Even if there are recognised technologies for sanding and finishing surfaces or for applying wood preservatives, the diversity of species and even wood from the same species, working conditions, application methods or finishing materials sometimes leads to unforeseen situations. Long-standing experience helps production workers and wood enthusiasts to discover tricks to solve difficult situations or find shortcuts without jeopardising the quality of the end product. Many of them have become so widely used that they have become part of the technology, being used more than traditional methods. Here are some of the tricks used when sanding, preparing, staining and varnishing/painting wood surfaces.
1. Don't you have putty for the holes in the wooden surface? Use wood dust and wood dust!
Wood often has imperfections - small holes, scratches - that need to be repaired so that the surface is perfect after finishing. Usuallywood putty (also called knife putty) or special putties. A handy method, which also has the advantage of achieving a wood-like colour, is to cover defects with a mixture of sanding grit and wood dust. Use fine dust, not sawdust. The mixture should be made so that the glue becomes more consistent but does not lose its adhesive properties. Usually each craftsman has his own recipe because the result depends on the viscosity of the glue and the fineness of the wood dust. The mixture should end up with the consistency of marzipan. It is put in excess in the hole cleaned of dust and impurities, left to dry and then sanded to the surface. It has to be put on in excess because, by drying, the quantity decreases.
Another method is to mix nitrocellulose varnish with wood dust. In this case, finishing should only be done with nitro varnish because otherwise stains will appear in those areas.
2. Does the softwood have knots and you want to lock the resin inside? Use shellac!
It is a known fact that resin from softwood is very hard to lock in. That's why the resin bags come off and nodes are replaced with twigs that mimic the appearance of the knot. They imitate it, but they don't replicate it, which is frustrating for those who want the authentic knot. This is why many choose to leave the knot as it is at the risk of the resin coming out and staining the finish. There is, however, a solution to lock the resin in - shellac. By brushing 2-3 coats of shellac onto the knot, the resin is locked in and will not come out even if the temperature rises. You can find ready-made shellac in specialist shops, especially paint shops. Further information about shellac, as well as how to prepare it if you have found shellac in flake form, can be found at here.
3. Most defects are visible after staining. But you can also see them before
A big problem for coloured transparent finishes is defects such as scratches or fine dents that are not visible after sanding. You can make the surface visible if you go over it with a damp sponge. There are even bays that highlight defects - very light in colour and compatible with all subsequent finishes. By wetting with water or very light berries the surface of the wood changes colour and the defects become visible. The use of water also has the advantage that it will lift the grain of the wood if the sanding has not been done properly, allowing for better sanding.
After identifying the defects, the surface is sanded with a medium abrasive sponge or abrasive paper with a grain size of no more than 220 so that the very fine dust does not block the absorption of the stain or primer/lacquer into the wood. After sanding, the wood is allowed to dry completely before staining/lacquering begins.
4. Do you want to highlight the natural design of the wood? Use water-based wood stain in excess, followed by wiping!
Many people shy away from water-based wood stains for fear of peeling, longer drying time and increased moisture in the wood. You don't have to have such fears. If the gluing or veneering has been done correctly and with quality materials, you won't be put at risk from the amount of water in a berry. And if the wood has reached equilibrium, even if it absorbs water from the berry, it will release it immediately by drying. With water-based stains, the natural grain of the wood is more clearly highlighted and the colours are more vivid. And if applied with a spray gun, in excess, followed by wiping with a clean, soft cotton cloth, the stain will be even, without stains. Warning. If the surface is not well sanded and has small blemishes, the method will highlight them too.
5. Use aracite solution to reduce absorption in fibre end areas
In wood, absorption occurs mostly through the fibre ends, where the fibre has been cut. The transverse areas (where the cut is perpendicular to the fibre) and the milled or turned areas are where the fibre ends are very numerous. When beating, more colour is absorbed and the surface stains.
The oldest solution used to reduce absorption in these areas is water from aracet,i.e. a dilute solution of aracite. The solution is applied with a brush to those surfaces only. In the case of balusters or other patterned turned elements, the solution is applied to the entire surface. The aracite gets inside the fibre and hardens, thus blocking absorption. After application and complete drying, the surface is sanded, roughened, and can then be stained.
6. Do you want to smooth the wood after staining? Use the back of sandpaper!
The recommendation of finishing specialists is not to make sanding between layers than after applying a coat of primer/lacquer over the berry. Sanding the bath directly will cause the colour to take on a different colour and result in a blotchy appearance. If, however, for some reason you need to smooth a surface after staining, use the back of a used sandpaper. The sandpaper is not abrasive enough to take the color, but it does manage to smooth the surface, getting rid of the very rough look.
7. Don't want brush marks on the surface? Use a stiff sponge trafalet!
DIY enthusiasts often complain that after painting with a paintbrush, marks remain on the surface and brush bristles remain. The thicker the varnish, the more visible the appearance is. If, for example, water-based exterior varnish is applied, dilution is not recommended because the varnish has thixotropy (so that it can be applied vertically without run-off) and the extra water affects this property. In this case it is best to use trafficables. The best ones are the ones with a hard sponge because they apply varnish or paint more evenly and without spillage. If you are applying solvent-based varnishes, use a solvent-resistant sponge trafalet. Ordinary sponge, when in contact with solvents, swells and sags.
8. Do you have varnish spills on the edges or surface? It's fixed!
It is known that the varnished surface looks much better without the orange peel or plastic look, if instead of a thick coat 2-3 thin coats of varnish are applied, diluted accordingly. But what do you do with the spills? Thin varnish will be more fluid and flow more easily, forming unsightly run-off on the edges. On flat surfaces, the run-off will continue even after the application has stopped, until the varnish dries shallowly. Thick drops of hardened varnish are difficult to remove by sanding. To remove the thick layer the surrounding areas must be insisted on and thus affected. The best method is to use a țicling. What is that? A kind of chisel with a straight, sharp, narrow, fine blade. It is used to remove the excess, carefully and after the varnish has dried completely, after which the surface is lightly sanded with a fine abrasive sponge or sandpaper. If the spackle is removed at an intermediate stage of finishing, use 280 or 320 grain size. If it is the final coat of varnish or paint, first use a grain size of min.400, then polish with felt or soft cotton cloth and abrasive paste 800-1000, for matt varnish or 3000, for gloss varnish.
9. Want to make distressed furniture but don't want to put a lot of effort into it? Use wax!
Distress/distressed is the most popular method of wood antiquing. Burning the edges, i.e. sanding them down to the wood or the bottom layer, gives the impression that the furniture has been used for a long time. To suggest more intensive use, sanding is also done on flat surfaces, the general appearance being that of furniture that has been variously painted over time and has deteriorated due to intensive use. The method involves artistic vision and quite a lot of work, as sanding is not very simple. To avoid the effort involved in sanding, wood wax can be used. It is applied in a thin layer on the lower layer, in areas where you want to remove the upper layer (edges, surfaces). As the wax is the top coat, the top coat of paint will not adhere. After drying, it is easily removed by simply wiping with a soft cotton cloth. The effect can be fixed at the end with wax or varnish. If varnish is used, areas where wax has been applied should be wiped with thinner/alcohol if the paint is water-based, or with a weak soda solution if it is solvent-based.
10. Have you refinished an old wooden object and want to check if the new coating adheres to the wood? Use the coin test!
Varnish and paint coats adhere to the wood because part of the first coat is absorbed by the wood and the subsequent coats cling to the first. When refinishing a piece of furniture, visible paint layers are removed by sanding or paint strippers. The absorbed layer in the wood is ignored, however, and this leads to a decrease in the adhesion of the new finish. To ensure that the varnish will penetrate the wood, you must sand it after the total removal of the paint layers. Use a coarse sandpaper (60, 80) first, then a finer 150 or 180. This removes the absorbed lacquer from the surface of the wood and opens the grain to absorb again. If you have already refinished furniture and want to check that the new coating has adhesion, use a coin (a 50 is perfect). Draw a stripe with the edge of the coin on a hidden area of the furniture. If a white trace remains behind, it's not good. It means the lake has come loose and air has gotten under it. If the varnish is just shearing, without whitening. The finish has adhesion. Why is adhesion important? Because any stronger mechanical shock or impact causes the varnish to come away from the wood, then crack and flake.
There are certainly plenty of other tricks you've used when finishing wood. I'd like to consider this article as a start and fill it in with other tricks from your own experience or from those you've learned the craft from. I invite you to leave them in the comments area and I promise to add them, mentioning the name of the person who came up with the suggestion. What do you say, shall we make it 100?
Thank you for the invaluable information, I'm just starting out and it really helps me build my confidence.
Nowadays, at Dedeman I only find lazures - the bath is only available as a thin 2 in 1 lazure.
How does it apply? Can I treat it as a thin coloured varnish?
Hello!
Glad to be of service.
The lazings are produced for outdoor use. Morally it should just be a sunlight-resistant dip, but the commercial ones are really a kind of thinner, coloured varnish. Unless the manufacturer has other instructions, apply 2-3 coats to sanded and stripped wood.
If you just want wood filler, you should look at specialty stores, those that sell wood products, or distributors of professional wood products importers (ICA-Lomilux, Sirca, Sayerlack, Milesi, Renner, Remmers, etc).
All the best!
Thank you!
Another question: what is the difference between alkyd and polyurethane varnishes? Are they compatible with oiled (linseed oil dried) supreme?
Hello!
Basically, alchemical varnishes are a chemical variant of oil-based varnishes, have white spirit or other petroleum derivatives (gas, petrol) as solvent and can be used outdoors (especially paints). Polyurethane varnishes are very resistant because they harden through a chemical reaction. They are used for situations where resistance to chemicals, solvents, abrasion, abrasion or mechanical shock is required. They are both solvent-based and water-based. Solvent-based ones are pure polyurethane and are used indoors. The water-based ones are acrylic-polyurethane and there are also outdoor versions. In the USA there are polyurethane oil variants, but we have not come across them.
Alkyd varnishes can be applied over oiled surfaces, ooliurethane varnishes only the US version.
All the best!
Hello, thank you for the valuable information. I would like to make kitchen furniture out of beech paneling that I will paint at the end with a water based paint. How should I proceed in order to give better moisture resistance ( especially for the body that will support the sink)? I checked at Dedeman and they can do pallet staining for Oskar - water based paint. What coats should be before the paint or after? Thanks,
Good evening!
The most important thing for moisture resistance is that the wood is covered all over, even in areas that are not visible (edge, back of countertop, etc). This avoids moisture absorption due to possible water leaks.
If using paint, apply 2-3 coats, drying and sanding in between to make the surface smooth and pleasant to the touch.
If you want the natural wood grain to be visible, use bait and clear varnish. The putty is for staining and you can apply it only on the parts that are visible. You can use water-based or solvent-based putty. Apply the varnish after it is completely dry. Do not sand before the first coat of varnish as this will alter the colour. Apply with a brush, sponge or trowel, with a brush to avoid staining. Beech has a tendency to stain with water-based bait. Do not let the bath bleed. Apply it drier (brush well wiped, sponge well squeezed, trafalet with stiff sponge).
After drying, apply 2-3 coats of varnish, just like paint. Use water-based varnish for interior use.
Good luck!
Hello,
I ordered stained and lacquered hardwood panels for kitchen cabinets. My problem is that after a while some started to warp, altering the flatness. I suspect moisture differences. What do you think I can do?
Good evening!
The deformation can also be due to the different finishes on the two sides of the panel (one side finished and one unfinished or on one side 3 coats of varnish and on the other only a very thin one), the way the elements forming the panel have been cut or the construction solutions of the furniture.
If elements with different moisture contents have been used, cracks may occur.
Unfortunately, there's not much you can do. If possible, you can add fasteners so that the panel is forced to stand upright.
It can also be a temporary deformation due to a very large decrease or increase in indoor humidity and the panel will recover when it returns to its original conditions. But this possibility is very small.
All the best!