the material i used to make lightweight saaps is called Koma. i didn't want to use wood because the main mode of failure for wooden saaps is a fracture along the grain direction. that's the inherent weakness of wood, once it forms a small crack due to stress that crack quickly propagates along the grain of the wooden piece. the initial crack is usually caused by the screw rubbing against the wall of the hole in the wooden piece. so the best option besides wood is plastic, which is a great idea until you start considering cost, wood is cheap, enough plastic material to make 12 saaps is expensive, so that was out of the question. the first saap i made was made out of ABS plastice, the precut material cost me $50 just for that 1 saap. i did some research and ended up finding two brands of composite pvc trim boards. azek and koma. i decided to go with koma based on the densities, koma has a density of 0.59g/cm^3 and azek has a density of 0.56g/cm^3; which means that koma is a slightly stronger material and a little more resistant to deformation. for comparison water has a density of 1g/cm^3 and wood can vary anywhere from 0.4-1.2g/cm^3 depending on the type. i ended up getting a 4'X8' 0.5" thick sheet of koma for $130 and made 12 saaps using about 60% of it. since koma is a light density material i do expect it to deform over time as the saaps get used more, so i'm not sure how long it will last but it is definitely the material to go to for building the lightest saaps. if i decide to make another set i will most likely go with a plastic if i can get it really cheap, it won't be as light as koma, because most plastics have a density of between 0.7-1.3 g/cm^3 but plastic saaps will never break, unless you decide to throw them off a building.
i request that the moderators pin this topic.
