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  1. #16
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    This case demonstrates the ineffectiveness of most respirators, masks and in room air filters and why dust is best completely removed from the working environment.

    Respirators and room air fliters don't prevent dust from settling on hair and clothing and some of this dust is then breathed in when the respirator and clothing is removed. A friend of ours who is a medico indicated that continuing to the wear same dusty clothes for hours after the dust making activity is over is asking for problems. He suggest the respirator be left on and all clothing be put into a washing machine and then removing the respirator and stepping immediately into a shower is the way to handle this.

    In terms of air extraction, 4000 fpm (~20 m/s) at 1000 cfm at the source of the dust is the desired minimum standard. Getting 20 m/s linear air speed is not that hard but getting the volume speed is and is one reason why vacuum cleaners are ineffective on fine dust capture. One of the most difficult machines to grab dust from is the bandsaw. Bill Pentz website suggests that 3 intakes are needed to cover most of the dust from a bandsaw.

    Another issue is the over rated DC manufacturers claims for CFM/FPM. The numbers quoted for most DCs should be divided by ~2 to get realistic working figures

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  3. #17
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    Some interesting posts, particularly on the theme of dust extraction at source and filters.

    I do have a "spare" as-yet unconnected 3ph cyclone in my other part of the workshop. Presently - and for the last ten years - have been running portable dust extractors to each machine (combo, wood wizz etc).

    I'm giving serious thought into leaving the arrangements are they are - and hooking the cyclone up for my 2 big lathes (VL 175 and VL 300LB). An overkill perhaps, but not being able to turn the likes of redgum without annoying dust is..... annoying! I can put up with the noise but not the dust.

  4. #18
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    Jul 2005
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    Oberon, NSW
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    G'day Jeff!

    Allergic to DF?

    Now that sucks. Big time. You finally find a wood that's worth playing with and...

    You do know that you don't necessarily need to be breathing in dust to have an allergic reaction? Sometimes even just dust landing on the skin can trigger them. But I think that'd cause more the rash type of thing than sneezing.
    I may be weird, but I'm saving up to become eccentric.

    - Andy Mc

  5. #19
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    Jeff, +1 for the positive pressure respirator/air sheild. I use mine for sanding, along with the Big Gulp Dusty collector and fans and extraction fans going. I have been know to dust off my clothes with an blast of compressed air.

    Anything to stop the black boogers and getting more carp into my respiratory system.

    I may look like a spaceman some times, but I have enough problems with diagnosed allergy to an unknown allergen, that upsets my sinus' regularly.
    Pat
    Work is a necessary evil to be avoided. Mark Twain

  6. #20
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    Quote Originally Posted by Skew ChiDAMN!! View Post
    You do know that you don't necessarily need to be breathing in dust to have an allergic reaction? Sometimes even just dust landing on the skin can trigger them. But I think that'd cause more the rash type of thing than sneezing.
    The reason why dust on skin is more of a problem is described below.

    What a lot of people do not realise is the human body acts like a chimney. It produces heat and using an infra red camera it is possible to see currents of warm air rising from a person just like a chimney.

    Once the shed is full of fine invisble dust the rising air from and above a person draws dusty ladened air towards a person just like a magnet so the total volume of dust experienced by a person is much higher that the average dust density in the air. Any fine dust that settles on a persons clothes and skin can also take off like a balloon on the this rising tide of warm air and easily wafts up a persons nose or into their mouth.

    Just breathing, fluffs and pumps dust (from what even looks like clean clothing) into the air around a person. If an operator has their hands covered in dust and just touches their face this also transmits dusty air to vicinity of their air intakes.

    This is why for people with allergies, masks and filters and DCs that recycle air back into a workspace really are in the "too late mate" category.

  7. #21
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    He suggest the respirator be left on and all clothing be put into a washing machine and then removing the respirator and stepping immediately into a shower is the way to handle this.
    The vision in that sentence just ruined my week.

    Sorry to hear about your problems Jeff. Maybe it is all Acacias are going to give you grief.

  8. #22
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    Quote Originally Posted by View Post
    The vision in that sentence just ruined my week..
    OK - Shall we now discuss the dust levels inhaled during clothing management when going to the dunny? I wonder how many respirator users continue to wear their PPE while doing their business?

  9. #23
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  10. #24
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    Bob, you are a sick, sick puppy!

    The first comment brought out a request for eye bleach and the second brought tears
    Pat
    Work is a necessary evil to be avoided. Mark Twain

  11. #25
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    Quote Originally Posted by BobL View Post
    .... I wonder how many respirator users continue to wear their PPE while doing their business?
    If you have one of those helmets with the backpack intake.... don't phart while you are using it. DAMHIK.
    Cliff.
    If you find a post of mine that is missing a pic that you'd like to see, let me know & I'll see if I can find a copy.

  12. #26
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    Quote Originally Posted by Cliff Rogers View Post
    If you have one of those helmets with the backpack intake.... don't phart while you are using it. DAMHIK.
    Bin there and it's definitely eye watering! Fortunately it flushes clear fairly quickly.

  13. #27
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    keep hearing about this timber but never turned any , does anyone know if it grows down as far as me or is it only a northern timber .
    maybe i should just do some research on it .
    johno
    'If the enemy is in range, so are you.'

  14. #28
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    Johno,

    I have some pieces of Dead Finish from FNQ and inland NSW. The colour varies for some reason - the burgandy strain is most sought after.

    The allergic reaction is worst with the bark and less so for me anyway once the bark is removed.

    Under a strong light, you can actually see the dust that causes all the problems!

    Try to get some, it turns wonderfully once you work your way around the cracks.

  15. #29
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    'Tis indeed sad news Jeff... Don't make a dunny seat out of it then.
    Jim
    Sometimes in the daily challenges that life gives us, we miss what is really important...

  16. #30
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    The stuff you got from me Jeff was from Central Western Queensland, just West of Longreach.
    Cliff.
    If you find a post of mine that is missing a pic that you'd like to see, let me know & I'll see if I can find a copy.

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