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Straightening bent aluminum

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Kamikuza
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Re: Straightening bent aluminum

Postby Kamikuza » Thu Mar 28, 2019 5:14 am

Bent the LF fuselages several times from venting and diving into the bottom in the shallows. Straightened each time, and it was fine until I hit the bottom again.

Pretty easy to tell if those fuselages were straight though...

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Re: Straightening bent aluminum

Postby TomW » Thu Mar 28, 2019 12:34 pm

basically if you have bent the aluminum its history. it might hold in bent position because the fuses are seriously overbuilt. I would never try to bend it back.
It will " work harden" and then break off.

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Re: Straightening bent aluminum

Postby max » Thu Mar 28, 2019 12:43 pm

TomW wrote:
Thu Mar 28, 2019 12:34 pm
basically if you have bent the aluminum its history. it might hold in bent position because the fuses are seriously overbuilt. I would never try to bend it back.
It will " work harden" and then break off.

I have to agree with Tom here. I would just shim the wing as necessary to restore to the original angles if that was working great for you.

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Re: Straightening bent aluminum

Postby Greenturtle » Thu Mar 28, 2019 2:12 pm

I see now you got it straightend out at the metal shop. Enjoy, im sure it will be fine.

Work hardening is certainly a concern but this was a pretty minor bend back...

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Re: Straightening bent aluminum

Postby jumptheshark » Thu Mar 28, 2019 2:31 pm

It think that might be over dramatizing a little for these situations. If its a lot of movement I would agree, but were talking about a couple of degrees in most cases. Mine was minimal enough that I really didn't notice it riding. As you say, they are overbuilt. This is not a thin sheet or wire. So far we have heard from people who have bent em back, and they have had mixed result with about half saying it came back.

Mine has stayed straight without issue. I don't actually think the load on it from my riding is all that high. Impacts, yes, my riding..... not really. FYI I ride strapless, don't jump, and have only grounded it hard into a rock the once while learning with a front strap and a pretty heavy board. I was surprised at how little damage the fuse and wing sustained for the magnitude of the impact.

So far we have yet to hear of one actually breaking, so lets not get too dramatic on the "it's toast" line.

In posting that I was going to a bigger wing this year I got a PM from someone with a friendly warning that they bent theirs simply by jumping strapped with a big wing, so I'm not saying it's not possible, but so far my riding has not re bent my fuse, despite a bigger wing than the original. I will certainly watch it this season and report back if it bends, but I can't say I'm particularly worried the thing is going to snap.

Repeated groundings are obviously not a great thing for any foil, and this one is no exception.

The best advice is mind your depth, but to write off a foil as unfixable when it has a slight tweak is a little over the top. If I'm wrong and they all start snapping off, I'm sure we'll hear about it.

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Re: Straightening bent aluminum

Postby Flyboy » Thu Mar 28, 2019 5:10 pm

jumptheshark wrote:
Thu Mar 28, 2019 2:31 pm

So far we have yet to hear of one actually breaking, so lets not get too dramatic on the "it's toast" line.

The best advice is mind your depth, but to write off a foil as unfixable when it has a slight tweak is a little over the top. If I'm wrong and they all start snapping off, I'm sure we'll hear about it.
Agreed. The metal shop has been manufacturing parts out of steel & aluminum since 1953 & presumably has had some considerable experience with the properties of aluminum. They were under no obligation to straighten the fuselage for me & did not charge me for it ... so must have felt it was doable. They did not appear to think it was "toast".

The Zeeko fuselage is very strongly built, but does have a weaker point created by reducing the diameter so that the wing fits flush with the fuselage. I have no idea how it will hold up over time, but suspect it will be fine ... unless it is run aground again.

For the record - I was foiling in the Sound on Hatteras. I had about 800 meters of deep water & had to stay in that area. Pushed it a bit hard on one run & ended up suddenly in knee deep water. I realize that at that point there is really nothing you can do - you can't suddenly stop or slow down, you can only eject. Pamlico Sound would be a cool place to go on long foiling runs, but I don't know anywhere you can be sure of consistently deep water ... except way out & hard to get there without a lot of walking.

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Re: Straightening bent aluminum

Postby stevez » Mon Apr 01, 2019 3:35 am

max wrote:
Thu Mar 28, 2019 12:43 pm
I have to agree with Tom here. I would just shim the wing as necessary to restore to the original angles if that was working great for you.
What concerns me about shimming is the bolts will then be misaligned, directing a lot of the load on the bolt sideways. Especially, as is normally the case, for countersunk bolts.

I wonder how much deflection bolts can tolerate. I imagine anything more than 4-5 degrees could be potentially problematic.

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Re: Straightening bent aluminum

Postby tmcfarla » Mon Apr 01, 2019 5:05 am

stevez wrote: [quote=max post_id=<a href="tel:1049112">1049112</a> time=<a href="tel:1553773421">1553773421</a> user_id=604]
I have to agree with Tom here. I would just shim the wing as necessary to restore to the original angles if that was working great for you.
What concerns me about shimming is the bolts will then be misaligned, directing a lot of the load on the bolt sideways. Especially, as is normally the case, for countersunk bolts.

I wonder how much deflection bolts can tolerate. I imagine anything more than 4-5 degrees could be potentially problematic.
[/quote]

Surprisingly, bolt alignment didn’t seem to be an issue one mine, though I did have to buy a longer bolt for the front hole, as the shim was too thick there for the factory bolt. Not sure what the angle on mine was, but a lot, more than a few degrees.

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Re: Straightening bent aluminum

Postby 3InletsWindsports » Tue Apr 02, 2019 12:39 am

The Alloy used has a lot to do with if it can be saved or not.
I remember my Magura levers on my old KTM would take a heap of bending and straightening

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Re: Straightening bent aluminum

Postby Flyboy » Tue Apr 02, 2019 2:03 am

3InletsWindsports wrote:
Tue Apr 02, 2019 12:39 am
The Alloy used has a lot to do with if it can be saved or not.
I remember my Magura levers on my old KTM would take a heap of bending and straightening
That was the opinion of the metal shop I went to. They said without knowing what the composition of the alloy was, it was hard to know how it would react. However, they obviously felt that the amount of straightening represented a reasonable risk.
Last edited by Flyboy on Tue Apr 02, 2019 3:12 am, edited 1 time in total.


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