Sanding sealer - Zinsser versus Minwax

[JohnT Fitzgerald]

Thoughts and opinions on Minwax Sanding Sealer versus Zinsser Sealcoat? I have never used sealer before. This will be for oak treads going down into my basement. They don't need to be fine-furniture quality, but i would like them to look decent and to be durable.

[Casey Gooding]

First question that comes to mind is- Why do you need sealer?? I find that many people apply it when it's not really necessary.
If you do need it, I would go with Zinsser. I only tried Minwax once and found that it took a long time to dry and wasn't very user friendly.

[Steve Schoene]

Zinnser SealCoat is simply dewaxed shellac. Zinnser's unfortunate marketing tries to equate it with other sanding sealers. It works fine as a sealer since virtually all finishes will adhere to it, and it is quick drying. Nothing special as been added to make it easier to sand. It won't hurt your overall finish durablity. It isn't needed here either.

Minwax makes two flavors of sanding sealer, an oil based and a waterborne. These are your typical sanding sealer, which generally means it constains a stearate which makes it easy to sand. This is purely a time saving expedient (and devise to get you to spend more money) since it also weakens the finishing system, making it less water resistant and less durable. Sanding sealer, except for some specific uses under specialized catalyzed finishes, are mostly just a time saver, and waste of money, except for commercial operations where time is money.

However, why should you need a separate sealer? On eak stair treads there is no good reason. You are likely to be topcoating with a polyurethane varnish designed specifically for floors. (Why specifically for floors--for one thing they will meet traction requirements that make them less slippery than products not designed for floors.) These products do not, in general, need any specific sealer and are best used as their own sealer. You can thin the first coat of an oil based varnish if you wish, this makes it a thinner coat so you can sand it after a short time.

[JohnT Fitzgerald]

First question that comes to mind is- Why do you need sealer??


why should you need a separate sealer?

Excellent questions. I honestly do not know - never used it, but there's a lot of info out there that a sealer does a good job at 'filling' all the grain and helps get a good smooth surface with a coat of poly. Come to think of it, I can see where much of the benefit is in time - less time to apply and dry and sand, to get a second coat on and done.

[Steve Schoene]

Those questions are meant to be rhetorical. The sealer does no better job a filling all the grain than the first coat of finish. It is a bit easier to sand because it contains the stearate, which is a chemical soap that makes the sealer coat weak and less water resistant than the finish itself. It's trading a little time for quality. The "info" out there is marketing BS by and large. Sometimes it comes from guys who have cheapened their wares by using the sealer and seek to justify themselves.

[Steven Hsieh]

FIRST COAT is always the seal coat!!!

[Casey Gooding]

Steven makes a good point. For your purposes, using a sealer would just mean spending more money on a product that you don't need. A good floor finish is all you need. Skip the sealer.

[Quinn McCarthy]

John,

I never tried the zinser but really like the MInwax.

Quinn

[Howard Acheson]

Minwax make three sanding sealers. One is intened to be used under lacquer, one is intended to be used under oil based finishes and the last is one that can be used under either oil based or waterborne finishes. The Minwax Seal Coat is nothing more than a 2# cut of dewaxed blond shellac which can be used under oil based or waterborne finishes.

Sanding sealers are not recommended under floor finishes. They are quite soft and will not stand up even when a harder finish is applied on top of them. There is no need for a sanding sealer on a floor or stairs. If using an oil based finish, just thin the first coat about 25% with mineral spirits. Apply, let dry and scuff sand with a 220 sanding screen on a pole sander. Then apply 2-3 more full strength coats. If using a waterborne finish, follow the directions on the label.

Use a finish intended for floors. They are formulated to be less slippery.

[JohnT Fitzgerald]

Thanks Howie - good advice! I like the idea of thinning the first coat instead of buying something different...

[Scott Holmes]

Howie said "The Minwax Seal Coat is nothing more than a 2# cut of dewaxed blond shellac which can be used under oil based or waterborne finishes."

I think he meant to say "Zinsser Seal coat is nothing...

[Howard Acheson]

>>>> I think he meant to say "Zinsser Seal coat is nothing...

Yup, got hung up typing MINWAX.......