To use concrete forming tubes, dig a hole 6 inches deeper than the total length of the footing, fill these 6 inches with concrete-rated gravel, cut the tube to length, and lower it into the hole. Center and level the concrete forming tube using a mason's level, and then back-fill around its sides to secure it in place. Finally, fill the forming tube with concrete, and allow it to cure.
Use concrete forming tubes for free-standing pilings by first constructing a bottom collar around the base of the tube. For very tall above-ground pilings, additional bracing timbers around the forming tube's midpoint may be necessary. Use oversized nails or stakes to secure the bottom collar and bracers securely to the ground.
If using a concrete forming tube to make a base for a post or pillar, insert the post or pillar into the concrete before it cures. Make sure the post is centered and level, and use wooden bracers to hold it in position during curing. For ferrous metal posts, use galvanized or plated posts to prevent corrosion. Avoid corrosion entirely by using aluminum posts. Preventing rot on wooden posts requires using pressure-treated lumber or applying a preservative, such as a creosote alternative, to below-ground portions of the post.