Incorporating
bends into furniture will make the piece. They add attractiveness, creativity,
style, and art to an otherwise simple product. Some projects are impossible to
complete without bending. For example, fishnets, snowshoes, canoes, boats, and
guitars rely on bending to the max.
Bending
can be an enjoyable process if these simple principles are followed.
1.
Select the right
method of bending for the task.
~Will
your bend have to support itself? Or will it be braced by other parts of your
project?
~Some
types of bends will work better in various operations.
2.
Always consider
your choice of wood for bending. Some woods bend better than others.
~Select a
straight-grained piece for a higher quality bend. Knots and curved grain will
result in cracks and splits.
~Quarter-sawn wood is
better for bending then flat-sawn.
3.
Design forms or
molds that are effective and well suited for the bending operation at hand.
These are required for most bending operations.
This small
fishnet displays an example of two types of bending, lamination bending and
hydro bending.
Lamination Bending
Taking two or more pieces to achieve a certain thickness and degree
of bend. A mold is required for this operation,
it holds the degree of bend while the glue cures. You will need to use thin
stock, amounting in several thin laminations for tight bends (1/8”-1/4”). For
larger bends you can use thicker laminations (3/8”-5/8”).
Make a
two-part mold by removing the middle section of a laminated block.
Plan on spring back! After stock is removed from the mold or form, the work
piece often expands slightly straighter than the curve of the mold. Another
method of holding spring back is to incorporate a brace to hold the bend on
your project. However, be aware that too much tension will likely self-destruct
your project.
Re-saw your stock! To prevent waste re-saw your stock on the tablesaw or bandsaw using a
fence.
Gluing Make sure you select the appropriate type of glue for
your bend. Remember some glues are rigid and some are non-rigid. Non-ridged
glues will lose their bend unless “clamped” in place.
Kerf Bending
Cutting kerfs or saw cuts across or with the direction of
the grain, causing the stock to bend. This practice is more effective when
cutting kerfs with the grain. Always back your kerf
bending with a thin lamination on the backside. This will help hold the desired
shape for a lifetime.
Bend stock by cutting evenly spaced saw-kerfs
Practice kerf bending on a scrape piece!
-Cutting kerfs too deep will
leave lines on the visible surface of the bend.
-Cutting kerfs too deep will
result in a break on the bend.
-Cutting kerfs too shallow
will not allow the work piece to bend.
Steam Bending
Appling steam to the wood to help soften grain fibers
causing it to bend. Requires a
steam box or enclosure, which can trap the steam and help it absorb into the
wood. Caution: Steam can be pressurized, to much
pressure will result in an explosion.
-Source of steam can be as
simple as a kettle on a one-burner stove.
-Wood should be steamed for
one hour for every ¼” of thickness.
-Use care not to over steam
the wood, this will weaken it.
-Use a flexible metal strap
on the backside of the bend as a support for difficult bends.
-When steaming multiple
pieces, allow room for the steam to flow between each piece.
-Tilt the steam box slightly
so the water can run out the other end.
-Use three different
supports, all at different heights.
An economical stream oven for occasional uses
For Under $50
AVOID STEAL
OR IRON FASTENERS IN YOUR STEAM BENDER, THE COMBINATION OF TANIC ACID IN THE
WOOD, MOISTURE AND IRON WILL STAIN YOUR WOOD BLACK
Hydro-Bending
Soaking wood in water for a period of time to enhance the
flexibility of the wood and allow it to bend. The stock will need to be fairly thin
for this operation. If the stock is too thick the water will never make it to
the middle of the stock.
Soaking can be done in:
-PVC
pipe.
-Aluminum
or vinyl gutter.
-Ceramic
Cylinder or Container.
AVOID STEAL
OR IRON FASTENERS IN YOUR SOAKER, THE COMBINATION OF TANIC ACID IN THE WOOD,
MOISTURE AND IRON WILL STAIN YOUR WOOD BLACK
Soaking too long can
cause damage! The grain structure is
weakened significantly if left submerged in water for too long.
Veneer Bending
Using veneer or thin plywood to accomplish a bend. A form or mold is necessary for all veneer bending.
Veneer is sometimes permanently adhered to the mold or a form that will remain
part of the project.
-Use vacuum pressure to
accomplish quality veneer bends.
Lamination Bending
Used In:
Advantages: Disadvantages
1. 1.
2. 2.
Kerf Bending
Used In:
Advantages: Disadvantages
1. 1.
2. 2.
Steam Bending
Used In:
Advantages: Disadvantages
1. 1.
2. 2.
Hydro Bending
Used In:
Advantages: Disadvantages
1. 1.
2. 2.
Veneer Bending
Used In:
Advantages: Disadvantages
1. 1.
2. 2.