My last few stocks were done using the method described below. It is a combination of the 'in-the-wood' and the 'on-the-wood' method and gives a good water-proof finish that looks good and is easily repaired if scratched.
Before a stock is finished, there a few steps that should be done to ensure a proper job. After final sanding to 320, the steps include whiskering(raising the grain), sealing, filling, final finishing and (optional) rubbing out with rottenstone.
Supplies
- at least a liter if good quality marine spar varnish with UV protection. I use Interlux Original.
- a liter of mineral spirits or paint thinner
- 320, 400, 600 grit wet/dry sand paper
- lots of paper towels.
- rottenstone(optional)
Whiskering
This step is necessary because when the wood is sanded, at the microscopic level, the fibers are torn from the surface. A bent fiber that has been pressed into in the grain, or into a pore of the wood, may later rise up. To whisker the surface, gently steam the wood to raise the bent fibers, then sand them off.Once I've got the stock shaped and sanded to 320, I whisker it 3-6 times then sand again to 320.
Sealing.
This is a really important step. Done properly, it can result in a water-impervious layer of wood that can be up tp a 1/16" thick on the side-grain and up to 1/8" thick on end-grain. I have verified this using scrap blocks of wood.
My method is to soak the stock in a 50:50 mix of varnish and thinner. I use a shallow cardboard box lined with plastic. The soak is for 10-12 hours with turning every two hours or so.
After soaking I wipe off excess and let the stock dry for 4-5 days. Pour off the excess mix for use later.
Filling the pores
I use the sealing mix to fill the pores in the wood. Dip a piece of 320 wet/dry in the mix and sand the surface with the grain. This process creates a mixture of wood dust and finish. It should look like mud. Be sure to change your paper every so often so you are cutting well. Once the stock has been completely wet sanded take your clean paper towel and very gently wipe the surface cross grain. Wipe as though you were dusting a fine piece of porcelain. This will push the mud you created into the pores. Let dry a couple of days. Repeat this procedure until all the pores have been filled. Different stocks will take require more wet sandings than others. It will depend on how porous the wood is. The stocks I work with usually take 6 wet sandings to fill the pores. The final time you do this wipe off the stock completely with the grain. Leave no mud on the stock. Let dry for at least a week.
If the filling step is skipped, the stock will be covered with tiny dimples after final finishing.
Finishing
Again using the varnish mix,I wet sand the stock with 400 then 600 grit with a day or so of drying between sanding. I then apply 5-6 coats of the mix with my fingers. Pick up a small drop and rub it in throughly on a small area of the stock. Repeat until the stock is done. These coats are very thing and will dry quickly. Let the stock dry overnight and repeat.
Rottenstone.
This finish will give a fairly high shine that can be knocked back by polishing with rottenstone.
This stock was finished as described above but I didn't use the rottenstone.
