Sanding the Interior of the Kayak

"Why sand the interior of the kayak? No one can see it," a friend asked.  I will sand it perfectly smooth because I will always see it.  Once seen, never forgotten.  And so started the long, arduous and very dusty task of cleaning the hot glue spots and excess wood glue from the interior of the kayak and sanding it smooth, ready for the fibreglass cloth and carbon kevlar to be added to the interior.

Hot glue spots on interior

I had finished epoxying the outside of both the hull and the deck, and that had turned out well, so I made some forms for the two parts to sit in so that I could access the interior.  They sat upturned next to each other.

Hot glue spots cannot be sanded because they melt and gum up your sandpaper, so they have to be scraped off the wood where they have adhered to the interior.  I have a number of wood scrapers that I had previously used.  There is a secret method of sharpening a scraper blade.  It has to be sharp—not like a block plane—because you use the scraper not to cut shavings off a piece of wood but to scrape the shavings off.  Consequently, one sharpens the scraper blade and then runs a steel over the sharp edge and turns the edge into a hook or burr, which forms the scraping blade.  This will ensure the scraper produces fine shavings that are of uniform thickness.  A true art learnt over many years.

Scrapers ready

One starts with the obvious spots with some easy results, but then as you get closer and closer to the final output, you see how the wood glue and hot glue has settled into the cracks.  Now, strip planking a kayak seems like an easy task: lay the strips on the forms and make sure they are glued to their neighbour.  But that is not so simple because the forms are round from the part line to the keelson, and what's more, from bow outwards to the widest part and then it narrows to the stern.

I had addressed this challenge on the outside of the hull when I came to sand that surface prior to applying the fibreglass cloth.  The difference on the interior is that the strip joins may look great on the important outside, but they may not exactly match on the inside.  Furthermore, one is dealing with a concave surface into which a flat scraper or sandpaper block will not fit.  The solution is to use one of the four scrapers I had sharpened.  The large flat scraper was good for the initial glue removal and then to scrape the raised strips down to the same thickness as their neighbour.  The smaller scraper was great on the curved sides, and what's more, with their handle I was able to get a good clean shaving from the Myrtle wood.

Using the small scraper

Next comes the dirty part: sanding the surface smooth such that the fibreglass or carbon kevlar cloth will lie flat on the surface to be wet out by the epoxy.  I put on a beanie, full breathing mask and safety glasses, but still the wood dust seemed to get everywhere.  The only solution was short bursts and then retire to wash my face and head to get the dust out.

Sanding the interior

I could only continue these sessions in short bursts, so the whole operation of sanding the interior took about seven days for both deck and hull.  Once finished, I mixed up some epoxy and wood dust to make a filler and applied that along some of the open joins—again to be sanded smooth.

Filling some gaps

Now the weather again came into play, and I had to wait for some winter days that were not foggy and had a number of hours during the day that rose above 12 degrees Celsius.

Both units ready for cloth and epoxy

The fibreglass cloth and expensive carbon kevlar were waiting to be placed in the interior and wet out to add strength to the kayak and keep the wood from getting wet.