Originally Posted by hellosailor
Silica gel works in sealed containers. So unless your tool box is a Pelican case...odds are it is just the wrong application for silica gel. If the box can breath, the gel will absorb all it can but the sea will patiently keep supplying more moisture.
HS is correct. Silica gel just reduces moisture in an enclosed space until saturated. Oxygen absorbers (iron powder) might do a better job as oxygen IS what rusts metal, though they will eventually "saturate" as well. My guess is that since they are a rusting metal themselves they will remain able to absorb oxygen for longer than silica gel will remain useful.
"True, your boat will outperform mine to windward, but my boat will always outperform yours at anchor." --MedSailor