Thursday, March 22, 2012

Cursing at Dodgers

Fortunately, I have a job and have been too busy to play with sailboats this winter.  I have neighbors who aren’t so lucky.  Unfortunately, however, I have a job and have been to busy to play with sailboats, thus the 4 months since my last post.2012-01-28_18-46-40_320

I’ve been slowly working on the dodger. I made a form and laminated two pieces of 3mm marine plywood, glassed them and painted it with Interlux Pre-Kote in preparation for
Brightside.  I found that the ends had too tight of a bend radius, so I put 1.5mm deep cuts with my Skilsaw every half inch for 12 inches on each end, which worked well. By happy coincidence, my work bench was almost the ideal size for strapping the plywood to the form with motorcycle straps.  In the process I made two serious mistakes.

First, doing math in my head under the influence of wine, I mis-calculated the ratio for the epoxy.  I filled the pot to the 3 oz mark with part B then to the 12 oz mark with part A.  12:3 is 4:1 right? 2012-02-04_11-49-13_941 Would you believe I’m a licensed professional engineer?

It was from Tap Plastics and was a 4:1 ratio, and apparently doesn’t cure well at 3:1.  I’ve since learned that 1:1 or 1:2 ratio epoxy is more forgiving.  After laminating the two sheets, I just kept using the same amounts.  When I finished glassing the top.  It just didn’t feel right – it was hard, but sticky.  When I got to the bottom, it was worse.  I actually used a torch to heat and remove the uncured epoxy and glass and re-glassed it.  The re-glass job was gratifyingly hard and not sticky. 

Second, I misunderstood the use of Pre-Kote and effectively was trying to use it as a fairing compound. It would gum up the sand paper. Perhaps it just needs time to harden, I thought..  Being busy, a month went by and it was still like day old latex paint.  I could scratch it off with my fingernail.  2012-02-10_08-43-48_690

At this point, I’m of two minds.  One is to use the 7/8 dodger frame I got as dumpster salvage and go traditional canvas and the other is start over.  The little bit of stripping I did suggests that starting over would be the lesser amount of work if I wanted to stick with the hard dodger.

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