Sanding Sealer and Water Dye – A PROBLEMubeaut
Our Sanding Sealer is shellac based and its purpose is to raise the grain after sanding. When dry the sealer makes the raised grain go brittle and makes it really easy to remove these annoying nibs that otherwise would make`a final finish feel like a hand full of sand has been thrown into the wet finish.
The dried Sealer isn’t actually sanded off, but instead it’s wiped over with a fine grit abrasive (800 grit or even better still 1200 grit) thus removing the nibs but not actually re-sanding the wood surface which could end up raising more torn grain.
The surface should feel almost sensual like silk and will then be ready to accept a finish.
Even better still: it is possible to ad our Water Dye to the wood, after the above has been done. The dye will go through the sealer and penetrate deep into the surface of the work just like it would do on raw wood.
WARNING: Be a bit wary of polyurethane over fine sanded wood as it actually needs a rough surface to adhere to, hence the need to sand between coats, unlike shellac that can have multiple coats applied without the need to sand unless you muck it up.
Back to Water Dye over Sanding Sealer and a little problem.
A long time friend and brilliant, musical instrument maker, contacted me the other day with a problem of really blotchy colours on a sound board.
He had sanded and then used Sanding Sealer and a wipe over with fine abrasive. He then applied the Water Dye and after it had dried, noticed he had some sanding marks still on the work. So he sanded them out and re applied Sanding Sealer, a wipe down with fine abrasive, reapplied the dye and all of a sudden there were blotches of deep colour and light colours on the work.
A call for help was received and some photo’s sent of the problem, which to me was immediately obvious.
My response was “Did you sand back the entire surface or just the areas where you saw the sanding marks?”
“Just the marks. Why?”
He had sanded off some of the sealer and then applied a new coat to all. That’s 1 coat to the newly sanded area but the rest got a second coat which stopped the dye from penetrating through the sealer and into the surface of the work.
SIMPLE (BUT ANNOYING) FIX:
Sand the entire surface back to raw wood and start again. This time making sure to eradicate all sanding marks.
I wait with baited breath to find out the result, and see the finished piece.
Cheers – Neil