If you are someone that lives in an area where you can get easy access to your own trees you might want to consider milling your own lumber. Trees like spruce and pine are pretty easy to come by throughout the country and other woods like Oak, Maple, and Walnut may be prevalent in your area.
Many people that make custom furniture for a living will find ways to get logs from people that need trees cut down. If they don’t cut down the tree themselves they might have a connection with a arborist that can alert them when a nice hardwood tree is available. In reality getting hold of the trees and logs is not the difficult part. The hard part is taking those logs and processing them into usable lumber that can be used for building or projects.
Once the logs are harvested some people will use a chainsaw mill to process the logs into thick slabs or lumber. Other people that do a lot of this work might have access to their own lumber mill. Lumber mills are not too expensive if you use them a lot and can generate a good amount of lumber for a relatively low cost. If the trees are on your own property or if you can get them for free then the cost is really low. If you have to pay for them you need to factor that into your cost. However when it comes to some specialty woods it might be worth the cost to pay for some of the raw materials.
For lumber you want to process the logs into nominal sized lumber. You will notice when you go to the lumber store and buy a 2 x 6 inch board it is actually only about 1 1/2 x 5 1/2 in size and this is because during the drying process a dimensional or full sized 2×6 will shrink and that is why they call it nominal lumber. It is lumber that is cut wet and then dried and then after drying it is close to the dimension that you want.
When lumber is wet it can have 20% or more water in it and after it is dried and ready for use it will be down to 8% to 12% moisture content.
Some woods are prone to checking and cracking during the drying process so woods like walnut should be processed into 2 inch or thicker slabs that will eventually be resawn into thinner boards. You really want to be careful with the higher priced hardwoods because the entire time to process it can take two to six months or more and that is a lot of time to lose if you end up with cracks in your beautiful hardwood slabs.
How Do You Dry Wood For Lumber And Furniture Use?
The first step in drying wood is to stack it using the sticker method. Stickers are just sticks that are placed between a row of boards so that air can pass through the stack. You would first level out the area where you want to stack your wood even a concrete slab is helpful for this initial drying. Then you will place down sticker boards at about 2 to 3 foot intervals on that level surface. If you want you can also place some 4×4’s in the ground and build a deck that is level.
Lay down your first row of boards giving them at least 6 inches from the ground. A foot from the ground or more might be better if you have moist ground under the stack. Now add your stickers on top of your first row of boards and place your second row.
Each board should be separated on all sides to allow for even drying. The more air that can get to the boards means the more moisture that will be removed in a shorter time. You also want to make sure that the wood in the center of the stack drys at the same rate as the wood on the outside of the stack. Proper spacing is important and you will want it covered with a roof to keep rain off of it.
Once the initial drying has happened the moisture content in the wood will still normally be over 15% and that is too high for furniture, flooring and finish carpentry. Also for lumber it is best to kiln dry it not only to stabilize the wood but to sanitize it from bugs that might be in it.
What Is Kiln Drying And How Can You Process Your Wood
If you ever made any pottery you might think that a wood kiln is some furnace driven device that heats the wood up to thousands of degrees to make it usable. In reality its not quite like that but no one can stop you from thinking that.
A wood kiln is normally a large room or shed that is highly insulated and when lumber is placed in it there is a dehumidifier that will dry the wood. In reality it can be that simple. I have seen some furniture makers that just have a basic shed with a dehumidifier in it but the process takes a long time. A professional kiln will have a dehumidifier and heater that will heat the enclosure from about 120F to 150F and a number of fans that will circulate the air constantly to provide even drying so there isn’t any cracking.
Lets go over the importance of the Temperature. The wood is normally heated at about 120F during the drying process which can take days or weeks and then at the end of the process when the right moisture content is obtained the wood will go through a sanitation process where it is brought up to about 150F for 12 to 24hrs to kill any bacteria, mold spores, fungus and most important any bugs that might be in the wood.
The air that circulates through the stack of lumber must be constant and the fans that move the air must be rated for high heat conditions. Some people try to use box fans and this might work for a short time in small loads but the motors can’t stand up to the heat so you want to use either a belt driven fan where the motor is outside of the heated room and a belt or chain runs the fan blade or you can use higher temp fans such as attic fans for a longer life than just consumer indoor personal fans.
In summer months an ordinary shed might get hot enough to provide the initial drying of the wood but you will still want to remove the moisture. During the sanitation process you will most likely need supplemental heat to achieve the proper temps. Personal box heaters are not going to be enough for this but a good garage heater could put out enough BTUs to get it done.
Final Note
In this how to we went over the basic idea behind kiln drying your wet or harvested lumber into dry lumber that can be used for building or furniture making. We didn’t hit every aspect of this process but you should have enough information to get started in the right direction.
First you have to obtain the logs and process them into lumber or thick slabs depending on the wood type.
Next you need to stack that lumber for initial drying down to about 20% moisture content or about the same moisture content that seasoned and dry fire wood would have. You also need to stack the wet lumber evenly and level so it won’t warp during drying. Stack it on a flat base and separate it for good air flow with stickers.
After you have got to this far you can kiln dry the wood until you reach about 10% moisture content. The amount of moisture in the wood you are drying should be researched for best results. There will always be some moisture in the wood but for it to be stable a level of about 10% maybe less is necessary.
Building your own kiln is difficult and can be expensive if you use professional kiln drying equipment. For this reason you might want to find someone in your area that can perform this final step for you. The most important step would be the sanitation step and possibly stacking your lumber in a regular shed in the summer time can get that temperature up above 100F for the moisture extraction process.