Tuesday, January 1, 2013

Dusty business...

Winter finally arrived on Christmas with several inches of white stuff and the first really cold temperatures of the year. We live northwest of Denver where winters can be quite harsh, however, this fall has been the mildest I can remember since moving here in 1978.
I was lucky to be unhampered by bad weather throughout the fall, but knowing what was coming, I installed a 5,000 watt ceiling mounted electric heater in the shop. Previously, I got by with two small electric/oil radiator type heaters, not adequate when the outside temperature is below 25 degrees. The new heater works great and will allow me to keep the shop at the right temp when I glass the hull.

I glued the last two strips in place on Christmas eve and toasted the occasion with friends, family, and some very stiff eggnog. A hull at last! Christmas morning was spent drinking coffee and planing my next move. I decided the hull will be easier to glass before I apply the skeg. Later on, after the centerboard trunk is installed, I have to flip the boat again to glass the joint. I'll apply the skeg, bottom rub rail, and outer stem at that time.




Fairing the hull


While boat building is new to me, shaping wood is not. I was a professional cabinet maker and luthier for many years, and I've turned a lot of wood to dust. Weather you are building furniture, guitars, or boats, the process of preparing the product for finish is basically the same. I want to be as efficient as possible and use the tool that allows me to remove the most material in a controlled way. Starting with hand planes and spokeshaves and ending with scrapers and sandpaper. I don't advocate the use of electric sanders for fairing the hull. It can be done if you're careful, but it is easy to create dips or ripples that will show up later, after the glass is applied.

  
 
I've tried to keep tolerances tight so to minimize the cleanup effort, but I still need to remove quite a bit of material. I've learned it is best to go incrementally, especially when symmetry is important. I started with a small hand plane at the chines, where the 3/8" bottom transitions to the 1/4" sides. This is really the only place I could effectively use a plane as mahogany is very prone to tearout if one is not careful. Thankfully, the bead and cove worked well to align the planking and I mostly used a cabinet scraper to do the initial leveling.

I worked my way along, starting at the transom and switching sides periodically, being careful to remove material evenly. It is important to constantly feel the surface for high spots and waves, keeping an eye on the symmetry. The key is to keep moving and not fixate on one area.

The cabinet scraper is a great tool if you know how to sharpen it. Lots of folks spend way too much time sanding when they could be using a scraper. For me, scraping is preferable to sanding and, if done properly, leaves a glass like finish. I keep a variety of scrapers in different shapes and thicknesses. The scraper is the perfect tool for dealing with curves.

 
It is important to work in more than one direction while leveling with a scraper. The scraper must be sharpened regularly. A sharp scraper will produce very fine shavings, like a plane. You will know it is time to sharpen when the shavings start to look like dust. A sharp scraper removes material much faster than sanding and provides a smooth finish in one shot.

 
If life was simple one could avoid sanding altogether, however, the scraper cannot adequately deal with the long curves of a 16' boat like the melonseed. To make sure the hull is truly fair it is necessary to use a long board. I could have made one, but I opted for an expensive 3M product with fancy hook/tooth sandpaper. The board is 30" x 4" and it's flexible. A rip off at about $60 bucks, but well worth the money if one factors in the time saved and the excellent results. Using it is a great workout.

 
I'm currently at about 80% with the fairing. Since I began the planking process in October the mahogany has darkened considerably, making it very easy to see the low spots. The emerging hull is an amazing thing, graceful, with sweeping curves and a distinct fish like quality. I love it!
 

 
Happy New Year!


1 comment:

  1. Hi Tim, really nice mellonseed your building. I too am a guitar builder who is currently building a boat.
    Have a look if you like. http://sailboatforme.blogspot.com/

    ReplyDelete