Lapwing mast tube question

[Richard Whitney CS#70]

Laid up my mast tube yesterday using Tom's method with the plastic strips.  Worked great - no trouble getting it off.  What I wanted to check is I have about 6mm of play (not as tight fitting as the mast tube I had on my cs17).  I assume this is OK but just wanted to check.

[Tom Lathrop]

You must have laid on several layers of plastic in addition to the strips.  6mm sounds like a lot.  You could add a coat or two of epoxy on the mast at the heel and covering the exit area to tighten it up a bit.

[Richard Whitney CS#70]

Thanks Tom  I used 6 mil thick plastic.  I ended up with 3mm space around the mast (6mm if you push it hard up against on side.  Your suggestion of just thickening it up a bit at both ends sound good.  I will put it to one side now until I get ready to instal it.

[Ken_Potts]

With the mast fit I would think it would be better a little too loose than a little too tight.

[Tom Lathrop]

Definitely don't want it too tight or it wont rotate very well.  That puts stress on the sprit and can wear it against the sail track.

[Designer]

Richard, it just occurred to me that we may be speaking a different language. 6mil plastic over here means .006" thick, so there is no way that you could have that much clearance if we are talking the same plastic thickness. With 4 wraps and Toms strips you should have had .06" clearance or nearly 1/16" . You want an easy fit without too much slack so I would do as suggested above and reduce the id, top and bottom of the tube until it feels right.

[Richard Whitney CS#70]

Yes I was reading it as 6 mm  - had difficulty finding plastic that thick so used the heaviest sheet plastic I could get and folded it over multiple times.  Should be able to fix it without redoing it.  Thanks

[Richard Whitney CS#70]

Come to think of it - maybe it is easier to do it again.  I should have checked it out ahead of time rather than be 'southern hemisphere literal'  :

[Tom Lathrop]

Ah so.  Another problem in translation of English mils to metric mm.  Blame it on the Brits.

[Docpal]

Since I am slinging a lot of graphite glop in all directions these days I thought I'd try to incorporate the stuff into the building of my mast tube.

I started with a 3'section of 6061 which I had bought to align the mast step, and wrapped it in some plastic. Then I just rolled on some 6 oz cloth and used a brush to apply the glop as I turned it on a 3/4"dowel mandrel. The theory is that if this works I'll get a slick face on the inside of the tube which will facilitate both stepping the mast, and allow it to rotate as much as it wants to...