DIY air filtration unit for <$200

[Robert Silvers]

Reflecting on this post, if you had to start over - what about just buying one of these eBay units designed to keep people from smelling your weed?


Are they appropriate for the laser?

[Dan Hintz]

It would make for more convenient changes of the carbon filter, but this does not include a HEPA filter nor a bulk capture filter, and the entire unit would still need a housing to control airflow through each filter.

[Robert Silvers]

On the typical Chinese laser, what size duct do they use? I want to buy a grow-house unit that fits the same duct size, and then I will find a way to get a HEPA after it.

Speaking of which, what about not using a HEPA after it, but using something like this after the charcoal?

http://www.amazon.com/Honeywell-CF10...ef=pd_sim_hg_1

[Robert Silvers]

http://www.epa.gov/iaq/pubs/airclean.html

• Medium efficiency filters with a MERV of 5 to 13 are reasonably efficient at removing small to large airborne particles. Filters with a MERV between 7 and 13 are likely to be nearly as effective as true HEPA filters at controlling most airborne indoor particles. Medium efficiency air filters are generally less expensive than HEPA filters, and allow quieter HVAC fan operation and higher airflow rates than HEPA filters since they have less airflow resistance.
• Higher efficiency filters with a MERV of 14 to 16, sometimes misidentified as HEPA filters, are similar in appearance to true HEPA filters, which have MERV values of 17 to 20. True HEPA filters are normally not installed in residential HVAC systems; installation of a HEPA filter in an existing HVAC system would probably require professional modification of the system. A typical residential air handling unit and the associated ductwork would not be able to accommodate such filters because of their physical dimensions and increase in airflow resistance.

http://www.mechreps.com/PDF/Merv_Rating_Chart.pdf

So it looks like MERV 13 or better is decent.


Here is a MERV 12:

http://www.amazon.com/Honeywell-CF20...ds=HVAC+filter

MERV 13:

http://www.amazon.com/Nordic-Pure-14...ywords=MERV+14

15:

http://www.amazon.com/Carrier-Bryant...ywords=MERV+15

16:

http://www.amazon.com/Lennox-X6666-M...ywords=MERV+17

http://www.amazon.com/X6675-Lennox-2...ywords=MERV+20

[Dave Sheldrake]

On the typical Chinese laser, what size duct do they use?

100mm, 125mm and 150mm normally depending on machine size.

I want to buy a grow-house unit that fits the same duct size

I've done the same on my home laser (the one I play with when I'm not working) seems to work very well but I don't need "breathable air" coming out as it still vents to the outside (I just wanted it to smell nice for the neighbours)

best wishes

Dave

[Dan Hintz]

My HEPA cost $50... tough to beat that.

[Robert Silvers]

My "laser" has a 150mm exhaust. I ordered a 6x26" scrubber from eBay. Cost $89 shipped. Has 2 inch thick layer of charcoal.

I will use a 6" elbow through the side of a 44 or 50 gallon trash barrel and then seal a MERV 13 HVAC filter onto the top of the barrel.

[Robert Silvers]

Just got this from eBay for about $90. Seems like a really good deal.

[Dave Sheldrake]

Just got something similar Rob, the only downside is the air has to travel from outside to inside to prevent the filter clogging. Did you get a prefilter kit with it?

best wishes

Dave

[Robert Silvers]

It came with a prefilter wrap.

I didn't know that - but I will set it up that way. I will go to Lowes and look for a trash barrel or plastic container and a way to rig it.

[Dave Sheldrake]

Just been playing with mine Rob, it reduces the smoke but doesn't remove it totally,

I have a fan extracting to a wooden sealed box with the filter inside the box and a second fan pulling from the filter to atmosphere.

I'll keep it going for a while longer and see what happens but so far it's not going to be "inside room" capable for sure on mine.

cheers

Dave

[Robert Silvers]

I have 2 inches thick of carbon. Do you have 1, 1.5, or 2 inches thick?

[Robert Silvers]

I want to work one of these into it:

http://www.amazon.com/24000-Honeywel...ds=HEPA+filter

[Dave Sheldrake]

2 inches of Carbon Rob, I'm lacking the HEPA though that Dan used in his which is where I'm probably losing the performance.

It's great on acrylic but on a 180 watt cutting MDF it only reduces the smoke by around 40%. I'm off into town tomorrow to find something similar to yours and Dan's HEPA to add that in and see what happens.

best wishes

Dave

[Dan Hintz]

When I'm engraving/cutting heavy wood (large wood plaques and such), I get zero smoke in the room after a couple of hours of straight work. First it hits a furnace filter, then the 2" bed of carbon, and finally the HEPA. I purchased one of those Honeywell Electronic filters thinking I could trap a lot of smoke that way and increase my carbon life... I skipped it after I determined the amount of airflow would make it all but worthless, and I'll likely install it in the home HVAC next remodel session.