How to Soften Wood

Softening wood is a helpful bit of knowledge for most handymen and DIYers to have tucked away in their back pockets. Softening wood is common in two situations: carving wood and bending wood. So, if you have a dream of sitting on your front porch in a homemade rocking chair, I have tips for softening your wood.

Simple Options to Soften Wood

The pliability of green wood is obvious. Greenwood is wood that has been freshly cut. Look at branches swaying in the wind. The pliability in swaying wood comes from the wood’s high moisture content.

Ideal moisture content for wood intended for carving is 10% to 12%. A wood moisture meter is relatively inexpensive and available at most home improvement stores. 

Pick up a wood moisture meter and monitor your wood as it either seasons or absorbs moisture.

Use Green Wood

The simplest way to soften wood is to prevent your wood from becoming thoroughly seasoned or dried. If you harvest your own wood, you can allow the wood to partially season for up to six weeks in most environments without it losing its softness.

Freeze Your Wood

If you have found the wood of the perfect softenness, you can freeze the wood between carving sessions to slow down the seasoning process. Freezing the wood helps to preserve the moisture content in the wood.

Freezing the wood can also cause some of the cell structures to burst within the wood as water molecules expand when they freeze. Degrading the cell structure in the wood can also lead to softer wood.

Bath Your Wood

A simple, passive way to bath your wood is to submerge it in water. This is also a great way to bend your wood.

Check the submerged wood periodically with a wood moisture meter to see if it has hit your ideal levels. Moisture levels can be adjusted based on your own experience.

Create a PVC Steam Box to Soften Wood

Creating a steam box, while more work up front, is one of the quickest methods to softening wood. Heat, pressure, and steam combine to penetrate deep into wood resulting in prime carving and bending wood.

There are dozens of steam boxes in many shapes and sizes. The steam box I recommend uses PVC and is easily scalable depending on the size of your wood. An added bonus: PVC is generally inexpensive to work with and long lasting!

Please read through all of this section before purchasing your materials. Remember that the more voluminous your steam box, the more time it will take to raise the interior of the box up to the proper temperature.

Materials:

• Schedule 40 PVC pipe
• 2x flat slip caps for your PVC pipe
• Meat thermometer
• Large metal can with lid (to boil water)
• 2 x 1/2 inch pipe flange
• Connectors to attach pipe flanges to boil pot and to a flat slip cap 
• Flexible, heat-resistant tubing to carry steam from boil pot to PVC pipe
• 2 x hose clamps
• 1/4 inch dowel rods (enough to support your wood at every 4 inches)

Tools:

• Gloves for handling hot objects
• Eye protection
• Hearing protection
• Marker
• PVC cutter, reci saw or a basic miter saw
• Drill press or power drill
• 1/4 inch drill bit
• 1/16 inch drill bit
• 1/2 inch hole saw (with metal cutting capabilities)
• Socket set for tightening pipe flange connectors
• Screwdriver

Method:

Preparing the Pipe:

1. Determine the size and length of PVC pipe you need. The diameter of the pipe should be more than twice the size of the piece to be steamed. The length should be at least 4 inches longer than your piece to be steamed.
2. Put on safety gear. 
3. Cut your PVC to length using either a reci saw, miter saw, or PVC cutter.
4. Along the length of the pipe in a straight line, use a marker to mark a drill hole every 4 inches.
5. Using either a drill press or power drill equipped with a 1/4 inch drill bit, drill holes for dowel rods that will go uniformly across the width of the PVC pipe.
6. Cut dowel rods to length to go across your PVC pipe. I recommend leaving the dowel rods about an inch longer than the diameter of the pipe.
7. Center a pipe flange on the outside of one PVC flat slip cap.
8. Mark the locations for connectors (we recommend bolts).
9. Mark the interior diameter of the pipe flange.
10. Use an appropriately-sized drill bit and hole saw to cut your openings.
11. Attach the pipe flange to the outside of your PVC end cap.
12. Place end caps on your PVC pipe. Do not glue them into place.
13. Use a 1/16 inch drill bit to drill a hole for your meat thermometer. This hole should be on the top side of your pipe, perpendicular to your dowel rods.
14. You will need to drill holes to allow steam to exit your PVC steam box. I recommend starting with a 1/8″ hole on the end of the pipe opposite the entry point for the steam. 

Tip: If there is too much pressure built up within the pipe, more holes can be added. You will know if there is too much pressure if the end caps are forced off of the pipe. If the holes for steam to exit are on the bottom of the pipe, both steam and condensation can drain away from the pipe.

Preparing the Boil Can

1. Place your pipe flange on the lid of your metal-can lid.
2. Mark holes for your flange connectors. I recommend using bolts that fit snugly in the openings of your pipe flange. You should also have washers and nuts for the underside of your lid to hold the pipe flange to the metal lid.
3. With the flange aligned with your connector marks, mark the internal opening of your flange.
4. Use an appropriately-sized drill bit and metal-cutting hole saw to cut your openings. If there are metal burrs left on the metal lid, these can be filed away.
5. Attach your flange to the metal lid.
6. Put a hose clamp loosely over each end of your flexible tubing.
7. Slide your tubing over the pipe flanges
8. Using a screwdriver, tighten your hose clamps until the flexible tubing is firmly secured to your pipe flange.

Tip: Your flexible tubing needs to be long enough to easily stretch from your metal can to the PVC pipe. The metal can will be over a heat source such as a propane burner.

Steaming Your Wood

Now that your PVC steam box is constructed, it is time to soften wood. Your PVC steam box should be set at a slight downwards angle with the pressure relief hole at the lowest point. However you choose to create steam, be sure to use all heat sources safely and responsibly.

1. Fill your metal can with water then place over your heat source.
2. Slide your wood over the dowels in your steam box.
3. Place caps firmly on both ends of the steam box.
4. Boil water. Steam will travel from your metal can through the flexible tubing to your steam box.
5. Monitor the temperature of your steam box. The ideal steaming temperature is approximately 212 degree Fahrenheit.
6. We recommend steaming your wood for two hours for every inch of thickness of your wood.
7. Carefully remove your softened wood after the appropriate time has elapsed while wearing gloves and eye protection.

Conclusion

While there are many simple options for bending wood, a steam box is the quickest method for softening wood. It can be constructed from simple, easily attainable materials. PVC comes in a variety of sizes that can accommodate many dimensions of lumber for carving or bending. Good luck constructing, bending, and carving!