Don't use a mattress its way too soft.

Get a log with the bark still on it; a good size is about 6 to 8 inches across about 3 feet long so there is a good weight. Start with laying it flat later you can switch to a tree. This can be used by cupping the hand to fit the rounded log as well as flat strikes with the base of the palm and center of the hand etc... There are three key elements, first don't hurry,hit harder than is slightly uncomfortable- stay constant with the training routine and schedules-three use a jow before and after.
This is not really iron palm development as it is only one phase the conditioning phase but it is an important part and it is the place to start. You need some conditioning developed before you start an effective program.

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