I was wondering if I made a rail out of metal pipes hat were 5" apart and i just had a 2x4 in the middle a little lower would that elimintate the need for HDPE in the middle? Also i am not planing on doing it straight, ever
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2x4 2x4 2x4 2x4 2x4 2x4 2x4
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top veiw ^
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\ \_____[2x4]
\_______[Metal Rail]