Formwork - Form3.1

Our third functional formwork, Form3.1. The same basic design as Form3 but with a few improvements: stronger side panels made from Cyprus instead of pine, and evenly spaced clamping frames to allow for easier shuffling of the frame along the walls.

Form3 – First Section

   

Formwork – Formwork mark 3

Thanks to some advice from Rowland at Ram Cast CIC, Form3 is free of bolts and hopefully a lot quicker to put together because of that. The design is based on the example here. 

	Form3 assembled. Not shown is the rope wound around the top of the posts
	Form3 disassembled, showing the side panels and the clamping frames
	Detail of one of the clamping frames; the joins are not glued as they’re taken apart each time  the frame is moved.
	And here is the first attempt.

 

 

 

 

 

Formwork – Formwork 2 test

schpeal coming soon, in the interim mouse-over for details.

  

Formwork 2 - Fabrication

After the failed first test a number of lessons were learned: that the form needed to be stiffened dramatically to stop flexing, the areas around the bolts needed reinforcing and the form needed to be narrowed by a couple of centimeters to protect the edge of the foundation cap.

The materials of Formwork 1 were recycled to form the basis of formwork2. A new set of braces and brackets were fitted to the outside of the forms, and the clamps were replaced with pairs of through-bolts.

Formwork – Test

The formwork was constructed by local carpenters using a locally available pine. The design was based on a rolling formwork design by Middleton. After some delays finishing the form and the mallets the testing began. Because it was late in the day, low section of wall under a window was selected to be the test wall.

 

It was immediately obvious that the timber was too green and soft for the number of braces used, as it started to flex in between the clamps on only the first course. As the ramming continued the foundation cap began to chip-off in a couple of places. A second course was added to one end section that wasn’t flexing and, before it was rammed firm, one of the end bolts pulled through.

The rather paltry wall sample was left in place to see how it would fair in the elements and if it would firm up with time.