Carpentry, Crafts

How to bend wood: steps using water, steam or fire

How to bend wood: steps using water, steam or fire

This guide outlines the steps for how to bend wood using three methods to choose from: water, steam or fire.

Vases, hearts, climbing aids, jewellery, a sleigh, a canoe, a chair, a man-sized ball… or perhaps fix a chair back. Even if someone only wants to bend smaller objects at first, this can be a lot of fun.

We all appreciate wood as a material for its diversity: colour, hardness and possibilities for processing vary from variety to variety and play an important role in the selection for the various projects. One aspect that rarely plays a role for most woodworkers, apart from boat building, is the ability to bend, but this is exactly what plays a special role for projects in which permanently bent parts are to be used.

And even if you’re not building boats, bending wood opens up completely new design dimensions. When heated with steam, a hot water, or our fire method below, the lignin in the cells becomes softer. The wood can be stretched onto a mould and permanently bent well above the bending radius it would have in its dry state.

However, not all wood is the same. After all, not every type of wood is suitable for steam bending – and not every type of wood is suitable for the same radius. Softwood is not suitable for bending due to its fundamentally different cell structure and breaks quickly. Only yew can be shaped in large radii – the classic yew arches are probably the best-known example of this.

However, it is much better to work with hardwoods. And the good news is that they don’t have to be exotic. Beech, oak, elm, ash and walnut are particularly suitable, and some fruit woods can also be bent well.

If you look closely, you will probably also find some wooden objects in your home that contain bent wood. These are often inexpensive composite woods.

Hand-bent wood is more complex to produce and therefore more expensive. Basically, however, the bending techniques implemented by hand are usually based on the same prerequisites.

ALSO READ: How to use driftwood for craft projects

How to bend wood with hot water or steam

Wood pieces are easier to bend when they are thinner, of course. Beginners could start with very thin wood of about 5mm thick and please make sure that the fibers in the wood are aligned as straight as possible. You could even practice with a popsicle stick, but according to the experts, hardwood is easier to bend than softwood.

  • For many pieces, you can map out the bend you want, and create a ‘bending board’ or ‘jig’ with nails following the curve of the bend you want.
  • It is advantageous if you design the jig in such a way that you can let the bent parts dry while clamped in it.
  • Once you have your jig made and your wood selected, put the wood in gently simmering water for about 3 to 5 minutes, or if your jig is small enough to fit in a steamer, do that for at least 30 minutes. The process here is about making lignin — the wood’s own glue — become flexible again.
  • For this next step, please wear gloves. Once the wood has been in the water or steam long enough, take it out and bend it around the nails in the jig — always keeping the tension. The wood is flexible as long as it is warm and damp.
  • When you have the desired curve, then you have to fix the workpiece in this position and then let it cool down and let it dry.
  • After that, it can be taken out of the “bed of nails” and will stay bent into the curve you wanted

How to bend wood — or straighten it — with fire

Learn how to bend or straighten wood into a desired shape in a very simple way, without steam or hot water. Compared to professional wood bending with a steam chamber, the technology presented offers an easy-to-implement alternative.

Requirements: Heat and humidity

In order to be able to bend natural wood into a desired shape, two important requirements must be met:

  • Heat
  • Humidity

Wood bending works best when both conditions are met and interact. For example, artisan wood bending artists have steam chambers in which wood is exposed to 100 degrees hot steam for a desired period of time. After about an hour, such heated and damp natural wood is as pliable as rubber.

Outdoors, of course, you don’t have a vapor chamber. There are other alternatives here to be able to bend your wood even under the simplest conditions. However, you have to be a bit inventive and improvise.

If you know that you need heat and humidity to bend wood, you can improvise outdoors with this knowledge. You also know that wood should not be heated too much for the bending process (see the 100 degrees in steam bending).

With this basic knowledge, you can now immediately start bending wood over fire yourself.

Step-by-step instructions for how to bend wood with fire

Suitable tools

Saw can be useful to bring strength to length before bending. If you have a working bushcraft knife, you can do without the saw.

Outdoor knives with a wide full-tang blade, which are also suitable for chopping and batons, are particularly helpful for bushcrafting.

#1 Choose and prepare wood

The thicker the wood, the more energy you need in the form of heat for bending or straightening. If a branch is 3 cm thick, it should either be made of fresh wood or be watered before bending or straightening.

Thinner sticks made of fresh wood up to about 1 cm thick only need to be heated over the embers for a few minutes. They can then be brought into shape (depending on the wood used).

Wood from deciduous trees is better suited for bending wood than wood from most conifers (exceptions: yew, cedar).

Suitable types of wood for wood bending over fire:

If you plan to remove the bark from the bent wood, be sure to do so AFTER bending the wood over the fire. The shell prevents the moisture required for the successful bending process from escaping too quickly (without breaking the wood).

#2 Make a fire and prepare embers

Prepare the fire pit in time and light the fire. If you want to start bending wood, there should be enough embers. Because bending is done over the embers and not over the flame. The type of fire is a simple hunter’s fire.

#3 Heating the bending point evenly

  • Heat the bending point evenly by slowly turning the piece of wood you want to bend over the embers.
  • Don’t make the bending point too narrow, but rather a little larger and then keep working ‘around the bend’.
  • In this way, the angle can be bent over a longer distance, which somewhat dampens the forces when compressing and pulling the wood fibers.

#4 Timing

  • For a 1 cm thick wooden stick, expect about 5 minutes of heating before you can perform the first bending pull or bending pressure. The first sign of abundant heating is moisture leakage from the bark at the bending point.
  • If you notice that the stick is slowly yielding on pull, then start by exerting a steady pull. While you continue to hold the bending point above the embers, you will deform the wood at the same time.
  • Bend slowly and carefully
  • On the outside, the wood fibres are pulled and can tear if the tension is too strong. On the inside, the wood fibres are bent during bending and can break if the bending pressure is too strong.

#5 Cooling

  • Cool down at the (slightly overcurved) bending angle.
  • When deforming, bend the piece of wood a few degrees above the desired bending angle. This is because when the wood cools down, it tries to pull a few degrees back into its original shape.
  • Keep the wood still hot in the desired deformation until it has cooled down. After cooling, it should now keep its new shape

Wood bending tips: What you should consider

To ensure that the wood does not break and that you get an optimal bending result according to the circumstances, follow the following instructions.

Bend with the grain

If you use fresh wood from branches or thin trunks outside, you will automatically bend with the grain here. With sawn boards, on the other hand, you have to be careful that the bending line actually always runs along the grain.

Also, make sure that there are no knots or inclusions at the bending point. These would weaken the material in the appropriate places and it could break more easily.

Suitable wood for bending

Use the types of wood described above. Wood from deciduous trees is more suitable for deformation than wood from conifers. Reeds can also be bent very well when they are still green. Experiment with different types of wood and see what works best.

The right wood thickness

The thicker the wood, the more difficult it is to deform it. Branches, sticks, slats, boards up to 1 cm thick are the easiest to bend because they need to be heated for less time.

Don’t heat the wood too much

Avoid holding the wood in the open flame when bending. There it can burn, moisture comes out of the wood faster, and the burnt areas do not look nice later.

Bend the wood over embers, which give off about enough heat that you can hold your hand over it for about 1 second.

Use already damp wood

To be able to bend wood, it must be moist and heated to over 100 degrees. Therefore, either use fresh wood or soak wood in water for some time before the fire deforms.

To moisten the bending point and at the same time protect it from burns, surround it with a wet clay coat. Then heat the bending point directly with the surrounding clay mantle over the embers.

Questions and Answers

What are the easiest methods for how to bend wood?

Well-known options are bending with steam or at home with hot water in the bathtub. Plywood has different bending properties than non-glued natural wood. For bending natural wood, you always need sufficient heat and moisture.

What wood is easy to bend?

Wood from deciduous trees is better for bending than wood from conifers. Oak, beech, ash or walnut wood can be bent and straightened very easily.

Can you bend balsa wood?

Thin balsa wood can often be bent even when dry. It is also considered very flexible when dried. However, it springs back slightly when dry. In order to be able to bend or straighten it sustainably, balsa wood should also be moistened and heated accordingly.

How to straighten warped wood?

Wrap it with warm and humid towels until the wetness is absorbed. Heat the moistened wood additionally (e.g. at home with a hair dryer). Thin wood is easier to straighten than thick wood.

Summary

Even with the simplest of means, you can bend outdoor wood into the desired shape. You don’t even need steam or a bathtub with water if this is difficult to arrange. What you do need, however in that case, is damp wood (preferably fresh wood) and a campfire.

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