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Thread: What am I doing wrong??

  1. #1

    Default What am I doing wrong??

    At long last I have had an opportunity to use my hobbyair set up (full face mask) - i bought it about 6 months ago (from here) (maybe a bit longer), but have been tied up with other things

    using it for the first time today, i have discovered that unfortunately, something is not right - i know this because when using it i could smell (quite strongly at times) the painting fumes - this is a ppg paint, an Acrylic Modified Alkyd Enamel (ALK 200) with a hardener (ALK-201) - i am using it to refinish some old machinery - in know how dangerous these paints are...that is why I bought a fresh air system

    i followed the instructions to the letter - most importantly i tested the seal by putting my hand over the intake hole and breathing in - the seal was tight, mask collapsed (this is a full mask)

    i used the meter to check the air pressure and i set it at right in the middle for the full mask

    i feel like when in use the positive air pressure creates little gaps in the seal and that is where it is coming in? - but i don't know! - that is just a guess

    i have nothing on (headband, cap, hood, etc) - fairly cleanly shaven

    i noticed in the instructions that over-tightening the straps can be a problem...so I played with that...to no avail - the pump was far away

    i would welcome any suggestions

    thanks!!

  2. #2
    Join Date
    Nov 2005
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    35,758

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    You shouldn't be smelling paint as long as the pump is located in fresh air. Be sure that the air going into the pump is clean, place the pump outside the painting area. One thing good about using a Hobbyair or any supplied air breathing system is the any leaks leak OUT and don't let contaminants in. We use mostly the direct feed hood which is open at the bottom where the air exits the hood and we never smell paint. Be careful to place the pump in clean air.

    If this is the first time using the system you may be smelling some off-gassing of the plastic hose, allow the system to run with the hose installed for an hour or so and it should help eliminate that type of smell.

  3. #3
    Join Date
    Aug 2017
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    2

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    I have used positive pressure masks for years. First I would take the advice of running the system for an hour to be sure the smell isn't just a new system smell. The other two things that will cause you to smell the paint with a positive pressure system is 1 - the pump is pulling in fumes or 2 you are over breathing the supply. My mask has a regulator on it. It ads about .05 atmosphere to the inside of the mask and then stops. If I hold my breath and I have a good fit, the airflow stops and goes into bypass at the regulator. When I start to take a breath and the pressure drops under 1.05 atmosphere inside the mask the regulator opens and air delivery continues. If I take a rapid breath in I will out breath the regulator and pull a vacuum in the mask. If I have a leak I will smell the fumes, but only for a moment until the positive pressure purges the mask and I again have clean air.

    If I had to guess, I would say your paint fumes are somehow making it to your pump. If you are in positive pressure mode, you really should not smell fumes, even if you have a small leak. Now if you have a bad leak you may pull air in the leak with every breath, but at the same time you will feel the air rushing out when you hold your breath or breath out.

    You can test your seal with a strong aerosol room freshener or you can buy a bitter tasting spray made for testing mask fit.

    Good luck

  4. #4

    Default

    thanks guys

    1. as to pump location, i will do as you say, but i don't think so - i am painting at the threshold of the garage door, door open fan in garage blowing out - when i paint upwind of the object, no issues, downwind (i.e., much higher concentration of paint/fumes) I get it - pump is out a separate door on the other side of the garage about 40 feet away - but i will test as you say

    2. i think it must be a leak...but i can't figure out how - they way i tested is with the hose detached, breath in with the inlet covered - creates a ton of vacuum, mask starts to collapse, no leaks! - i am guessing that perhaps with movement or whatever there are slight gaps and it is getting in...but as Len says, it shouldn't...because it is positive pressure

    3. i'll try the fragrance/bitter test to see if i can figure it out - very frustrating!

  5. #5

    Default

    it is not the pump or the pump location

    it is the mask

    i find if i use a hood on top of the mask it helps, but why should there be any leaks???

    can anyone suggest some trouble shooting for mask fit?

  6. #6
    Join Date
    Nov 2005
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    35,758

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    Quote Originally Posted by edl View Post
    it is not the pump or the pump location

    it is the mask

    i find if i use a hood on top of the mask it helps, but why should there be any leaks???

    can anyone suggest some trouble shooting for mask fit?
    Unless the mask is almost off your face a leak won't allow paint in. Check the valve on the mask to make sure that it's working properly, it's the only thing that could allow fumes into the mask.

  7. #7

    Default

    Thanks Len

    How is that done?

    thanks

  8. #8
    Join Date
    Nov 2005
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    The valve should only allow air out and not in so you could put the mask on, block the incoming hose and inhale to see if air comes in the valve. You may get some leakage elsewhere but you should be able to tell if the valve leaks because you wouldn't be able to generate negative pressure.
    Last edited by Len; 08-31-2017 at 07:10 AM.

  9. #9

    Default

    thanks Len

    in that case, i have done that ... and the valve/seal is super strong - when doing this test i can collapse the mask

    even in use...i accidentally kinked the hose and no air was coming in and i breathed in and collapsed the mask

    so why am i smelling paint when i go through a particularly high concentration or if i am downwind of the piece?? - very frustrating...i wish i could figure it out.......

  10. #10
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    Nov 2005
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    Quote Originally Posted by edl View Post
    thanks Len

    in that case, i have done that ... and the valve/seal is super strong - when doing this test i can collapse the mask

    even in use...i accidentally kinked the hose and no air was coming in and i breathed in and collapsed the mask

    so why am i smelling paint when i go through a particularly high concentration or if i am downwind of the piece?? - very frustrating...i wish i could figure it out.......
    How many hours do you think you have on the system? Are you sure it's paint you're smelling?

  11. #11

    Default

    Thanks Len

    I have about 10 to 15 hours...and it is definitely paint

    I have found the problem...it is the pump

    I was certain that i had it far enough away and the times i smelled the fumes seemed timed with activity that i was doing on the part so it appeared connected to the mask

    but upon a close inspection of the filter...paint overspray! - amateur mistake!

    Len - how do i change the filter?

    to all: i had the pump probably 30 feet away...outdoors and the spraying was around the corner on the other side of the garage...this paint i am using is really sticky and apparently travels far and doesn't flash instantly...so the pump really really needs to be completely out of the way

  12. #12
    Join Date
    Nov 2005
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    35,758

    Default

    Quote Originally Posted by edl View Post
    Thanks Len

    I have about 10 to 15 hours...and it is definitely paint

    I have found the problem...it is the pump

    I was certain that i had it far enough away and the times i smelled the fumes seemed timed with activity that i was doing on the part so it appeared connected to the mask

    but upon a close inspection of the filter...paint overspray! - amateur mistake!

    Len - how do i change the filter?

    to all: i had the pump probably 30 feet away...outdoors and the spraying was around the corner on the other side of the garage...this paint i am using is really sticky and apparently travels far and doesn't flash instantly...so the pump really really needs to be completely out of the way
    The filter should just pull out and or you can twist it out. New filters are $6.95ea. or 10 for $62.50


    You may also need another 40' length of hose if you can't get the pump far enough away from the action.

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