When to apply sanding sealer?

[joefrog]

Hey all,

I'm just un-educated on some of the finishing techniques. I'd like to know, what's the can of "sanding sealer" for that they keep pushing, and why should I use it? Is it for mainly open-grained woods like oak? Can it be used underneath other finishes?

Inquiring minds, and all...

thanks!
Joefrog

 

[monophoto]

It can be used for a variety of situations:

1. Open grained wood.
2. Anytime where you want to apply a water-based finish, abut you want to apply an initial coat of something to counteract the tendency of water-based finishes to raise grain. Sanding sealer also can provide a controlled 'amber' tone that counteracts the natural 'bluishness' of some waterbased finishes.
3. Oily wood (cocobola, botote, etc), or wood where you want to apply an initial coat of BLO or tung oil and when you want to apply a finish such as WOP that won't cure when applied over oil.
4. And some sanding sealers can be a final finish. For example, one of the best sanding sealers is nothing more than shellac thinned in DNA.

 

[Russianwolf]

also, Some woods will blotch when you apply stain directly to them. Maple for example.

sanding sealer allows for more uniform absorption.

 

[Wildman]

Sanding sealer is almost never mandatory. Yes, will level and seal surface of wood, and help build a film finish. Some woods soak up finish faster than others so applying a sanding sealer save time and finishing material. Some people will apply sanding sealer to end grain on a table and not other parts of a project. Sanding sealer should not be used to fill pores of open grain wood.

Wood conditioner is intended to be use prior to applying a stain. They are designed to penetrate into the wood pores and allow the stain to be absorbed evenly and avoid light and/or dark blotchy areas in your final project.

Sanding sealer and wood conditioner often have similar qualities in that they both act as a "sealer" of sorts and of course, both act as an adhesion promoter. However, the primary difference in the use of these two products is that wood conditioner is applied pre-stain. Sanding sealer is applied post-stain.

Never use sanding sealer if going to use a penetrating oil finish.

You can make a wood sealer/sanding sealer using any oil or water based film finish Lacquer, Shellac, Poly, or Varnish using appropriate thinner for topcoat going to use. Thinned shellac (spit-wash coat) most compatible and used most often as a sealer

 

[Wood Butcher]

Check this out:
When to Use Sanding Sealer - Buzz Saw, The Rockler Woodworking and Hardware Blog
WB

 

[gbpens]

Sanding sealer is intended to seal pores of open grained wood before staining. Spring growth in a tree is fast, creating larger space between the wood fibers. As the growing season comes to an end the growth slows producing the darker/denser ring. Pine is an extreme example. If stained without a sealer the light/dark rings are reversed. Using a sealer coat should fill the open pores so that a stain is absorbed equally though the surface of the wood. Shellac is a good sanding sealer.

 

[patmurris]

Not sure if this applies to 'sanding finishes', but i got into the habit of applying several coats of thin CA on any wood before sanding up to 800 grit - even on very dense timbers. This allows for a very even and smooth surface to apply the finish on (CA finish most of the time), and it will also work with no finish at all.

 

[leehljp]

IF you are asking about "sealing" in context of "pens" - CA in general is a great sealer. Use thin on the first couple of coats and then medium or thick after. Shelac is a good sealer as a prefinish for other finishes.
Lacquer is a good sealer and dries fast but sometimes Shelac under it does well.

If using CA as a finish, do not use other oils on oily wood before the finish or the chances for the finish "lifting" or separating is increased considerably.

Sealing is also recommended for some woods to prevent color bleed when segmenting. Lacquer can cause bloodwood to bleed over onto other woods, and in the case of holly, is very noticeable. DAMHIKT! Some black woods will also bleed onto lighter woods if segmenting. CA coatings as in sealing, will prevent the bleed overs.

Another thing to consider - you don't see the normal wood finish terminology used as much here very much. The wood blanks on pens are wood, but are used TOTALLY different from furniture and most flatwood, and even large wood turnings. They (pens) are examined extremely close because the pens are smaller than most wood objects. Flaws in the finish are more quickly noticed on pens. Pens are held by oily grimy hands and often placed in humid shirt pockets that furniture or bowls are not. They need different finishes to protect it than most wood objects - but they don't have to have it. Many people still want to finish a pen like they would normal wood objects, and that is fine. Just remember, you don't put normal wood objects in a humid shirt pocket or a hot car and then take into an air conditioned room. Pens need something different OR they need to be taken care of much more often than a wood bowl or chair or other.