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Sunday, August 18, 2013

Caprail Trim and T-Track are IN!

Ok, this took a lot longer than expected. I will save the minutiae of the actual install and just give a summary of the good, the bad and some tips and tricks for anyone considering something similar.

Plasteak

We went with Plasteak, which is this fake plastic teak make from recycled HDPE plastic. It really does not look like teak, but it is brown (close enough?). It is UV resistant, lighter than teak, cheaper than teak and it NEEDS NO VARNISH!
Plasteak on forward caprail

The Pros...


I really like working with this stuff. It cuts, drills, joints, routes just like wood. A high melting point means friction from tools wont melt the stuff. The method of manufacture involves a foaming agent, which means the core is less dense than the edges. With the lower density, a plank can be bent more readily than wood, especially if it is warm during installation. On the Westsail's canoe stern, I was able to bend one plank around each side of the curved stern without scarfing it in sections.

The Cons...


This stuff expands and contracts with the ambient temperature. A twelve foot plank can expand/contract as much as a quarter inch in length. Because of this, when pre-drilling and dry-fitting a plank, you need complete the final install with fasteners and sealant, on the same day. If you wait till the following day, after things cool, you will find the pilot holes do not line up with those in the cap rail.
Wrapping butyl tape under the T-track.

On Adhesive and Sealants...


Nothing sticks to this stuff. That DOES NOT mean the adhesive just "slides off". Your typical polyurethane adhesives will stick insofar as to keep things sealed from water. But it will not stick enough to provide any strength. If the plastic works enough, the seal will break. For this reason, I recommend Sikaflex 295-UV polyuerthane over 3M 5200. The Sikaflex is more flexible when cured and can move with any working of the plasteak. Sikaflex is easier cleanup and has good resistance to gravity (unlike 5200, which will move and drip once you turn your back on it).

This Installation


Port forward T-Track installation

Laying the planks was pretty straight forward, until I got to the areas pre-drilled for the T-track (32 feet of it). Way back in time, when we were planning the hull-to-deck join, I pre-drilled the caprail and glued threaded backing plates up underneath. During the test-fit of the plastic trim, with repeated screwing and unscrewing of the temporary 5/16 bolts for the T-track, some of the backing plates loosened and fell away. Some had easy access inside to re-set/-re-glue the plates. Some not so much. It required some creative thinking to fix involving fishing line, paracord, tee nuts, coosa board, etc. I felt like McGyver (but I cursed more than he did).

In the end, the layers for the T-track fastening looks like this (from bottom to top):

  • Alumunim backing plate (for the thru-blots)
  • hull/deck joint (previously sealed with 3M 5200)
  • Sikaflex 295-UV (keeps water from getting in under the trim)
  • Plasteak 1 x 4 trim.
  • Butyl Tape (keeps water from getting in between the T-track and trim)
  • Aluminum T-track. (1-1/4 inch, Schaeffer brand)

Thru-bolts are stainless steel 5/16 flathead socket cap screws. The threads are treated with Tef-Gel (to minimize corrosion). A dab of Sikaflex was squirted underneath the screw head before final tightening.

If water gets through these joints, I will be very surprised.
The best "top" view I could get.

Recommendations and Tips


If you are considering your own caprail trim installation with Plasteak, I recommend the following:

  • Allocate plenty of time to dry-fit and final-fit/seal each plank. Plasteak planks can be installed over a few days, but once a plank is cut and drilled, it should be sealed and screwed down the same day or it will shrink on you.
  • Use Sikaflex 295-UV. Do not use 5200. Sikaflex trims and cleans easier and is more flexible. 
  • And, when sealing anything  in compression (like a caprail), lay the sealant down, fit the piece and screw it down LOOSELY (like when it is just about to ooze out the sides). Let it cure enough so that it is oh-so slightly tacky to the touch. Then tighten the fasteners. This helps the sealant form a more substantial sealing gasket.
  • When sealant does ooze out the sides from compression. DO NOT attempt to clean it up. Let it fully cure, then take a sharp knife, razor, or scraper to cut off the excess. If you try to cleanup uncured sealant, you generally make a bigger mess in the process. This is why I like Sikaflex as it holds its form pretty well, and cured Sikaflex cuts real easy with a utility/exacto knife. 5200 not so much.    
  • Unless you are really good, don't panic if your scarf joints have a small gap. Even screwed down plasteak will expand and contract a bit. Acknowledging this, I tried to "hide" the outboard seam behind a chainplate, where I could, to hide any ugliness.
  • Do not worry about getting sealant on the exposed sides of plasteak. Cured adheasive will peel right off. Uncured adhesive wipes away with an acetone damped cloth.
Its not a perfect installation, but it passes the five foot test.

I still have some cleanup of sealant and need to cut some plugs and bung the counter sinks where tapping screws were used. A minor (but tedious) task.
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