Igor_Korousic
new user
Reged: 23/04/2008
Posts: 5
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Has anybody wrapped a carbon mast with a thin layer of wood? I'm concerned with the quality of bond especially when under heavy loads.
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Bajansailor
regular
Reged: 27/12/2004
Posts: 2238
Loc: Barbados (East coast)
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I know that many of the carbon spars on classic sailing yachts have been very cleverly painted to make them look like timber - this might be an easier option than trying to bond a thin layer of timber on to the carbon mast?
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Peterduck
regular
Reged: 10/04/2002
Posts: 994
Loc: Melbourne, Australia
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Your limiting factor here is the ability to clamp the veneer to the mast uniformly, so that all parts of the veneer are under equal pressure. Vacuum bagging is the only method that I can think of right now which would do this, and the number of companies set up to do this on the scale that you are obviously thinking of are very few and far between. Be prepared for costs that look like telephone numbers!
Peter.
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B175Chris
regular
Reged: 06/06/2006
Posts: 5721
Loc: B'ham + Port Grimaud
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I think the guys who were racing Griff Rhys Jones' boat who had an identical type of yacht had a painted carbon mast instead of a wooden one - looked great, couldn't tell 
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I think you'll find it goes without Sailing
Inflatable for Sale!!! Bargain Price!!! Tender Moments
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Igor_Korousic
new user
Reged: 23/04/2008
Posts: 5
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I'm thinking of using 1" Douglas-fir strip planking with round edges to cover a 50' mast. I would use Sika between wood and carbon and epoxy (or something more UV resistant) between the strips of wood. Bronze mast fittings would firmly hold the wood at the deck level, gooseneck, spreaders and stay attachment rings. The question is should I use Sika between the wood and carbon or nothing to allow more movement between the two masts. Or is this a very stupid idea?
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Big_Southern_Jesse
regular
Reged: 20/10/2005
Posts: 597
Loc: Emsworth, Hampshire
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I'd have thought the carbon mast is carefully designed to flex in a certain way, and a certain amoount under loading. Certainly that's the best way to use carbon. The problem you'll likely have is a difference in the flexing between the wood and the carbon.
If you glue the two together, you'll be putting the glue under stress each time it flexs. If they are seperate, then you have one moving over the other, possibly abrading the carbon. You may also end up causing a "hard point" in the bend characteristic of the carbon mast that would quickly weaken it.
You'll also be adding lots of weight at a large rotational moment that is not needed.
I'd go with the paint, or possibly very thin laminates - 1 or 2mm thick.
If you're going for inch thick Douglas fir, you're most of the way to a wooden mast all in it's own right anyway! Forget about the carbon mast and just get a wooden one!
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Roach1948
regular
Reged: 27/04/2006
Posts: 1012
Loc: London - Suffolk
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Wm Fife's "Lady Anne" has problems with her CIM rating due to having carbon mast and bowsprite. They are both sheathed in wood. Maybe you could find out who did the work and get the low-down on the problems you will encounter. http://www.classicyacht.info/modules/yachts/The+Lady+Anne-TName-yachts_detail-942.html
Or as Big_Southern_Jesse suggests, get a decent wooden mast. A well built hollow Sitka Spruce mast will be stronger and lighter than it's aluminuim equivalent.
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Roach
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Peterduck
regular
Reged: 10/04/2002
Posts: 994
Loc: Melbourne, Australia
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The reason for having a carbon fibre mast is to save weight aloft. By sticking 1" thick timber on it you are cancelling out that advantage. When you glue two different materials together it is important that only one of them has the strength; the other one has to conform to the strong one. By having carbon fibre and 1" thick timber you have two competing media, each wanting to have its own way. While Sikaflex may stick to timber quite well, i would want to see some impressive test results of its adhesion to Carbon fibre before I would have a bar of your proposal. Paint it; it will be cheaper and more durable.
Peter
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Foxy
regular
Reged: 08/03/2006
Posts: 111
Loc: Cruising
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I dont know if its much of a comparison, however, most wooden floors in television series are really just paint on a resin floor - there are even special machines to create this look. The resolution is obviously much less than the human eye, however if more time was taken, a really good finish could be achieved.
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Npm
regular
Reged: 16/11/2005
Posts: 54
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I agree with everything said so far. If you really want something better than paint, a thin veneer of softwood vacuum bagged on with epoxy resin glue is the only safe engineering way to go. Putting enough wood on so that it contributes to the structural loading really is asking for trouble even if the glue line is adequately strong. By allowing the two components to creep between hard spots(deck, winches, gooseneck, hounds, halyard attachments etc) will cause failure.
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