Replies

1. 
   BG | Apr 26, 2003 02:32am | #1

   LParks,

   In general, I would say you should stain first and then shellac and yes, you can use poly over the shellac. However, you could use a sealer first to avoid blotching, but that is usually not an issue with oak, and then stain and shellac afterwards.

   Are you building with white oak or red?  You could stain by fuming depending on how dark you want to go.  Lastly, you mentioned filling the pores with Shellac...there are better ways to do that.

   I just screwed up big time with some birch.

   
   

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   Edited 4/25/2003 7:35:12 PM ET by BG

2. 
   SgianDubh | Apr 26, 2003 03:12am | #2

   Some woods tend to blotch rather when stained or dyed, but oak is not one that I've had problems with in that regard, with the exception of ragged grain where the surface has been poorly prepared-- and I've never been guilty of that foopah, ha, ha. This general maxim applies, in my experience, to both the red oaks and the white oaks, although I've not used much red oak as I'm not a fan of the stuff.

   There are several options for polishing oaks though. Here's just one generalised strategy.

   Get a background colour with a clear drying dye-- it can be water based or spirit based, and dyes by definition dry clear. Open grained woods like oak are then often further coloured with a pigment stain. Pigment stains are generally a mix of dyes with solid pigment, and applied to oak the pigment lodges in and highlights (emphasises) the open grain, which is a popular look. Sometimes this all that the client wants.

   This can be followed up with any number of film finishes, and a good strategy is to use a super blonde dewaxed shellac. Dewaxed is important because regular shellac generally contains wax that can adversely affect the adhesion of the following polishes. Zinnser make stuff called Sealcoat which is designed for just this sort of purpose-- and others. Now you can apply any other film finish you want, such as polyurethane in your case.

   This routine doesn't fill the grain much though, although if you put enough coats of shellac or varnish on, it will eventually get filled. The only problem with filling the grain with varnish particularly is that it tends to shrink later as it completely cures. A lot of people fill the grain after an initial barrier coat has been applied to the dying/staining routine, such as the shellac I mentioned in the previous paragraph. If you plan that your final polish  will be polyurethane, there's no reason why your initial barrier coat can't be the same stuff. Just thin it out about 50% or 60% with mineral spirits (or perhaps with faster drying naphtha)  and brush on a light coat. An option for filling the grain might be a proprietary product that comes ready mixed in a can. You rub it in, burnish it off, do a little light sanding, and complete your varnish coats.

   I've missed a bunch of stuff out for brevity (well, okay, not very brief, ha, ha) such as not mentioning glazing coats, and other stuff, but I didn't intend to be comprehensive anyway. A good place for further reading is Jeff Jewitt's website-- it's URL is something like homesteadfinishing.com and he has a bunch of essays on finishing oaks and other open grained woods. Also, there are lots of finishing products described, as well as being for sale. A trip there should put you in the right general direction. Slainte.

   Website                                   The poster formerly known as Sgian Dubh.

3. 
   Paul_Snyder | Apr 26, 2003 06:18pm | #3

   Lance - using shellac to fill the pores is an option, but a better alternative is to use a paste wood pore filler.

   There's a couple ways to fill the pores with shellac. The first is to apply multiple coats and then sand it back until the pores are level with the surrounding wood. The second is to use a padding technique to apply the shellac.

   Applying multiple coats of finish, then sanding the finish back will do the job; but it's time consuming, wasteful, and not very compatible with staining the wood. The time factor comes from applying multiple coats of finish, allowing the each coat to dry before applying another and then sanding the dried finish back. It's also wasteful because you sand off most of the finish, leaving it only in the pores.  If you stain the wood first, you run the risk of sanding through the finish and cutting into the stain creating a difficult colroing repair.  If you fill the pores with finish before staining, you will have problems getting even coloring without re-opening the pores (you have to sand the finish back to bare wood in order to apply the stain and slight oversanding will re-open the pores).

   Applying the shellac over stained wood using the padding technique is an alternative.  The padding technique will keep the shellac very thin in the field of the wood and slowly build the finish in the pores.  This etchnique takes some practice and is slower than using a paste wood pore filler, but if you're interested you can learn the technique from this article - http://antiquerestorers.com/Articles/jeff/padding_shellac.htm  Replace the "oiling" step with staining - apply the stain before padding on the shellac.

   A simpler alternative is to use a paste wood pore filler.  First you stain the wood, allow it to dry, then seal in the color.  After the sealer is dry, you smooth the seal coat and apply two coats of pore filler over the stained and sealed oak.  There's a detailed article on the process at this link - http://www.woodcentral.com/bparticles/fillers.shtml  Using pore filler gives you a number of options - you can use stain or dye on the wood and then fill the pores with any color you like.  You can create a stark contrast bewteen the pores and surrounding field, or you can match the color to reduce the appearance of the pores.

   
   Paul
   F'Burg, VA

4. 
   Alan | Apr 27, 2003 02:07am | #4

   Lance,

   As to your question, to shellac or stain first:  you can do either.  Shellac is often used as a barrier between stains.  On oak, for example, you can put on a stain such as Spanish oak, then shellac, and then apply a golden oak stain.  Shellac can be used beneath any finish I'm aware of, so you can use whatever finish you want.

   Putting on stains with a shellac barrier coat between them lets each color stand out:  the golden oak will add highlights and will temper the color of the darker stain beneath.  If you applied both stains without a barrier coat between them they would mix and produce a horrible muddy brown.

   Using shellac as a barrier you can put on as many different stains as you want; I've used as many as four layers of stain (I didn't plan it that way; the first stain wasn't dark enough, so I added three more layers of a darker stain).

   As always, the best advice is to experiment.  On some scraps try out the different methods to see what look you like the best.  (Write what you've done on the back of each sample with an indelible pen.  I know to do that because I've never mixed up samples.)

   Alan