I need form some ali sheet to approx 50 cm radius. I have been successful in the past using various plastic drain pipes as formers for lesser radii but clearly a 1 metre drain pipe is not something you find in B & Q. Allowing for spring back I probably need something around 75 cm diameter. The length of the sheet to be formed is about 1 metre. Any suggestions? TIA.

Does the bend have to be spot on with accuracy ?
As when I made the panels on my demised Locost, the scuttle and bonnet were bent around the lamppost across the road!

Just start with a small bend, move on, and keep going, and eventually, a curve will appear

steve

Slipping your local fab shop a tenna at lunch time would be the best bet. Wouldn't take 5 minutes on a set of pyramid rollers.

Chris

Bolt a few car wheels together to make a roller?

I also formed some large radii on panels around the Lampost outside my house

Car wheels are an excellent suggestion. I have a set of track wheels doing nothing at the moment. Unfortunately my lamp posts are square section!

Tall gas cyl? as its done progressively the radii of the form doesnt need to be as much as the target.

This is a trick I have done many time and it works a right treat. . .

Get a sheet of foam, or you can lay a load of towels out on the ground. The tighter the tad the softer and thicker the foam. The foam sheet needs to be wider than the metal sheet you are rolling.

You also need a bar to form with. It does not to be the rad as the required bend, something like a thick walled gutter pipe.

Put the foam down and the metal sheet on top, then use the forming bar and (gently at first) apply pressure while rolling the bar up and down the sheet. Your weight will compress the foam and by gauging the amount of pressure you apply, and the amount you roll up and down, it curls the metal sheet up. Try to apply consistent force as you roll or you can kink the sheet.

Regularly pick up the sheet and see how its curling.

With this technique I have been able to roll metal sheet to rads as small as 25mm and as large as 300mm.

bi22le that is absolute genius!

45g oil drum ?