Hygrometer

Re: Hygrometer

Bill Tindall, E.Tn.

Why aren't you using a humidifier for adding moisture?

I don't think your plan has enough capacity. You will be amazed how much water you need to add to "move the needle".

If you have hard water humidification by boiling water in some device becomes a problem of dealing with scale.

It is a simple matter to make a "wet-bulb, dry bulb hygrometer and they are the standard for accuracy.

Re: Hygrometer

Jack Guzman from Maine

I just assumed a household humidifier wouldn't add sufficient moisture. My propane heater dries the air significantly. Do you think a regular household humidifier will work?

Re: Hygrometer

John Veerkamp

there are many sizes of Household humidifiers. Google is your friend. We have one that can add up to 6 gallons per day to 2600 sq ft.

Re: Hygrometer

Jack Guzman from Maine

Found a kit for the wet bulb/dry bulb. Never heard of such a thing.Thanks for that.

I use a steamer on a regular basis for bending. I have to deal with the scale anyhow.It's a simple matter of removing the end of the hose from the steam box and filling the shop with the steam. It moved the needle on the cheap gauge noticeably. It is a small room. I think it may work.

Re: Hygrometer

John K Jordan

Does the air from the propane heater by convection or blown through a fan? In a previous house I had a humidifier added to the house heater - it had a rotating squirrel cage with foam kept wet by dipping into a tray of water, air directed through the foam put moisture into the air. The tray was connected to a water supply with a float valve that added water as needed. It worked without attention except for occasional cleaning. Maybe check with HVAC people as to what is available.

For measuring humidity I built a sling psychrometer. It had two thermometers, one with a cotton sleeve kept wet, one dry. Swing at around in the air and read the thermometers. A table gives the relative humidity. Very accurate.

JKJ

Sling psychrometer

Jack Guzman from Maine

That is an interesting name. I just bought a kit to build one.

My heater is a vented propane unit and I believe it pushes the warmed air with a squirrel cage blower. I have to look into modifications.

Re: Sling psychrometer

Barry Irby

Your heater does not "dry the air', at least not technically. It draws warm moist air form inside the space, used it for combustion and dumps it outdoors through the vent or flue. This causes cold dry air to be drawn back into the space to replace the combustion. In Maine your outdoor air is pretty cold and cold air can not hold as much moisture as warm air, so bring it in and warm it up and it seems very dry.

If your heater had a source of combustion air from outdoors, the effect would be hugely reduced. Newer high efficiency furnaces are set up like that. Unlikely yours can be converted.

Be carefull with a humidifier. They can be mold factories. A little sawdust, a little water...perfect place for mold.

Arduino?

Tony - Memphis

I made my own. I am in the opposite situation here in Memphis. In the warmer months, my shop is wet! Even with the ac running. The control on my de-humidifier was a relative dial and broke twice. So, I used an Arduino with a decent sensor:

https://www.adafruit.com/product/393

That, with an LED display, is a good way to monitor. One step further and you can close the loop. I use a PowerSwitch tail to turn the de-humidifier on and off based on my program. Works great. I leave the dehumidifier controll set to max and my program turns it on/off.

I am pretty sure there are devices on Amazon that do the same thing that are all packaged up and are "reasonably' priced. Search humidity controller.

Turns out that humidity is a difficult thing to measure accurately.

If you don't care for slinging....

Bill Tindall, E.Tn.

just fan the wet bulb.

Re: Hygrometer

TomD

I can't recommend a gage, but what is wrong with the woodworking standard of a thing about like a 6" ruler where one side is long grain, and the other is side grain. Basically you could just cut one layer off some 3 ply plywood. It responds to humidity by bending a lot. Might not be perfect for a grow op, but since your actual concern is wood, you could make several out of the different woods you actually use, say pine and birch. Whatever you make your chairs out of.

I would love to have googled one up for you, but everything I tried gave me commercial moisture meters.

Maybe this, though it seems a different design:

https://www.youtube.com/watch?v=112v0QJz8EI

Some info:

https://www.youtube.com/watch?v=ogvIzueCOSM

Maybe this:

https://www.youtube.com/watch?v=B9FPBQzlhbc

Re: Hygrometer

Jack Guzman from Maine

That's a good idea. thanks.

Re: Hygrometer

Mark Hennebury

Lots of ways to make a hygrometer.

From a simple slice off a the end of a table top glue-up, fastened from one end on your shop wall, with a few lines to see how much it shrinks and expands. or glue a long grain strip to it to see how much it bends.

Something like this idea with a balance should be pretty sensitive.you could add a sliding weight on the long side of the arm to calibrate and balance it. And a piece of wood that was an endgrain section so that it would respond quickly. As the wood gained moisture it would get heavier and lighter as it lost moisture.

Re: Hygrometer

Yonak

Mark, that's a clever and, to my mind, workable, solution except, in my shop, the weight would soon get a build-up of wood dust, spoiling the accuracy, which would constantly require re-calibration.

Re: Hygrometer

Jack Guzman from Maine

I got my sling psychrometer in the mail today. I'll be setting that up tomorrow.

Re: Hygrometer

Walta

Before you start adding water to you air you should try cutting your losses. Most of your losses will be air leaks near the ceiling or floor. Put a fan blowing out a window or door and seal around the fan temporarily. Use the smoke from incense sticks to locate the air leaks and seal them with calk.

Your windows will become the limiting factor for how much humidity your shop will hold as soon as the window surface temp gets below the dew point of the air in your shop it will condense water out of the air as fast as you can add it.

Walta