CURIOUS

[lawson56]

Living here in Southern Tn, the weather is always changing, Having a bad back bad feet I get down to my shop early in the A,M, suffer from sleep disorder as well. I do what I can when I can. Once I get to my shop I try to stay as long as I can.

[OCtoolguy]

10 hours ago, Grumpy Old Bear said:

I also have my saw in a spare bedroom. Very nice not having to go up and down stairs. Last night I finished a new dust sucker thing-ee for the saw, so the little vacuum I use will grab both the top and bottom dust. That keeps the wife happy.

Pictures. Need pictures. We all need to see your dust sucker thingee!

[Rolf]

18 hours ago, Grumpy Old Bear said:

I also have my saw in a spare bedroom. Very nice not having to go up and down stairs. Last night I finished a new dust sucker thing-ee for the saw, so the little vacuum I use will grab both the top and bottom dust. That keeps the wife happy.

 Can you post a picture, it is always nice to see how innovative folks are with their dust collection. 

[CharleyL]

On 6/30/2021 at 5:25 PM, Rockytime said:

Evaporative coolers are widely used in Colorado as we are semi arid. We've used them in houses We've owned in the past. They are quite efficient. 

Out there, yes. The humidity is low, so adding some more moisture to the air is a good thing. We, our wood furniture, and our tools are quite comfortable working in 30-60% moisture, but it is "relative humidity". As the air temperature changes, the amount of moisture that the air can hold changes, even if you aren't adding moisture to it. This 30-60% is right when the temperature is around 70 degrees F. Cool this same air and it can hold less moisture, so this same air will have a higher relative humidity reading of likely 70% and higher as the temperature goes lower. Go low enough and this same air will begin to condense water droplets on your metal tools. 

As the air outdoors heats up during the day it can hold more moisture, and will collect it off evaporating lakes, trees, grass, etc. Then as the Sun goes down and the air cools, this air temperature to moisture content ratio will reverse, and the cooler that the air gets, the less moisture the air can hold. What it collected during the warm day is now too much for the cooler air. Dew falling and collecting on surfaces as the air cools is this excess moisture that the air can no longer hold. 100% relative humidity is the dew point. Keeping the relative humidity in your shop well below 100% will prevent this moisture from rusting your tools. Dehumidifiers and AC units cool the air enough to get the moisture out of the air by lowering the air temperature and getting this moisture to collect on the cold coils inside. Then the air passes through the warm coils (in a dehumidifier) and is warmed back up. An AC unit condenses this excess moisture out, but also cools the air by moving the heat from the inside of the shop and releasing it outdoors. It does not do much cooling until it can remove much of the humidity in the shop, but then can become quite effective at cooling the shop once the moisture has been removed. 

If you can learn that there is a relationship between air temperature and the moisture that this air can hold is relative to each other, and that cooler air cannot hold as much moisture as warmer air, all this becomes easier to understand. 100% relative humidity is the maximum that the air can hold at any given temperature. Cool this air and the moisture in it can no longer fit in it, so it will become dew and fall or condense on things. This 100% humidity is also called the "Dew Point" - the point at which dew (excess moisture) begins to form as the air cools. Keep this dew point relationship well below 100% and both you and your tooling will be happy, with 50-60% being the most comfortable levels. 

This is also why your shop and home have lower humidity in them during the Winter. The air outside is cold, so it has very little moisture in it, even though it's relative humidity may be 80-90%, but when this same air comes inside and is warmed up to 70 degrees or so, the relative humidity becomes very low and you become uncomfortable because it's too dry for you at 15-25%. Cool this inside air back down to the outside air temperature and the relative humidity of this same air will increase back to what it was when the air temperature again matches what it was outdoors. When the relative humidity of the air increases above 100% at any temperature, it's going to rain or condense on the cold surfaces because some of it no longer fits inside the air. 

This is a bit long, but I hope it gives you all a better understanding of why your tools rust in an unheated shop as the shop air temperature falls, why it rains at the beginning of a Cold Front moving in, and what dehumidifiers and AC units can do to help us and our tools remain rust free and comfortable. Don't open your shop overhead door to the outside when it's raining or very warm and humid outside. 

Charley