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Porta Mount tripod leg improvement project

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#1 sewhite


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Posted 06 January 2013 - 12:22 AM

The tripod legs are the weakest link in the Porta Mount system so to improve their properties; I decided to inject them with a hardening insulation foam in a can (used Great Stuff found at Home Depot). The Porta Mount legs are thin and have poor twisting resistance; also they are very prone to high frequency vibrations. The foam when injected in the legs expands, hardens, and bonds to the interior walls to create a much stiffer structure of dissimilar materials that cancel out each other’s natural vibration frequency. This improvement cut large twisting vibrations in half and the tuning fork type high frequency vibrations approximately 80% by my estimation while only adding about 1 pound to the tripod. This project would be applicable to any similar tripods.

If you decide to do this to your tripod, disassemble the legs for complete access to both ends. Cover your work table with newspaper and get a roll of paper towels, this stuff will go somewhere you don’t want it to be. Maybe even wear some disposable gloves. The can comes with a straw type dispenser nozzle that would not reach halfway into the legs so I injected as far as possible for several seconds and then started withdrawing the nozzle while continued to fill the leg. Stop injecting a couple inches from the end as it will expand and may come out the end as it cures, repeat process from the other end of the leg. Once you start, do all the legs within an hour or less as the can is best used only once. Clean up as best possible larger amounts with paper towels and after full curing use a razor knife to trim and clean. Sufficient curing to use the tripod is overnight and a full curing will take a couple of days. Reassemble and enjoy.

Another minor improvement is to sand smooth the ends of the leg clamp screws so they don’t dig into the soft aluminum upper leg as easily as the rough factory screw end. I am considering going back in and JB Weld a small steel pad on the upper leg to take the abuse in this area.

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