# Workshop air filter for £3.53!!!!!!!!



## SVB (23 Sep 2006)

I just thought I would share with you what I use for my general workshop air filter.

It is simply an old (read free) industrial fan rescued from the tip, mounted in the back of a 1/2" ply box with a 12" sq filter mounted in the mouth. The filter (£3.53 ea) is taped in place against blocks to prevent any side leakage and is rated at 1 micron effective.

I don't suppose it will have microclean revising their business model but it seems to work reasonably well (the filter has plenty of dust on the face anyway!) and will certainly serve the purpose until the lottery ticket comes good!


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## tim (23 Sep 2006)

Nice work - where did you get the filter fro?

Cheers

Tim


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## SVB (23 Sep 2006)

I got it from RS (www.rswww.com) They have loads of different sizes / shapes.


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## Fecn (23 Sep 2006)

Excellent work... You're as much of a cheapskate as I am


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## Russell (23 Sep 2006)

Excellent idea hows the noise


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## SVB (23 Sep 2006)

Reasonably quiet. I listen to the radio at a normal level. I have not heard the bought air cleaners to make the comparison but I don't suppose there will be much difference as they are all just a fan in a box!


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## mel (23 Sep 2006)

do you realise how many patents youve broken by using that black tape on the filter ????? 
:lol:  :lol: 
any more ideas like that ??? 
mel


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## wrightclan (23 Sep 2006)

Like it. Any idea what micron the filter goes down to?

Brad


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## A_n_g_e_l_a (23 Sep 2006)

Here is a link to microclene replacement filter pads that claim to work down to 0.4 microns.

Angela

If you fly you
can use YAWS


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## DaveL (23 Sep 2006)

Simon, 

Well done with this, you beat me on a cost front but I am not sure how long your filter will work before it gets well clogged. 

I built a similar unit, look here, using filters from Axminster, the cost of the filters has of course come down since I bought mine, but I bought a second set when they were on special offer. I will keep them as spares or if another fan shows up I might make a second filter. This is a course pre filter and a fine inner, I vacuum the out filter when I clean up in the shop, its surprising how much dust it does collect.


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## SVB (24 Sep 2006)

Dave,

Yes, clogging is something I am a bit concerned about. (Not because it will happen, 5 mins, a face respirator and a wall will sort that out) but because I may not realise it has happened.

I have resolved to give in a bang out after half a dozen half days in the workshop and replace after 3 or 4 cycles. I am not sure if that will be ok but it should give me less than a fiver per annum running costs at my current level of time in the workshop!!!!

I link the look of your filter by the way, a bit more respectable than mine for display on this forum!


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## A_n_g_e_l_a (24 Sep 2006)

> Yes, clogging is something I am a bit concerned about ... because I may not realise it has happened.



I read a good tip, I can't remember where, to tie a short length of thread in the expelled air stream and note the droop with a fresh filter. Later when the droop increases significantly, the airflow must have been decreased by a clogged filter. The thread is a small windsock in reality!

Angela


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## wrightclan (24 Sep 2006)

SVB":1libajwu said:


> I have resolved to give in a bang out after half a dozen half days in the workshop...



Or even hoover it out.  

Brad


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## wrightclan (24 Sep 2006)

SVB":2jzo688z said:


> I got it from RS (www.rswww.com) They have loads of different sizes / shapes.



Do you know the stock No.?

Brad


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## Project88 (4 Oct 2006)

Sorry if this is a bit OTT, but I intend to build an air cleaner and this thread has prompted some action and hence research; which I thought I would share.

I looked at the RS site and deduced from the picture and price in this thread that the unit was made by Camfil and was probably their part number PP12122 NOM (RS Stock 185-0749), this is 12”x12”x2” deep. The important rating is the Filter Grade which is G4. This rating comes from EN779, which I managed to get a look at. 

The EN divides filters into two groups G rated and F rated. Classification of F filters is based on performance with respect to 0.4um particles. Filters found to have an average efficiency value of less than 40% will be allocated to group G. The classification of G filters is based on their average arrestance with loading dust.

Average efficiency is the percentage of 0.4um particles which have been prevented from passing through the filter. Arrestance is the percentage of all particles prevented from passing through the filter. Loading dust is a controlled dust to ISO 12103-1 (Arizona Road Dust). This loading dust contains a range of particle sizes to 80um where 97% of the volume of the dust is larger than 1um.

So G class filters are rated by how much loading dust they arrest and F class filters are rated by how efficient they are at stopping 0.4um particles. To get an F rating the filter has to be more than 40% efficient at stopping 0.4um particles.

To obtain a G4 rating requires that more than 90% of the loading dust must be arrested, but by definition more than 60% of the dust that gets through will be 0.4um or smaller.

I don’t know what size MDF dust is, however after speaking to a few filter suppliers they suggest for this type of application a G4 rated filter as a pre filter and a F7 rated final filter. This is the standard for filtered air in office buildings. The EN standard indicates that F7 rating have an average efficiency of 80% - 90% of 0.4um particles.

I have some other technical data available if anybody is interested.

Bottom line for me however is, something; G4 rating or F7 rating; is MUCH better than the nothing I have at the moment


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## Losos (25 Oct 2006)

Simon,
Very interesting thread & you've started me thinking.

Would the fan motor assembley from a car heater work OK?? Being 12volt I could run it from a battery & maybe charge the battery from a solar panel (Would need a bit calculation of current drain versus charge rate etc.)

On the noise front I have the Microclean 100 (Their smallest model) and I find it very noisy, I can't hear the radio clearly over it  so I only use it at night.

The Microclean 100 is way too small for my shop now so I think I'll definately have a go at making one similar to yours. I have some spare Microclean filters so I could start by using them.

Thanks for the idea.


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