pvc mast?

[fishmonger]

My 12 foot skiff calls for a 16 foot mast(sprit rig). It would be very easy to make out of laminated 2/4's but it wouldn't fit in the boat. Being the kind of guy who LOVES pvc pipe, I was wondering if a couple layers of biax fg tape and epoxy would do for a small, 2 piece mast? It would be cheap to make. Because none of the materials are UV stable, I would have to paint it. Other than that what do you think?

[John B]

If you're thinking that way. why not just find an old windsurfer mast. cut it and sleeve it.

[ 04-06-2005, 07:02 PM: Message edited by: John B ]

[Bruce Hooke]

I don't understand what your plan is. Where does the biax fg tape and epoxy come in? Is it wrapped around the PVC? Are there shrouds and stays supporting the mast?

[Frank Wentzel]

I'd suggest that you use PVC pipe for plumbing as it was intended to be used. :D It has vitually no good qualities for a mast. It is relatively heavy and MUCH too flexible. Wrapping it in glass will make it much heavier. Glass, althought stiffer than PVC, is still too flexible until you get up to excessive wall thicknesses.

For less cost and mess you can whip up a light, stiff mast out of wood using the birdsmouth system. Try out a small spar with the birdsmouth method. It's much easier than you might think. Spruce should be available locally. And, with the size of staves required for that mast, you should be able get enough knot free pieces out of a couple of 2 x 6s. Of course, some scarfing may be required. Good luck!

/// Frank ///

[Donn]

How about bamboo? There are lots of sources on the web for bamboo masts and spars. You can buy ferrules to make them two-piece if you need to. It's got lots of good qualities for marine use. Stiff, light, weather resistant, and not too expensive.

[Bruce Hooke]

Maybe the first question here should be is it reasonable to make a two part mast, no matter what material is used? Does such a mast need extra support from shrouds at the connection point?

[NormMessinger]

Sounds as if you want to use the PVC pipe as a form around which to build a fiberglass mast. My vote is for the two by's.

[ssor]

An aluminum flagpole will serve as will a TV antenna mast. Anyway epoxy won't stick to pvc you need polyester resin(don't Shoot). They make street light poles of fiberglass and resin(filiment wound). There is no need to reinvent the wheel here, there a many sources of sticks that will serve quite well.

[ 04-06-2005, 08:08 PM: Message edited by: ssor ]

[Bob Smalser]

http://pic3.picturetrail.com/VOL12/1104763/7099973/92113916.jpg

Some cheap Doug Fir construction lumber, a table saw, some epoxy, and a (preferably pretty) helper come assembly time....and it's nothing to write home about.

[John B]

biggest damn hose clips I've ever seen. ;)

[Hal Forsen]

Donn,
Can you share some of the sources for the hardware for bamboo you mentioned?
HF

[fishmonger]

The point of the pvc is the ease of making a coupling so the entire spar would fit in the boat. The FG tape is to make is stiffer. 2/4, birds mouth, aluminum, stainless steel filled with lead. . . it doesn't really matter on a spar this small. I'm not worried about weight. I just want an easy 2 piece mast for an unstayed sprit rig (ie. all the Bolger boats). I've seen a couple of posts on this forum for two piece box masts. What about that? Why does everyone hate PVC so much? I made a bed out of it once, spray painted it metalic silver, and used it for years.

[NormMessinger]

Why ask us then? GO for it.

[paul oman]

I made a pair of oars out of PVC and they had so much flex I had to wrap them in epoxy and cloth. They still flex but are workable.

For an unstayed dinghy mast (8 ft D4 dinghy) I used a 2 piece TV antenna pole as mentioned by someone above. Got it at one of those big hardware stores for a very low price.

You might also search the net for a 'snow rake' - a long pole with a blade on the end used to remove snow from the ground. They are sort of bendy, but light and you could perhaps glass and or reinforce.

paul oman
progressive epoxy polymers

[Dave Lesser]

This link leads to a description of cold molded spars (http://catalog.com/bobpone/coldmoulded.htm) using PVC as a mandrel inside layers of epoxied veneers. I don't know if he ever did any strength testing. You might be able to join 2 short spar segments together with a solid plug inside the PVC.

[Bob Smalser]

16' mast in a 12' hull seems a lotta mast.

My pic above shows a 14' mast for a 20' boat.

Hardly God's gift to the sailing world here....but I suspect there's an alternative of equivalent square feet that'll store the spars in the hull. Looked at a gunter rig?

[ 04-06-2005, 10:45 PM: Message edited by: Bob Smalser ]

[MJC]

Originally posted by Hal Forsen:
Donn,
Can you share some of the sources for the hardware for bamboo you mentioned?
HFI'd like more info about bamboo masts as well.

[Donn]

Sorry, Hal, I didn't see your question last night. I don't know where to buy the ferrules, but I used to rent "big-top" type tents, and the tent poles were up to 30' bamboo, with two friction ferrules (like fishing rod ferrules, but 3" in diameter). Shorter side poles were 2 piece, 2" bamboo with threaded ferrules similar to the one on my Shakespeare VHF antenna.

Search Google for "bamboo poles" and you'll find lots of sources for the boo. You can buy poles over 8" in diameter and 50' long, but I'll warn you that the freight may exceed the cost of the bamboo.

Bamboo Fencer (http://www.bamboofencer.com/s.nl/sc.2/category.53/it.I/id.29/.f) sells up to 23' x 2" poles specifically for spars.

[shadow99]

Why not build the mast out of 2x4's laminated together? The original mast on my Swifty 12 was 4 2x4's, hinged in the middle using an aluminum sleeve. Simple & easy to store in the boat.
The hinge was a piece of 1/8" x 1" x 8" S.S., slots were cut into the upper & lower spar, the 2 1/2" I.D. aluminum sleeve slid over the hinge. It was a good & solid, unstayed system.
I did try a PVC mast on an iceboat I built several years ago, but compression seemed to a major problem, the mast would flex & wobble in the wind.

Rick

[pipefitter]

We used to make heavy duty fishing rods for what they call "stir polin" down here in FL. for snook off the piers and bridges at night. No reel,just a length of ¼" rope half knotted everyother joint in the bamboo incase it broke. These were about 12ft long and the fish was heaved up and over onto the deck in one swift motion. Regular bamboo rotted and became brittle so we used a different type called calcutta. It never rotted and stayed flexible. Dont know if it is available anymore tho.

[Cuyahoga Chuck]

fishmonger,
Forget about PVC. It's way too heavy and bends like a noodle.
But you can use it to make a carbon fiber mast.
Bateau.com sells fiberglass and CF in woven tubes (like a Chinese finger trap) that can be epoxied over a mandrel (PVC)to produce a space age mast.
Why be seen at the lake with a cheap PVC mast that when you can wow your friends and enemies with a genuine CF mast.
It might even help you stay upright.
Keep us informed.
Charlie

[Brian Palmer]

16 feet for a 12 foot boat with a sprit rig does seem tall. Generally, sprit masts are just about as tall, if not a bit shorter than, the boat is long. The sprit mast on my 20 ft yawl is only 15 ft long.

I would agree that a wood mast is the way to go. There are many ways to build a joint in a wood mast that would be easier than trying to build a composite mast on a PVC core. Lighter and cheaper, too.

-- Brian

[Dan McCosh]

Technically, I can't think of anything much worse than PVC to make a mast from. The stuff is heavy, poor in compression strength, and fractures when cold. It has virtually no stiffness. A broomhandle would be a major improvement.

[fishmonger]

Shadow 99, do you have a picture of the hinge that you could post? It sounds almost perfect. The bamboo also sounds interesting.

[Hal Forsen]

Calcutta is also known as tonkin cane which is solid as opposed to bamboo with it's hollows. The jack poles for tuna are still made from it and sportfishing boats use it for gaffs on BIG fish. Plenty strong for mast/spars for a small boat.
HF

[Donn]

Not quite, Hal.

Calcutta is Dendrocalamus strictus.
Tonkin is Arundinaria amabilis.
Tam Vong is one of the 'almost solid' bamboos, Dendrocalamus Strictus.
Another Vietnamese 'almost solid' bamboo is Tre Gai, Bambusa stenostachya.

The bamboo on the right is Tre Gai. Wall thickness is 70-100% of total diameter.
http://www.amazuluinc.com/images/custom/bambooWallThicknesses.jpg

[shadow99]

Fishmonger, I do not have any pics of the old mast assembly, but you can see pics at the Shell Boats webpage www.shellboats.com (http://www.shellboats.com)

It took less than a weekend to build the assembly, start with (4) 2x4 by 8' long, use good quality spruce with no twists, hooks or bows. Glue the 2x4's together, on the 3 5/8" side with epoxy & filler, clamp & let cure. I rough shaped the mast on a table saw to an octogon, finished with a homemade lathe setup to 2.5" diameter tapered to 2" at the top,(a 2x12 by 12' with a 2x4 on one end & a live center, the other end had a 1/2" gear driven drill attached to another piece of 2x12, and a piece of course sandpaper attached to backer board).
The hinge slot was done with a saw-zaw, the hinge plate was secured with a #12 S.S. wood screw.
Fitting the aluminum sleeve so that it slides easily from the lower mast section, up to the upper mast section, was the biggest pain, remember to add extra clearance for the sleeve, when the mast is in the rough, cause after 12 coats of clear varnish on the mast, that's the wrong time to realize the sleeve won't slide over :mad: !
Good Luck,
Rick

[shadow99]

Fishmonger,
Send me and e-mail titled: "Folding Mast" & I'll reply with a paintbox picture of the mast constuction. Its not a CAD drawing, but it will give you something to work off of, rather then trying to visulise my words :confused: .

Rick

[Bob Cleek]

No question that a wooden mast is probably the better option, but if "quick and dirty" is your intention, together with the "break down" feature, PVC CAN be used. The trick is to make it stiff. What you do is rip a bunch of wooden strips, small enough to slide into the inside of the PVC. It doesn't matter what size they are, just the longer the better. Start with a big one and then stuff smaller ones down along side it, so you can fill as much of the inside of the PVC with scrap strips as possible. Then, after suitably sealing one end, pour polyester resin down the pipe, filling the voids between the wood. When it kicks off, you should have the world's most rigid piece of PVC. As the resin is inside the PVC, you won't have to worry about UV breaking down the resin. You will pick up a bit of weight, for sure, but if you use light wood and more of it than resin, it shouldn't be too heavy. Sure a lot cheaper and easier than laying up a carbon fibre job!

[ssor]

Check this out. telescoping aluminum tubing.
http://www.texastowers.com/aluminum.htm

[Cuyahoga Chuck]

Let me get this straight. You get several pieces of PVC, which is fairly heavy, and you stuff it with wood and then pour resin in the voids (at about 9.5 lb to the gallon)and you say this is a fair replacement for a CF mast that weighs about 75% less?
I would think that such construction would be fairly expensive. Once you factor in the cost of a wet suit, the CF mast would be a bargin.
Charlie

[Donn]

It'd be a fair lot cheaper than doing a carbon fiber mast. How many gallons do you think it'd take to fill a 2" diameter void, 16' long, and ~75% filled with wood strips (I'd use bamboo splits)?

I'd think the hard part would be filling the voids with 'poxy. How do you get it in there?

Let's say you go to McMasters and buy a set of ferrules, so you can do 2 eight foot segments. How do you fill the voids with strips of wood and 'poxy? I think I'd fill the 8' tube, maube half-way, with the epoxy first. Then start stuffing in the wood strips, until the epoxy runs out.

[ssor]

Toto, I don't think we're in Kansas any more! :confused:

[StevenBauer]

Fishy, come on over to my house and I'll show you the sliding gunter rig on my 14' John Gardner skiff.

http://www.imagestation.com/picture/sraid138/pa79a2e45d94b11d1ef1d0e650e6cbd28/f7223664.jpg

http://www.imagestation.com/picture/sraid138/p79c3037c2736150b000c687c34993618/f722365c.jpg

Steven

[ 04-07-2005, 08:37 PM: Message edited by: StevenBauer ]

[Tom Lathrop]

This is one idea that should die before anyone gets the notion to really make a mast this way.

It will be heavier and more limber than anything suitable I can think of. Stuffing it with wood strips and filling the voids (a lot of that) with epoxy is, from an engineering sense, bass akwards design.

I forgot it was suggested by a lawyer. All is forgiven. :D

I use PVC for mounting bird feeders on where its lack of stiffness makes it marginally adequate. As a structural member of any kind, It is near the bottom of the list.

[Hwyl]

Originally posted by Cuyahoga Chuck:
fishmonger,
Forget about PVC. It's way too heavy and bends like a noodle.
But you can use it to make a carbon fiber mast.
Bateau.com sells fiberglass and CF in woven tubes (like a Chinese finger trap) that can be epoxied over a mandrel (PVC)to produce a space age mast.
Why be seen at the lake with a cheap PVC mast that when you can wow your friends and enemies with a genuine CF mast.
It might even help you stay upright.
Keep us informed.
CharlieI am absolutely in Chucks camp here. There is alink on the Cherub site on how to build a carbon mast around a PVC mandrel. That involves slicing open the mast to take the PVC out and then puting another layer of mat to repair the slice.

I think this guy leaves his pipe insulation in, first he says he doesn't then he does.

16' mast $180 and weighs TWO POUNDS

http://www.lmorocz.com/BoatBuilding/mast01.htm

[ssor]

There has been a great deal of superb advise given on this thread, most, if not all of which fishmonger seems disinclined to accept. Perhaps we should just tell him what a marvelous idea he has, let him spent his money and learn. It might still be an inexpensive education. And maybe he is right. And maybe the sun will rise in the west tomorrow. :rolleyes:

[fishmonger]

SSOR, have I declined anything? Have I disputed anything? I haven't even replied to anything since Wed. I haven't even had a chance to look at the computer since then. Personally, at $2 a foot, bamboo sounds great!

And on top of that, why are you such a sour-puss?

Boat building is fun. Trying new things is fun. Sailing is fun. People like you who write non-pertinent posts without any good information just to critisize other people are not fun.

[ssor]

Originally posted by fishmonger:
SSOR, have I declined anything? Have I disputed anything? I haven't even replied to anything since Wed. I haven't even had a chance to look at the computer since then. Personally, at $2 a foot, bamboo sounds great!

And on top of that, why are you such a sour-puss?

Boat building is fun. Trying new things is fun. Sailing is fun. People like you who write non-pertinent posts without any good information just to critisize other people are not fun.I guess mostly because I am a grouchy old phart with small patience for people who fall in love with an idea, ask the advise of knowledgable others appearently in search of an endorsement. Yes, messing about in boats is fun and learning from people with the benefit of years of experience in this craft as well as in many related areas can be immensely rewarding.
I did not say that you had declined any of the consul offered here. I said that you seemed disinclined to accept. Have you had an epiphany and now you find that others who have taken time to provide you with the benefit of their knowledge, probably have had by experience, observation, listening opportunity to know what works and what doesn't.

[NormMessinger]

Okay, let's let that be the last word on that conflict. Anyway, I'm the self appointed curmudgeon around here. Don't need no competition. tongue.gif

[fishmonger]

Norm, you are right. I do want to say one more thing to SOS though. . .

I haven't had an epiphany, but I have learned an awful lot of cool stuff. First, I love the idea of a veneer mast. It's super cool, and I like the way it looks. I'm having a hard time finding veneer locally though. Second, I haven't gotten to email the fellow with the 2 piece mast yet, but I'm really excited to see how he did it. His idea sounds like it might work perfectly. Third, bamboo sounds like it might be the best way to go. It's very little work compared to rounding a 4/4 or building a birds mouth mast, and the cost is very attractive. Fourth, I can't find the fg and cf tubes on bateau :confused: Fifth, I didn't even know you could buy tent pole connectors, and now I have a website for them. Sixth, this forum is about the coolest thing in all of boat building. There are several hundred ways to skin every cat it seems, and for someone who has never built a boat before, and who doesn't have any friends who've built boats before, it is a blessing to be able ask knowedgable people what the heck I'm supposed to be doing!!!!

Thank You ALL!!!!!!

[Stiletto]

Please post us some pictures of your final result.

Good luck!

[RodB]

No offense but...

Lots of ideas here mostly humoring you...but everyone is sidestepping saying the truth...trying to be nice. PVC used as a mast is really rediculous (using the PVC as a mandril of course is not actually using the PVC in the mast).

If you are not interested in laminating up a mast from 2X4's or using wood in some other manner...I would think buying epoxy and carbon fiber fabric to fabricate your own composite mast would NOT be a simple approach ... "how thick to laminate"..."how strong " ...would take some testing.

The simplest solution is (as mentioned above by John B.) to just find a used aluminum windsurf mast...most were 16 foot or greater. I have one 17 footer and one 19 footer left over from my windsurfing days, and either could be cut in half, and with a little ingenuity, one could fabricate either an aluminum or composite sleeve (ferrule) to join them. I would opt for an inner ferrule that was fitted perfectly to the inside diameter of both pieces (it would have to be beveled for the top section...as these masts are tapered). I would bet you could pick up one for $25 to $30...most windsurfers today use carbonfiber masts. I

If you could live without a two piece mast, then you could just use her like she is...just cut to length. Those aluminum masts for sailboarding were very strong and designed for lots of torque etc...and took lots of abuse. They came anadized in lots of colors, I have a red one and a green one. I used to put a 7.5 meter sail on my largest mast and bend the hell out of it sailing in 25 mph winds on my 9.6 ft board.. .Sailboard masts were designed and built for the express purpose of flexing and the stresses in sailing.

See below as an example...I was just messing around tonight and decided to draw up my idea in photoshop...

http://www.imagestation.com/picture/sraid164/p72917218d6d996898f73e9a9efcc3fdd/f4887dde.jpg

Personally I would go for laminating the 2X4's or the the birdsmouth as this would be well worth learning for the future and wood is always King for most of us.

Good luck

Rod B

[ 04-09-2005, 03:53 AM: Message edited by: RodB ]

[Mark Van]

I made a pvc mast for a dinghy once. You can stiffen it up a lot just by sliding a tight fitting piece of wood in it, it doesn't have to fill the whole space. I used a square peice, and planed off the corners so it fit snugly in the pipe. The only excuse was to make a rig very cheap. I made a square sprit-sail rig out of a blue polytarp. The whole rig costed about $20.00.

The problem with the rig mentioned, assuming it is simmiler to the Bolger sprit-boomed rig that he uses on a lot of his small boats, is that the mast is tapered quite a bit. It goes from 1 3/4" at the base to 3/4" at the top, so a staight piece of pipe or bamboo wouldn't work. I assume that the mast is supposed to flex more at the top.

[shadow99]

Fishmonger,
Got your e-mail, hinged mast drawing is on its way! Sorry for the delayed response.

Rick

[Luther]

Take your pvc and drill enough small holes (1/4 inch) to get the tube of 3x foam in the holes and fill. The foam is light and you will be surprised at the stiffness of it. We use to use pvc as a green house frame with the top of the pvc open so we could pour sand into the pipe. You couldn't bend it once it was full of sand. It would be the same with the foam.

[Tom Robb]

I've got a two piece fg (I think - too cheap to have been made of carbon) windsurfer mast in my shop. It looks like and is made like a rather stout fishing rod. Why re-invent/re-engineer unless this is a science project? Making the bird's mouth or even the laminated 2X's would be more fun and become part of your learning curve.
It's not for nothing that they called this the "WoodenBoat Forum" :rolleyes:

[RodB]

Amen

RB

[Tom Lathrop]

I'm not in favor of most abortions but someone should take a "morning after" pill on this one.