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From a Bare Hull:  The Deck (Page 7)

 
Fairing and Surfacing
Once the deck was sheathed in fiberglass, the next step was to fill, fair, and surface the decks.  Before I could continue with this, however, I needed to build the cockpit, since some fiberglass needed at the upper cockpit edge would affect how the decks were faired.

Once the cockpit was built, and the fiberglass in question installed, I could begin fairing the decks.  Surfacing may be a more accurate term, actually, since the decks were quite fair by nature of their construction; however, the fiberglass cloth needed to have its weave filled, and some minor undulations in the surface addressed.


Surfacing would in all likelihood require multiple applications of fairing compound, interspersed with lots of long boarding and sanding.  For the fairing, I chose System Three Quik-Fair, a 2-part fairing paste that is designed to eliminate the need to mix messy powders and such.  I found that mixing the material was messy in its own right because I had yet to figure out a good way to measure out the two parts accurately; spooning or scooping the two thick components into a mixing container seemed like the neatest way, but I feared that the accuracy of the mix would be compromised.  Scooping the material into measuring cups was messy as all get-out, but this is how I proceeded nonetheless.  Hopefully some easier means of mixing the material will come to light.

Using a variety of tools--but mostly small plastic squeegees--I spread a thin coat over the entire deck.  My goal in the first coat was mostly to get a solid base for sanding, after which areas requiring additional compound would be clearly visible.  I used a total of about 60 oz. mixed product for the first coat on the entire deck.  I found the Quik-Fair to be stickier than a traditional fairing mix made from microballoons and cabosil, but otherwise decent to work with.  One advantage is that the material is designed to cure within 4 hours, so 2 coats in a day are possible if starting early enough.  In this case, I didn't begin the fairing till afternoon, so I left the first coat to cure overnight before continuing.

In the morning, I attacked the cured fairing compound with a longboard (manual) and 60 grit paper.  The fairing compound sanded fairly easily, and only clogged the sandpaper in a few areas of the deck.  On the sidedecks, I held the longboard at an angle (relative to an athwartships line) and sanded, noting the low spots that showed up; the inner and outer edges of the deck should, in theory, be the known reference marks for fairness, so I sanded more or less until I had just removed the skim coat of compound at the edges.  This left numerous low spots in the field portion of the deck (the darker purple areas in the photo), which I would fill in the next round.

Sanding the entire deck by hand took a couple non-sequential hours, as I had to leave shortly after beginning for an appointment, but returned later to complete the job.
Once I had rough-sanded the whole deck, I vacuumed the sanding dust and washed with acetone, then applied a second coat of fairing compound, hopefully concentrating on the low areas left behind after the first sanding. Again, this ended up being in the late afternoon, so I called it quits for the day and left the second coat to cure overnight.



I began sanding the second coat the next day, much later in the day than I had hoped, and, frankly, I ran out of steam before the job was done.  The sanding seemed more difficult, and there were still numerous low spots that would require filling.  I decided to switch back to traditional self-mixed epoxy putties for the remainder of the deck fairing, as I had in the past found these compounds to be more user-friendly when it came time to apply them; the Quik-Fair turned out to be terribly sticky and unruly, and was difficult to spread cleanly as a result.  I thought this was complicating the process, and decided to return to the old standby. 

After completing sanding the second application, I spot-filled the remaining low spots (still rather widespread) with microballoons and epoxy.

Unfortunately, I could not return to sand the 3rd application until three days later.  This complicated the sanding process because the epoxy had had three full days to cure.  Epoxy, like most paints and resins, has several cure stages, and becomes increasingly hard and resistant the more time that has passed.


I found the sanding to be much more difficult after several days, and it took me about 4 full hours to sand the entire deck again.  I nearly perished trying to finish up the foredeck, which I had left till last; the epoxy compound there seemed  particularly firm.  In any event, after those hard-won hours of hand longboarding, I finally completed the 3rd sanding, and was pleased that there were only a number of small, shallow depressions remaining in the deck, signaling that the end of major fairing was near--perhaps only one more application away.  In the photos, the low spots are clearly visible as the darkest brown areas scattered about; the mottled colors of the other areas are the result of three different applications of fairing compound, each with its own color characteristics.

After vacuuming the dust and then washing the deck with acetone, I applied the 4th coat of fairing filler to the low spots and left it to cure overnight; I planned to sand it immediately the next morning to avoid the difficulties experienced with the previous coat.



Unfortunately, the next morning I found that the heat in the shop had shut off overnight, so the temperature was in the 40s.  This affected the cure time of the epoxy, and I was not able to sand the epoxy that day, as it remained sticky and loaded the sandpaper badly, so I allowed it to cure the remainder of the day and the next night, and sanded it thereafter.  The sanding was surprisingly time-consuming, but the 4th application of filler seemed to pretty much take care of all the low spots, with only a few areas remaining.

I filled the final areas with a thin coat of Interlux Interfill, which I had bought thinking it would be similar to the product that it replaced--and which I had used before, Interlux 418/419.  Strangely, this was not the case:  the Interfill was an odd mixture of a carbon-black tinted epoxy base and an almost gritty amine catalyst, and was not at all particularly smooth, either in texture or application.  Nonetheless, it was good enough for the task at hand, but I didn't think that I'd be using it for a final, silk-smooth coat of compound anywhere.  For that, I planned to turn to the line of fairing/surfacing products from the paint company (Awlgrip or similar).

The next day, I sanded the final application, this time using an electric palm sander for the bulk of the work.  When that was done, I sanded the whole deck one more time with the long board, using 100 grit paper.  This completed this stage of the deck fairing. 

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