Author Topic: Cutting down a 90cm Axis Alu mast AND potting a carbon mast head  (Read 2713 times)

wingdingjoe

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Greetings and salutations fellow Junkies. Just wish to CONFIRM that the alu mast holes are threaded FOR THE ENTIRE LENGTH so that if I cut 20cm off the end I'll just need to chase the threads a bit with a tap and good to go? I realize I'll have to try to fill the air space or re-use the factory installed "plug" from the chopped end.

Secondly, I've read several times the process of "potting" last year's carbon mast head but just wondering if anyone took any pics or has a step by step guide of the best way to do it?

Someone mentioned that could use tefgel, modelers clay and 2part marine epoxy.. Are beads really necessary also?

Califoilia

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Re: Cutting down a 90cm Axis Alu mast AND potting a carbon mast head
« Reply #1 on: October 26, 2022, 01:28:46 PM »
Did you not get the PM w/ pictures I sent you wrt to recasting the carbon masts? Or are you still looking for something else?
Me: 6'1"/185...(2) 5'1" Kings Foil/Wing Boards...7'10 Kings DW Board...9'6" Bob Pearson "Laird Noserider"...14' Lahui Kai "Manta"...8'0" WaveStorm if/when the proning urges still hit.

Califoilia

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Re: Cutting down a 90cm Axis Alu mast AND potting a carbon mast head
« Reply #2 on: October 26, 2022, 01:48:11 PM »
Thank you,! For your detailed reply on the new PC masts! But I already pulled the trigger on the 860 and it arrived in Mexico today. Hopefully, it will still be an upgrade over the alu.. Although I WILL be using it with the 999 and 1050 and 880 HPS.. I'm hoping the bending and torsion isn't too obvious.
If you're going to be using it for winging, it should be OK with minimal bending or torsional flex. I used the 76 carbon in the surf, where we're being a little more aggressive with our turns, and where the torsional flex was really not noticeable with the smaller wings we use (910b and smaller), but became noticeable with the 980 and larger wings. So as long as you're not trying to hit the whitewater to bank/turn back off of it when winging, you should be fine for the most part...but I'm just speculating, because I've never used the 860 carbon length at all.

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.did you happen to take any pics or videos of the process of "potting" by any chance?
Here are a couple during the process of how the fuse needs to be leveled, and then how the mast must also then be leveled once you insert it into the fuse (acting as the mold) and then must stay that way while the epoxy cures completely...

Note: Those are two different masts above. The last one I leveled the fuse on my bench with the wood shims and tape, and found that I didn't need to use the clamps to help level it.

Also, notice the "painter's tape" around the mast just above the fuse connection. This is to keep the excess epoxy compound off the mast for easier wiping, and cleanup.

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Think I. Could use tefgel. Instead of the release agent putty you mentioned?
I don't know for sure, but my guess would be no, simply because I don't know all of the ingredients in Tefgel, and if they might interfere with proper curing, and bonding of the epoxy onto the mast. Here's a website that gives you some other options the sound better than Tefgel.

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Do you think that JB MARINE 2part epoxy is good enough?
That I don't know, but I personally wouldn't chance it since it's not the normal 2:1 mixing ratio used with regular surfboard epoxy, and is opaque, not transparent like regular resin.  My concern would be that it wouldn't release from the mold, and you might end up with a fuse permanently mounted to your mast. But that's just me being very cautious, and having used JB WELD, but not JB MARINE epoxy, and reading the literature of the two, they sound very similar.

If that's all you can find in your area, I would definitely a test mold and fit, and use whatever mold release you decide on to make sure that the JB MARINE will release from the mold, while staying permanently adhered to your released test part.

Here's the Amazon link to the mold release stuff I use...and this is the Amazon link to 2-part surfboard epoxy that should be more that enough to recast a mast, with enough leftover to do a board repair or two afterwards. This is the clickable link to Amazon for the Cabosil resin thickener, but that is a lot of Cabosil for such a small amount that you'll need, that I wouldn't bother with adding it. The epoxy alone should be strong enough to accomplish the leveling of the top of the mast...if you will even have to do it at all.

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Thanx for any clarification!
You're welcome, let me know if you have any additional questions, happy to help where I can.
Me: 6'1"/185...(2) 5'1" Kings Foil/Wing Boards...7'10 Kings DW Board...9'6" Bob Pearson "Laird Noserider"...14' Lahui Kai "Manta"...8'0" WaveStorm if/when the proning urges still hit.

wingdingjoe

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Re: Cutting down a 90cm Axis Alu mast AND potting a carbon mast head
« Reply #3 on: October 27, 2022, 09:23:52 AM »
Omg.. No.. Somehow I didn't see this second reply. From you with the pics and the links.. Thanx so much that's PERFECT!

And as far as cutting down a 90 cm alu mast? Are the holes threaded the ENTIRE length of the extruded 90 cms?

VenturaSuppper

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Re: Cutting down a 90cm Axis Alu mast AND potting a carbon mast head
« Reply #4 on: October 27, 2022, 10:16:53 AM »
I am attempting this tonight....wish me luck. From what I have found online, the holes are drilled but not threaded all the way through. The mast's are fairly cheap so I am not afraid of ruining it for this project.

PonoBill

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Re: Cutting down a 90cm Axis Alu mast AND potting a carbon mast head
« Reply #5 on: October 27, 2022, 10:45:18 AM »
No, the holes are NOT threaded the entire way. You just need a 8X1.25 tap to cut threads after you cut.
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.

VenturaSuppper

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Re: Cutting down a 90cm Axis Alu mast AND potting a carbon mast head
« Reply #6 on: October 28, 2022, 07:09:12 AM »
Little Update: I cut the mast down to 30" and the holes were drilled but not threaded. I used a fine tooth new blade on my chop saw and went very slow. It cut very clean and square. Took a small file to the interior and exterior edges to clean up any burrs and there were very few. Tapped the holes with a 8x1.25 tap and fluid. Once that was done I used caulk from the hardware store to seal up the main cavity as I hate how water just sits in there when I am done riding.

Hope this helps.

jondrums

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Re: Cutting down a 90cm Axis Alu mast AND potting a carbon mast head
« Reply #7 on: October 28, 2022, 12:19:42 PM »
let us know if the caulk holds long term, and if you don't mind, can you share the exact product you used?

seastudent

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Re: Cutting down a 90cm Axis Alu mast AND potting a carbon mast head
« Reply #8 on: October 30, 2022, 08:10:10 AM »
I read all the posts here even if I don't think they apply to me. Well eventually they apply. I broke my mast yesterday and will try to repair it like this.
Here's the background for accident investigation. It's a 75cm Naish aluminum mast. Somehow I bent it earlier this season. I ordered a replacement but kept the bent one. I got it straightened back out as roughly measured with straight edges and eyeballs. I was using it yesterday and hit something submerged at speed. A glorious wipeout ensued. Then I saw my foil floating no longer attached to the board. Some friendly fishermen assisted me back to shore. The mast broke inside the base right at the screw holes. If I was guessing there was probably significant metal fatigue at that weak point and the impact pushed it over the edge.
Here's my question. I didn't see what I hit. I'm guessing my speed was around 15 kts. Would hitting a large freshwater fish be enough impact energy to bust stuff? I didn't see any logs or other debris.

PonoBill

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Re: Cutting down a 90cm Axis Alu mast AND potting a carbon mast head
« Reply #9 on: October 30, 2022, 10:06:28 AM »
No, a fish wouldn't do that, maybe a big turtle but even that is unlikely. You won't see deadhead, they float thick end up and eventually float nearly flush with the water as they get more waterlogged. Worse yet if they sink in fairly shallow water the skinny end gets planted in the mud and the log stays just under the surface, waiting for you like a spear with the butt grounded (as many boaters have discovered when they rip through the bottom of their boat). But even a fairly small log can offer huge resistance in the incompressible water if you hit them at speed. The log stays still, just like your paddle does if you hit it with a foil and turn it into a two-piece.

Aluminum work hardens when it's bent which makes it much easier to break it on either side of the bend. The method used to straighten a mast has a lot to do with how strong it remains. It should be done in a hydraulic press, slowly, with the mast supported as close to the bend as is feasible. Naish masts AFAIK are 15 mm and not very strong to start with. They have the substantial advantage of being even cheaper than the axis 19mm masts since they are used by many manufacturers. I recently bought a slingshot 15mm x 75 mast on sale for 40 bucks though apparently, the usual retail price is about a hundred bucks.
« Last Edit: October 30, 2022, 10:14:38 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.

seastudent

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Re: Cutting down a 90cm Axis Alu mast AND potting a carbon mast head
« Reply #10 on: October 30, 2022, 10:43:53 AM »
Thanks Bill.

 


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