… and if so, how to go about it

Im looking to use a length of this alumium U profile, as a threshold guard on my van. The floor is made up of three lengths of ply, and i figure using a U threshold tapped over the ends will help tie them together, act as a threshold protector AND fill the small gap between the ply and the steel floor.

THIS is the stuff

for those of you who cant/wont click, its a U profile, 15mm in both directions, 1.5mm thick aluminium.

I want to bend it only gently, in line with the vertical axis if you are looking at it in the U position.

Im thinking maybe make a former from spare ply, and then gently hammer it around to the curve? or should i just suck it up and accept the fact that i will have to cut it? I would be more than happy to give it a bash, but at that price (for such a small length) i dont want to have to do it twice!

Any thoughts?

Depends what radius you want to form it round.

I don’t get how you want it to look.

My non scientific opinion is that it looks like it would be hard to bend

I’m thinking that’s an extrusion and therefore not formed by bending or intended to bend

But its the worst sort of STW just sayin type of expertise

Unlikely. I used some 90 degree Ali angle to cover the edge of my ply floor and the gap to the plastic trim caused by the ply sitting on the floor ridges. You can get it in more sizes than U profile so there is a reasonable chance you can get a good fit.

I cut mitres in it to follow the indented door step at the sliding door.

Think it was a better price in wickes too

It will take a gentle bend, too tight and the sides will start to flair.

No hammer required, that will just put dents in it.

If you are not going to fix it with anything more than tape(?) then cut a form at a tighter radius to allow for spring back. If you are going to use screws and adhesive then you can just work to the line you need.

Next time please supply a scale drawing.

Cannot see it bending without buckling.
Images or diagrams would be good of what you wanna achieve!

If its anodised then it will not bend unless you start breaking the anodised layer……

Aluminium bike rims are extruded and bent?
Presumably they’re bent while they’re still hot. Into a helix round a drum maybe? Then cut along, to leave a circular section?

Anyone know?

Just been youtoobin’. Extruded, cut to length while straight, then bent. Must be pretty cool by then. Then trimmed to exact circumference, then welded.

I expect they are extruded into a bend. Same issue trying to straighten a bike rim I imagine!

I watched an H Plus Son vid. I imagine that’s pretty standard.

I watched an H Plus Son vid. I imagine their way is pretty standard.

I think you are getting extrusion and forging mixed up.

You can bend most metals if you have enough force to control the movement and flow of material. So all you need are a set of dies to pass the section through which will give the radius but not allow the section to deform or crack.

[video]http://youtu.be/xYUOLGEPw9Q[/video]

Who’s mixed up about forging/extrusion?

You.

Nope, don’t think so. Don’t know where you got any reference to forging from?

I brought up the rim in the first place in response to this:

I’m thinking that’s an extrusion and therefore not formed by bending or intended to bend

Interesting that your vid has the coil thing I imagined. Less wastage than the method in the H plus son video.

Sorry for the thread derailment OP!

Sorry, long day yesterday, no offence intended.

Back to the OP – I don’t understand which way or how much you want to bend it

I want to bend it only gently, in line with the vertical axis if you are looking at it in the U position.

How much is only gently? Approximately what what radius (or, if that’s too technical, how much more or less curved than a wheel rim)?
Which way are you bending it? With the bottom of the U on the outside of the curve, the bottom of the U on the inside, or is the bend in the plane of the bottom?

As noted above, you’ll crack the anodising whatever – but B&Q also sell raw aluminium which would probably look better

I seem to remember a tip to anneal the aluminium before working is to smear washing up liquid on the surface before heating with a blowtorch. As the washing up liquid turns brown, the correct heat is reached for annealing – should be able to bend and beat the thing then without cracking.

If the bend is severe you could make a few cuts in the two side walls but that wouldn’t look very nice.

Alternatively use a plastic U shaped profile instead?

bren2709 – Member
Cannot see it bending without buckling.

Me neither.

Can’t you go in to B&Q and try it out when no one’s looking?
If it kinks, just put it back quietly and wander off.

Think you’ll be fine, but if not, maybe copper is an option?

neil – no worries, no offence taken at all, just confused!

Sounds like your trying to do almost exactly what Locost builders use to form the windscreen surround from ali channel. Can’t find a pic of the method, and its going to sound more complex than it is but here goes:
1) Cut a wooden former that is the shape of the bend you want to make, drill a thru-hole at the centre of the arc you’re trying to bend around. This thru hole is your pivot. The former wants to be thick enough to fill the channel in the ali.
2) Make a couple of identical arms (from 1″ x 1″ or whatever, long enough to make a decent lever), with a hole at one end for the pivot, and a hole just outside where the arms will cross the ali.
3) Assemble the arms to the former with a single bolt through the hole, and one arm on either side.
3) Find something to use as the forming roller; this then fits between the two arms with another bolt. Could make this with a big holesaw and an offcut of the former sheet, or use an old cartridge bearing.
4) Trap straight length of ali beneath roller, strap to former, and rotate arms, rolling the ali into the bend.

Difficult to describe in words, but easy to do in pictures (and practice). Worth bending to a slightly tighter radius and further than you need in practice to allow for spring back.