Humidity Gauge Made Out of Wood

I decided to make this humidity gauge out of wood I had around my workshop. Using this gauge you can get a quick reference as to the humidity level in your home/workshop or out doors. Humidity is the concentration of water vapor in the air. In this case the water vapor comes in contact with the two pieces of glued wood, one is cut on the end grain the other is cut with the grain. When mist/humidity meets the wood it will cause it to bend in one direction, as the wood dries it will cause it to bend in opposite direction. I will show how a different thickness of wood reacts to water vapor in the air.

We have two time lapse videos. The first one is gauge1, 37 seconds long, shows us wetting the Indicator and it moving to the right. The actual time it took was around 20 minutes. Gauge 2 is 41 seconds long it shows the time it took to dry out and return to room humidity. The time it took for it to do this was a little longer than 3 hours.

We had a really great time presenting this instructable to you, and hope this will inspire you to create your own Humidity Gauge.

Basic Supply list for Humidity Meter

• 2 Pieces of wood 2"X12" 3/32" thick ( Wood from neighborhood Home center )

1 piece cut across the grain

1 piece cut with the grain

• 1 Wood piece 2"X12" Long 1/4" thick
• 1 Wood Piece 2"X7" Long 3/32" thick
• 1 Wood Dowel 2 3/4" Long 3/4" Diameter
• 2 Wood Screws
• Two Part Epoxy
• Label maker or wood burner or a black marker (your choice)
• Table saw
• Drill

For our further experimenting we used these thicknesses of wood for the indicator.

• 2 Pieces of wood 2"X12" 1/8" thick

1 piece cut across the grain

1 piece cut with the grain

Cut two pieces of wood 2"X12" 3/32" thick. One is cut across the grain and one is cut with grain. Picture one shows finger is pointing to across, the grain picture two is pointing to with the grain. These cuts are very thin so the the cut across the grain I did have to cut several time to get a nice piece.

Glue them together, using 2 part epoxy, apply an ample amount and a good even coat. Make sure they are as follows: the one cut "with the grain" will have the epoxy glue spread on first . The one that is cut "across the grain" will be placed on top of the piece that is with the grain. Then as in the photos, I used spring clamps to hold the two pieces together (see the attached photos) Allow to dry.

NOTE: Do not use a wood glue or Gorilla Glue as it will soak into the woods pores and it will not allow the wood to move. The 2 part epoxy will only adhere to the surface and will allow movement of the wood.

As you will see, if you are using thicker pieces of wood the moisture will takes longer to soak into the wood so it does move slower, also if the wood is thicker it will not bend as much as a thinner piece of wood.

1. Cut the next piece of wood with the following dimensions: 2"X13" 1/4" thick. With your drill and a 3/4" drill bit, drill a hole 2" from the bottom of the wood.
2. Cut the 3/4 inch wood Dowel to 2 3/4" long. Next make a 2" vertical cut across the length of the dowel, make an additional 1/2"cut on the opposite end of the dowel.
3. The last piece of wood cut to the measurements of 2"X7" long, 3/32" thick.

Take the piece that measures 13" long, get your drill and 3/4" drill bit. At 2" from the bottom of the wood drill a hole, go all the way through.

Take the two pieces of wood that are 7" long and the piece of wood that is 13" long glue them together (you can use regular wood glue)to form a "T" (see photo).

After you have glued them together apply a clamp to assist with holding them in place and allow to dry (cure), and remove the clamp.

Take your dowel that you have cut to 2 3/4" long. On one end make sure you have cut the dowel on the end about 2" deep. (see the photo). Then make your next cut on the opposite end end of the dowel about 1/2" in. (see photo)

Insert the dowel into the hole make sure the 2" cut towards the top (Do not glue the dowel)Take the Indicator (the one that measures 12" long and glued together). Place the end grain cut side to the left. Insert it in the 2" opening in the top of the dowel, now, take one of the two screws. Drill a small pilot hole and apply the screw just above the indicator to hold it in place, (See photo).

Turn the whole thing over and apply the other screw into the cut on the bottom of the wood dowel. (See photo)

Once you have assembled your Humidity Gauge. After it cures, you may want to test it. Use a spray bottle with water in it. Spray the indicator, and wet it down. Make sure the indicator is well saturated. Watch to see how far it goes to the right, (This can take up to 30 min. or longer, the indicator needs to stay wet) once it has stopped moving you can label that end "Rain". (See Photo)

Allow to dry, keeping your eye on the gauge, watch as it moves to the left (this may take some time). In our house, while running the air conditioner, we are still around 20% Humidity. I make "a mark" a little bit beyond where it stops and label it " Desert". (See Photo)

Using the Gorilla Glue it soaked into the woods pores. While it was curing it started twisting and bending, this because the Gorilla glue is water activated, (see the first two photos). After allowing it to cure, I tested the indicator noticed that the movement of the wood does not react in the same way as the 2 part epoxy.

The 2 part epoxy adheres to the surface of the wood and allows the water vapor to come in contact with the pores, thus allows the desired movement of the indicator.

As promised, the last two pictures show a thicker indicator strip. The first picture was dry and the next picture was after being wetted. The second photo shows some movement but not as dramatic as the thinner indicator that we presented as in our instructable.

Another thing to consider is the different types of wood have different properties. That allow different movement with moisture. So give it a try and have fun, I would like to see some of the ones you make. I will be looking through my scrap pile and if I find something interesting I will add pictures.