Hi Tom, I'll give you my own thoughts on the respirator. Since you have a beard you should not consider any type of negative pressure, cartridge type of respirator even if you didn't use hardeners...you will never be able to get a proper fit. You are correct in thinking about a fresh air system. You are not limited to just a hood though. The key is to always maintain a positive pressure inside the facepiece or hood, even when inhaling. If your air supply is sufficient (4 cfm for a facepiece or 6 cfm for a hood) to do this, the tightness of the seal is less important since there will always be an outflow of air. I too have a beard and use a full facepiece. I always assure myself of a positive pressure when inhaling. It's easy to do. Just check the exhaust port for an outflow of air at the same time that you take a fairly rapid, deep breath. You'll notice a significant decrease in outflow when you breathe in but as long as there is still an outflow you can be assured of maintaining a positive pressure and your face seal need not be perfect. I would not recommend using your standard compressor as the source of your breathing air. Capacity could be a problem and if it is a lubricated machine, you will notice an unpleasant (and unhealthy) "aftertaste" to the air. There is also the potential, although remote, of CO poisoning. Your air supply should be from a non-lubricated unit that has an inlet where the air is known to be fresh and uncontaminated. This means a significant distance away from your spray area, preferably with physical barriers such as walls or buildings between you and the air intake. It should also preferably be a tankless unit so that the possibility of any nasty microbes that could exist in a moist, closed tank atmosphere would not be fed to the mask (and to your lungs). Lubricated compressors are, indeed, sometimes used for breathing air but complex and expensive air purification & monitoring systems are then called for. This is generally not realistic for the DIY home user to either purchase or to maintain. Alternatively, you could go with a dedicated blower unit as CNKS indicates. The Hobbyair is a relatively inexpensive commercial system (about $400) that uses such a blower (turbine). Caveat: Above is from my own personal, non-medical experience. It would ONLY be appropriate for a personal use where no laws, contracts or regulatory requirements exist, such as labor contracts, OSHA rules, etc., etc. Use at your own risk :o). Rod
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