color break
k2 red telephone box
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How I made my K2 Telephone Box
Author: Les Kenny; Editor: Maree Anderson


Step 1.3. The form (mold) for the hypertufa.

Hypertufa (in a sense) is a lightweight concrete.

In order to cover the top of the head with hypertufa I had to make something to hold it in place until it cured (set). This involved covering the current structure with polythene (plastic) sheet to stop the hypertufa falling through the support structure, and also fixing a wall (form) around the sides to stop the hypertufa running over the sides.

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forming the base of the telephone box head I stapled and taped some polythene (plastic sheet, such as plastic rubbish bags) over the top of the head and pulled it tight.

Then I ran some tape over the polythene along the top of the inner support structure frame-work, and stapled that as well to ensure extra strength

Then I made a form around the sides of the head to contain the hypertufa (lightweight concrete).

I made the forms out of spare plywood that was 5/16" (7mm) thick. The forms were discarded after use.

forms around the side of the telephone box head Below is the pattern for the temporary form pieces that went around the sides of the head.

the plan for the forms that go around the side of the telephone box head

The line spacings on the grid above represent 1" (25mm).

Once cut, the form pieces were screwed to the sides of the head. The top of the forms sat a little over 1½" (40mm) higher than the sides of the head.

Note - release agent: Before any hypertufa was poured, I brushed release agent on the inside of the plywood form so that the hypertufa would not stick to the form. The release agent was a mixture of diesel and used car oil.