PDA

View Full Version : Compressed Air Can Sprays are very dear



Digby
03-03-2018, 07:53 PM
Hi
I find that the cans of compressed air are very dear.
They are about $18.00 now at PBTech, The Warehouse, Office Max etc etc.

Two questions why is compressed air so much dearer than a can of fly spray at $5 or 6 that has stuff in it!

Are there any cheaper places and are we being ripped off in NZ to places such as Australia or Singapore or Chile or the USA.

dugimodo
03-03-2018, 08:23 PM
Yes it's ridiculous, I use an airbed inflater instead or my vacuum cleaners blower.

kahawai chaser
03-03-2018, 09:16 PM
You can DIY hack it with Tyre valves. Vid here (https://www.youtube.com/watch?v=cbUV2iekEyo) - attaching a valve in pre-drilled hole, then pumping in air. Or this vid (https://www.youtube.com/watch?v=KWIL_jhk-y8)placing valve where the nozzle sits - then inject air, and liquid if need be.

I bought 3 cans of butane gas for 5 dollars at K-Mart. Cheap. Dunno why free aerosol canned air is costly...

Kame
04-03-2018, 12:45 AM
Any empty aerosol can you can add air to, normally to get the last drop of liquid out of a can I add air to it, but even an empty can would be able to store air.

I'm not sure what pressure aerosol cans can withstand but the bottom of the can will pop out if you pressurise it too much.

I normally aim for 60psi but if you buy a sureshot canister, you can get 200psi, although my air compressor is limited to 100psi so thats my max pressure.

NZ has a very high markup, a lot of places are above 300% but its quite the norm when they go through middlemen rather than import directly.

piroska
04-03-2018, 07:46 AM
A vacuum cleaner on reverse does the same thing.

me, I just use a clean paintbrush to clean out my PC parts...the bristles get into those crevices and it works well. Still have the same brush from the 1980's....

KarameaDave
04-03-2018, 10:57 AM
Vacuum cleaner = ESD

dugimodo
04-03-2018, 11:10 AM
Vacuum cleaner = ESD

Depends how close you get and you could always rest the end against the metal case to bleed off any static if you wanted, or put an anti static wrist band on your vacuum :)
Personally I only use the Vacuum for cleaning out out cases and heatsinks etc where it's not an issue. A smaller jet of air is better for cleaning some things.

Terry Porritt
04-03-2018, 11:29 AM
I would expect those air cans to be filled from an oil free compressor, well filtered, and be perfectly dry. Your common or garden compressor will also be putting oil and water vapour into the air if you don't have have good filters/separators.

This was always a problem in the early days of gas bearing development, trying to get really clean dry air, before oil free compressors were more commonly available.

However, the price really is a rip off, and they're not essential at all.

Digby
04-03-2018, 12:47 PM
I would expect those air cans to be filled from an oil free compressor, well filtered, and be perfectly dry. Your common or garden compressor will also be putting oil and water vapour into the air if you don't have have good filters/separators.

However, the price really is a rip off, and they're not essential at all.

Yes I dont really like the idea of using a common or garden vacuum ( mine does not blow) and I just wish the cans were about a third of the price.

Digby
04-03-2018, 12:52 PM
Just as I thought

https://www.walmart.com/search/?query=compressed%20air%20can&typeahead=compressed%20air%20can

$7 US for one can, or less than 6$ if you buy 3.

If you scroll down they also have a 16 pack



So we are paying twice as much in rough terms.

piroska
04-03-2018, 01:14 PM
Vacuum cleaner = ESD

Sigh.....
Explain how.

I have done this for years. It is plugged in you know, albeit switched off, and therefore earthed.

Kame
04-03-2018, 02:17 PM
The vacuum maybe earthed but static is caused by the friction generated by air and dust rubbing against the tube/hoses. A brush could also generate static from the bristles, nylon be the worse but even animal hair could alao become statically charged.

However, components are quite well protected, using an anti static silicone, which shield it quite well except for the contacts. Else components would fail with the amount of dust build up and fan movement.

It really depends on whether you want to risk it or not, it'd be safer to not do it but the probability is very slim these days too. Either way, blowing/sucking both have the ability to cause static, so do it at your own risk.

KarameaDave
04-03-2018, 03:48 PM
Sigh.....
Explain how.

I have done this for years. It is plugged in you know, albeit switched off, and therefore earthed.
The hose does not conduct back to earth, yet can build up a charge.
This was demonstrated to me when I was trained as a computer technician.
Oh and by the way...

Sigh right back at you.

wainuitech
04-03-2018, 03:55 PM
Just use a cheap air compressor from Mitre10 /Bunnings ( cant remember which) about 10 years ago, cost about $150, put on an air/oil filter, you can adjust down the air pressure so as not to damage any components, It also has a lot of other uses, like blowing up the tires on the wheel and sack barrows, other cleaning and sometimes even the odd small spray paint job.

Terry Porritt
04-03-2018, 04:06 PM
It wouldn't be very difficult to modify a small old out of date cng gas cylinder and fittings to take a filler valve and an outlet with hose and air gun, to use as a portable air tank, pumped up to about 100 psi??

You could then use one of those small 12 volt tyre inflators, run off an old PSU which I do for tyres and wheel barrow etc, to pump it up.

Main cost would be the hose and air gun.

apsattv
04-03-2018, 04:09 PM
Maybe cheaper just to buy a blower for the price of a couple of cans?
https://www.youtube.com/watch?v=SjUNNCh94Kk

Terry Porritt
04-03-2018, 04:30 PM
Whilst on the topic of dust, does anyone know if it would be worthwhile wiping fans blades with antistatic wipes or spray, or teflon spray, would it work last to prevent dust sticking ??

kahawai chaser
04-03-2018, 07:43 PM
As linked above are the hand held electronic air dusters - basically a mini blower. Similar to some larger garden blowers

But there are also the 18 V drill shaped blowers/Tyre inflators. Ryobi has one here (https://www.homedepot.com/p/Ryobi-18-Volt-High-Power-Volume-Inflator-P738/300997599) (cheap at home depot) Don't seem to be any here in stores. PC suppliers ought to have something similar. Simple hand pistol type rechargeable blower...rather than messing about with vacs, floor blowers, compressors, cans, etc...

piroska
04-03-2018, 07:58 PM
The hose does not conduct back to earth, yet can build up a charge.


Sigh right back at you.

So? So does touching the components with your hands. Can happen filling your car too....

It's EARTHED. It's why you always earth it when building them, never mind cleaning one. And earth means just that, not some dumb bangle round your arm connected to nothing that I have seen techs do.

When you vacuum, leave it plugged in. Also, you don't shove the cleaner right in it, you'd like damage a capacitor or diode or two, you use the brush and the vacuum sucks up the dust as you brush it out.

So yes, sigh.

KarameaDave
04-03-2018, 08:56 PM
So? So does touching the components with your hands. Can happen filling your car too....

It's EARTHED. It's why you always earth it when building them, never mind cleaning one. And earth means just that, not some dumb bangle round your arm connected to nothing that I have seen techs do.

When you vacuum, leave it plugged in. Also, you don't shove the cleaner right in it, you'd like damage a capacitor or diode or two, you use the brush and the vacuum sucks up the dust as you brush it out.

So yes, sigh.
Sigh you obviously fail to understand the voltages involved and the source of the electrostatic discharge.
Just because you are ignorant of this doesn't mean that it is not a threat.
OK :)

Ofthesea
04-03-2018, 10:01 PM
Wouldn't you be able to fill a scuba tank for similar money?
I know a scuba tank costs more but you would get a zillion times more air, nice and clean

1101
05-03-2018, 09:37 AM
Vacuum cleaner = ESD

case fans = ESD
sitting on your chair for some time = ESD (Ive actually had a small zap from that)
walking across the carpet = ESD
wearing synthetic clothing = ESD
compressed air = ESD

:)

If worried about ESD , then do things properly , as we were taught
anti static matts , cotton or natural clothing only blah blah blah

Digby
05-03-2018, 10:17 AM
case fans = ESD
sitting on your chair for some time = ESD (Ive actually had a small zap from that)
walking across the carpet = ESD
wearing synthetic clothing = ESD
compressed air = ESD

:)

If worried about ESD , then do things properly , as we were taught
anti static matts , cotton or natural clothing only blah blah blah

So how do you clean your PC?

KarameaDave
05-03-2018, 10:20 AM
case fans = ESD
sitting on your chair for some time = ESD (Ive actually had a small zap from that)
walking across the carpet = ESD
wearing synthetic clothing = ESD
compressed air = ESD

:)

If worried about ESD , then do things properly , as we were taught
anti static matts , cotton or natural clothing only blah blah blah

I do.

1101
05-03-2018, 11:32 AM
So how do you clean your PC?

either an ESD safe vacuum cleaner (we have one) . But with that you still have to get in there with a paint brush to loosen all the dust
I hold the vac nozzle away from the board , lossen all the dust with a paintbrush .
I guess if you put the vac nozzle right next to the board , that would be more of a risk

or just compressed air, via a home air compressor if its really really dusty. Sometimes there is no other way to get all the dust out.

Terry Porritt
06-03-2018, 01:42 PM
Here you go, a low or no cost compressed air can, easy as peasy DIY:

Procure or buy a tyre valve. I bought a rubber valve stem, hardest and longest part of the job is removing the rubber down to clean brass. Measure diameter of stem.

Take one empty fly spray can.

Make sure it is empty. Flush through with compressed air to make sure no hydrocarbons present.

Drill hole in can to size of stem, slightly under size, and taper ream hole if needed to make stem a tight fit.

**tape down the valve lever at the top of the can to open it to atmosphere, otherwise the air will expand when the can is heated and maybe blow out the hard solder**

Silver solder with gas torch (Easi-Flow hard solder) stem to can.

Pump up with compressed air ........done

Notes: These cans according to manufacturers data have a burst pressure of > 2Mpa.....300psi.

The higher the pressure the longer the air will last, my 12v tyre pump only goes to 120 psi. 150 or 200 psi would be better.

For cleaning a computer you may have to re charge a few times. :clap

tweak'e
06-03-2018, 06:58 PM
a can of compressed air at 200psi is not going to last long.
"can of air" is refrigeration gas. so its liquid in the can, so it holds a lot of "air" for its size.

edit: if using compressed air, make sure its fairly dry. draining the water out of the filter/tank still means the air is 100% saturated with moisture. you need a drier in the system.

Digby
08-03-2018, 07:05 AM
I am thinking of a two pronged approach.
I like the idea of using the compressed air cans, as they may be as Tweak says above - refrigeration gas, that is why the air is cold.
But a can only seems to do one clean.

So I may buy a small compressor and use that to do the case and grilles and non critical parts, and then finish off with a can to do the CPU fan and the motherboard.

Terry Porritt
08-03-2018, 08:07 AM
I am sure sucking the dust away with a vacuum cleaner is infinitely superior to blowing dust all over the place and it being forced into nooks and crannies, even into fan bearings, or back into the room to be drawn in again by the fans :clap

When I was in bearing research and machine tools and precision bearings of all sorts, compressed air was an absolute no no.

Ok when you are machining and blowing off suds and swarf, if done prudently taking care with your eyes, common workshop practice.

But I'd never happily use it on a computer. Still if you can afford the rip off price then go ahead, your decision.

dugimodo
08-03-2018, 09:17 AM
I am thinking of a two pronged approach.
I like the idea of using the compressed air cans, as they may be as Tweak says above - refrigeration gas, that is why the air is cold.
But a can only seems to do one clean.

So I may buy a small compressor and use that to do the case and grilles and non critical parts, and then finish off with a can to do the CPU fan and the motherboard.

I use a ryobi cordless compressor/ inflator myself - for all of it. If there's any contaminants in the air I can't tell - I spayed a piece of clean white paper and can detect no residue.

The comment about refrigeration gas prompted me to google it and yep it's not air in those cans https://en.wikipedia.org/wiki/Gas_duster.

One little picky point I can't let go, the "air" in the can is not cold - it's at the same ambient temperature as everything around it. When it expands it absorbs heat energy from everything it touches and that has a cooling effect, but the "air" itself is not cold.

Terry Porritt
08-03-2018, 09:33 AM
.....snip

One little picky point I can't let go, the "air" in the can is not cold - it's at the same ambient temperature as everything around it. When it expands it absorbs heat energy from everything it touches and that has a cooling effect, but the "air" itself is not cold.

I'm going to be picky too :) Of course the gas gets colder.
If it was a perfect gas and true adiabatic expansion there would be no temperature drop. However the gas is expanding through a nozzle, and you get the Joule -Thompson cooling effect, the basis for refrigeration and liquefaction of gases.

Neither is the gas "perfect, so there will be an additional cooling effect.

The gas absorbs heat from what it touches and the surroundings because it is at lower temperature QED.

1101
08-03-2018, 09:40 AM
I am sure sucking the dust away with a vacuum cleaner is infinitely superior to blowing dust all over the place and it being forced into nooks and crannies, even into fan bearings, or back into the room to be drawn in again by the fans :clap
.

actually no. :-)
if the PC is really dusty , you need compressed air (from air compressor) to get all the dust out . Vacuum cleaner does a half arsed job, but is good enough most of the time.
the cans arnt much good on really dusty PC's.
You just need to be carefull using compressed air from a compressor , dont blow into the fans , or hold the fan to stop it spinning if no other way.
Compressed air gets the dust out of nooks & crannies, vac cleaners leave it in there

Also, there is no other (easy) way to get the dust out of the power supply . They can be choc full of dust , on really dusty machines.

Terry Porritt
08-03-2018, 12:51 PM
I had a computer to look at from a woodworking firm, the PSU was as you said choc ful............. of sawdust :)

The only way to clean it was to open it up and brush and suck the crap out, the rest of the machine was as bad too. I still don't believe in using compressed air is a good idea on anything resembling instruments, bearings etc, it's the way I was brought up :)

edit: Especially as I had a piece of steel swarf go into my eye on more than one occasion !!