How do I change the radius on this?

So this is an aluminum fender and I haven't bought it yet. It's 0.090 thick aluminum and it's 34 inches long. I'd like to make it more like 28 inches. First thought was to buy a shrinker from the hammer store, but they're only good for 0.050'' thick. Second thought was to wrap it around a tire and wheel combo and reform it with a ratchet strap, but I have to wonder if the edge would kink. The fender is 20" wide and I would cut it down the middle to make a pair of fender extensions/flares for the Challenge Corolla. Any other ideas that I can do in my ill equipped home garage?

Pie cut the lips.

In reply to Keith Tanner :

If it were steel , I would do that and MIG it.  Because it's aluminum cutting it isn't going to work because I can't weld it.

Anneal and shrink like in the video below.

Should be able to get you close.

If you try to bend it to a tighter radius the lip at 90° will bend outwards and be more like 70° when done. I bet you could do a little tuck shrinking on it to do the job.

I will guess that fender is made from a 3000 series alloy which is usually sold and stamped in a half hard condition.  I would anneal the lips before doing anything.  Put a sharpie line on the lip and heat the area with a propane torch until the sharpie fades. Then create the tucks either with pliers, fork or weld a couple of pieces of bar stock 10mm apart and make the tucks with a hammer and chisel. Then work the tucks flat. It really won't take much to change the radius what you need.

Google "tuck shrinking"

I would still give it a go with a Lancaster style shrinker first. That aluminum in a dead soft condition should be fine, even at 0.90" if it fits in between the jaws

In reply to Trent :

This was my immediate thought. I have abused the shrinker stretcher a few times and got away with it,

I never even thought about annealing it first. That's why I ask questions on this forum before I dive in and ruin stuff.

In reply to Trent :

If the edge did move to something less than 90 degrees it might actually look better if I don't put it on the car exactly horizontal, but tipped a little so the bottom edges are a bit closer to the rocker panels .

In reply to NOHOME :

Pete, if you have a shrinker could you look at it and see if 0.090 material will go in between the jaws?

DeadSkunk (Warren) said:

In reply to Keith Tanner :

If it were steel , I would do that and MIG it.  Because it's aluminum cutting it isn't going to work because I can't weld it.

 

Who needs to weld when pop rivets are awesome? 

In reply to RevolverRob :

While there would be rivets involved, I didn't envision them in the fender flare lips.

Change length from 34" to 28".    Easy, but think this not exactly what you are looking for.

DeadSkunk (Warren) said:

In reply to RevolverRob :

While there would be rivets involved, I didn't envision them in the fender flare lips.

They're a design element if you say they're a design element, damnit!

DeadSkunk (Warren) said:

In reply to NOHOME :

Pete, if you have a shrinker could you look at it and see if 0.090 material will go in between the jaws?

Closest I could find in the offcut pile was 84 thou. I did slide a bunch of paper sheets in to measure 110 thou before it started to get tight.

This is the 84 thou with a few cranks on the shrinker

In reply to NOHOME :

Thank you, Sir.