Shop Climate

[soliver]

I've been reading Graham MacDonald's Mandolin Project and I'm thinking of starting to build a mando (or 2 or 3 or many ). I have a fully tooled shop as I have been a woodworker, trim carpenter and cabinet maker for many years. My only concern is climate control in the shop. My shop is essentially a 12X16 shed in the back yard. It has served me well, however, it is cold in the winter and hot in the summer and has little in the way of insulation or relative humidity control.

What are the bare minimums for climate control for luthiery?

Would love some general input on the topic.

Thanks I advance.

[Rdeane]

I'm no luthier, but I would assume that if you are storing wood for instruments in your shed, it should not be extremely humid or extremely dry, pretty much in the same humidity range as we store our instruments (but I could be wrong here). I have heat in my workshop but it's not humidity controlled or temperature controlled unless I'm working there. I am building a kit mandolin now, but I'm bringing the mandolin parts and clamped-up pieces into the house until I'm ready to work on it again out in the shop. It's freezing as well now overnight, so I bring in my glues as well.

[Marty Jacobson]

Argument A:
You should keep your shop and wood storage at the temperature and relative humidity at which your instrument will be stored, transported, and played during its lifetime. Since we can't do that, realistically speaking, you can pick a reasonable environment for a human and try to keep it there. Probably 70F and 45% RH is a good middle ground which also works well for glues drying and varnishes curing.

Argument B: Most instruments made historically were made in completely uncontrolled environments. Stradivarius didn't have a dehumidifier, and probably did glue-ups some days when it was hot and rainy (so high RH). Of course old violins have been through their share of cracks, disassembly, rebuilds, etc.
But think about a factory in the 30's. No air conditioning, probably little or no heat in the winter. If they did heat well, it would have brought it to 10-20% RH in a big warehouse, so that doesn't help much.

So.... Building an instrument in sub-optimal conditions is probably better than worrying about it too much (and not making progress). If you can put a dehumidifier in your shop, here in Georgia it almost never gets below 35% RH. So set it at 40 or 45 RH, and the heat from the dehumidifier will also keep your shop from freezing.
I had two different dehumidifiers which were recalled in the last few years due to being fire hazards. These are name brand units from Amazon. So I'm a little scared of them now that my shop is in my house instead of being in a separate building. That said, I try to do all glue-ups at 45% RH and 70 degrees or so F.
My instruments have ended up in several countries, all over the US, including deserts, and I haven't heard anyone complain about seam separations yet.
The crazy extremes which really damage instruments are way outside of what you can plan for anyway.

[soliver]

Thanks Marty... I'm considering what it will take to insulate my shop, or at least start to... but I am certain wifey will give me the hairy eyeball if I try to keep it temp and RH controlled 24-7... but it does get cold in there for sure. Armrest money will now be going to upgrading he shop I s'pose!

[Tavy]

What Marty says.

Be aware that changes in humidity can have a pretty big impact on top plate geometry once the braces are on - to the point where if you glue braces at low humidity and high temperature, and it then goes cooler and humid - just watch your top bend in two - to the point where you may not be able to fit it to the rim without breaking something.

That said, you only really need to be super-careful when gluing braces, and that's a very small part of instrument building, so depending where you are you could just wait for a suitable day. I guess if you live in Arizona or somewhere and humidity is super-low, then you would need to think differently, but for most of us that's not the situation (nor was it for Stradivarius for that matter).

[soliver]

Thinking about hygrometers for the shop so I can know what the RH is... any affordable recommendations?

[Gary Leonard]

Thinking about hygrometers for the shop so I can know what the RH is... any affordable recommendations?

Caliber IV hygrometer. Pretty darn good and accurate.

[soliver]

A lot of what I see listed as "Caliber IV" is intended for use in a humidor... are these ok for this use?

[Walt]

I'm working on a similar project--we just moved to a place that has a 30x30 pole barn that I'm converting into a shop. I'm still looking into insulation options, but as far as climate control, I'm installing one of these heat/ac window units. That one runs on 220 and covers 1000 sq ft, but they make a smaller model that runs on 110 and covers 300 sq ft.

My father-in-law has one of those ac/heater window units in a 20x20 area of his shop. It works great and regulates the humidity nicely. They actually lived there for about a year while their home was being built.

[HoGo]

My shop is rather small (7'x13') in the basement and I like to keep the climate at 22 degrees C and 40-45%RH all the year round. I have small interior dehumidifier for humidity control and the heat is kept by house heating system.
Before I got the dehumidifier I at least kept an eye on hygrometer (old school lab hygrometer with real hair) and worked on jobs accordingly to RH reading. I glued up bodies only when the RH had been stable for few weeks at 40-45% to prevent humidity cracks down the road. Fortunately there were not great RH swings where I live (we have stable 40% inside almost all the winter so sometimes I turn the dehumidifier off and we are at 55 in summer) I would really be scared to send instrument to dry country if I built it above 50%. It is always better to build in drier environment for safety. Humid environment won't damage your instruments as bad as dry.
Caliber III (or now the newer IV) has been recommended by one of the best violin makers of our era. check his web he has some good reading about humidity (be prepared for simple old school web :-) )
http://www.burgessviolins.com/

[Rob Roy]

Soliver,
I'm a ways south of you in Florida and my shop is considerably bigger (16x36 block out building) but I face similar conditions. Where I am, AC is a necessity otherwise cast iron tables rust in a hurry. A small window unit keeps it at 78 degrees and RH 50-60% through the Florida summer and the electricity is so small I can't tell the difference on the bill. The first thing to address is insulating the ceiling, that's 60% of your heat load in the summer and of course when you're heating in the winter, well…we all know where heat goes. 12" in the ceiling makes a huge difference. Good time to upgrade the lighting if you haven't in last decade. The new options are much brighter and more efficient. I also replaced my windows with thermal pane as the old ones were junk jalousies. I'd insulate the walls in the traditional way and face them with plywood so you can screw/hang things anywhere. Tighten the seals on any doors. For a shed that size, the smallest window shaker you can find should make it quite comfortable for pennies a day. To heat in the winter, I'd think an electric space heater would probably cover it, the ceramic ones seem to be the safest- just go out and turn it on an hour before you head there to work. Enjoy the new adventure, mandolin curves are enticing!