The towels you use should ideally be large enough to cover the entire wood piece. Choose towels or rags that can withstand the heat of an iron. When moistening the towels, drench them thoroughly and wring out the excess water. The towels should be damp but not dripping wet.
The concave or inward curving surface should face down. The surface you place the wood on must be rigid. It should also be able to withstand the high heat of an iron.
Give the iron two to five minutes to heat up. Note that the iron should be designed to work with steam. A dry iron is not recommended.
Hold the iron on each spot for 5 to 10 seconds before sliding it to the next spot. Each spot should overlap slightly to ensure that the entire wood piece is covered. Do not leave the iron unattended at any point. An unattended iron can burn the press towel and the wood beneath it.
Once the wood has un-warped, turn off the iron and unwrap the wood. Allow the wood to dry thoroughly before use. This process may not work on severely warped pieces. If you do not notice any progress after two or three tries, you may need to try another method.
You can use towels, sheets, or rags. The material you use must retain moisture and be large enough to wrap around the warped wood piece. Run the towels under water until they are soaked, then wring out as much excess moisture as possible. The material should be moist when you wrap it around the wood, but it should not be drenched.
You may want to place a plastic tarp beneath the wood to prevent the water from soaking the surrounding area. This method works best during warm, dry weather. It may not work in cold, cloudy, or wet conditions. For best results, place the wood on top of a rigid surface, like a driveway or deck. You can place it on top of your lawn, but the process may not be as effective if the wood sits on a soft surface.
As before, the material should only be moist and not dripping wet. The sunlight should heat the covered wood and encourage it to absorb moisture from the towels. As moisture is absorbed into the surface, the wood should begin to warp back into its proper position.
When the sun disappears at night, you should bring the wood inside. Keep it in a warm place overnight with the inward curve facing down. If you do not notice any progress after a few days, you may need to try a different method.
Paper towels are ideal for this method, but a thin steaming towel or standard paper can also be used. The material you use must be moistened, however, and it must be large enough to cover the entire warped area. Rinse the paper towels under water, then carefully wring out the excess. The material should be moist when you drape it around the wood, but it should not be dripping wet. Only apply the wet paper towels to the concave side of the wood for this method. By concentrating the moisture on the side, you can help direct the warping back to its original flat position. The concave side will absorb more moisture while the convex (outwardly bent) side will dry out.
The plastic should slow down the process of evaporation, keeping the paper towels and wood moist for a longer period of time as a result. Make sure that the plastic wrap covers all sides of the wood, not just the side covered by paper towels.
Work carefully while tightening the clamp. If you tighten it too much, the wood might split apart instead of straightening out.
Check regularly and remove the wood from the clamp if you see signs of possible damage. The storage area should be as warm as possible during this first week. Ideal temperatures would be as high as 149 degrees Fahrenheit (65 degrees Celsius), but if heat that warm is impossible to maintain, the hottest room you have should suffice for most purposes. You can keep the wood warmer if you let it sit in direct sunlight, beneath a heat lamp, beneath an electric blanket, or over a warming mat. Keep the heat on the wood for at least six to eight hours per day.
At this point, the wood must be allowed to thoroughly dry. Check the progress of the warp. If it has vanished, the wood piece is ready to use as soon as it dries and not additional pressure is needed.
The temperature can be somewhat cooler for this stage, but the ideal temperature is still 77 degrees Fahrenheit (25 degrees Celsius). The air of the room should also be dry during this stage. Do not store the wood in a humid room.
If the wood has not unwarped after you complete this process, the damage might be too severe to reverse.
