Replies

1. 
   IanDG | Oct 18, 2004 11:57pm | #1

   Masonite is hardboard -- tempered is oil-tempered and a little more moisture resistant than ordinary.

   IanDG

2. 
   DanH | Oct 19, 2004 12:13am | #2

   Hardboard is a form of pressed wood product. The difference between tempered and untempered is that the tempered has been saturated with a sort of oil and then baked (polymerizing the oil into a sort of plastic a la Bakelite), creating a product that is relatively impervious to water. But there are differing degrees of tempering, from cheap siding that is just tempered on one surface to heavily-tempered hardboard that is one step shy of Bakelite.

   Masonite is a brand/corporation name. Their best-known products have been hardboard, generally of the tempered variety, but they have pretty much gotten out of that line (in large part due to massive problems with hardboard sidings during the 70s). However, you will frequently hear the term "Masonite" erroneously applied to any brand of hardboard (just as you hear the term "Sheetrock" applied to any brand of gypsum board).

   Tempered hardboard is usually rated for exterior use. (Untempered hardboard should never be used where it might get wet.) You can generally tell tempered hardboard from untempered by the color -- the tempered will be darker, and the most heavily tempered hardboard will be the darkest.

   Hardboard is nice for some uses since it is smooth (usually just on one side, with a screen pattern on the other), has no grain, cuts/machines relatively cleanly, and in the thinner sizes flexes nicely for fitting to curves. It also is fairly strong/puncture-resistant, given it's thickness.

   It's often used for making jigs and templates, thanks to these properties.