Activated carbon filter fume extractor works or not?

[neazoi]

Hi, I have made a homemade solder fumes extractor using two PC fans that sandwich an activated carbon filter between them tightly. Similar to the commercial models but it cost me onle $10.
But when operating, I can still see the solder smoke come out of the back side of the filter.

Is that normal, or should I exect to see no solder smoke at all if the filter was effective?

 

[schmitt trigger]

This may mean that your airspeed, m/sec, thru the filter is too high.
Try to reduce the fan speed and see what happens.

Of course there is the tradeoff of reduced airflow M^3/sec. (read: amount of air being filtered)

Of course you could increase the filter's surface area to reduce the airspeed while maintaining the airflow.

 

[Audioguru]

Why don't you get a temperature controlled soldering iron that does not get so hot it burns everything?

 

[neazoi]

This may mean that your airspeed, m/sec, thru the filter is too high.
Try to reduce the fan speed and see what happens.

Of course there is the tradeoff of reduced airflow M^3/sec. (read: amount of air being filtered)

Of course you could increase the filter's surface area to reduce the airspeed while maintaining the airflow.

So normally I should not see ANY smoke out of it, for this to operate correctly?

 

[dick_freebird]

The carbon is meant to adsorb certain things (like vapors).
It is not a fine particulates filter. And you can't expect the
carbon to take out everything that goes past, in one pass -
more usually the carbon is in a recirculating system where
it has many opportunities to catch "whatever".

 

[neazoi]

The carbon is meant to adsorb certain things (like vapors).
It is not a fine particulates filter. And you can't expect the
carbon to take out everything that goes past, in one pass -
more usually the carbon is in a recirculating system where
it has many opportunities to catch "whatever".

Cheap commercial fume extractors use only one filter https://www.youtube.com/watch?v=FWwtHxc7uRU
I do not think they are different than my homemade unit, all they have is a fan that passes air through the filter.
The filters I have bought, are replacements for these commercial fume extractors.

Do you think that a second filter in series with the first one will do a better job (despite the reducing of air flow)?
I have not used these commercial fume extractors so I cannot see the difference from mine (if they allow any smoke to come out).

 

[chuckey]

Activated carbon filters for cooker hoods seem to be a perforated plastic container that are filled with carbon granules. The problem is that holding them up to the light, you can see light through them i.e. there are air paths through them. Is you filter like this?. I would use only one fan and use the paper like material that is used as the front filter in a cooker hood. You need a large area for the filter to keep the air velocity low.
Our head of department insisted that our wire man used one, but it seems to have no effect. The problem seemed to be that the hot gases from the heating of the flux had more convection energy to rise verticaly, then the filter units suction to draw them into the filter unit.
Considering the legions of wire women who toiled in wiring shops since the 1940s, I have never heard of a single case of disease being laid at the doors of soldering flux. Its a theoretical problem invented by elf and safety officers.
Frank

 

[neazoi]

Activated carbon filters for cooker hoods seem to be a perforated plastic container that are filled with carbon granules. The problem is that holding them up to the light, you can see light through them i.e. there are air paths through them. Is you filter like this?. I would use only one fan and use the paper like material that is used as the front filter in a cooker hood. You need a large area for the filter to keep the air velocity low.
Our head of department insisted that our wire man used one, but it seems to have no effect. The problem seemed to be that the hot gases from the heating of the flux had more convection energy to rise verticaly, then the filter units suction to draw them into the filter unit.
Considering the legions of wire women who toiled in wiring shops since the 1940s, I have never heard of a single case of disease being laid at the doors of soldering flux. Its a theoretical problem invented by elf and safety officers.
Frank

Thanks for the info chuckey.
I solder since 1992 and back then we were not even aware of the lead hazards. I do not know any hobbyist that has ever got ill from solder smoke, so I would not spend $50 for a such filter, no way. Even a single fan that puts fumes away from your face when soldering is enough I think.
However if there is a case that this cheap filtering can do any good, why not?

In my filters, I can see some light passing through ( https://www.ebay.com/itm/301287899247?_trksid=p2059210.m2749.l2649&ssPageName=STRK:MEBIDX:IT ).

So you believe, the filters must be thick (maybe stack more than one together) and the air flow must be low, am I getting it right?

 

[chuckey]

I think its better if the air velocity is low. If there is too much air pressure the air will just seek out the "holes" and go through them.
Frank

 

[neazoi]

I think its better if the air velocity is low. If there is too much air pressure the air will just seek out the "holes" and go through them.
Frank

It that normal to see some smoke come out? or ideally it should be absorbed all of it? That is my point.

 

[Audioguru]

If it does not filter out ALL of the smoke then it is useless, isn't it?

 

[neazoi]

If it does not filter out ALL of the smoke then it is useless, isn't it?

It is not obvious.
It's purpose could be only to filter only certain substances and let the rest of the smoke come out.
I am asking because I do not know

 

[Audioguru]

I use an activated charcoal filter (Brita) to filter chlorine from my tap water and another one to filter the water in my fish tank.

My soldering iron (Weller) is temperature controlled so it never gets too hot to incinerate the rosin in my solder.
Some cheapo controlled temperature soldering irons simply use a light dimmer circuit to reduce the power to its soldering iron so it still gets too hot while doing nothing then it gets too cool when it is soldering for a while.

 

[FvM]

It's purpose could be only to filter only certain substances and let the rest of the smoke come out.

How could this happen? If you see smoke passing the filter, you confirmed that it can't retain particles, at least not completely. So gaseous components will very likely pass the filter, too.

A different question is if the "cheap commercial fume extractors" from youtube are working anything better.

 

[ads-ee]

I think you want both a HEPA filter and the activated charcoal filter. You want to build something more like **broken link removed**.

Now about those that haven't noticed any "problems" after years of soldering https://en.wikipedia.org/wiki/Lead_poisoning. Trouble with lead is it builds up over decades of exposure and the symptoms could be confused with something else.

And something to read while you are inhaling those wonderful solder fumes: https://www.sentryair.com/solder-fumes.htm:thinker:

 

[Audioguru]

I have been soldering all my life and did not know that it is SO dangerous to breath the pleasant aroma.
I get asthma when I am near a live rabbit (my daughter had a pet rabbit when she was young) but I doubt it was caused by my soldering.
This is what you need for protection from soldering fumes:

 

[neazoi]

Thank you all for your answers,
Now I did not deny the lead problem and that is the reason last year I switched to lead-free solder and donated many kilos of old projects that have been soldered using lead based solder and the lead solder itself. I warn you, to try to clean a "lead-using" lab could be a nightmate, if you are extremely concerned about lead you will find that almost everything is contaminated with lead. At least I believe I did as better as I could, however new non ROHS components arrive ocassionally, so I do not think even the very careful fellows can ever be completely safe unless they are very carefull about every single component they buy. But indeed the main source of danger is the lead-based solder itself. Throw it away and you are done. I believe all fellows in my age (around 35) and older ones, have lead in them, as back in our first steps in electronics there was no internet and no one told us about the dangers. But I do not think we need to freek out about this fact anyway.
Now about the solder fumes, I have seen several systems, the problem is that these are all EXPENSIVE. Now, how one judges the term expensive is subjective and it is how much priority you give to your health. But come on guys, there has to be a simpler non costy solution for solder fume extraction, homebrewers cannot afford $400 for such a system and they should not.
A vacuum cleaner with a long tube outside the house seems to be the cheapest safest solution.
But maybe a series of activated carbon filters in conjunction with low speed air flow solves the problem..?

 

[Audioguru]

In google, medical people say that the best air purifiers have activated carbon and Hepa filters.
They do not say how long they last nor how to know when to replace them.