Carbon Mast/boom Project

Those pics are from the mast That I built in 2001 for the Truewind 32 (originally Conser 30) catamaran. The pictures were taken in my shop. The curing oven is in the background. You will need one of those if you decide to do a mast yourself since the only practical way is to use a very slow curing resin system. (think days or even weeks to cure at room temperature). Then of course you don't wait days or weeks but put the whole rig in the oven. Or let the oven come down onto it, but that's another story.

Jimbo

 

Where did you get the material? Was it woven carbon socks? Can you elaborate some more on this process?

Thanks millions!

-jim lee

 

A & P Technology

 

And what resin?

Tks

 

I formulated my own since no commercial formulation made in 2001 would work for me. Now you can find a system designed for infusion that should work just fine.

Jimbo

 

The answer is "it depends".

There are many types of Carbon Spars. There are less expensive tubes made in filament winding machines. There are also much more expensive pre-preg laminations.

 

Making Carbon Spars

Well, have the project fairly well planned, on paper...trying to complete with readily available materials.

Two PVC mandrels one for 10 feet mast and another shorter mandrel for added 2 feet 2 inches of mast (top) to joined to longer section--because I cannot find longer mandrels... may taper, may not.

Plan to use one full length bi-direction carbon/graphite sleeve plus one full length uni-directional sleeve directly over mandrel...

Wax release agent on mandrels (like paste Johnson's floor wax or similar...

Long cure epoxy resin...60 minute pot life at 80 degrees.

Lower 3 feet of spar will be bi-directional sock to separate carbon from aluminum lower mast section.

I am guesstimating for moderate flex...and if too flexible, can stiffen with added graphite.

Current wood spar is quite flexible, as in old Finns, and the alum spar set is not quite as flexible, so am guessing the difference will not be all that difficult to determine and adjust. Inasmuch as the rig is experimental...

The spar will have no hardware, save perhaps, tip-top female receptacle for wind indicator...not major concern.

All for next season, unless I can locate hot inside workspace...

At this point total cost for materials is approximates $370 USD, sans my time and labor, which is the fun part.

 

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I'd suggest using Partall Paste #2 wax covered(sprayed) with PVA.
And the properties of most epoxies are greatly enhanced by post curing in an oven. You can just build a temporary box or whatever to raise the temp for curing. Find out what the ideal post curing temp is for your epoxy then see if you can match that in a temporary "oven"-before you start(!).

 

Making Carbon Spars

Doug, thanks for advice. I thought of fashioning a sort of "heat lamp oven" using infra red heat lamps and foil coverall over the spar...but really not sure if that will make a for certain difference.

Still, might do anyway...want to keep simple in both materials and apparatus, so others can give it a go, if it works...this mast is not so large...and looks as though some Cherub carbon mast devotees have had some success without the heat...

Still, seems easy enough to construct and use...have some time to gather pros and cons.

Anticipation, like curiosity, makes it all the more interesting, doesn't it?

You would flip if I confessed my desire/plans to make winged rudder and dagger board foils for this wee dinghy, to lift it ever so slightly to get it to plane in lower pressure.

 

JFWIW
Try this link http://www.saunalahti.fi/~pekkajlh/boat/story_e1.htm go down to summer 2005 I think it is for his heat lamp oven used on carbon mast.

 

It would be worth your while to contact Wind_Apparent on Sailing Anarchy (He sometimes checks in here as well). He's built a curing oven for composite builds that meets the needs for cheap. Temperature regulated and big enough for serious parts.

--
CutOnce

 

Be careful with heat on the pvc. It will shrink. Bad news during cure, but necessary to remove the tube from the mast, as no matter what release you use, it will be very hard work to get it off.

rob

 

Jimbo1490, thanks for the link! I called and they are sending samples. I think I'm going to see if we can do this.

-jim lee

 

Making Carbon Spars

Determined a plan regarding project-

Mast will be two sections: 8 feet and 4 feet for top section. No hardware...basically two carbon rod sections. May then join both sections to form single upper spar.

Using one conduit mandrel and one PVC based on diameter to achieve.

Bi-directional carbon sock for both sections.

Bi-directional glass for lower section only where it contacts aluminum mast base to separate/insulate.

Release agent for mandrels as Doug suggested.

Perfed release film; Peel-ply to use when joining sections permanently later.

Long cure epoxy resin. Have not decided. Have some stuff left from past job, but not long cure???

Four heat lamps, cheap shades and sockets etc.

Alum foil for making tent oven long enough to cover layup with blocked sides to retain heat. I did this once before using plastic paint floor coverings with care, and it worked fine in that case.

Plan to apply wet on wet (tacky), two layers carbon, wrap, and bake.

A. Reinforce mid section where top joins mid section, with layer of carbon with small end wrap, like carbon fish rod ferrule but with one wrap of glass to hinder split potential.

Sections joined similar as Force 5 and other small dinghies using sectional alum masts...with stock class rubber fittings, epoxied in place and using similar insert depth. Or,

B. May join two sections to form single spar.

I may have missed something.

Figure with the heat at 80 or so, should be good to go before wife returns after trip to Chicago...few days.

Idea is to make the spars light at outset, and, if the mast is too flexible, I can add carbon as Rob Denny suggested above.

(Rob, I did not send the info as you suggested, as I thought the sections or mast was too small for make a big deal over as they are basically two carbon tubes.)

Guess weight aloft will be half than it was with wood and a third less than alum.

May seal top section so it will tend to float when knocked down maybe use foam. Will worry about that after initial job finished.

You guys think I am wasting time or crazy or have comment, have at it, please. I need all the help, mental and project, I can get.

 

Carbon Mast

Local Laser sailor informed me he is going to make carbon mast for his boat to handle a smaller sail, that I think is called a Radial...that job will be more complicated due to mast/boom goose-neck etc, which need reinforcement Kevlar or whatever.

I have decided not to consider boom, at this point, just to keep it simple for me.