Bending Aluminum for Cloches

BSea

Using the cloches Monty Don uses as my model, I’d like to make my own version using angled aluminum sheet metal.  Has anyone found a good technique for making the bends? My first attempt will be using tin snips to make small cuts to release the tension as I pull it around a wooden template. If you’ve built something similar, I’d would appreciate your advice 

Lyn

Might be easier to use water pipe from a builders merchant.  You can push the ends well into the ground.
My son’s just built a poly tunnel with that.

BSea

Yes, that would be easier but that is not the path I’ve chosen. Same reason why I drive a MG. Improving my metal working and carpentry skills will add much needed structural elements.  

Fairygirl

I doubt if anyone here would be able to help, although a photo of the stuff you intend using might. I can't visualise the material you want to use.
Most people are looking for the simplest way of constructing anything, hence @Lyn 's reply. 

nick615

Echoing Lyn and Fairygirl, I didn't see Monty in action but I use 5-litre plastic water containers with the bottoms removed - 2-litre ones if desperate - held in place by a vertical stick or metal rod.  Once no longer necessary, 10-12 of them can be strung on to string and hung in the shed/garage for next time.  I have three such strings in my garage.  Cost nil.

BobTheGardener

Without seeing a photo or sketch of such a cloche, it's difficult to say (Monty has used a multitude of types over the years.)  I've built square (2 side and a top) cloches from 15x15mm aluminium angle and used 4mm twin-wall polycarbonate.  No bending involved and 6mm aluminium greenhouse type nuts and bolts were used to hold them together, so they can easily be stored flat when not in use.

BSea

Here are a couple pictures, the top one has a vent at each end. I made a simple metal brake for the 90 deg bends from a softer gauge aluminum. If it cracks or stretches funny I’ll try galvanized steel. IKEA also has a galvanized steel greenhouse/garage shelving unit called Hyllis that is made of similar materials.

I like the idea though of being able to store everything flat when not in use, thanks @BobTheGardener. 

steephill

Right angle section is specifically designed to resist bending so would seem to be the worst possible choice for creating a curved structure. Those curved sections in your photos would have been stamped out on a large press which few people would have access to. It would be much easier to keep to straight lines but you might be able to use a single bend on each side to create a mini-greenhouse type structure.