Technical guides

How much rubber sheet do I actually need? Weight, area and the 200 kg minimum
Sheet is sold by the square metre but shipped by the kilogram. Here is the arithmetic, and why a 200 kg minimum is less material than it sounds. Read more...
Shore A hardness explained: what 40, 60 and 80 actually feel like
Hardness is the number people specify with the least confidence. Here is what each band feels like in the hand and what it does in service. Read more...
Silicone vs FKM: heat, chemicals, and what each one actually costs
Both survive heat that destroys ordinary rubber. They fail in completely different ways, and one costs five times the other. Read more...
Nitrile vs FKM (Viton type): when is the expensive one worth it?
FKM costs roughly seven times what nitrile does per pound. Most oil-sealing jobs do not need it. Here is how to work out whether yours does. Read more...
EPDM vs neoprene: which rubber sheet belongs outdoors?
EPDM wins on weather, steam and water. Neoprene wins the moment oil, fuel or fire enters the picture. Here is how to tell which problem you actually have. Read more...