A solid base for a top finish
Many types of wood have open pores. It is a question of taste whether you want to keep it open naturally, or whether you want to fill it up. The choice of your type of finish is important here; a finish with oil or wax is very natural and you can leave the pores open, a finish with lacquer will benefit largely from a smooth base where the pores are filled. The lacquer will sink into any irregularities and it will be close to impossible to get that mirror like finish.
For filling pores these are probably the 2 most used: Grainfiller and Epoxy.
Grainfiller:
Grainfiller can be used under every finish and can be used both before and after staining. Generally, 1 treatment is sufficient.
With Grainfillers you can choose from oil-based and water-based fillers. The biggest difference is in the drying time and the processing time. Water-based fillers dry much faster. When applying these fillers, you do well to work in segments. Water-based fillers can be diluted with water, but are a bit thinner by themselves. The oil-based fillers have to be diluted with white spirit before use until it has a thickness as yoghurt.
The wood must be clean and free of grease, finely sanded (grit 400) and can be pre-treated with sanding sealer. Wipe the diluted grain filler firmly in the wood against the grain with a cloth. By looking over the surface with a slanting eye, you can see whether the pores are filled well. Then wipe away the excess, preferably with a rubber scraper or a credit card. The smoother you wipe it off, the less you will have to sand later. Allow oil-based fillers to cure for about 12 hours and water-based fillers for at least one hour. Sand to the right grain for the desired finish.
Tip: If you are still staining, test the effect first on a piece of scrap wood. You can also color the Rustins Naturel Grainfiller with pigment powder.
Z-poxy:
This is a type of epoxy or resin emulsion that dries hard and does not collapse over time. Z-poxy can only be used under lacquer finishes because oil is no longer absorbed. If you want to stain your wood, do so before treatment with Z-poxy. The advantage of this way of filling pores is that you immediately have a base coat for your lacquer and the wood will absorb less lacquer. The processing time is about 20 minutes and the drying time is about 24 hours.
The Z-poxy dries crystal clear, but can also be colored with pigments for a special effect and can be used to fill larger holes and cracks. For filling pores, 1 session is usually sufficient, but depending on the absorption of the wood, a second round may be required.
The wood must be clean and free of grease, finely sanded (grit 400) and may be pre-treated with sanding sealer. Make your Z-poxy mixture mix by thoroughly mixing 1 part Resin and 1 part Hardener. We usually use 2 spatulas to work it through. Do not make too much at once, because once mixed, you cannot keep it. Usually an amount in the size of a one euro from each component coin is sufficient for one side of your instrument. Apply some of the mixture and rub it diagonally into the grain with a spatula or plastic card. Spread away excess mixture in the grain direction. Allow to harden for about 24 hours and sand back. Repeat if necessary.