A sanding sealer is not the same as a wood conditioner. Whereas a wood conditioner is a pre-stain treatment that reduces blotchiness when staining, a sanding sealer is applied only to bare wood that is not going to be stained.
Sanding sealer is similar to polyurethane and shellac, with one major difference: zinc stearate additive.
Wood conditioner is a very thin sealer. However you would need many layers of wood conditioner to actually seal the wood. If you're interested in sealing the wood before finishing or staining, you're better off using Zinsser's Shellac Sealcoat.
Applying sanding sealer is a vital step in finishing high-quality furniture and trim. Sanding sealer gives an added layer of protection to the wood and creates a nice smooth finish. It can be used on stained or unstained wood. Staining or leaving the wood natural is your first step in finishing.
A pre stain wood conditioner is like a primer for stain. In porous woods, the grain often absorbs stain unevenly. Applying a wood conditioner helps stabilize the grain, giving your project a beautiful finish.
Wood conditioner substitutes
You can also use: Vegetable oil (3/4 cup) + white vinegar (1/4 cup) Polyurethane (1 part) + Mineral spirit (2 parts) Shellac + Denatured alcohol (equal parts)
If your wood is soft and porous, it usually saves money to use conditioner because it can prevent you from using multiple coats of stains. Hardwood doesn't need a conditioner because it isn't porous and the stain isn't absorbed deeply into the wood.
Sanding sealer can be used over many surfaces:
Raw wood: Use as the first coat when clear coating raw wood. Painted Wood: Use as the first coat when clear coating painted surfaces. Stained wood: Use as the first coat when clear coating a stained surface.
Use the shop vacuum to remove the sanding sealer dust, followed by clean rags to clean up any remaining dirt. After cleaning off the dust, you can paint or clearcoat the surface.
Apply 1-2 coats. We recommend no more than 2 coats, then finish with 1-2 coats of topcoat. Hand Application: Apply a liberal amount of product using a synthetic bristle brush, foam brush, pad applicator, or roller.
Water-based wood conditioner will cause the wood fibers to swell slightly. After the wood conditioner dries, lightly sand the wood with #180-grit sandpaper to smooth out the raised grain.
Start with bare/stripped wood that's clean and dry. Sand with #220-grit sandpaper in direction of the wood grain and remove sanding dust. Pre-Stain Wood Conditioner can be applied over any wood, but especially necessary when working with soft or porous woods such as pine, fir, alder, aspen, birch and maple.
Let Pre-Stain Conditioner penetrate the wood for 10+ minutes. Wipe off excess with a clean, dry cloth. Apply stain over conditioner. Let Pre-Stain Conditioner dry at least 30 minutes, but no longer than 2 hours before applying stain, in ideal conditions: 70°F/20°C; 50% humidity.
Apply one single coat with a brush or cloth and wait for it to dry. Not very long, an hour or so in warm conditions. Apply a coat of wax, or you can give it a second application of sanding sealer and then wax it.
Michael Dresdner: "Sanding sealer is never mandatory. It is an option that saves time and material in some situations, and is unnecessary in others. Some woods, like cedar, spruce, and poplar, are so porous that they tend to suck up the first few coats of sprayed lacquer as if nothing were applied.
The thin viscosity makes it easy to spread and allows it to penetrate into porous woods. To start apply 1 thin coat and allow it to dry. Lightly scuff sand to remove any raised grain fibers, then apply an additional 1 to 2 coats to seal wood and provide an excellent surface that will be ready to topcoat.
Ingestion May cause nausea, headache, dizziness and intoxication. Skin contact This product is rapidly absorbed through the skin and may cause symptoms similar to those of ingestion. Repeated exposure may cause skin dryness or cracking. Eye contact Causes serious eye damage.
Regular readers will know that we do not recommend over-thinning the Cellulose Sanding Sealer; it's a common myth that it needs to be thinned 50/50 to work better, but as a general rule this is incorrect.
It's a good idea to do this fine sanding between coats anyway to remove dust nibs. But polyurethane doesn't bond so well over finishes marketed as sealers, especially over sanding sealer. This sealer is good for use under non-polyurethane varnishes because regular alkyd varnishes gum up sandpaper.
Primer is used to create a base for the paint, improve adhesion, and prevent stains and bleeding. Sealer, on the other hand, is used to seal the surface and prevent the topcoat from being absorbed or bleeding through. Undercoat is used to cover imperfections and create a smooth surface for the topcoat to adhere to.
I know conditioning is an extra step that may just seem like a hassle, but depending on the longevity of the project, it's absolutely worth it. Since wood pores are irregular, a conditioner can be used to reduce the likelihood of blotchiness from the staining process. This is especially true of soft or porous woods.
Always work in the same direction as the grain for the best results. Afterward, let the stain stay on the surface and penetrate the wood for between five and 15 minutes and wipe off any remaining product.
No mineral spirits are not a good conditioner for wood. Solvents in general will dry wood out and break down any oils that are in the wood. This leads to decay of the wood.