Before spraying nitrocellulose lacquer directly on to open-grained, spongy timbers you should use sanding sealer. Zinc stearate is added to lacquer, creating a sanding sealer that quickly builds up a layer sealing timber quickly. It can be painted or preferably thinned down and sprayed.
This single pack nitrocellulose sanding sealer has excellent sanding attributes and high grain filling power and is very fast drying (touch dry in 4 minutes, sandable in 60 minutes). It dries clear and has a coverage of approximate 8-12m2/L. When spraying it should be thinned down by approximately 15% Lacquer Thinners and is suitable for application by conventional, gravity feed or airless spray, applying one or two double header coats as required.
When spraying over open grain timber, apply initial coat at the lowest pressure possible to ensure that the sealer flows into the grain and does not just bridge across the grain.
Once sanded back (use 240 - 320grit abrasive) and finished with clear coat over the top it is completely non-reactive with natural oils and waxes as well as nitrocellulose lacquers. It is also non-reactive with most standard varnishes but test prior to applying to large areas.
This product is classified as a dangerous good by shipping companies so it is not available to order online and can only be purchased in-store.