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Air purification for table top sharpening station

Discussion in 'Maintenance, Tinkering & Embellishment' started by razor-edge-knives, Apr 2, 2017.

  1. razor-edge-knives

    razor-edge-knives Moderator Moderator Knifemaker / Craftsman / Service Provider

    Apr 3, 2011
    While in my shop I use a 3m Breathe Easy Turbo PAPR system to protect my lungs and am very conscientious about protection as long term exposure can be very serious. I am curious as to some sort of dust management system for inside at my permanent sharpening table where I have my Wicked Edge set up. Of course, the easiest way for full protection is to sharpen while keeping your stones wet, but unfortunately I do not always have this liberty as the liquid can stain expensive blades I work on.

    Right now, I am thinking about a desktop air purifier at this point, to protect against the shed abrasive diamond particles as well as metal dust. I know some have tried magnets but this would only 'solve' half the problem.

  2. Joe Manco

    Joe Manco

    Jul 6, 2016
    I'm glad to hear how serious you are being about this, seeing how much time you spend sharpening and grinding. I have no answers for you except to use as much protection as possible.
  3. bucketstove


    Sep 23, 2014

    pressurized air nozzles and metal shroud ducting and shopvac and HEPA filters and boxfan and furnace HEPA filters?

    This in addition to the respirator and hearing protection

    What room in the house? Has a window? Do you seal the door/vents?

    Worth a look
    Hi My name is Patrice and I am addicted to dust collection!
    Metal Dust Collection - The Knife Network Forums : Knife Making Discussions
    J. Phil Thien's Cyclone Separator Lid w/ the Thien Cyclone Separator Baffle
    Wood Products: Sawmills eTool | Plant-Wide Hazards - Health Hazards > Wood Dust
  4. HeavyHanded


    Jun 4, 2010
    I'd want some sort of cyclone separator with hepa filter if possible. You could use a blower unit to create draw - these are not cheap but generally a lot quieter than a vacuum. Or place the vacuum in another room or closet.

    I have used the boxfan and HEPA filter solution and it seems to do an OK job (is tough to say as you cannot readily detect particles in the single micron size floating around unless its a real cloud). This is fairly quiet as well, and doesn't rely on outside venting either.

    I would not trust the air purification qualities of that desktop unit as it probably does not move enough CFM to provide adequate protection.
  5. cbwx34


    Dec 27, 2004
    Hey Josh:

    I've used a larger "Shop Vac" air cleaner... and found it only marginally effective... it has to be used where the intake is pretty much right at the source of the "dust creator". :) I doubt the one you linked to would be of much help.
  6. mattal21

    mattal21 Titanium Anodizing

    Oct 15, 2014
    I'd suggest buying/building a downdraft table.
  7. razor-edge-knives

    razor-edge-knives Moderator Moderator Knifemaker / Craftsman / Service Provider

    Apr 3, 2011
    Thanks for the links and suggestions, what you seem to be suggesting are great shop solutions but I'm looking for an inside desktop solution for manual sharpening... in my shop I grind wet which cuts down a great deal on the dust, and wear this (can even wear headphones and have a beard ;)), but inside I need something that is quiet yet efficient and small enough to sit on a desk top...


    And here is the dust it saves and keeps out of my lungs (both the dirty and clean side), yes this system is expensive but well worth it!

    Good points... I was thinking about some sort of fan on one side and intake/filter on the other, just not sure exactly how I would set it up or what I would use... I need it to not be loud or air blowing papers all over the place (my wife's desk is next to mine). I do have a window right next to the table though... I was thinking the same thing that one would not provide enough air flow, but wondered if I did a small fan on one side and then this unit on the other if that would work? We are not talking about large volumes of abrasive dust here.

    Here is a quick pic of my inside set up...

    I found this... may be worth investing in, I'm sure it's $1k-2k though, don't have that kind of cash right now unfortunately!


    Thought about that and looked into it... that would be ideal it's just that they are so huge most of the time. We shall see though!
  8. Jason B.

    Jason B. KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 13, 2007
    The standard is 4 air exchanges per hour, meaning the air within the room must make a complete change 4 times in one hour. I forgot the equation but I can look it up when I get home.

    One of the most commonly used (in my industry) Air Filtration Devices (AFD) is the Driesz HEPA 500. https://www.drieaz.com/DEC_Product_Base.aspx?decID=1041

    I use one of these daily in abatement and they work very well. There are smaller units but I like the volume of air these can move.
  9. WC53


    Dec 15, 2016
    My experience with woodworking and smaller chip carvying tools is that the desktop units are worthless as they don't move enough air. That said, you are not making a lot of dust.., but the intake would need to be right next to your work and almost envelope your WE to be effective. At the time, I ended up running pipe from my main dust collector and would do small work inside an open dust collector box.

    Depending on the cfm, a unit with a remote blower would be much quieter. I don't know the weight of diamond dust, but once stuff gets air borne, you need complete room exchanges to clear it. Could also be putting others at risk who come into the room at a later time. As someone who is paying for poor dust collection 30years ago, be safe.
  10. Rey HRH

    Rey HRH

    Oct 6, 2014
  11. razor-edge-knives

    razor-edge-knives Moderator Moderator Knifemaker / Craftsman / Service Provider

    Apr 3, 2011
    Thanks Jason! That product looks awesome, bet it works great! Unfortunately I think it's too big for my indoor settup, although it would likely be perfect for the shop!

    Hmmm...yes I definitely need to do something, I'll keep these points in mind. Thanks!

    That's perfect but I'm really wanting something that uses a HEPA rated filter... Wonder if I could get one made aftermarket?!
  12. Jason B.

    Jason B. KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 13, 2007
    Just remember there are HEPA filters and then there are HEPA certified devices. Adding a HEPA filter to something can help but IMO it's kinda wasting money... better off with a regular pleated filter. If you were dealing with lead then I might recommend a HEPA but for wood and metal dust it's a bit overkill.
  13. bgentry


    Aug 3, 2009
    Just wanted to chime in about the seriousness of lung exposure to metal particles. 10 years ago or so, I used to play billiards several hours a week; mostly on the weekends. I met a guy at the place I would go every weekend who was a regular. He was obviously skilled, but he had a really hard time making shots. After a short time of playing billiards with him, he told me that he had Parkinson's disease and that he was a knife maker. He had spent many days out in his shop grinding metal and breathing in the dust. This lead to his condition, at least according to him.

    I always think of him when I grind metal with a power tool.

  14. Rey HRH

    Rey HRH

    Oct 6, 2014
    Wow. As I heard it said, the best way to learn from experience is from other people's. There's a couple of people that I have in my past that have taught me lessons in the same vein.
  15. Bob6794


    Apr 21, 2013
    With HEPA filters, pre filters are important if you want it to last. A True HEPA will capture 99.97% down to 0.3 micron and there are versions that capture even finer amounts. Now the issue with this is they will get clogged on their own very fast, so prefilters such as carbon prefilters and easily cleanable ac pre filters should be on the list of things to do if it doesn't come with one. Keep in mind these things will decrease air flow, but will greatly increase longevity. I would also go overboard for the size of the room your trying to keep clean with a HEPA, lets call it from experience as I own a few HEPA's due to bad allergies. Going with one sized for your room just doesn't cut it sometimes, and going oversized allows you to drop the noise down a bit by not running it on full blast as they seem to go from quiet-moderate-jet engine loud from my experience. Clean from dust particles on one side of the room compared to the opposite side may be another problem if you are really concerned about this too, so have 2 or may be of use. I would locate it wear you are producing the most metal debree that can go airborne, and next the quite a bit farther away where your at often.

    Than there are HEPA "Types" which use HEPA material but don't meet the rating so these can be anything from something that are almost on par with a HEPA to something that is equalent to almost no filtering ability as there is no standard. So for the HEPA "Types" further research is advised.

    Chances are there are industrial tools that are made to do just this, but pairing it up with a good HEPA would be a nice touch. And I would still wear a good mask to be on the safe side.

    If you want my prefernce on good HEPA filters, I go with Winix. I am very satisfied with my Winix 9500. It's not something that will suck particles away from the work area (HEPA's aren't really designed for that), but it should help capture the small airborne stuff. Than the one I am less satisfied with is my Holmes (don't know the model number) but the filters are universal now so they easy to acquire and you can find them at department stores most likely.

    Here is the rating for some 3m Filtrate filters taken from an amazon review, so you can have an idea of what to use to make new higher effenciency filters
    Elite Extra 2400
    3-10 microns - 96%
    MERV 13
    pressure drop .21

    Elite Allergen 2200
    3-10 microns - 94%
    MERV 12
    pressure drop .18

    Maximum/Ultimate Allergen 1900
    3-10 microns - 93%
    MERV 12
    pressure drop .16

    Allergen Deep Pleat 1550 (4").
    3-10 microns 97%
    MERV 12
    pressure drop .12

    Ultra Allergen 1500
    310 microns - 90%
    MERV 12
    pressure drop .15

    Odor Reduction 1200
    3-10 microns - 85%
    MERV 11
    pressure drop .24

    Micro Allergen 1000
    3-10 microns - 80%
    MERV 11
    pressure drop .21

    (merv rating guideline https://www.filters4life.com/What-is-MERV-rating-s/4961.htm)
    Last edited: Apr 5, 2017
  16. Glock Guy

    Glock Guy Gold Member Gold Member

    Jul 28, 2012
    I use a Benchtop Power Carving Dust Collector with great results. The filter lasts forever, and you can easily just vacuum it out when it gets a little too dirty.

    Here's a link: https://www.woodcraft.com/products/benchtop-power-carving-dust-collector

    And the details:
    Virtually dust free power carving and sanding. The fans of this compact, portable unit draw up to 500 cubic feet of air per minute past your work. The two fans have computer grade, maintenance free motors - designed for years of trouble free service. Each motor is individually switched so you can control the amount of air flow you need. Easy-to-clean industrial filter traps over 90% of even the finest carving debris. Self-contained unit has dual 115V outlets to power your sanders or power carver. Includes a Plexiglas shield that attaches to the dust collector for increased efficiency. Overall dimensions 8" x 10-1/2" x 21".
  17. bucketstove


    Sep 23, 2014
    One thing I've noticed is how all the sales listing are useless for comparison shopping as they don't list the numbers that are on the box, you have to try dig those up from images/pdfs if possible

    Some interesting quotes
    SWARF! | scienceofsharp
    Clean Air Delivery Rate (CADR)
  18. WC53


    Dec 15, 2016
    Set ups like those 3 sided hoods are key to keep the dust from getting into the room. Some of those can vent outside if the home hvac will allow for it. I run an expensive hepa filter on my woodworking stuff and like was said by bob, I have two cyclone prefilters before the filter, and I still where a respirator these days. But the hi speed stuff throws alot out around the blades that a hand sharpening won't. The better fit the hood is around your sharpener, the higher airflow you will have across the key areas.

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