Dealing with humidity, lumber, and uncontrolled shop environments.

Discussion in 'Luthier's Corner' started by eddododo, Jul 2, 2020.

  1. eddododo

    eddododo Supporting Member

    Apr 7, 2010
    I live in south Louisiana, the worst combination of heat and humid in the universe. My shop is my garage, and there is no climate control, and no easy short term fix for that. Theres also the unfortunate and irritating factor that my dryer vent exhaust is in the garage too, but the solution for that is obvious, if difficult.

    So I have 2 or maybe 3 things I’d love to see what solutions you guys have come up with over time.

    1- my tools rust fast and constantly.. they’ll get rust spots in literally a day or two. I spend a lot of time with a wire brush wd40 and paste wax. I have a feeling that besides maybe another product that this one pretty much ‘is what it is’

    2- storing and drying lumber. I’ve pretty much just accepted I can’t do this. Even if I solve the dryer exhaust, it’s just so unbelievably humid that drying lumber is a myth. I’m going to be building some installed benches in my dining room, with flip top storage, so I may be able to claim one or both of those for wood, but that’s a battle to be won against the wife lol

    3- guys, it’s so hot. It’s just so unbearably hot. There’s no window for an ac unit. Anyone use any of the oddball portable ac stuff?

    4-bonus- 300+days a year it’s too humid for what is suggested to spray laquer. I’ve read a bit on this, so don’t feel too obligated to rehash, but I also wouldn’t mind having some tips and discussion happening while I’m being needy here.
  2. dwizum


    Dec 21, 2018
    Wow, that sounds terrible. I'm assuming there's a typical big garage door? Hopefully it's well sealed?

    I would absolutely consider a portable AC, or just cut a hole in a wall, install a window, and put in a window mount unit in.

    In the meantime, you might be able to at least solve the humidity problem with a portable dehumidifier. I have one in my basement near my shop, set to 50% and it runs lots some seasons and not at all others. Really helps with stability in terms of lumber.
    RSBBass likes this.
  3. Arie X

    Arie X

    Oct 19, 2015
    yep, get a dehumidifier, maybe two. this will net you the biggest gains. if you can build a cabinet or a suitable box to stash your wood and pipe controlled air into it, that would be a plus. at glue up time you can tent the work area and pipe the dry air into the tent. i've seen builders do this and have done it myself.

    some ac couldn't hurt but those portables at least the ones bigger than a desk top size, have to vent to the outside. we have a Solus and exhaust it through a window with the supplied kit. these will help with humidity as well but you will have to be vigilant on draining the water out from the ac and the dryer reservoirs.

    rusty tools? that's tough. again with trying to control all of that humidity. beware of oils and stuff coming off of the tools and onto raw wood. this can show up at finish time. maybe some firearm wipedown cloths can help? they have preservatives and other things that may do more?

    temperature often isn't a huge deal when it's constant, only when it fluctuates a great deal. If i recall the south, that isn't often.

    lacquer? i don't use it so i have no help on this.
    Last edited: Jul 2, 2020
  4. T_Bone_TL


    Jan 10, 2013
    SW VT
    Deal with the dryer exhaust - adding hot, wet air to the shop is simply going to make bad into terrible. Difficult is not impossible, and not dealing with it just makes life more difficult than it would otherwise be.

    Tools - sealed, tight, tool boxes/cases/cabinets and vapor rust inhibitor (possibly more known as Vapor Corrosion Inhibitor) in the boxes. Or connect them to a dehumidifer...but if they are not well sealed (or in a closet, etc. that's well sealed) before dehumidification, see below...

    Before you worry at all about dehumidifying or cooling the shop, deal with insulating and sealing it, or you're bailing a sieve with a thimble.

    You'll basically just raise your electric bill and make almost no dent in the flow of hot moist air from the world to your dehumidifier or A/C (which also dehumidifies.) Since you are in a "primary cooling" situation, vapor barrier goes outside where it's hot & wet, then insulation and interior. Sealing it will allow dehumidification to work. Insulating it will permit A/C to work, and the more insulation, the less you'll pay to run the A/C. Forget window or portable, put in a mini-split, and pick an efficient one.
  5. Arie X

    Arie X

    Oct 19, 2015
    what he said ^^ obey the owl.
  6. p12bassnut

    p12bassnut Supporting Member

    Aug 27, 2009
    Install a Daiken or LG Mini-Split system. Condenser is outside and wall mount coil inside. Super efficient and great for humidity control.
    Perfect for a garage or shop environment.
    Get a certified AC Tech to do a load calculation to determine the size needed.

    Vent the dryer outside somehow- may need to install an in-line booster fan.

    Insulate the garage walls and ceiling.

    Insulate the Door.
    eddododo likes this.
  7. turindev

    turindev Commercial User

    Jul 1, 2005
    Chattanooga, Tennessee USA
    Hey eddododo! Didn’t know you were in Louisiana, I lived there for quite a while and love it! I’m in central Florida now and the heat & humidity sucks here too.
    +1 on the mini split AC once you have insulation. You still won’t be able to store wood, but at least you can work at a decent temperature.

    Whatever you do, do not buy a portable AC, complete waste of money. Don’t ask me how I know.
    eddododo likes this.
  8. eddododo

    eddododo Supporting Member

    Apr 7, 2010
    That’s what I was looking for , they just smelled bogus to me lol.

    I’m wondering if I can use one of those standalone units that run a vent hose (the non-window window units essentially) and vent it in the attic. Luckily I know many handy people who could answer my queries once I pick a lane.

    I’m liking the idea of storing lumber in the built-in benches more and more, it may just be perfect
  9. turindev

    turindev Commercial User

    Jul 1, 2005
    Chattanooga, Tennessee USA
    Ive heard of people doing that, but its still nowhere near as efficient as a mini-split or even a window-unit in the wall/door/window from what I have read.
  10. Gusdfunk


    Aug 10, 2017
    Bay Area
    Pardon me if this is not the place... I'm not a builder, but I have a question for those who build (and I suspect this is related to the curing of wood, so maybe a good thread.) ----- Pictured is the heel of my 90's Pedulla. You can see the center piece of the 3-piece-neck is lower than the surrounding 2 parts of the capillary neck. I see this on a lot of basses in general; it seems common and not a "problem." Just a build characteristic (I think.) (For me, it's a curiosity and no "fix" is needed.) I speculate it's that the wood dried and shrank a bit (less than 1mm) and that it would have been prevented if the neck were left to dry for a longer time and then sanded... (I think of how Ken Smith in his "Ken's Corner" youtube vids described how he glues up a bunch of necks and lets them sit for 6 months (or more?) to dry and catch any problems before the rest of the build). However, in this pic, I notice that the poly finish is not cracked around the parts which is not what I would predict, but I'm not a builder... IMG_6285.jpg
  11. Bruce Johnson

    Bruce Johnson Gold Supporting Member Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Yes, that's a good example of a problem that we Luthiers constantly have to deal with. Wood may continue to shrink and expand and move for a long time after a bass is built. In this case, if Pedulla had let the neck lamination sit on a shelf for another year before final sanding, it may have reduced the differential shrinkage. But, it may not. Wood will shrink and expand a small amount with the seasons, changes in humidity, for many years after it's initially dried out. Even if those wood strips had spent ten years on the shelf before being finished into a neck, there still would have been some movement eventually.

    The main reason this example shows more of a "step" is because it looks like the center strip has the grain going cross-wise (flatsawn). Wood strips will shrink and expand more in the direction perpendicular to the ring lines, than in the direction parallel to the ring lines. So, if you build up a lamination where the strips have ring lines that are perpendicular to each other, you get this. The center strip shrunk more vertically than the outer strips. If the center strip of wood were rotated 90 degrees, it would still be level with the outer strips.

    You can have the same problem if the strips are different woods. Different wood species have different rates of absorbing moisture and expanding/shrinking.

    So, if you build up a multi-lam neck with strips of different woods and rings going different directions, you are going to have this problem. Even if you let the strips dry for ten years and seal up the neck in a thick coat of polyester.

    For more about all this stuff about grain, rings, sawing and neck stability, check out these two threads:

    Sizing up a Neck - quality evaluation

    About That Quartersawn Maple.....
    Last edited: Jan 1, 2021
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