The predecessor of the skateboard
The skateboard gained popularity particularly during the 1990s – just think of the numerous music videos from back then. However, the predecessor of the skateboard is the longboard. It was invented by surfers, who wanted to live out their passion on the street as well and therefore attached wheels to their surfboards. Over the past few years, the longboard has become increasingly popular – especially since many YouTubers have published captivating videos. But the smooth skating on a longboard also fascinates older generations.
Longboard versus Skateboard
As the name already tells, the longboard is longer than the skateboard. It usually has a length of 90 to 150 centimetres. Because of its length, it also has a longer wheelbase. While the skateboard is better for doing stunts, longer distances can be covered with the longboard. The wheels are made of polyurethane and they are more lightweight and elastic, so the longboard adapts better to different surfaces. That makes skating more comfortable and smoother than it is on a skateboard. The longboard is also faster – it can reach up to 100 km/h.
Choosing the right material
A longboard consists of a deck, trucks and wheels. Depending on the shape and width, there are different types with more or less concave decks: Freeriding, boardwalking, cruising, carving und downhill.
During a training course on fibre composites, I made a prototype of a carbon fibre-reinforced plastic longboard myself. Most boards are made of wood or bamboo with outer layers of fibre-reinforced plastic composites like carbon fibre-reinforced plastic. Carbon fibre-reinforced plastic has 50 percent more fibre volume content (more fibres than resin) compared to metals or woods. Due to this sandwich construction, the mechanical properties of the longboard can also be adjusted to its use. That makes it particularly lightweight.
The production
We decided to produce the board using the vacuum infusion process with a semipermeable membrane. A semipermeable membrane is a membrane which allows air to pass through, but not the resin. Everyone knows this principle from breathable outdoor clothing. This production process is particularly useful when producing a curved shape high in quality – with low quantity and low level of automation.
For bonding the material, a special epoxy resin was used. This is highly flowable and has a long pot life as well as good adhesive properties for bonding the fibres.
First, we cut the sandwich core, the fibres as well as all other support materials to the right shape. In order to do so, we needed extra sharp scissors, like our WEICON Cable Scissors No. 35, as the carbon fibres are very rigid.
Then we put the carbon workpieces (different fibre orientations and interweaving) in a specified order.
After that, the sandwich core followed, which was made of a balsa wood composite in this case. This was perforated evenly spaced with a drill (diameter 2 mm) for the resin to soak through the wood better.
Then, the layer structure was built in reverse order (from the inside out), as a separating layer is needed on the outside, too, in order to demould the base after curing. Then the board shape is cut out of the base.
When inserting the carbon work pieces into the concave shape, Adhesive Spray was used for fixation.
As our production was only a prototype, a small void became visible later on. We touched it up using WEICON Casting Resin MS 1000.
After attaching the bushings, I mounted the trucks. To secure the screws on the bushings, I used WEICONLOCK AN 302-42 Threadlocking.
