The simplest type of vacuum press uses a sealable bag and some
form of vacuum generator. By placing materials in the bag,
sealing it and then sucking out most of the air, a pressure
differential is created between the reduced pressure inside the
bag and atmosphere on the outside. It is this pressure
differential that is used in vacuum pressing.
Most vacuum pumps and generators achieve around 85% vacuum. As
atmospheric pressure is about 10 tonnes per square metre, this
means that a pressure of 8.5 tonnes per square metre is being
exerted on everything inside the bag.
The introduction of vacuum
pressing to the education market is one of the most exciting
developments in design and technology in recent years. The process
of vacuum pressing is very simple yet it produces professional
quality results and the potential for its uses are limitless.
Typical school projects might include making chairs, skateboards,
salad servers, picture frames and clocks.
The Bagpress system that you buy for your school is not a
defeatured, smaller scale, educational version of the equipment but
is exactly the same piece of machinery that is sold into a wide
variety of industrial manufacturers throughtout the world. It allows
you to teach the design and prototyping process far more thoroughly
than if you are having to use the alternative ‘male and female
former’ method of laminating.
school lamination projects using the traditional male/female tooling
system have failed over the years due to the difficulty in producing
accurately matched pairs of moulds. Vacuum pressing overcomes this
problem by only requiring a single mould, and this can be cut from a
block of styrofoam or extruded polystyrene. This dramatically
increases the amount of time a student has available to devote to
the product itself and enables much easier fine tuning of the
design. This exposes the student to a true prototyping and product
development cycle as would happen in industry.
The use of a mould and the repeatability of the process also allows
students to consider batch production techniques and the way in
which jigs and other tooling can be used to ensure efficiency and
accuracy in manufacture.
The range of projects that can be
tackled is wide and a Bagpress system can be safely used by every
age of student from primary through to graduate level. In many cases
we are told that the Bagpress never gets put away as there is always
someone who needs to use it at some point during the day.
have developed three sets of pre-cut moulds for schools referred to
as Nested Mould Kits 1, 2 & 3. They have a selection of moulds for
specific projects such as salad servers and chair backs as well as a
variety of abstract circular and elliptical curves and wave forms
which can be used in the production of a wine rack for example.
The abstract forms ensure that students aren’t all tempted to make
exactly the same thing. They can study the shapes available and use
these to inspire their own imagination and creativity for personal
design projects. These mould kits offer an ideal way to ‘hit the
ground running’ when you first purchase a vacuum press system.
Bagpress they tried and tested more than 15 different types of PVA
before choosing the one they now use in their own manufacturing
workshop and this is the same product we sell. 99% of all the panels
they laminate and veneer are bonded using a high grade D3 (water
resistant) PVA adhesive. This type of adhesive has improved
significantly in the last 20 years and, with the introduction of
specialist materials such as flexible plywood can now be considered
as ideal for most veneering and laminating jobs.
The Pizzi glue spreader is the only spreader we use here at Bagpress and, once you’ve used one, you won’t want to use
core material used for creating curves and shapes is a flexible
plywood which is extremely versatile and bendy until bonded with
adhesive and other layers such as birch plywood or veneer when it
then holds its rigid form. We supply flexiply in 3, 5 and 8mm
supply birch plywood in 0.8mm thick 1200 x 1200mm sheets and 1.5mm
thicknesses in 1525 x 1525mm sheets.
We have a mixed pack of coloured and exotic veneers - ideal for all your veneering projects and covering a total area of one square