My Moisture Control for Wood Self Bows
The biggest challenge I had when I started making self bows was getting and keeping the moisture content within a workable range. Even after completion, a white wood bow will change draw weight if the moisture content is not monitored.
I created a hot box (see below) but found I was drying the staves to much. I wanted a way to keep the hot box (for epoxy curing and accelerated drying) but still have a place to help control the moisture content in my finished bows and stave that were dry enough to work on without over drying them.
So I created a moisture controlled closet. I used the chart on page 30 of volume 4 of the Traditional Bowyers Bible to try to maintain about an 8% moisture content.
I purchased this control
I also ordered this Indoor Thermometer, Room Thermometer for Home, Humidity Gauge Digital Hygrometer But one wasn’t enough for all the places I wanted to monitor, so I bought this 2-Pack Mini Digital Hygrometer Gauge Indoor Thermometer
I purchased this Small-Size Thermo-Electric Dehumidifier this I just keep running.
I have one 250 wat heat lamp running off the control.
I set the control to keep the room between 40 and 45% relative humidity. According to the chart on Traditional Bowyer’s Bible, Volume 4 page 30 should keep everything between 7% and 8% moisture content. That seems like a good number for hickory and hophornbeam which most of my bows are.
I am still playing with the settings. Now the fan and heat lamps are on the control and the dehumidifier running all the time. When the temperature may drop below 40 degrees in the shop. I’ll switch so the heat lamp is on all the time and the dehumidifier is running off the control.
I use this Pinless Wood Moisture Meter
along with this General Tools MMD4E Digital Moisture Meter
For the hot box. The hot box uses this control
I can set the temperature to what ever i need. I found much above 95 degrees can lower the relative humidity to a very low 12%. So I watch the weight, and once it stops loosing weight for 3 or 4 days i move it to the moistur3e controlled closet and keep it there.
The hot box is up out of the way (I am basically out of space in the shop), so it’s not extremely convenient, but it works very well.
I have two 250 watt heat lamps that runs off the control. It also has a small fan that keeps the air circulating.
It insulated using 2″ ridged insulation.
I hope this helps. It took me a while to figure it all out.