Batten Bending (Patent Pending?)

[Eric]

Hi,

I think this is a flight-related topic...

I was out on the training hill yesterday, and I turned my back on my glider for a split second then... weee... it tried to make an escape worthy of a Steve McQueen movie. Anyway, in the process of tumble-weeding along, a few of the battens got bent. (Fortunately, there was no other damage.) Does anyone have a recommended method for gently bending battens, aside from... gently, lol?

Thanks to Ward for helping me gain control of my glider again as I was picking thorns out of my legs, and thanks to him for recommending "The Claw" as a great, portable tie-down solution.

[Ward Odenwald]

After a quick check of your cambered battens, I believe that most of the bends did not affect their camber but altered/bent the aft portion of their straight ends so the correction(s) should be somewhat straightforward. Here’s what I’d do:

If possible, mount your batten template on a wall at eye level. I’ve used basement and garage walls with pushpins but any vertical surface do. If this doesn't work, tape the template to a hard surfaced floor.

Using a tire or sofa back/arm or bed mattress corner or any surface that will spread the “bending force”, apply multiple, gradual corrective bends with your hands positioned equal distance from the ark of the bend. The key is gradual/small applications of corrective force and avoid over bending. Equally important is to spread the gradual bending force along the ark of the bend by moving/sliding the batten over the bending surface while applying pressure and moving your hands. Plan on several incremental events and after each straightening check your progress on the template.

Ward

[bowen.tim]

Another tool you can buy are bending springs plumbers use to bend flexible copper pipe. They can be found at Home Depot or Lowes. You would usually find them in a multi-pack with different diameters. They are used to bend flexible copper pipe to prevent "kinking" of the pipe.

My 2 cents..

Tim Bowen

[silverwings]

Similar to what Ward said, I use a spare tire with good success and also use my knee and thigh for small corrections. I have also found that copper tubing benders don't work that good for our batten material.

[Brit_in_SoMD]

Thigh has worked for me too. Also, you can make the batten a little bit more compliant if you heat it up by rubbing your hand up and down around the area that you need to straighten. Just wrapping your hand around lightly around the batten and then rapid movement up and down is enough to get sufficient friction heating that you'll feel the local temperature rise in the batten after a relatively short period. The extra bit of heat is enough to reduce the bending force required to make a permanent change to the profile, so you can control things a bit better. But I don't think cheating and using a heat gun is necessarily a good idea - the risk of localised hot-spots and consequent creasing is too great IMO.

[Eric]

Thank you all for the suggestions. I will give them a try then report back.

[Eric]

The curves were fine. Both of my #2s were bent fairly badly and one of the end battens, but they were repairable. No biggie.

I laid the template out on the floor. I found that warming the battens up definitely made them more pliable. Instead of using my hand, I used a piece of cloth, so I could generate more friction and more heat. I took care not to heat them up too much. I used an old, leather medicine ball I had to correct the bigger bends. For the finer bends, I used the fabric covered wood on the back of my couch. I found holding one side of the batten in a fixed position then focusing on bending the other end to be more controllable.

Thanks again for the advice.