[EricR]

I want to build my own ski pylon using aluminum tubing. I have checked with the local shop that builds T-tops, custom fishing boat towers etc. and they have not called me back as to if they would sell just materials.

Please do NOT direct me to "DIY wake" or whatever, the links to material suppliers are all dead.

I boat in fresh and salt water, so making one out of easily availible pipe and painting it is not a good idea, too heavy and would rust.

I don't wanna spend three bills on some generic POS from Overton's etc.

I do not want a nosebleeder high center pylon for boarding, just a tripod over the outboard for tubing and kneeboarding.

There has to be somewhere that sells the aluminum polished tubing and clevis style ends on the internet!

[Liquid_force]

An ebay seller ("Velocityair") has a listing for 2" AL tubing in 36" lengths. Looks like $15 or so shipped. Also says other sizes available.

[tommays]

To get lengths of metal a decent prices your going to have to find a LOCAL metal distributer


On long Island that would be Yard Metals(Or many others) and most stuff is sold buy the pound in full lengths


I believe you will find the finished products cheaper

[MikDee]

You might want to rethink that idea, ski pylons are made of stainless steel tubing, not aluminum! Aluminum would not be strong enough, and stainless tubing is not cheap.

[EricR]

Gotta disagree with ya MikDee, wakeboard towers are aluminum, stainless is HEAVY.

[45Auto]

I'm pretty sure EricR is referring to a ski pylon like this, NOT a wakeboard tower:



Every ski pylon I've seen is made of stainless steel. No reason you couldn't use aluminum if you used appropriately sized tube. But like Tommays said, I think that by the time you buy the tubing and fittings it would be cheaper to buy one of the pre-made ones for a couple of hundred dollars from one of the big discount houses. The one in the picture is $219 from Overtons.

If you really want to do it yourself, Online Metals

http://www.onlinemetals.com/

sells aluminum tubing online. For example, an 8' piece of 2" diameter, 1/4 wall tubing is $80 plus shipping. I have no idea of what size tubing you would need or where you could find the custom end fittings to fit the tube. They won't be cheap though.

[MikDee]

Originally Posted by EricR

Gotta disagree with ya MikDee, wakeboard towers are aluminum, stainless is HEAVY.

Heavy, No, not polished thinwall stainless, as far as I know every ski pylon is made of stainless, not aluminum tubing (that would destruct in seconds) and what do you suppose EVERY boats bowrail is made of? STAINLESS TUBING!

[Liquid_force]

sorry mik, that's just not true.

Aluminum is the most common material for wakeboard towers. Its corrosion resistance is excellent, its strength to weight ratio is better than stainless, and it's cheaper.

Stainless is available, just not as common.

I'm in the process of having one welded up from stainless right now, but only because I have an uncle that's been a stainless welder for 25 years and he's doing it for free

FWIW - strength isn't an issue - tensile strength of common structural grades of aluminum run in the 40-50ksi range, while stainless is 70-80,000, but stainless weighs around 3x as much. Stainless has some advantages in salty/extreme environments, but really not much of a factor considering what a tower/pylon is designed to do.

[45Auto]

Stainless usually has an advantage in a ski PYLON (which is usually a simple vertical tube, sometimes with a couple of compression braces or tension wires) because it is STIFFER than aluminum. Steels typically have a Young's modulus (engineers call it E) of 30,000,000 while aluminums are around 10,000,000. Young's modulus is a measure of the stiffness of a material.

For example, the equation for elastic deformation of a simple beam (or pylon) is:

fB = F·L3 / (3·E·I)

where

F = force acting on the tip of the beam
L = length of the beam (span)
E = modulus of elasticity
I = area moment of inertia

As you can see, if everything else is equal (force, length, and moment of inertia) then the stainless pylon will deflect about 1/3 less because steel is stiffer than aluminum. If the top of your stainless pylon deflects 3 or 4 inches, an equivalent aluminum one would deflect about a foot.

A wakeboard TOWER is usually a welded or bolted truss-type structure mounted across the boat. Aluminum usually has the advantage here because the inherent geometry of the truss structure makes the stiffness less of an issue, and the weight and cost advantage of the aluminum makes it more desirable.

No physical reason to stop anyone from making either one out of either material as long as it's designed correctly.

[Liquid_force]

I think you'd find if you plug in some numbers the deflection of thin wall aluminum tubing on a pylon would be a small fraction of an inch. (I found an estimator on line using 2" square aluminum, 1/8" wall, E=10Mpsi- with a 60" cantilever and a 500 lb load the deflection was .10").

Obvously SS would be less, but either way I believe it would be negligible.
Plus - the pylons I've seen are supported primarily by the harness that goes over the bow so it's possible there would be no deflection at all even with the weakest of aluminum alloys.

[45Auto]

Maybe you should go into the business and take over from the Barefoot International/Sky High guys!



"Stainless Steel Fly High Extended Pylon
People search the world over looking for a low stretch rope and then hook up to a pylon with 1" nylon webbing that stretches and is made of less expensive aluminum that flexes. This revolutionary 7' pylon allows wakeboarders to get more air and hang time off the wake. NOW made from Stainless Steel, creating a stiffer stronger but lighter pylon. And stiffer means a more solid pull! This pylon has a swivel Delron top and pylon height ski tow hook up. Great for barefoot starts. This pylon is built tough for years of use. Designed with double cables, over-the-center buckle rated at 5200 pounds, and a Poly Carbonate plastic tube inserts to protect the pylon. For added safety and durability, stainless steel over center buckle is standard on all Fly High Pylons and Monkeybars."

http://www.cybercyclemag.com/enthusi...tCategoryCode=

Not a professional wakeboarder or kneeboarder here, but I wouldn't be surprised if it was the "feel" of the stiffer material rather than the absolute movement.

[MikDee]

Originally Posted by Liquid_force

sorry mik, that's just not true.

Aluminum is the most common material for wakeboard towers. Its corrosion resistance is excellent, its strength to weight ratio is better than stainless, and it's cheaper.

Stainless is available, just not as common.

I'm in the process of having one welded up from stainless right now, but only because I have an uncle that's been a stainless welder for 25 years and he's doing it for free

FWIW - strength isn't an issue - tensile strength of common structural grades of aluminum run in the 40-50ksi range, while stainless is 70-80,000, but stainless weighs around 3x as much. Stainless has some advantages in salty/extreme environments, but really not much of a factor considering what a tower/pylon is designed to do.

You'll notice I didn't say anything about wakeboard towers, simply because I have no idea of what they're made of? Nor do I care, just a new gimmick that everyone wants to copy nowadays anyway

[Liquid_force]

Originally Posted by MikDee

just a new gimmick that everyone wants to copy nowadays anyway

seriously?
A gimmick?
wow.

[Liquid_force]

Originally Posted by 45Auto

"Stainless Steel Fly High Extended Pylon
People search the world over looking for a low stretch rope and then hook up to a pylon with 1" nylon webbing that stretches and is made of less expensive aluminum that flexes. This revolutionary 7' pylon allows wakeboarders to get more air and hang time off the wake. NOW made from Stainless Steel, creating a stiffer stronger but lighter pylon. And stiffer means a more solid pull! This pylon has a swivel Delron top and pylon height ski tow hook up. Great for barefoot starts. This pylon is built tough for years of use. Designed with double cables, over-the-center buckle rated at 5200 pounds, and a Poly Carbonate plastic tube inserts to protect the pylon. For added safety and durability, stainless steel over center buckle is standard on all Fly High Pylons and Monkeybars."

Ah, the "feel".
That's marketing department terminology for "There's really nothing better about this product than any of the other ones, but you'll "feel" better if you buy ours."

I really don't know what you're trying to point out with that paragraph. It's nothing more than a sales pitch.

I have no dog in this fight. Either material will work just fine -- pylon, tower -- whatever.

[EricR]

Wow. I did not check the email notification box, and a week later I return to find I started a dogfight and I'm not even piloting the Sopwith Camel....

Yes, I have no doubt the ones you can buy from Oveton's, etc, are made of stainless, and sure I could just buy one. But that would defeat the entire purpose of making one. I love to make my own stuff.

I work on big boats, as in 40 feet on up into the 200 foot plus range. Aluminum tubing is used extensively.

I also see a lot if inshore fishing boats those that boat in fresh water lakes do not see, that use platforms mounted above the outboard motor for poling the boat in shallow water. Wieght is a concern, and all of these are made of aluminum tubing. Many these days are dual purpose boats, and will have a ball for towing skiers and wakeboarders on them, and brackets to hold wake boards.

I wanted to make my own setup. I went to a place that makes custom fishing towers and purchased a 4' stick of 2" tubing and 5" of 1 inch for the braces.

I still have to mock it up, and figure the ends I will need, but the tube will go into a base mounted to the deck/stringers of my 1969 Glasspar right in front of the motor splash well, and it will have braces on a 45 degree angle about 12-18" from the top that go to the inner transom, all will be attached with pins for removal.

I have absolutely NO fear this will not be strong enough to do what I want it to, I spent $80 yesterday and will probably have another $100 in it with the rod ends etc I will need.

[NSBCraig]

Dude make sure you post some pics when your done. I plan on getting one made and I'm really interested in what you come up with.

Are you using a swivel tip or the ring type?

Personally I don't want any adjustment or any removal pin type hardware. I want something nice and solid made for the boat.

It's going to be awhile but once I get the boat back in one piece I'm getting a hand rail and some steps fabbed up too, that way I came powdercoat all my hardware the same.

Originally Posted by MikDee

what do you suppose EVERY boats bowrail is made of? STAINLESS TUBING!

Aluminum that was powdercoated is the choice of a lot of high dollar companies not that pre-made stainless kit stuff.

[EricR]

Well I did it, some said it could not be done or was a waste of time but a big thppppppppppppp!!!! Rasberry to 'em!

I bought four feet of 2" aluminum anodized tubing and 6 feet of 1 1/2" from a local outfit that builds t-tops, railings and tuna towers on boats.

I mocked up the base, it is two 2X6's lag bolted and laminated together with PL construction adhesive, then lag bolted soldily into the stringers.



It ain't going nowhere! More solid to me than the base on one of those stainless generic adjustable things sold at Overton's etc.

I drilled it for a pin at the base. Now the struts attatch to the inside of the transom, not the deck or motorwell like the generics. I had some aluminum angle scrap scrounged from the scrap bin at a boatyard I was doing some work in (I am a marine diesel tech by trade, in and out of coastal boatyards all the time)



Simple notching of the tubing with a hacksaw and a file to slide over the brackets worked like a charm. I use stainless lags into the transom on the angle, and stainless 1/4 X 20 bolts with wingnuts to hold it.

A welder at one of the boatyards welded up the tabs for the struts on the pole end for me on his lunchbreak and would not take any money. I owe ya Bill!!



He then capped it once I cut it to the maximum length I could get and clear my Bimini top- and welded a tee to it to hold the rope.



I have to upload some kneeboarding pics, but it is AWESOME to pull behind compared to the transom rope hookup.

I have about $100 in it including hardware, and it's sturdy as can be!

[MikDee]

No Wonder!, That's not aluminum tubing, That's aluminum pipe! It looks like schedule 40 thickness? Now you're talking something substantial!
Good Job!, and good luck with it, it looks fine! Mike

[EricR]

I guess I should have clairified it was pipe and not tubing I had in mind! I have some vid of me kneeboarding behind it I'll upload soon!

[TBarCYa]

Just keep in mind that pipe is not designed to support a load rather it's designed to hold pressure inside. Tube on the other hand is designed to support a load and would have been the correct material to use.

I'm not saying that pipe won't work for you, as I'm sure it performs just fine. I build rollcages for Jeeps and have had that pipe vs. tube discussion a few times.

[Viavant@mac.com]

go to lowe's get some 1" 1/4 or 1" 1/2 conduit tubing it comes in 10ft sections for less than 10 dollars. cut to size with a $5 hacksaw drill a few holes for i bolts, and strap down to boat with some ratchet straps with a 2x6 board with a hole dug into it.

rock solid bought supplies and built in less than 2 hours

(i put a couple of small screws into the base just to be safe)