Replacement mast wedge

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walterg
Posts: 38
Joined: Tue Aug 30, 2016 6:48 am
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Replacement mast wedge

Post by walterg »

The polyurethane mast wedge in Nova Vita has become pretty dog-eared, more so since I've had the mast unstepped each of the past few seasons. My search for an off-the-shelf replacement was not successful. None of the polyurethane suppliers I contacted could supply a piece to the necessary tapered dimensions without the expense of a custom mold, they could only supply bar stock that would need to be cut on one side to provide the taper. They cautioned against my idea of using a band saw to cut the material, recommending instead that I take it to a machine shop with a water jet cutter.

The shop I was working with asked me to buy an oversized piece as they were unfamiliar with working with polyurethane and might need some practice to dial in their water jet settings. I ended up getting a length of polyurethane bar stock from Polyurethane Products (www.polyprod.com) to the final 2" height of the wedge on my Mull 28, but both wider than the necessary maximum 1-1/8" and a few inches longer. In addition to the dimensions, it's necessary to specify the hardness or the "Durometer Shore" number. From what I could find online I think this should be a 70A to match the original specs; I was a little reassured to learn that the different hardness specs for polyurethane have standard colors, and the color of the bar stock I received matched that of the original. It also passes the very unscientific "squeeze test".

Old and new mast wedges. The water jet cutter did a great job with a nice finish, in fact I ended up with 2 wedges since I bought it oversized and there was so little waste.
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Walter Gotham
Salem MA USA
'87 Freedom 28-Mull #33 "Nova Vita"

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gamayun
Posts: 232
Joined: Thu Dec 06, 2012 9:14 pm

Re: Replacement mast wedge

Post by gamayun »

Great post and information! This is a very useful approach to a common problem.
Kynntana, Freedom 38

bad
Posts: 160
Joined: Sat Jul 09, 2011 11:14 am

Re: Replacement mast wedge

Post by bad »

Good to know the material can be water jet cut. I am trying to remember how I cut the wedges that I cast, may have been a table saw or a jigsaw, or just a carpet knife. I also think I wet sanded it. Given the shape you are trying to achieve, I think a DIY option is to tape together an acrylic mold, wax it, and cast the polyurethane.

Erik

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