not getting exp. iridescence + depth with shellac French polish?
I am preparing to coat about 20 pine shelves with Zensser Bull's eye amber Shellac.
Prior to starting the "big job", I sanded a plank of pine (220 grit), swiped both sides clean with a rag dipped in paint thinner, waited a few minutes, sealed the two sides with thinned down shellac (shellac + ethanol), then:
- On side #1 I applied two generous coats of shellac (within 5 minutes of each other) using a lint-free cotton rag
- On side #2 I applied about 8 thin coats of shellac over two days using a French Polish technique as described in http://www.milburnguitars.com/fpbannerframes.html and http://www.woodfinishsupply.com/GuideToFrenchPolishing.pdf
In the end both sides achieved the same tinting (nuance). Although side #2 (french polish) achieved a more uniform tint than piece #1 (two thick coats), piece #2 FAILED to achieve piece #1's depth and iridescence (mother-of-pearl-like effect) when examined in the light from different angles.
Essentially, side #2 looks fine, but it appears merely "stained" to the desired amber tint, whereas side #1 has that additional "lacquered" depth (that one can also get by dipping a small, previously sealed piece of wood in shellac then letting it dry.)
Why does side #1's shellac (two thick coats) look "deeper" than side #2 (8 thin coats with French polish)? Have I wrongfully assumed that the shellac has the same thickness on both sides when the same tint was achieved? Have the multiple FP coats fail to properly amalgamate on side #2 (did I not apply enough pressure? would this be a factor?)