Sanding Sealer

Re: Sanding Sealer

Mark Kauder, Phenix City, AL

>Deft Sanding sealer is a Lacquer based sanding sealer. You can get it at Lowes or Home Depot, and probably Walmart.

Truth is, most sanding sealers just contain a talc that works as a lubricant for the sand paper. You can just use a thinned down lacquer and achieve the same thing.

Mark

Re: Sanding Sealer

Stuart Johnson

>Thanks Mark, this is just the information I wanted.

Stuart

Re: Sanding Sealer

EaglescU*S*A

>In a book on finishing by Bob Flexner he states that a sanding sealer is a thin coat of the finish you intend to use on the rest of the project.

I realize the book relates to mostly flat work,but is that definition valid for sealers that are appied on the lathe?

By this I mean that there is a difference in time lapse and heat due to friction.

Are sanding sealers used for for turning projects formulated differently?

Re: Sanding Sealer

Russ Fairfield

>We need a glossary of terms. There are a lot of words with different meanings floating around, and that makes a definition of a "sanding sealer" more difficult. These words have different meanings for different people. The following are mine. They may not always agree with the experts.

For finishing of wood, a "Sealer" is anything that is put IN the wood to prevent the penetration of a finish INTO the wood. We would call it a "primer" if we were using paint. In wallpaper, it is called "sizing".

The sealer can be either a thinned wash coat of the same finish, or it can be something else such as lacquer, shellac, or a CA glue that forms a barrier.

In the normal use of a sealer, we want the barrier to be BELOW the surface of the wood, and it is sanded back to the bare wood surface before application of the "finish". This can be difficult because not all things used as a sealer are easily sanded.

A "sanding sealer" is any sealer that has had something added to it to lubricate the sanding and prevent loading up the sandpaper. The old-time way was to add raw talc to a thinned quantity of the same finish that we going to apply.

The commercial products are either lacquer or shellac that have had a "stearate" added to them to lubricate the sanding.

A "stearate" is a white crystalline form of a fatty acid (stearic acid). That means it is made from tallow (animal fat). In its most basic definition, a stearate is a soap.

The fact that many woodturners use a "sanding sealer" as a finish only confuses the issue. The truth is that they are using either a lacquer or shellac that has been made sandable by the addition of a lubricant.

I don't use a sanding sealer because I see the stearates that are in it as being somewhat opaque. I am trying to accent the wood grain and give it more brilliance with the finish, not cover it up.

There is no difference between the sealers that are used for furniture and those used for woodturning. The difference is that we have more end grain to worry about, and the higher rate of penetration by a finish into end-grain make the use of sealers more attractive to us.

We can also restrict the penetration of a finish into the wood by sanding to a finer grit.

That should add sufficient confusion to the issue.

Re: Sanding Sealer

Stuart Johnson

>I don't know about adding confusion but you have added to my understanding.

Thanks, Stuart