Computer dust bag.

[Richard Hole]

Hi Rob or whoever can help,

I thought it would be an idea to put my computer in a bag to prevent dust or insects getting inside. I could make one out of sandfly netting or buy one like at http://www.dirtbag.biz/  or http://www.computerdust.com/ .

Do you think it would be all right to run the computer 24 hours a day inside such a bag so long as the bag is not tight up against the vents? The bags on the above links seem promising. However, they are from overseas companies. Do you know any that are available in Australia?

I heard that insects like cockroaches can cause problems in computers. I have had a gecko cook one of the boards once. As a result I leave my computer on all the time to hopefully prevent insects and geckoes getting in.

I could also make a net bag for the computer. If I do this do you think sandfly netting would be good?

Is there a way to see in the settings if the computer is overheating? A concern could be if the net bag did get blocked up with dust and I did not get a chance to clean it for a while. It would be good if there was a way to work out when it needed cleaning.

Your help is appreciated,
Regards Richard.

[The Radio Geek]

Hi there Richard,

A great question, and a nice bit of research on the dust bags.  Righto - here are my thoughts:

* As long as your computer has all the back plates (those little slot covers) installed, then you should be fine for Geko's & cockroaches.  I have repaired quite a few machines that suffered from gecko's, but in all cases they had larger open holes in the machine case that allowed them to get in.  So, my initial thoughts are that insects should not be your problem.

* Those dust bags are good for just that - Dust !  This is one of the primary computer killers in our environment, so a dust bad sounds like a good idea.  In that case, a sandfly net would not give you as much protection as those fine mesh bags.

* Yes, I agree with the cooling problem.  In fact, that would be my main concern.  In the tropics, we need to get much more air through our machines compared to those down south.  In that case, I would be concerned that air is just re-circulated within the bag, rather than getting pumped in & out.

* Knowing when they need cleaning should not be a problem - just look at them!  If you see dirt on the outside of the bag, could be time for a clean   It should not happen too quickly however - their is a large surface area on the bag, so as one area gets blocked it will draw air from other parts of the bag easily it would seem.

So - if insects are your concern, just make sure that there are no major holes in your computer case.   If dust is your main worry, then the micro fibre dust bags sound like a good idea, however you might need to get a little clever in terms of making sure that air is definitely moving in & out of your whole system rather than getting pumped around inside the bag.

Hope that helps!

Cheers,
:)RG

[Richard Hole]

Hi Rob

Thanks for the answer.

Is there a way to see in the settings if the computer is overheating? If not, is there a way to install a temperature sensor or thermometer easily to alert me of a possible problem?

It could be hard to know when the bag needs cleaning or replacing just by looking at it. I do not have time to do it too often so I do not want to do it if it is not necessary.


Your help is appreciated,
Regards Richard.

[The Radio Geek]

There are several temperature sensing methods available for computers - some modern motherboards actually have temperature sensors on them so that power management and fans/cooling systems can be activated automatically when needed.

There are also lots of "after market" cooling systems available - these are particularly advanced for the computers built for "gaming" applications as they tend to have the highest heat load.

In Cairns, most computer shops have an array of cooling devices, the largest range I have seen has been at the  "Add To" computer shop.  (Phone 4031 6883 or visit Cnr McLeod & Florence Sts, Cairns)

In terms of looking at the bag - it is on the outside of your computer and would be pretty easy.  I can't think of a technical solution that would be any simpler than checking every few weeks and marking it on your calendar!

Cheers,
:)RG

[Richard Hole]

Hi Rob

Thanks for the info.

Someone suggested making a bag out of air conditioner filter foam. However, it is rather thick. If it is used I feel it would be important to keep an eye on the temperature with software at least for a start and in hot weather. Do you think it would be worth a try?

Your help is appreciated,
Regards Richard.

[Richard Hole]

Hi Rob and those interested,

Something that could work better than air conditioner filter foam is fine curtain material that has holes in it that are smaller than sandfly mesh. It would be more flexible than filter foam as well and could be easily creased and tied around the cables. Do you think that could be worth trying and do you think it could be as good as if not better than air conditioner foam?

I was also referred to SpeedFan software that allows you to have a deeper view of the status of your computer and monitor the temperature. See http://www.almico.com/sfdownload.php
Could this be worth trying?

Your help is appreciated,
Regards Richard.

[The Radio Geek]

Hi there Richard,

Thanks for calling in to the show yesterday - it was great to hear from you.  I really am interested in what you come up with in terms of dust protection.  In fact, I am about to build an "industrial" equivalent for our server racks for the business - I will let you know what we come up with!

Essentially everything you are engineering will come down to trade-off's.  The micro-fibre of the dust filter bags will remove more dust - but will be harder to clean (and will need it more often).  The curtain materials will need less cleaning, but will inevitably let more dust in.

Perhaps you can take some photo's of your project?  Some construction photo's will assist those that might be interested in building their own versions

Might be the next great invention? 

Cheers,
:)RG

[Richard Hole]

Hi Robert

Thanks for your interest. It is hard to know whether it would be best to use curtain material or air conditioner filter foam. I may try curtain material first due to the below reasons. Curtain material could be easier to put on and take off the computer as it can be creased and more easily slid under the computer while only lifting one end at a time. Also, the curtain material may trap less heat than the air conditioner filter foam because the filter foam may act more like a blanket. The curtain material also dries quicker after it is washed.

The commercial dust bags at http://www.computerdust.com/ are not washable and would need to be replaced which would mean extra cost and ordering from overseas. I still think a bag made from curtain material should stop over 10 times more dust than no bag at all and most people do not have any protection.

I value your opinions.

Your help is appreciated.     
Regards Richard.

[Richard Hole]

Hi Robert and those interested,

I finally got the computer made up so I am now in a position to make up the dust bag. Were you ever able make up one and test it yourself? One computer technician said it was a bad idea to have a bag. However, I still think it should probably be all right provided enough air entered the bag. Do you have any idea what size air holes I should try in the bag for the first prototype? I could use a light net material with similar holes to sandfly netting with holes that are about 0.5mm across. However, there are finer curtain materials with holes that are less than 0.1mm across. Air conditioner filter foam is another option. However, curtain material could be easier to put on and take off the computer as it can be creased and more easily slid under the computer while only lifting one end at a time. Also, the curtain material may trap less heat than the air conditioner filter foam because the filter foam may act more like a blanket. The curtain material also dries quicker after it is washed.

The commercial dust bags at http://www.computerdust.com/ are not washable and would need to be replaced which would mean extra cost and ordering from overseas. I still think a bag made from curtain material should stop over 10 times more dust than no bag at all and most people do not have any protection.

I could put a probe of a digital thermometer inside the computer box to measure the air temperature inside it where the probe is not touching anything. What maximum temperature would be considered safe?

I value your opinions.

Your help is appreciated.     
Regards Richard.

[The Radio Geek]

Hi there Richard,

Great project - still very interested in you posting pictures of your invention!

My thoughts so far:

1) The ideal temperature is basically as low as you can get it.  While your PC will have rated working temperature limits (usually around 50c) each computer is different - and mainly the problem will then be cooling.  Air cooling is directly proportional to :
a) the surface area of the cooling surface and
b) the temperature differential between the surface area and the air used (to cool).
The reason we use great big fans in computers up here is simply so that the air inside the computer case  is refreshed with new air as soon as it heats up - thus improving the cooling.
I would suggest that you run your PC with a temperature probe inside the case without the dustbag first, and note the temperatures.  This will provide you with a baseline.  I would suggest that you do this with a standard load (eg play a DVD) and then note the temperature of the outside ambient air, and the air inside the case.  Use the same conditions then to compare your bag once you have constructed it.

2) "Hole size" of the material should not affect the airflow, so long as you increase the surface area as you decrease the hole size.  The smaller the holes - the larger the bag needs to be.  The hole size should ONLY affect the amount of dust that you collect.  That is unless you make all the bags the same size, in which case the hole size affects both. 
If you have the time and patience, I would start with a small size and get larger looking at how the temperature is affected.  Test each configuration using the method outlined in #1 to compare to your baseline.  Basically you would benefit from the smallest hole size that doesn't cook your computer.

3) Design - check out your computer case and see how the airflow works.  Depending on the placements of case fans (those that sent to the outside) you will notice that your computer case should draw from one area, and exhaust from another.  As a simple example, you might have a case design that "draws in" from the front, and "exhausts" hot air to the rear.  In this case I would strongly suggest that you "tape" the case in the middle, so that hot air that exhausts from the rear cannot recirculate inside the bag to the front.  You need to prevent this at all costs as it will cook your computer quickly.  If your case has side vents, I think you can easily tape them up to develop a "front to back" circulation without any ill-effects.

4) Fans - being that you will probably be taping up some vents, and will definitely be adding some kind of airflow restriction in the form of a bag, it is important that you have enough fans to pump air around.  Most importantly you will need case fans of sufficient size and power to draw air in, and exhaust out from the computer case.  It would be work the few dollars extra to ensure that you have enough case fans - each case has fittings for different sizes and placements.  Remember - you are mainly looking for ones that will either draw or exhaust the case - internal fans will be useless in your situation.

Hope that helps,
Cheers,
RR

[Richard Hole]

Hi Robert

Thanks for your comments.

I could make a bag fairly large and peg the slack up to make it like a smaller bag to see how a small bag would work. Then I could unpeg it to make it larger if needed. This could save making up another bag

Where you suggest that you "tape" the case in the middle, are you suggesting that I have the bag tight up against the computer box in a section between the front vents and the back vent near the fan where the air is blown out? This would mean a separate compartment in the bag so that the warm air leaving the back should not mix with the cooler air coming in the front. I could put a strip of foam between the computer and the bag to make it seal better. Instead of tape, I could even tie some string around the outside in that case. I cannot see why I would have to tape up the vents in the side if I tape or tie the bag tight against the computer between the side vents and the back. The tape or string to tie the bag tight around the computer could be towards the back if there are side vents so that the side vents are in a separate compartment to the back vent where the warm air is blown out.

Do all new computers generally have case fans these days which I thought were mounted internally? Are you also suggesting I have another fan outside the computer box and inside the bag to blow the air through the bag or are you suggesting I should have another fan inside the computer box which I thought would be considered internal. In the last paragraph I initially thought you indicated that the computer technician should put an extra fan inside the box. However, then you said “internal fans will be useless in your situation” which may indicate that it would be better to have the fan outside the box which I could set up.

Another way would be just to try the computer with the one fan for a start to see how it goes with a large bag. Then if it gets too warm I could get another fan put in.

Your help is appreciated
Regards Richard.