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Floor Finishing Issues: Nibs, Abnormal Grainraising |
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If you and properly and use grit 120 or finer for the final sanding, there usually aren´t any problems. However, if a coarser abrasive than grit 120 is used, the finish tends to penetrate deeper into the pores of the wood and gives more grainraising.
This is one possible reason why abnormal grainraising occurs. Another is the amount of finish you use, if too much finish is applied on the sanded wood, more water comes into contact with the wood fibers and more grainraising occurs. Follow the recommendations given by the manufacturer.
If the first coat of finish hasn´t been given enough time to dry, this can also cause grainraising. Suppose abrading is performed as soon as possible after applying the finish and then another coat of finish is applied immediately after. As the underlying finish hasn´t had time to dry properly, the new coat can penetrate through to the wood and more grainraising occurs.
Naturally, some species of wood are more vulnerable to grainraising than others. Pine is especially problematic.
Practical tip: remember that proper sanding is very important when abrading between coats. Do not use a screen to abrade a waterborne finish as it creates too much friction and can cause swirl marks. The Scrad system is recommended for abrading BonaKemi´s waterborne finishes. |