Replies

1. 
   SteveSchoene | Jun 24, 2006 02:17pm | #1

   Your proposed finish won't work.  First, I suspect you wrote "methylated spirits" when you meant mineral spirits.  Methylated spirits in American English is denatured alcohol (ethyl alcohol plus methyl alcohol) will not mix 50-50 with poly. 

   Then, if you propose a polyurethane varnish as a top coat you need to be more specific about the shellac undercoat.  Polyurethane varnish (whether oil based or waterborne) won't adhere well to shellac containing wax.  You must use dewaxed shellac, whether mixed from dry flakes with methylated spirits or purchased as a ready-mixed liquid.  In the US, Zinsser's Seal Coat is dewaxed, but the more widely available Amber or Clear are not.  Alkyd or phenolic oil based varnishes will adhere to shellac with wax.  (By the way, the wax is a natural part of the raw shellac, not added by a manufacturer.)

   Finally, while poly will adhere to dewaxed shellac, unless there is a particular reason--color, or to seal in a problem, the only advantage to shellac under the poly is speed, since the shellac will dry more quickly.  And, you can accomplish the sealing with one or two coats.  But using varnish directly on the wood will be more durable over the long haul.  Varnish needs no "primer".  So you could apply about 6-8 coats of varnish thinned with naptha or mineral spirits, over the course of three or four days and build up a very durable long lived finish. 

1. 
   Gretchen | Jun 24, 2006 02:20pm | #2

   Steve has covered it well but for a child's table I would up the coats to 8-10.Gretchen

1. 
   SteveSchoene | Jun 24, 2006 02:48pm | #3

   I wouldn't argue with 8-10 at all. 

2. 
   WillGeorge | Jun 25, 2006 11:58pm | #14

   but for a child's table I'd get that diamond plate aluminum they use on trucks.. Well, at least if your grandbabies like mine.. I used aluminum but mine are Girls.. Boys. Armor plate?

2. 
   psmfisch | Jun 25, 2006 01:05am | #4

   thanks for the tips will use shellac flakes for colour and varnish

1. 
   Little_Joe | Jun 25, 2006 07:27am | #5

   Be sure your shellac flakes are DEWAXED flakes... or the poly will not stick to it.

1. 
   psmfisch | Jun 25, 2006 12:32pm | #6

   Reply from Aussie woodworker.

   Thankgoodness for this forum!!!

   After reading the product info. there is absolutely no way I can determine the waxing status of my flakes. Why is there such minimal info with these products, the same goes for sandpaper. I watch a DVD I have ordered from the states detailing how to identify sanpaper characteristics. In Australia the back of the paper detail includes the grit, and that is it. You guys are so lucky that you have a critical mass of people to have such details available.

   Imagine reclaiming the second hand hard wood, cutting it, handplaning it, dovetailing, etc, etc only to go wrong with a finishing frustration!

   I am only going to varnish the beast with a 50/50 varnish mineral turps. combo.

1. 
   Gretchen | Jun 25, 2006 02:16pm | #8

   I haven't re-read the thread BUT if you use NON-poly varnish you do not have the problem of having to use dewaxed shellac.  It is only POLY that has adherence problems (even to itself between coats!!).  So get some non-poly varnish to go over whatever shellac you put on it.Gretchen

2. 
   JMadson | Jun 25, 2006 04:47pm | #9

   If you start with a 3 pound cut of shellac and let it sit for a day, the wax will be obvious if it's not dewaxed already.“The significant problems we face cannot be solved at the same level of thinking we were at when we created them.” – Albert Einstein

3. 
   EdHarrison | Jun 25, 2006 05:14pm | #10

   >Imagine reclaiming the second hand hard wood, cutting it, handplaning it, dovetailing, etc, etc only to go wrong with a finishing frustration!<

   Hah!  Don't have to imagine that, I've done it!

   But for a quick, bullet-proof finish - this works if you can get it.  Three coats of Zinsser Seal Coat (dewaxed, fairly blonde or clear shellac), sanding with 220 or higher, between, then three coats of Minwax wipe-on poly.  To me - I'm not nearly as good a finisher as the others here - this finish is quick and bullet-proof.  You have to wait about an hour (maximum) between coats of shellac and six hours between coats of poly, so you're done with a hard, smooth, error-free finish fairly quickly.

   I recently made myself a drawing board out of birch ply edged in maple and re-did the head of my large T-square in figured walnut and finished as the above - works fine.  The shellac and the poly are both very hard, although applied very thinly.  Good luck.

    

4. 
   forestgirl | Jun 25, 2006 06:15pm | #11

   "After reading the product info. there is absolutely no way I can determine the waxing status of my flakes. "  Chances are, if it doesn't say "dewaxed" it is not.  Click here for a picture and description of the Zinnser SealCoat.  Can you find it at any Australian woodworking stores??forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) 

5. 
   Little_Joe | Jun 25, 2006 08:00pm | #12

   I share your frustration... been there... still learning... :)http://woodworkstuff.net/shellac2.html"Natural shellac contains about 5 percent wax and will produce excellent results; but dewaxed shellac, whether pre-dissolved or in flake form, is more water-resistant. You can remove wax from regular shellac by letting it settle and then decanting the liquid."After you dissolve the flakes and have let it sit for a few days (3-4), if there is wax present, you will see a definite division in the solution. If there is wax, it will sink to the bottom. They say "decant"... I'm really not sure how that's done... I have not had to do this... My guess is very slowly dipping small a spoon or ladle into the solution and putting it into another jar... I would think using straws to suck it up (only to a point) and moving it to other jar may work... One could try to VERY SLOWLY pour the top part off to another jar... If you disrupt the solution, you may have to let it sit some more.That's the way you remove the wax from your shellac, if there is any there.Poly. should be applied to a dewaxed shellac finish if you're going to use shellac.Also, sanding shellac between coats should be done VERY LIGHTLY... Each new coat of shellac actually dissolves part of the previous coat and becomes part of it while adding the new coat... You can add as many coats as you desire before quitting... You will be able to see when you are happy with it... trust your senses.Depending on the temperature & humidity, shellac dries very FAST or very SLOW... The hotter/drier, the FASTEST... Feel for any tackiness... if tacky, not dry... Better to wait too long to dry than not enough.EDIT: If it seems to NEVER dry, stays tacky forever, the shellac is too old and should be discarded... Typically after 6 months, it could go bad.More on shellac & finishing...
   http://woodworkstuff.net/woodidxfin.htmlI sure hope this helps you... Whatever you do, it's a good idea to TEST the finish on a piece of scrap.EDIT: BTW, I prefer to work with no more than a 2lb cut (2# cut)... Higher than that, to me, really gets messy fast!
   JoeEdited 6/25/2006 1:14 pm ET by Little Joe

   Edited 6/25/2006 1:19 pm ET by Little Joe

2. 
   Gretchen | Jun 25, 2006 02:14pm | #7

   I think you have to dewax most shellac made from flakes.Gretchen

1. 
   Little_Joe | Jun 25, 2006 08:11pm | #13

   As a general rule (of probabilities), the Blonde flakes are dewaxed...

   ...while the other Garnets and darker flakes contain wax.

   Joe