Author Topic: bending aluminum masts in the surf  (Read 2948 times)

liv2surf

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bending aluminum masts in the surf
« on: October 13, 2020, 08:36:54 AM »
what is peoples' experience with aluminum masts bending if/when getting pounded in shore break especially with big foil wings? In my somewhat limited experience on this subject I currently think carbon may be more resilient to damage. Curious others' experience and thoughts. 
5'6 Quatro Wingdrifter Pro 105L; Cabrinha Mantis 3.1m, 4m, 5m and 6m; Axis 1000 (1150, 1020); Project Cedrus 91 cm carbon mast (68 cm fuse, 440/5000 rear); 9'6" CRUZ Surf foil SUP (152L); Chinook Thrust 92 Paddle -- fixed 78" length; 'prone' longboards on the rack, kites in the garage.

PonoBill

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Re: bending aluminum masts in the surf
« Reply #1 on: October 13, 2020, 09:24:07 AM »
Been there, done that. I put a nice kink in a 75CM Axis 19mm aluminum mast. It sure did screw up my surfing since I didn't discover it until the next morning. I thought my balance had suddenly deteriorated further.

Carbon might resist bending better, but it will have to be seriously stout to not just simply break. I've never seen one break, so obviously the premise that they'd do better is mostly correct.

You can straighten a bent aluminum mast, but it needs to be done by someone who knows what they're doing. The aluminum work-hardens in the area of the bend. just clamping one end and jumping on the other will create an S-bend. The mast needs to be straightened in a press, with support close to both sides of the bend and pressure applied to just the bend. I've done it, but I have a 25 ton press and years of experience fixing bent motorcycle fork tubes--something probably no one does anymore.
« Last Edit: October 13, 2020, 09:26:43 AM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

liv2surf

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Re: bending aluminum masts in the surf
« Reply #2 on: October 13, 2020, 11:21:14 AM »
I've also noticed several aluminum masts that are twisted slightly around their long axis....which is observed by one or both of the mast edges being noticeably out of alignment with the center line. Is this mode of bending fixable?
5'6 Quatro Wingdrifter Pro 105L; Cabrinha Mantis 3.1m, 4m, 5m and 6m; Axis 1000 (1150, 1020); Project Cedrus 91 cm carbon mast (68 cm fuse, 440/5000 rear); 9'6" CRUZ Surf foil SUP (152L); Chinook Thrust 92 Paddle -- fixed 78" length; 'prone' longboards on the rack, kites in the garage.

DavidJohn

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Re: bending aluminum masts in the surf
« Reply #3 on: October 13, 2020, 01:01:07 PM »
I’ve seen some bend and it’s normally right near the base plate.

I think the best fix is to just cut about 10cm (a few inches) off and tap the holes.

juandesooka

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Re: bending aluminum masts in the surf
« Reply #4 on: October 13, 2020, 01:32:28 PM »
Buddy has successfully bent back a few slingshot ones.  In a machinist shop I think, so probably using heavy duty methods like ponobill describes.

Carbon won't bend but it can snap, pros and cons there I guess.

soepkip

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Re: bending aluminum masts in the surf
« Reply #5 on: October 13, 2020, 11:56:27 PM »
I've also noticed several aluminum masts that are twisted slightly around their long axis....which is observed by one or both of the mast edges being noticeably out of alignment with the center line. Is this mode of bending fixable?

I have an aluminium mast that is twisted at the fuselage connection.
It probably happened because the screws came loose a little bit first and I ran into a sandbank with loose screws.

I think it is very important to make sure your screws don't get loose.
Tef-gel is good for that I think?

But when you feel a wobble you have to fix it first!

I will have to find a machine shop to fix my mast , probably it will have to be shortened....
« Last Edit: October 14, 2020, 12:02:29 AM by soepkip »

PonoBill

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Re: bending aluminum masts in the surf
« Reply #6 on: October 14, 2020, 10:09:40 AM »
Tef-Gel doesn't keep screws from coming loose, its an antiseize compound that keeps them from welding in place.

Shortening a mast is an easy job for a machine shop and relatively easy for DIY. You can cut the mast with a hacksaw. If you wrap masking tape around the mast where you want to cut and use the upper edge of the masking tape to guide the saw you can get a cut that's straight on both sides--requires a bit of care, but it's easy enough. The bolt holes will need to be drilled and tapped. If that's not something you know how to do, then yes, machine shop.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

 


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