STARTING FROM SCRATCH
This chapter contains in step-by-step, the full process by which we take bare wood and deliver to it a lasting and beautiful coat. It is designed to be largely complete, without lots of cross-references, and so will contain some duplication of procedures and information found in other parts of this book. This is deliberate, to provide an ordered approach to your job whether you are a beginner or not.
If the work is on your own boat, or it is a recurring responsibility you have on someone elseâ€™s boat, starting from bare wood is the best position from which to begin because then you know exactly what has been done and therefore can realistically predict the future service requirements and times.
1. EXPOSE THE FULL JOB
Pretty much the first thing to do is to remove anything that will be an obstruction to your access to the area being worked on. All fittings should be removed like cleats and stanchions, chafe plates, light fittings etc. The reason for this is not just that it makes it easier to sand the area and to coat it, but also the integrity of the coating is enhanced where fittings are replaced over the top of the newly finished surface as opposed to being islands in the middle of new work. The latter situation will inevitably produce an earlier than deserved source of breakdown around the edges of the fittings. Remember â€“ Golden Rule No 2…………..Varnish almost always breaks down from an edge first!!
Please note however that there is a difference between fittings and fixtures. It would be unwise to remove a stanchion if it is supporting an upper deck, or a cleat which is bolted through a cap rail and the nut is only accessible by spending a day dismantling the deck head lining of a cabin below. Be realistic, but clear as much as you can. A smart thing to do is to sketch a plan of where everything has come from and to attach the relevant fastenings to the fitting with tape. This will avoid much head scratching when it all goes back together.
We have discussed the variety of tapes available so choose the one that is applicable in your situation. It is important to protect the areas around those upon which you are working, in particular, painted and gelcoat surfaces. Tape the outer margins of your work area and also any fixtures that have not been removed. If you are starting the sanding process with a heavy grit paper, it could be prudent to put down a double layer of tape to protect the edges for a longer period of time. If the tape gets sanded through replace the section as soon as you see it. There are few sights worse than a beautifully finished piece of timber trim with sanding score marks on all the adjoining surfaces.
When the sanding or other prep is finished, always remove the tape and replace with new before the coating up process is started, because the edge of the tape is always weakened if it has been sanded, and the tape will not come off cleanly when it is removed. Better to find this out before it also has several coats of varnish on it, where a ragged edge is the usual result and the tape removal, normally a job of a few minutes duration, becomes very much longer. Very painful if you learn this the hard way!!
3. PREPARATION OF THE BARE WOOD
The procedure for stripping is dealt with in Chap 3, so, we assume for the purposes of this exercise that we are at the stage of bare timber and that the timber is fair ie. it is straight and uniformly flat and radii are true. To make new or old timber conform to these specifications is an entire book on its own and is logically in the domain of the woodworker, be they boat builder, shipwright, carpenter or joiner. However, if you are at this stage, perhaps at the end of a difficult stripping exercise, or you have inherited a particularly weathered bit of timber, here are some quick tips, over and above the instructions in Sanding techniques Chap 3, on getting it ready:
- When a high gloss is applied to a capping or a rounded handrail or fiddle, it is immediately apparent that the radius is out of true because the light is naturally reflected in a line at some point in the radius depending upon the position of the eye of the beholder. The deflection is commonly referred to as a â€™woofâ€™ . To minimise woofs and achieve a more consistent radius over the length of the timber, fairing of a radius is achieved with a block or long block, with the sandpaper wrapped around it (see Sanding technique â€“ Chap 3). Starting on the flat on the top of the rail, move the block forward in the direction of the grain, while allowing it to slide over the edge grain all the way round to the underside, and then back along the same course. Do this a few times in the same place, varying the procedure by starting at the underside and moving forward ending on the top. Dust off and note by hand and eye if the surface is uniformly smooth. Touch is often the most reliable messenger. It may be that you need to work away at a few of the higher spots but do use the same technique. Do not simply rub at the high spot as this will of itself, produce a flat spot. Proceed up the length of the timber, fairing the same edge all the way. Then start on the other side.Those of you who are paying attention will already be exclaiming that we have broken the golden rule of sanding, because as the block is moving forward but also down across the edge grain, it is cutting across the grain. For this reason we use a lighter paper â€“ say 120/150 grit on harder timber like teak and 180/220 on the softer stuff. It is also true that the cut on an edge or radius is always more drastic than it is on a flat surface, so the cutting action will be as effective as if an heavier grit is being used.
Having sanded the whole piece of timber, the flat areas in the regular back and forward motion and the edges/radii with the rolling motion, the final mission is to remove the sanding marks that are across the grain on the edges. Take the MGC flexible block with paper wrapped around it and sand with the grain until the marks are removed. If the wood is very hard it can be beneficial to go up a grit size of paper to ensure you get them all. Wipe down with metho as a means of checking this.
- When timber has been left in a marine environment for a period of time with either a deteriorated coating or none at all, the grain can end up being very pronounced. This is due in large part to the softer sap wood eroding faster than the rest. The sheer task of removing several millimetres of hard timber to get down to the bottom of the grain is daunting, particularly on large flat surfaces. I have shared my views on electric sanders but this is probably an area where they become worth dragging around in a tool kit for years without being used. A random orbital sander is the best choice for cutting action combined with minimising marking to the surface, but the best sander for retaining the fairness of the surface is a flatbed orbital sander (See Chap 1 Power tools.) When sound colour has returned to the surface, bear in mind that the task of removing the sanding whirls left by the sander is almost as tough a job, and can only be done by hand-sanding with the grain on a hard block.If the restoration of uniform colour is still too far away, your energy is exhausted, and grey areas are still evident in the bottom of the grain, some relief from an ugly patchy finish, which will be the result if it is coated in this condition, can be gained from bleaching the whole area. A useful product for this is a two process product called Teak Wonder. The advantage here is that it is not extremely aggressive on surrounding finishes (except anodised fittings which must be removed or protected.) Also, be aware that any other bare wood in the area that is exposed to drops or splashes will be marked, so mask the perimeters of the area to be treated, preferably with masking film.
Before starting, sand the area to finish profile ie. one ideally doesnâ€™t want to sand again after the bleach and before the sealer coat. Dampen the area with water. Use rubber gloves and protect bare skin. Apply Part one, the cleaner, with a soft brush or white doodlebug (light abrasive fibrous scourer) brushing gently both with and across the grain. Concentrate more on across the grain as this will be less likely to erode sapwood even further. Allow to soak. Repeat several times without letting the frothy mixture dry. Rinse off thoroughly with water. Apply the Part 2, a brightener, before the timber dries, with a sponge or paint brush, leave a few minutes and rinse.
When the timber is well-dried you will notice that the grey grain is much improved in colour, but that the sanded high grain which was back to true colour, is now bleached. The over-all look however, is likely to be a lot more uniform than when you began. Wet out with metho to see how it will appear when coated. If thatâ€™s good enough, coat up from here with your first sealer coat. If you are not happy, another block sand with 240 grit will restore the true colour of the high grain, whilst leaving the bleached colour of the low grain, which over-all, when sealed, is probably the best look you can hope for if you wonâ€™t go the distance on doing the full job to achieve a uniformly flat/fair surface.