How do I remove a tubular concrete form?

They make cylindrical cardboard forms called Sonotubes that are designed for such purposes. They are available at home centers, concrete supply houses, lumber yards, etc. After you pour the concrete, use a sharp knife or Sawzall to cut through the cardboard and remove the exposed section of form. It will be much easier than trying to remove a metal form. Hope this helps.

Cardboard Concrete Forms

Concrete Form Tube

If the form is smooth and has no projections that would prevent it from being withdrawn from the cement when it sets. just use some motor oil to coat the inside of the form prior to pouring the concrete. This will act as a release agent. When the concrete has set, just pull the form off the casting. It may require a bit of gentle tapping to make the casting come out of the form but it will come out. Have you considered using a cardboard form from the lumber yard. They make cardboard forms specifically for concrete. I would coat the inside of the cardboard with oil but then when it was time to remove it, I would just cut it with a sharp utility knife and peel it away.

I think the form would be stuck on the concrete.

If you split the form and lashed the halves together before you

pour the mold would be re-usable.

Also, waxed cardboard tubes are available at most masonry

material yards. After the concrete hardens the tubes are peeled off and disposed of.

A cardboard tube will handle a pour like that with no problem and you can just cut it off later. Plus it is porous so the concrete will set faster.

You need a good concrete release agent. Check Home Centers or concrete suppliers.