Varnished areas can take a beating, and as a deckhand, you'll likely be asked to handle touch-ups from time to time. Here's how...
Varnished rails and other elements oftentimes suffer from the ravages of wear and tear — and at times, from simple silliness. While modern varnishes are relatively hardy, the result of these actions requires attention between charters. Damage to the varnished areas, particularly along the rail, needs to be addressed to maintain the beautiful symmetry that only a varnished rail offers and the magnificent brightwork you may have on deck.
Given that the average varnished rail has at least eight coats of material, sometimes the scratches do not reach the wood and can quickly be addressed with 120 or higher grit sandpaper and a quick dash of varnish with a delicate brush and a mixture of no more than 90 percent varnish and thinner.
Should the depth be sufficient to feel an edge, the damaged area needs to be sanded down to a smooth finish before recovering with a varnish and thinner mixture. Should the damage reach the wood and leave any deformation, splintering, a gouge, or other damage in the wood, this must be addressed before recovering and sealing, as the eternal fact of working with varnish is that you can almost never hide the truth below. All damage, discoloring, or other mishaps on the wood would be clear and evident to the discerning eye.
Once the wood preparation is complete, rinse and wipe the area with a clean cotton cloth — these are much better at picking up dust and debris than polyester materials, which usually only push it around. Be certain they’re white, as acetone tends to discolor the material and leave stains. Using acetone also dries up the wood, removing any humidity and some oils, and allows the varnish mix to better adhere to the material. In your work area, on a two-square-meter plastic sheet, heavy cloth, or wood panel, you should have the necessary materials, including varnish, acetone, brushes, pots, and stir sticks.
Prepare a 50/50 varnish and thinner mix to apply to the area of bare wood, and you'll see that it adheres well and dries quickly. Apply the next coat with a heavier mixture and continue doing so until you reach a 100 percent varnish mix.
The last couple of coats, if on a rail, should be stretched to the length between two stanchions. This would certainly help in easing the continuity of the line varnished without leaving an evident trace. As you proceed, be sure you cover the extended area after a light sanding, until you build up the eight coats and balance throughout the extended area of repair, resulting in a lovely, unbroken line of varnish for all to again enjoy.