Jump to content

Mast bushings for Spindrift Tens . .


Recommended Posts

I just reviewed Alan’s video on mast bushings where he used 29” of FG 3” tape (cut to 1.5” for the lower bushing) — to increase the 2” od tube up to the id of the 2.25” (bigger tube) — an increase of just 0.125”.  That’s in fairly close agreement with my calculation of 5.333... wraps, assuming FG thickness measurement of 4 layers at 3/64”, or 2 layers = 0.0234375” (one wrapping) and ignoring epoxy effects.  Five.333... wraps on a 2” od would be about 33.5”.  But I’m going to go with Alan’s 29” — which is just 87% of my calculation and thickness assumptions.

 
My calculation for the 1.5” od tube up to the id of the 2” tube (an increase of 0.375”) would be about 16 wraps around the 1.5” tube.  At that diameter the length (by my calculation) would be about 75”!  But by using Alan’s real-life experience to get an extra 0.125” on the 2” tube — wouldn’t 87% of my 75” (i.e., 65”) be a better choice?
 
From experience, do any of you builders have a length recommendation for adding a 3/8” thick FG bushing to a 1.5” od tube?


Sent from Yahoo Mail for iPad
Link to post
Share on other sites

I wrapped mine and at the green stage measured with calipers.  I added an extra wrap or two until I was just a bit over. The I took my orbital sander and brought it into a nice snug fit by laying the tube on a flat bench and rolling while I sanded. Very easy and it came out really nice.

  • Like 1
Link to post
Share on other sites

I spotted a method Alan described for joining two mast pieces; I don’t recall where it was. 
Basically, bushings were created, a couple glass strips were placed from the top bushing around the end and back up the other side (these strips held things together.) The wrapped end was inserted into the larger mast piece while everything was still wet. With even wrappings and a good tight fit, the joint self-aligned the two pieces. 
 

 

 

Link to post
Share on other sites
  • 2 weeks later...

Ah... I found the link I saved to Alan’s mast joining post:

https://messing-about.com/forums/topic/10540-capt-bones-core-sound-17-mk-3-14-kit-build/?do=findComment&comment=103113
 

B1D8126F-8937-4891-96DC-AA41D39F3845.thumb.jpeg.99fe705bc0f6d406009417a2dc497fab.jpeg

9893D8D2-67C9-4918-90F7-6A0B8D72D606.thumb.jpeg.8cc045c6cfccb55a9dd848f78538ce16.jpeg
I did this approach for my first of four joints. It used a lot of fiberglass tape, more than I thought I’d have available for the other three joints. I decided then to make 2 inch bushings to fit and added the cross-cross layers over them to hold things together when inserting the still-wet bushings into the other tube end. It worked very well for me. 

Link to post
Share on other sites

I didn’t realize what your goal was. I am unfamiliar with the details and options of other boats. 
My build called for permanent mast joints. I thought Alan’s approach was effective and efficient for that purpose. 

Link to post
Share on other sites
  • 2 weeks later...

Coincidentally, I just assembled masts for our CS 17 today.  I used 28" lengths of fabric cut from scrap, to use it up, but also to avoid the hemmed edge building up to ridges on the sides of the wraps.  I found I had to sand quite alot to get them to go together.  With the fabric I used, probably 24" or so would have been about right.  I pulled it pretty tight and squeegeed it tight in the wrap.  All went together great in the end.  Another check off the list. 

Matt

Link to post
Share on other sites

Got it done!  Not as difficult as I thought.  Alan’s 29” length of FG —  just about right to add 1/8” diameter to a 2” OD.  And I needed about 90” to add 3/8” diameter to a 1.5” OD.  Didn’t have to spend too much time scrubbing with 80 grit.  Here are the two small diameter poles nested within the big one.  Pretty neat.

6478406E-C723-485F-9882-FCF51DBEBD80.thumb.jpeg.4937ad982b4406c5d59e74701e860008.jpeg

 

Pete McCrary 

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

Supporting Members

Supporting Members can create Clubs, photo Galleries, don't see ads and make messing-about.com possible! Become a Supporting Member - only $12 for the next year. Pay by PayPal or credit card.




×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.