'd try to see how low I could run the can on for sure.

 

I buy WD 40 and PB blaster in the gallon jugs and they most often come with a free hand spray bottle to put it in. Way more environmentally friendly and lots cheaper too. And also much safer than re pressurizing a tin can to get an ounce of fluid outta it. Not trying to be a duck but, if every one is so concerned about polluting the air with wood smoke you might want to think twice about spraying aerosol vapors around all over the place too. I dont care but am just sayin.

 

Don't they use compressed air now a days?

 

I saved .39 cents and spent $759 on emergency room doctors to remove the shrapnel...............................................

 

I agree its more environmentally friendly to own the hand spray bottle... however I don't know for sure (since I haven't examined the numbers) but I'm guessing most ppl on a firewood burning website are less concerned with saving the planet (due to pollution from their wood burning stoves, furnaces, boilers, etc...) as they are with saving a buck... I could be wrong though. also, this trick is for ppl who already have an aerosol can, that has already displaced its cfc's into the atmosphere. leaving the rest of the can environmentally equal to a pump bottle. so refilling the can with common household air (thats been compressed) is not something damaging to the environment. or at least that's my take on it.

 

In the video he said not to pressurize the can over 90 psi. so if you can show me an instance that someone has had to spend $759 or more on a hospital visit due to inflating their can to 90 psi or less. I'd be very interested to see that information. or if it was 91 psi or more, then they did not follow the instructions correctly and they have caused their own problem.

 

I’ll add my 2 cents here since I have some actual industry experience in this. I worked as a packaging engineer for P&G for 5 years, 3 of which I was responsible for aerosols (Old Spice and TAG body sprays). We had a lab where I probably filled 1000’s of cans and bottles by hand for testing purposes. While our filling stations had lexan shields and were in an anti-static environment (no watches or cellphones allowed) with an automatic fire extinguishing system, the basics aren’t much different than what this guy is doing.

Most propellants in aerosols is propane, butane, or a mix of both. 90 psi isn’t out of line and really isn’t that unsafe, especially when you consider he’s using air and not a flammable gas like we used. I’ve put 100psi of propane/butane mix in a normal 20oz coke bottle (for work purposes) and it held fine until it was put in a 100 degree room for a few months, at which point it started blowing up like a balloon! A steel or aluminum can will be able to withstand even more pressure. The weak point of what this guy is working with is the plastic valve, as plastic can become brittle over time, especially when in contact with the original gas propellant. But as long as he’s wearing safety glasses (which I don’t think he was) he’s relatively safe from any real danger.

 

bassJAM , why do they use flammable gas instead of air? Does the propane /butane mix with everything better . Seems like air would work, or why would it not for a factory fill.

Clearly since it's not used there has to be a reason why, I'm sure it's been tested and tried, as I'm sure it would be cheaper.

 

It has to do with how the gas meters out. With air, if you fill to 90psi, every time you open the valve and let out product and air your pressure goes down. So you start out with a stream of WD40 or Fabreze that shoots out fast but every time you use it there’s less and less flow as the pressure goes down until the last 1/4th of a can you’d just have a trickle. There’s actually devices that address this but those require 2 chambers, one for the air and the other for the product, and then there’s a series of valves in between both to meter the air flow. This is expensive and a tad fragile so most aerosols stay with the tried and true method of using propellants like butane, propane, or a mixture of the two.

Gases like butane and propane behave differently than air. They’ll give you the same flow, say 90psi, from start to when the can is almost empty. That’s because when you over-pressurize these gases they turn into a liquid. If you had a clear aerosol can at the very top you’d see butane or propane in its gas state. Below that you’d have propane/butane in liquid state. Below that you’d have your product (WD40, Fabreze, Raid, etc) that actually mixes with some of the propellant. When you press the valve and product comes out the pressure actually never changes from 90 psi, because as product/propellant mixture is released from the can, some of the propellant in liquid form vaporizes into gas to take up the additional volume created and keep everything in equilibrium. This is why a can of spray paint gives you a consistent spray through almost the entire can.

Butane vs propane is used because each will keep the can at a certain pressure. Butane will work at a lower pressure, and propane at a higher pressure, and mixing both gives you anything in between based on the ratio. Something like a can of Raid you'd want a very high pressure to shoot out a 20ft stream of wasp killer, and something like body spray you'd want a lower pressure to create a fog to apply to yourself.

 

Very interesting, thank you for your reply on this.

 

I will bring him plenty of budweiser, but he will need to provide his own bed pan

 

Happy to help! Working with aerosols was some of the most fun years of my career. There was one test to qualify a package where we'd put in in a blast chamber and pressurize the can or bottle until it exploded. The DOT actually requires them to be able to withstand like 250 psi, so it was literally a blast doing this! I also had to do drop testing to make sure the package could withstand a 6ft drop from a store shelf onto concrete. The test fixture went up to 24ft though, so after the packages were dropped at 6ft and passed I'd take them all the way up and drop like 15 or so at a time. It was always a good time to see them burst on impact and fly and bounce around the blast closet like bottle rockets going off!!

After I left a buddy of mine took over that position and got a high speed camera to record and watch the carnage. He's shown me a few clips, it's REALLY cool to see a that stuff happen in slow motion!

 

That sounds cool. I got a minor in wood technology. It was basically aimed at you doing quality control, grading and destruction tests in a mill type setting or for an independent test company.

But I am a professional field forester, in a very tight niche. I basically oversee harvest operations on something like a quarter million acres. Nothing too exciting here other than being in the woods and around some heavy equipment and seeing huge trees put on a truck.

Here is a 12 tree load going out of the woods the other day. Not the biggest stuff I ever seen cut , and nothing to you west coast guys, but impressive for my area.

Had some big logs hauled out and at least one 100 ft pole that I can thing of in my career.

 

very good info and a good read. thanks for sharing.

 

Thanks for the explanation bassJAM. I learned some thing today so that makes it a good day. I will how ever leave the re pressurizing of aerosol cans to those who wish to do so. Now, give me a pound of triple F and some cannon fuse and hold my beer and watch this.