Replacing plastic mast cap

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Bobglas
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Replacing plastic mast cap

Post by Bobglas » Wed Apr 04, 2018 10:29 am

I'm considering running an antenna and installing a solar anchor light. Wondering if anyone has replaced the plastic mast cap w/ something that can be drilled for mounting stuff. Where to find? 2012 26M

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Re: Replacing plastic mast cap

Post by BOAT » Wed Apr 04, 2018 11:31 am

You can get them at BWY - I have several. I bought some spare parts right after I bought the boat because Mike Inmon told me that 'boat' was going to be one of the last boats built in Costa Mesa where I picked it up. So I bought a spare spreader, a helm seat, three mast caps, a stanchion with baby stay loop, mast bases, mast hounds, a door, hole caps, three goosnecks, and a partridge in a pear tree. Even other stuff not mentioned here.

I bought a LOT of spare parts because I knew about MacGregor boats for like 40 years going all the way back into the 70's when they were Venture boats. The reason i grabbed boat was that I got rumors they were closing the shop from some guys I know that work at the Hobie Cat factory here in Oceanside.

When i asked Mike if Roger was closing shop all he said was "Roger will have to retire someday but he has kids that work at the company" That's all he said - then I knew from that the factory was going to close.

So I picked out 'boat' during fabrication and also ordered a bunch of spare parts. The day I picked it up he finally admitted it was one of the last boats.

A lot of the fiberglass parts i got and stashed into the garage attic are not available anymore.

Call BWY and don't order one cap - order THREE. (while you still can).

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Bobglas
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Re: Replacing plastic mast cap

Post by Bobglas » Wed Apr 04, 2018 11:51 am

Yeah, I saw the replacement caps but I'm looking for metal that can hold attachments.

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Tomfoolery
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Re: Replacing plastic mast cap

Post by Tomfoolery » Wed Apr 04, 2018 12:03 pm

Don't discount making your own from Starboard (HDPE 'lumber'). That stuff is easy to work, and you can make a cap that can accommodate anything you want to mount to it.


Image

Image

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Bobglas
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Re: Replacing plastic mast cap

Post by Bobglas » Wed Apr 04, 2018 1:01 pm

Hadn't thought of that. Same as kitchen cutting board material?

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Tomfoolery
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Re: Replacing plastic mast cap

Post by Tomfoolery » Wed Apr 04, 2018 1:53 pm

Some of them. Most seem to be high-density polypropylene these days, which is harder to work as it melts more than it cuts with high surface speed tooling, like a bandsaw or table saw. Even sanding. But I do use the admiral's old cutting boards for things; it just takes a little more care in finishing the cut edges. You can sand the stuff, but slow is better than fast; a sanding disc on my lathe will load up with melted plastic unless I run it very slow (creep speed). Or work it by hand.

Starboard is high-density polyethylene, which cuts easier and doesn't melt. Starboard (a brand name) is also UV stabilized, and since I had some left over from my helm station throttle rework, I just used some 1/2" thick black scraps to make a mast cap.

If you look closely, there are only two screws at the front of the mast, at about ten and two o'clock, and a spacer in the back between the cap and the chicken head, with a long SS screw though the whole thing to another 'spacer' on the bottom (just like the one on the top side), which is just a rabbetted piece of plastic to hold the screw centered on the backstay portion. Very stable. I think I may also have put a third wood screw into the back of it, in the gut of the sail slot, where the extrusion is flat. Don't remember now.

But you could make your own easily enough by tracing the outside of the mast onto a thin cardboard pattern, offsetting the resulting line by the thickness of the mast extrusion wall, and cutting a slug to fit inside the mast. Another piece larger by at least the thickness of the mast wall then gets sandwiched to it with wood screws or machine screws and locking nuts, and you have a cap. Make the larger part with extra surface wherever you need it to mount extra stuff, like an anchor light. The most important part is a nice fitting internal slug - the rest is what you need for a mounting surface and good looks.

Pepper the perimeter with small wood screws to hold it. With small pilot holes, they aren't coming back out unless you want them to. And if you sand the cap edges from top to bottom (sanding disc/belt grit travel direction), you'll even form a little bit of a drip edge on the bottom as a free bonus, if you don't want water getting into your mast for any reason.

Image

The 5 degree tilt of the light was built into the socket, so I oriented it forward to counter the 4 degree aft tilt of the mast. :D

Image

You can see the spacers top and bottom of the chicken head boom, which are actually 1/2" thick, but rabbeted to have shoulders just the right thickness to provide solid support, and the right width to lock them into the space between the boom arms. The M doesn't have a backstay, so a few extra screws around the perimeter should be fine.

Image

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Re: Replacing plastic mast cap

Post by BOAT » Wed Apr 04, 2018 1:58 pm

Huh, hey Tom - does that stuff grind? Is it light? I want to try some - where do you get it?

(Starboard? So it's opposite of port)

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Tomfoolery
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Re: Replacing plastic mast cap

Post by Tomfoolery » Wed Apr 04, 2018 2:39 pm

Portboard works better for left-handers. :wink:

https://www.westmarine.com/buy/west-mar ... ?recordNum

As to density, it's about 1/3 as dense as aluminium, and about twice as dense as dry timber. Give or take. With a yield strength a little less than common framing lumber. Plenty strong for most common boat projects, but I wouldn't go building boat stands from it, mainly because it ain't cheap. But WM isn't the only place to get HDPE sheet material, and rounds for that matter.


This is actual StarBoard. I don't remember if the stuff WM sells still is, but it used to be. :| http://www.kingplastic.com/products/king-starboard/

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Bobglas
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Re: Replacing plastic mast cap

Post by Bobglas » Wed Apr 04, 2018 3:31 pm

Thanks Tomfoolery! I ordered some from Mcmaster Carr. They had 12"x12" pieces. I also ordered a solar powered 2nm buoy light to put on top. The cap will be large enough to hold the light (5"). Just have to wait for the remaining snow to melt so as to move the boat to a workable area.

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Re: Replacing plastic mast cap

Post by 1st Sail » Wed Apr 04, 2018 3:32 pm

Cheap HDPE source for building small things like a mast cap, drink holders, transom filler board. Cuts and machines easily. Built my: transom filler board(best thing ever, no exhaust down wind, significantly reduces engine noise), new mast cap, stanchion mount drink holders, remote control spot light mount on the bow pulpit. I'm thinking of building a new/larger helm box to fit my UFlex rotech steering system. Unfortunately you cannot fit the Rotech into an '06 helm box using the oem wheel position, but that is another thread.

Board is 1/2" x 15" x 20"

https://www.samsclub.com/sams/bakers-ch ... roduct:1:6

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Tomfoolery
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Re: Replacing plastic mast cap

Post by Tomfoolery » Wed Apr 04, 2018 3:38 pm

That's a really good price, and it's HDPE and not HDPP. 8)

But I'm not a member. :P

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Re: Replacing plastic mast cap

Post by Danhux » Mon Apr 16, 2018 10:02 pm

I made mine out of cutting board. I used three layers, one for inside the mast, the other two for the top. I used a piece of cardboard to make an imprint of the inside of the mast to get the insert layer nice and tight.

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Re: Replacing plastic mast cap

Post by rsvpasap » Tue Apr 17, 2018 12:12 pm

Alternatively, if you would like a 4 by 8 sheet of HDPE at a very good price
https://www.menards.com/main/building-m ... 093908.htm

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Re: Replacing plastic mast cap

Post by BOAT » Tue Apr 17, 2018 12:49 pm

Hey Tom! Image is this the right stuff ?? :|

Image

The Starboard and Portboard was confusing and I can't seem to get the right count of carbon atoms connected to the hydrogen atoms to come up with the right stuff. Is it the Styrene, Ethyl, or Propo? I'm lost now. (The way I am assembling the atoms I started getting search returns for Propane and Butane and H_-O-_H which turned out to be diethylene glycol - this is not working at all). So what am I looking for?

I'm totally confused trying to find any bargains because I search on STAR BOARD and I get all kinds of crazy stuff like Polystyrene? Or another site says Polypropylene :? and then I saw Polyethylene and so I tried CUTTING BOARD and got even crazier responses form Professor Google and his band of merry dunce heads like HDPE and Corian and I sort of just gave up. (What is HDPP???) I wanted to get a cheaper price but when i do they try to trick me with some other formula that does not seem to match with what you said. Should I just stick with the expensive one that is at West Marine:?

https://www.westmarine.com/buy/west-mar ... ecordNum=1

So, right now I mostly use MAHOGANY - it's a material that grows on trees (I think) and I get it at Home Depot. I can grind it and shape it and cut it and sand it with power tools.

Which product should I use if i want it to perform similar to the material: MAHOGANY ? :| :?:

(And sorry - I can not give you the chemical composition of MAHOGANY cuz I don't know what it is. :( )

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Re: Replacing plastic mast cap

Post by K9Kampers » Tue Apr 17, 2018 6:03 pm

I only use starboard that is sourced as recycled ocean waste harvest and carbon-free processed...

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