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  1. #1

    Default Shop dehumidification

    Hello everyone.. You guys were nice enough to provide me with some quality information on some issues I was having a couple years ago.. now I come to you again. I'll be moving to Texas very soon, and am concerned about shop humidity. The shop I'm moving to is 6,000 square feet with high ceilings, fully insulated. That's quite a bit of air volume, so I know I will need some fairly serious dehumidification to keep up. For you guys who live in humid parts of the country, what do you use/recommend?

    I live in northern Nevada now, and it is so dry here that bare steel and cast iron parts never rust when stored inside no matter how much time passes.

    Ideally I would air condition the shop to keep it more comfortable in the summer as well, but that would be very expensive and I'm not sure if that will even be an option.

    I'm concerned about my own comfort when I work, but also very concerned about bare sheetmetal parts rusting over time, and humidity interfering with when I can even spray.

    Of course I know I will need a good dryer for my air system, that's the easy part.

    I appreciate any advice you all might have. Thanks!

  2. #2
    Join Date
    Feb 2006
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    179

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    Quote Originally Posted by PaintEmIfYouGotEm View Post
    Hello everyone.. You guys were nice enough to provide me with some quality information on some issues I was having a couple years ago.. now I come to you again. I'll be moving to Texas very soon, and am concerned about shop humidity. The shop I'm moving to is 6,000 square feet with high ceilings, fully insulated. That's quite a bit of air volume, so I know I will need some fairly serious dehumidification to keep up. For you guys who live in humid parts of the country, what do you use/recommend?

    I live in northern Nevada now, and it is so dry here that bare steel and cast iron parts never rust when stored inside no matter how much time passes.

    Ideally I would air condition the shop to keep it more comfortable in the summer as well, but that would be very expensive and I'm not sure if that will even be an option.

    I'm concerned about my own comfort when I work, but also very concerned about bare sheetmetal parts rusting over time, and humidity interfering with when I can even spray.

    Of course I know I will need a good dryer for my air system, that's the easy part.

    I appreciate any advice you all might have. Thanks!
    Where in TX would be relevant to those with experience down there. I just checked the humidity in Houston TX, its the same as it is where I am. You won't have too much problem with flash for a few days, but you'll want to do something with bare metal that is sitting a week or more. Picklex or equivalent will tide you over, or just get used to spraying down your bare metal parts in epoxy primer. The primer will lock out the moisture that you'd find storing parts indoors. But keep metal off the concrete floor, I find the condensation will cause rust. Dehumidifer units are a thing, and that might help, but I think you'll be ok.

    As far as the air system. The best strategy I've found is get a large compressor (less cycling/heat) and lay out long (cools air off) air trunk lines that terminate with a valve you can clear the main trunk. Pull from the top of the trunk.... pretty much what Sharpe recommends for layout. I have use 5 micron filter, and a coalescing filter, and regulator (in that order) at one output. The other output has a Sharpe 880A air controller (oil/water separator with a regulator). The 5 micron seems to do all the work, I grabbed a wilkerson from ebay cheap (M18-04-BK00).

    http://www.sharpe1.com/sharpe/sharpe...+piping+layout

  3. #3

    Default

    I'm going to Wichita Falls, Texas. I know it's not as humid there as some of the coastal regions, but it's still way more humid than what I am used to. My goal is to get the shop humidity level down as low as I can. I spend a lot of time working panels and such in bare metal, and don't want to have to prime everything immediately. And it's not just body panels - I work with engines and such as well, and I do not want bare cast iron engine blocks to rust. This shop will be closed up most of the time, especially in the summer when it is hot and humid, and I will do everything I can to seal the shop up as much as reasonably possible (door weatherstrips, etc.). I need the shop humidity levels low for these practical reasons as well as my own comfort. I've spent most of my life living in one of the driest parts of the country, and I have no desire to work in high humidity conditions.

    I already purchased a refrigeration dryer for my shop air. I use a smaller capacity dryer in Nevada where the humidity is low, but I stepped up for the humidity in Texas and found a good deal on a much larger capacity dryer. Not taking any chances with moisture in my air. I have a 120 gallon Ingersoll Rand two stage 15hp compressor, which has served me well for many years. I have long used automatic drains for my compressor tank, and I plumbed in an automatic drain along with my water trap before the dryer. After the dryer, the air runs into another 120 gallon tank regulated down to 90psi, also with an automatic drain (that is totally redundant and unnecessary, but it remains just in case). I find this to be a very effective way to stabilize the air temperature before it finally reaches my gun. Overkill? Absolutely. I'm one of those guys that tends to do things overkill, rather than just good enough.

  4. #4
    Join Date
    Feb 2006
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    179

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    Quote Originally Posted by PaintEmIfYouGotEm View Post
    I'm going to Wichita Falls, Texas. I know it's not as humid there as some of the coastal regions, but it's still way more humid than what I am used to. My goal is to get the shop humidity level down as low as I can. I spend a lot of time working panels and such in bare metal, and don't want to have to prime everything immediately. And it's not just body panels - I work with engines and such as well, and I do not want bare cast iron engine blocks to rust. This shop will be closed up most of the time, especially in the summer when it is hot and humid, and I will do everything I can to seal the shop up as much as reasonably possible (door weatherstrips, etc.). I need the shop humidity levels low for these practical reasons as well as my own comfort. I've spent most of my life living in one of the driest parts of the country, and I have no desire to work in high humidity conditions.

    I already purchased a refrigeration dryer for my shop air. I use a smaller capacity dryer in Nevada where the humidity is low, but I stepped up for the humidity in Texas and found a good deal on a much larger capacity dryer. Not taking any chances with moisture in my air. I have a 120 gallon Ingersoll Rand two stage 15hp compressor, which has served me well for many years. I have long used automatic drains for my compressor tank, and I plumbed in an automatic drain along with my water trap before the dryer. After the dryer, the air runs into another 120 gallon tank regulated down to 90psi, also with an automatic drain (that is totally redundant and unnecessary, but it remains just in case). I find this to be a very effective way to stabilize the air temperature before it finally reaches my gun. Overkill? Absolutely. I'm one of those guys that tends to do things overkill, rather than just good enough.
    Seems you're already well covered already as far as your compressed air system goes, but I'd still put a 5 micron where you tap off just to make sure - they're not expensive. Generally AC will control the humidity and temp for you, dehumidifier would be something I'd use for an uncontrolled space. I leave my internal garage uncontrolled, doesn't freeze in the winter and that is all I care about for that space. I coat the machined surfaces of cast iron with something to protect. If its long term its generally axle grease, or short term wd40. I bag that stuff to keep the dust off too. I have at least 4 mopar 440 engines and probably 10 heads for those sitting around coated in that way.

    I think you should just plan on adding AC to your shop, likely you'll be unhappy w/o it. :-) You'll want to look for air leaks in the shop's exterior. If you don't have a dedicated temp controlled paint booth to put in your shop, then you'll likely have some trouble with air change-over/exhaust and controlling the temp/humidity while painting.

    A couple years ago I found inexpensive sensors from ebay that track temp/humidity and includes an app for you cell phone so you can download and see the readings. They store alot of history on them, and your phone will cache the results every time you download to inspect the graphs. I had one in the basement (which is HVAC controlled) and one in the attic (uncontrolled). The basement was super stable, attic was not. Later I relocated the basement sensor to the indoor (uncontrolled) garage.

    https://smile.amazon.com/gp/product/...e?ie=UTF8&th=1

    I don't have the basement metrics, but I've added a couple screen grabs from my android phone just now to demonstrate how you can track things. I was thinking of buying wired sensors and building my own software on a laptop to track, but when I found these gems - no reason to bother.


    attic1.jpgattic2.jpggarage1.jpggarage2.jpg

  5. #5
    Join Date
    Feb 2006
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    179

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    Well those screen shots suck.... Here is one of the garage ones blown up. I scrolled the humidity chart left to see what was going on there (not aligned to today) ... Not sure what caused the dip in humidity, kids might have left the door open between garage and house.

    HVAC controlled indoors is usually around 30% humidity.

    garageMonth.jpg

  6. #6

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    Air conditioning this shop may not be an option. This will be a rental shop, so I'm not going to spend a large amount of my money to set up air conditioning in it. I'll talk with the owner to see if that's something he's interested in doing, but I doubt it. So a dehumidifier is likely going to be my best option. My question was primarily asking what capacity dehumidifier I will probably need in a shop of that size to keep up.

    As for booth air supply.. I have a small air conditioned office in my current shop that I pull filtered air from to supply the booth. The time of day that I actually paint depends on the time of year. When it is really hot in the summer, I will usually spray in the middle of the night or early in the morning as necessary to maintain it around 70 in the booth when I'm spraying.

    In the new shop in Texas, it has a 1,000 square foot air conditioned office, which I foresee pulling air from as well. Obviously that means pulling in warmer and likely more humid shop air, so I will certainly need a dehumidifier in there to help control that. But properly dehumidifying the shop will be a big help. Self contained booth climate control systems seem to be very expensive, and difficult for me to justify when I don't paint that often. And such a system will do nothing to help in the rest of the shop. I expect to have to paint in the middle of the night or early morning more often in Texas than I do now in Nevada. I have no issue with that, and in some ways I prefer it.

    The system I have in place in my dry Nevada shop works very well. The question is whether or not it will be able to keep up in Texas.

    Dehumidifying the shop will also help keep my compressed air dry as well. Even though I have automatic drains, I still don't like lots of moisture going through the compressor, as I think that contributes to a shorter compressor life span, and of course more rust in the tank. You can drain the liquid out of the tank to prevent it from pooling up, but if it is constantly full of humid air it will still rust. I inspect the inside of my tank every couple of years, and have not seen an appreciable increase in surface rust over time. I'd like to keep it that way if at all possible.

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