Wednesday, October 21, 2009

Rounding the Mast

I cannot believe it's been a month since the last update. It feels like barely a week has gone by. The mast is almost ready for epoxy coating. I planed the ridges off to turn the mast section into an octagon.  Then I planed the octagon to a sixteenagon.  All this planing was pretty easy to do by eye.  Then I switched over to sanding.  I was not sure I would know when to stop so I penciled a wavy line on each of the 8 original octagon faces.  This acted like a guide coat of paint when fairing a hull in that I knew to stop as soon as the pencil line disappeared. This worked very well.

I made a semicircular sanding block to make sure I was sanding a round mast.  In order to get the right diameter I used a piece of 3" PVC pipe and wrapped a few sheets of printer paper around it to bring it up to the mast diameter.  Then I wrapper it with wax paper and laid up a few layers of scrap fiberglass mat over that.  (Cheap wax paper is porous.  Guess how I found that out.  Use name brand stuff.)  Once the resin kicked I cut it apart and used a light coat of 3M 77 spray mount adhesive to attache the 60 grit sandpaper.

I think I could have planed some more wood off the mast before switching to sanding.  The first sanding strokes were a bit tight but it got progressively easier as the mast became rounder.  Picture below is before the handle was glued on.

By stroke number 12387663346 the mast was getting pretty round.  The handle is made from the triangular scrap cutoff from the bottom of the dagger board.

Getting there.

Me likey round mast.

The tapered sections were sanded with the same curved block and as long as I did not sand too long in one spot the mast became nicely round, although slightly less perfectly round than in the un-tapered section.  Surprisingly the mast warped a bit during all this sanding.  It was very straight to begin with and now it has about 1/4 inch of bow in it.  This is insignificant but .... The sanding conicided with our summer heat and humidity breaking so maybe it is the lower humidity that is responsible.

Total time to date: 108 hrs.