Shellac or Poly??

Re: Shellac or Poly??

David Yoho

No advantage I'm aware of. Go straight to the poly.

Re: Shellac or Poly??

Bill Tindall, E.Tn.

shellac seals the wood so the water does not raise the grain. That said I have had the water in shellac raise the grain.

Re: Shellac or Poly??

walta

Most shellac has a strong orange tone and water base poly is very clear.

When go with water ploy I wet the wood with RO water and resand with 220 twice.

Walta

Waterborn poly is all you need

Re: Shellac or Poly??

Derek Cohen (in Perth, Australia)

It depends on the wood. Shellac can add a range of colours, from clear to deep amber, and this will generally be used to tint a light wood, such as Hard Maple. Dark woods will not benefit in the same way.

Regards from Perth

Derek

Re: Shellac or Poly??

Sgian Dubh

Apart from what others have already said shellac can act as a sealant creating a barrier between a surface with problems and the chosen or preferred top coat. Problem surfaces may be those, for example, with suspected or known contaminants such as silicone, grease, oil, dirt, etc. Shellac is more tolerant of less than ideal surfaces than many other finishes so can create a good surface for the subsequent finish.

One caveat is that water borne finishes don't adhere well to surfaces with wax present, and wax is present in many shellac formulations. So, in general, if the plan is to use shellac as a sealer for any other subsequent finish type to then go over, then use dewaxed shellac.

There's no reason to use shellac as a barrier coat if there are no suspicions of contaminants in the prepared wood surface: that doesn't mean that you can't use it if you want to, but you'd need an alternative and good reason to do so. Slainte.

Re: Shellac or Poly??

Pete in Holland MI

If you're going to seal it with a fast drying sealer, use Zinnser's dewaxed sanding sealer. I use it all the time. Dries quick and you can knock off all the pricklies before the next top coats within an hour or so. It is clear, so it won't amber your wood. As others have said, straight shellac has wax in it, and can cause bonding issues with the next coats.

I've never liked water based poly. Like latex paint, it dries quick, and doesn't have time to flow out. Not a good choice for a piece of furniture, in my eyes.

Re: Shellac or Poly??

David Weaver

if the wood is clean (not familiar with WB poly vs. the old oil finish that's called polyurethane - as bill has said - that finish itself is not similar to the high build two part industrial finishes), I've had no problem with poly itself on bare wood, but it can look really bland and unspecial.

Richard makes a good point, though - I always seal with dewaxed shellac (sometimes finish with it). It's predictable -never had an issue with any other finish and if you need to correct something, you have unlimited time to come back and do it before putting on the top coat.

Above and beyond all of it, though, it may not be correct to say that the wood itself looks cold with a WB finish, because it's the wood. But the look of a lot of different woods toned by shellac is nicer and looks less raw.

Re: Shellac or Poly??

Mark Mandell - Gone Round In New Jersey

Both.

Waterborne finishes will cause the wood fibers to pucker. Sealing with DEwaxed shellac (Super Blond or "Platinum") will prevent the grain/fibers from moving, but it will also provide a reflective surface (shinny) under the topcoat giving you greater visual depth and luster to the finish film.

Some have problems with shellac puckering the surface fibers as well because of some water content in the shellac mix. I had this problem until I discovered a method for removing water from the alcohol before mixing the shellac. The method used dry tapioca (from the grocery store). Measure the alcohol you'll use in a jar, pour in the tapioca, shake (lid on of course) and allow to sit overnight. The tapioca will absorb the water but not the alcohol. Strain the tapioca from the liquid and spread grain out to dry for re-use. The resulting "dry" alcohol will be about as close to anhydrous as you'll find without spending serious coin. Use the treated liquid to mix your shellac flakes, and your surface puckering problem will be solved.

A tip on mixing shellac: Measure out the dry flakes by weight. Then, in smaller batches use a kitchen chopper-in-a-hopper to break the flakes down into granuls. Add to your dry alcohol, cap and seal, and shake. The mix may be ready in a few hours.

I go 1 step further and run the fresh mix through a couple of coffee filters. The shellac comes out crystal clear.