Bending Timber Flashcards
What is the definition of a deforming process?
-Lucas M
Where material is reshaped without changing its state.
Bag press laminating is a method to…
-Lucas M
Bend timber
Why bend timber rather than cutting a curve from a solid block?
-Lucas M
Cutting a curve from solid timber creates a short grain section which is weak and liable to break along the grain.
What does PVA stand for?
-Lucas M
Poly vinyl Acetate
What is the setting time for Aerolite 306?
-Lucas M
25mins to 3 hours dependant on temperature
What type of process is bending timber?
Ivan K
Deforming process
Name this process for bending timber:
Many parallel cuts along the length of a piece of timber, but only some of the depth.
Ivan K
Kerfing
What is the rule of thumb for the length of time to steam timber?
-Ivan k
One hour for each inch or 25mm of thickness.
Cutting a curve from solid timber creates a short grain which does what to the timber?
- Humphrey Marsh
Makes the timber weak and liable to break along the short grain.
Kerfing with timber is created by…
- Humphrey Marsh
A series of parallel saw cuts.
When steam bending timber, the heat and moisture makes the timber…
- Humphrey Marsh
Soft and pliable.
What force does a bag press uses what to push laminated wood against the former?
- Humphrey Marsh
Atmospheric pressure from outside the bag.
Which deforming processes are commonly used with timber?
-Oscar Lawson
Bending or laminating of timber.
How do you maximise strength when bending timber?
-Oscar Lawson
Try to ensure that the grain follows the profile or curve
What conditions does a steam chest provide?
-Oscar Lawson
Saturated steam at 100 degrees Celsius
What are the two main steps for laminating timber?
-Oscar Lawson
- Glue strips or layers of wood together with a strong adhesive
- Clamp them in a jig or over a former to keep them in the required form until the glue had cured.
What is a former used for when bending timber?
-Oscar Lawson
A block around which lamina/ply of wood are put so that the strips adopt to the same shape.
Any adhesive to be used with a bag press must be able to cure in the absence of ….
-Caspar Tyser
Air.
What do curing times of adhesives mostly depend on?
-Caspar Tyser
Temperature.
Does cross-linking (D3) PVA need air to cure?
-Caspar Tyser
No.
Is Cascamite waterproof once cured?
-Caspar Tyser
Yes.
Name the device used to heat and moisten timber before bending.
-OTC
A steam chest.
What characteristic of grain is most important for timber which is to be bent?
-OTC
That it is straight grained.
What is Kerfing?
-Yan K
A series of parallel saw cuts made on one side of the timber to allow that side to compress.
What is the process of steam bending?
-Yan K
Lengths of wood are placed in a steam chest with saturated steam at 100 degrees Celsius.
The supply of heat and moisture makes the timber soft and pliable.
What does a bag press do?
-Yan K
Uses atmospheric pressure to push the laminated timber against the former.
Is aerolite 306 suitable for wood?
- Ssnehnil G
Yes.
Which needs to cure in air: Crosslinking PVA P3/D3 or regular PVA?
- Ssnehnil G
PVA.
Is bending/forming a reforming process?
- Ssnehnil G
No, it is a deforming process
1 hour per 25mm thickness is a rule of thumb for which process?
-Ed H
Steam bending
PVA P3/D3 is?
-Ed H
Cross linking PVA which needs to cure without air.
What is the main disadvantage of short grain?
-Ed H
It is weak and liable to break.
Whilst bending timber, what would you use a flexible steel band to do?
-Oscar Mabon
To pull strips over the former in laminating.
Do the cuts have to be parallel during Kerfing timber?
-Oscar Mabon
Yes
What is cascamite?
-Torsai K
A strong waterproof timber glue suitable for use outside.
What makes timber soft and pliable?
-Nathan P
Heat and moisture.
What visual feature gives away whether a timber component has been bent to shape instead of being cut to shape?
If the grain on a timber component follows the curves of the shape, it has most likely been bent to shape.
However if end grain is visible around curves, then it has most likely been cut to shape.
