Discussion in 'Sunfish Talk' started by alberto marin, Jul 9, 2016.
Filling a tube with epoxy mostly makes the tube heavy.
I hate to be a party pooper, but wouldn't it be simpler, easier and likely cheaper to buy a Sunfish mast?? That assumes Laser Performance is selling them these days.
Yes, but the halyard wouldn't make that annoying "clanking" sound at the marina.
Less than 10 pounds for the schedule-80 mast. (Somewhat heavier than aluminum). 'Don't know if it would actually need reinforcement, but a lightweight schedule 5 foamed inside would make it much stronger.
I think my original intention has been missed. I purposed the PVC mast
as a temporary work-around until an aluminum mast could be found. As in
any work-around new problems will present themselves. No you can not use
a PVC mast for racing and yes it will flex if there is enough wind. PVC will also weight
more than an aluminum mast. The tubing I'm suggesting has a heavy wall and is made not
to flex when it's full of water and crap. How much I don't know because I haven't tried it
yet but I know it would have worked fine for me today as the winds were light. Two feet of
the ten feet goes in the mast hole so we have eight feet to deal with. Also in our favor is
the Lantern Sail with it's low center of pressure which is why we don't need any mast-stays.
As for flexing, some flexing would be to our advantage as the mast would store energy and release it
but probably be far less efficient than a wood mast.
That leaves the question, how much for 10 feet pipe, a pulley, bolt, nut and a can of expanding foam.
Next time I get to the hardware I'll price it out. If it could get you on the water for $25 till a
better deal came along or you just like messing around with uncommon solutions to common
problems I say go for it.
Note: The tubing I'm suggesting is SCH 40. Sorry if I was not more
specific in my first post.
I used 2.5 inch PVC as a ridge pole under a light tarp to keep rain and leaves out of the boat... in a couple of weeks it was shaped like a "C"
Well, aluminum Sunfish masts bend in a blow in normal use. Fortunately they don't stay bent. If an aluminum mast bends some, a plastic mast will bend a whole lot more unless you sail only in light air. We foot I think you should conduct the tests and report back.
One can of Good Stuff foam would be too hard to control, and wouldn't be enough, anyway. Which is another good reason to get $3-worth of 10-feet of Schedule 5 (or 10), and dispense Good Stuff as evenly as possible while inserting it. (From that one can). Leave the inside empty.
That combination will be much stronger than straight Good Stuff, IMHO.
where can i get those prices??
heck my local lowes and home depot wants that amount for 1/2 pvc pipe dont get me start telling the other prices
Schedule 80 has the thickest walls. Schedule 5, if you can find it, should be much cheaper and could even be considered fragile.
Because my nearest Home Depot and Lowes are 1- and 1½-hours away, respectively, I'll not be checking those prices anytime soon. The PVC you've referenced in ½-inch would work, but might take two cans of Great Stuff. So the savings with one can suggests the use of a larger diameter for the internal strengthener. We're just "home-engineering" around a problem Sunfish masts have with freight.
Yes, Webfoot1, a PVC mast is definitely a "workaround", but a member/reader in the Caribbean Islands could have a much worse problem with "freight" in getting a genuine Sunfish mast. I still think the idea has merit.
I motion that we have a vote as to whether Webfoot and LAVW test out their PVC mast ideas to see what happens. I vote yes!
but light and variable where do you get the schedule 5 pipes for cheap???
im looking to upgade my super snark witha bigger sail and proby need another mast
thxs in advance
I do have schedule 10 (marked "drinking water") pipe scraps. Schedule 20 is skinny and very suitable. (Buy a straight length, and don't leave it in a hot car).
While you could use whatever thickness that's available locally, specialized PVC pipe qualities are likely to be found at irrigation-supply outlets. My local irrigation-supply outlet wouldn't sell "retail".
oh ok thxs
We've now got two sponsors for this mast project!
Here's someone who used PVC and jammed a stair rail in the mast. It is real bendy
but it seemed to work, kind of. I'll see if I can get time to try it. I intend to fill it with
expanding foam. Failure would be excessive cost or weight to make it work as I'm sure
something can be jammed in it to make it work but might be much too heavy.
Quick Mast and Spars From PVC By Paul Herting PDRacer 596
If a stair rail (1.6 inch dowel basically...) didn't stiffen the PVC enough... filling it with foam will be worse.
Shop L.J. Smith Stair Systems 1.63-in x 8-ft Stain Grade Un-Plowed Handrail at Lowes.com
More "operations" can be gained from one can of Great Stuff by sticking a straightened coat hanger or small wood dowel into the "straw". Remove it, and the straw can be re-used. A reviewer said an ordinary soda straw will work, but I haven't tried that myself.
Interesting PDRacer article, but to save money, why didn't he just buy a Super Snark?
It's bendy (as expected), but it's a 12-foot mast—plus—the gooseneck is too far back. To get the "benefit" of a modern sail material, why didn't he use Tyvek?
Lowes says the handrail is "Hemlock" (a "soft" wood), but Hemlock can be Western (fairly strong, used in plywood) or Eastern (weak but cheap—even then—few will buy it).
I wouldn't spend a lot of money on PVC testing: the benefit of Great Stuff (or a stronger epoxy-based expanding foam) should be detectable using 3-foot scraps of PCV. Using scraps, "autopsies" can be made to detect the peculiarities of the hardened foam.
A friend suggested looking at flagpoles as a replacement mast.
He also suggested using "structural foam" instead. Great Stuff's ads show a variety of their foam products, one of which should be ideal.
How about finding a decommissioned radio broadcast tower and take a 10 foot segment of the proper diameter?
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