Sealing wood. Was: Restorations
Denny Anspach <danspach@...>
There are two types of wood or paper sealing, whether sealing for moisture protection, or in addition, also sealing to improve the surface for painting.
1) Simple application and re-application of any clear finish or paint to the extent that the grain is filled and the wood is protected from external moisture.
2) Sanding sealers: Essentially the same thing as above except that the sealing substance (almost always clear and relatively fast-drying) also contains a fine sedimentary filler substance, almost always talc, to the effect that the grain can now be usually filled in just one or two applications.
If any one exposed side of the wood or paper is left unsealed, then warping and bowing can actually be accelerated or promoted- thus the importance of disciplined sealing of all exposed surfaces, *inside* as well as out!
Any type of sanding sealer can be used, I believe. As mentioned I use a lacquer-based sanding sealer commonly available at R-C hobby stores.
Sanding: Too many modelers do not properly seal and sand their wood models- a happenstance which certainly has contributed significantly to this type of model's current reduced reputation.
1) Before any sealing application first sand the wood lightly and very carefully with a minimum 250 to 400 grit sand paper (finer sandpaper will only clog). Pay some attention to the scribed wood joints which are commonly filled with fine "whiskers" remaining from the milling process, but do not over do it!
3) Wipe the wood clean with a "tack rag", a commonly available sticky cloth that will pick up all the dust (you can also in a pinch just use a small rag with almost-rung-out mineral spirits- just be sure that any residue evaporates).
4) Apply the sealer generously with a brush enough times to visibly and tactiley fill the grain and the surface becomes smooth. Sand lightly with increasingly fine sandpaper between each coat, finishing each time meticulously with the application of the tack cloth.
5) After each application of sealer, sand again with finer and finer paper.
6) Fill divots with Squadron putty (the consistency is roughly the same as the wood so that it will sand like the wood around it, rather than end up standing proud).
The wood is now ready to be painted or assembled, or both.
I see so many (understatement) otherwise very neatly built wood models (i.e. Ambroid, Northeastern, Suncoast, Quality Craft, LaBelle) that are simply beyond any salvation because the original modeler did nothing whatsoever to properly prepare the wood to begin with. When these models are discovered to have been originally assembled with Ambroid or Duco types of cement, I can sometimes "re-kit" the car by soaking it in a bath of acetone, but- a LOT of work!.
I will not pretend or assert that models made of wood are more accurate, or even can be as accurate in important ways as is possible with fine molded plastic or resin, but they can more than make up for it in the pleasures that result from exercising the skills required to work with such a fine traditional and natural medium- and IMHO the fine models that can result seem to have an extraordinary natural beauty of their own.
Denny S. Anspach, MD