Replies

1. 
   PlaneWood | Dec 23, 2002 08:44am | #1

   Don't know why it turned green, but some poly's don't like shellac.  Lacquer may not like it either if it's the waxed variety. 

   If the waxed variety, then mix in about 1/3 - 1/2 denatured alcohol then let it set till the solids settle out.  Decant the top liquid and use it.

   PlaneWood by Mike_in_Katy
   PlaneWood

2. 
   forestgirl | Dec 23, 2002 09:40am | #2

   Have you posted your question at Jeff's web site forum??  He will write back with info.

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)

3. 
   ChasStanford | Dec 23, 2002 03:03pm | #3

   I cannot for the life of me understand why anybody would want to apply one film-forming finish over another kind of film forming finish.  If you want to use shellac, then use shellac.  Wax it when you're done.  If you want to use poly then use poly.  Wax it when you're done.  If you want to use lacquer then use lacquer.  Wax optional.

   All this lacquer over shellac, poly over shellac, and all the implicit vice-versas are ridiculous, regardless of who the so-called 'expert' is who is hawking them.

   
   

   ---

   Edited 12/23/2002 7:08:14 AM ET by CHASSTANFORD

1. 
   garylundin | Dec 23, 2002 08:44pm | #4

   here's one answer to why one film over another.  I am finishing a cherry dresser.  I don't stain cherry.  I start by one coat of boiled linseed oil. Next I apply two coats of garnett shellac. Everyone just loves the resulting color.  Followed by two coats of blonde shellac for all but the top where my wife has a bad habit of placing hot coffee cups.  So instead of the blonde shellac on top, used for additional protection, I apply a couple of coats of varnish.  Same look but added protection.  Make sense?

1. 
   exhibitor | Dec 23, 2002 09:29pm | #5

   Keyword--varnish--not poly over ANY type of shellac.

2. 
   LarryPile | Dec 24, 2002 12:00am | #6

   There are considerable reasons for using polyurethane or other varnishes on top of shellac.

   I also build mission funiture and, as the first step, dye with water-based Trantint.  When I've experimented with putting varnish on top of water-based dyes or gel stains (when used as a pore-filling coat), the slow drying varnish has caused blotching of the dye/stain.  With Shellac, the first coat is dry before I lay the brush down...insuring no blotchiness.

   Here's my finishing schedule for the A&C dresser pictured in the gallery today:

   Vintage Maple Transtint (watee-based dye)

   2 coats of garnet shellac

   Behlens dark mahogany gel stain (wipe on, wipe off...just for dark pores in White Oak).

   2 coats of super blonde shellac

   2 coats of Old Masters Polyurethane varnish

   It's awesome!

   lp

1. 
   LarryPile | Dec 24, 2002 12:01am | #7

   Oh!  I almost forgot.

   The reason that I don't stop with shellac is durability...too thin, brittle and vulnerable to alcohol, other chemicals.  Poly isn't!

   lp

3. 
   IanDG | Dec 24, 2002 12:05am | #8

   "I cannot for the life of me understand why anybody would want to apply one film-forming finish over another kind of film forming finish."Polyurethane varnish over shellac is one of the 'tried and true' finishes for hardwood floors and considering the wear that it stands up to on a floor there can't be any doubt of its durability when used on furniture.There are several other combinations of dissimilar 'film-forming finishes' that are regularly used on hardwood floors.IDG

1. 
   Elcoholic | Dec 24, 2002 03:36am | #9

   "I cannot for the life of me understand why anybody would want to apply one film-forming finish over another kind of film forming finish."

   Here's one more reason and yet another approach to A&C furniture BTW.  I use a wash coat of decanted orange/yellow shellac to warm-up the greenish tone ammonia fuming sometimes creates and as a barrier for the coat of thinned, boiled linseed oil I put on to pop the figure in QSW Oak.  Then I top coat for durability.John O'Connell - JKO Handcrafted Woodworking

   Life is tough.  It's tougher if you're stupid - John Wayne

2. 
   MajorWool | Dec 25, 2002 02:04am | #17

   I did my CVG fir floors with 2 coats of bullseye sanding sealer followed by 3 coats of minwax oil based satin poly. Now to see how it stands up to my "anyday now" newborn son. If it does happen tomorrow, we may have to rethink naming him Nicholas. ;-)

1. 
   IanDG | Dec 25, 2002 09:20am | #18

   ----- or Rudolph!Sounds like a good specification -- the oil-based poly tends to yellow but you'll get away with that on fir.IanDG

4. 
   SgianDubh | Dec 24, 2002 05:26am | #10

   A de-waxed shellac can be very handy over a problematic base, Charles, as I'm sure you know. It is a very handy medium between oily timbers and subsequent coats of other film finishes. It's the most forgiving of film finishes being able to tolerate all sorts of problems that varnish--alkyd or polyurethane, or water based-- can't cope with.

   It's a similar story with the nitro-cellulose family of polishes, although vinyl sealers are intended to offer similar benefits-- but they can be a bit milky looking. Shellac, in one form is sold as 'knotting' and its purpose is to create a barrier between the timber and the paint and it's supposed to seal in the resin of softwoods prior to painting. It's standard procedure, as far as I know, to apply 'knotting' on resinous and knotty pine (and other resinous timbers) prior to painting..

   Whilst it is true that other techniques might be employed, such as thinning and so on for a first coat of polish or varnish to cope with 'difficult' situations, dewaxed shellac is always a safe bet as the initial first coat (or two) before any other film forming finish. Slainte.

   Some stuff I've made.

   Edited 12/23/2002 9:32:52 PM ET by Sgian Dubh

1. 
   ChasStanford | Dec 24, 2002 04:45pm | #14

   I absolutely agree with the characteristics of shellac as you've described them, however I'd simply stop with the shellac other than perhaps waxing the project.

   According to the original post, polyurethane varnishes present problems when going over shellac.

   I agree with shellac on knotty lumber when painting - I use Kilz which is a shellac-based product I think.

   Edited 12/24/2002 8:47:28 AM ET by CHASSTANFORD

2. 
   Alan | Dec 24, 2002 06:31pm | #15

   Yet another reason or two for using shellac under another film finish:  with shellac you can layer different colors of stain without them mixing and turning to mud.  It can also happen that the solvent in the final finish will attack the stain, thinning it in places, darkening it in others, and even turn it muddy (DAMHIKT).

   Alan

4. 
   noone51 | Dec 24, 2002 05:47am | #11

   Doug, way too much work for what you are trying to accomplish.  All that shellac and filler is way too much for a simple, (and I do mean simple) finish. Before you sand it all off, test a piece with a simple boiled linseed oil finish topcoated with a wipe on poly.

   The only draw back is that the BLO needs to dry until you cannot smell it anymore. That's usually about two to three weeks but after that you can finish it off with whatever you want and get the same results as those that it appears you are trying to achieve.

   If the end result of the test is what you want, (and I'll bet it will be), then sand it off and go for it.

1. 
   Paul_Snyder | Dec 24, 2002 07:39am | #12

   Hey no one - if you're going to use an oil-base finish like wipe-on poly, varnish, tung oil, Danish oil, etc., etc., etc. - skip the boiled linseed oil (BLO). All the oil-base finishes were made with an oil ingredient and the extra coat of oil does nothing except slow the work down a week or three. There's some discussion of this in this article - http://www.woodfinishingsupplies.com/varnish.htm Also, Bob Flexner touches on it in his book, "Understanding Wood Finishing" in the chart on problems with varnish (maybe other places also - I haven't looked). Of course it won't even slightly resemble the mission finish in the original question, but this makes the finish even simpler!

   Paul

   F'burg, VA

1. 
   noone51 | Dec 24, 2002 07:46am | #13

   Good point. I do use BLO a lot as a way to bring the color out in lighter woods and darken some of the darker woods like walnut etc. I wait the obligatory 3 weeks then I use a water based wipe on poly (minwax) and end up with a great finish and a dishwasher safe rag when I'm done. (humor intended). Your point is well taken but I really havent had the same results with the poly alone.

5. 
   douglesso | Dec 24, 2002 09:07pm | #16

   Here's a look at what I mean by green.