Sanding Sealer

[Al Chavez]

I'm beginning to focus on finishing what I've started.
It seems that sanding sealers are often applied to pieces at the beginning of the finishing process.

Any suggestions on a particular brand? I will be following up the sanding sealer with sanding (of course) then a shine juice application and more sanding (finer grit) and more juice etc..
Ultimately will apply a wax then buff out with a wheel. This schedule is not set in stone so anyone wanting to post their finishing process would be appreciated.

Back to the sanding sealer.
There are many brands and it seems that some are not shellac based. I'm leaning towards Zinnsler but I am wondering if this is just their regular shellac cut with alcohol? If anyone is cutting the regular shellac to make a sanding sealer what ratio of regular shellac to alcohol are you using? Should I just stick with the Zinnsler Sanding Sealer instead?

Is it not recommended to use the other sanding sealers (cellulose based or water based sanding sealers} under shellac/b.l.o./dna finishes? Again... I'm open to alternatives or what works for you.

Thanks in advance.
Al in Texas

 

[Doug Freeman]

Cellulose (lacquer) and shellac sanding sealers can be used. WB sealers/finishes can be used but have no chatoyance like the solvent products (refract light differently). I’m no expert on using shine juice but I have used it some. I dont see a need for a sealer but I may be missing something. Zinsser sanding sealer is a dewaxed 2# cut shellac. The can Bullseye is 3# cut wax shellac. Spray Bullseye is dewaxed. Either can be used under shine juice as a sealer.

I recommend sanding to a hi grit, 400-600, then applying sealer/juice in thin coats, no sanding in between. Shellac burns in (melts and adheres to previous coats) so no need to sand. If you get a streak or build up, a rag with dna will smooth it or you can sand. Practice a lot on scrap so you get a good feel for using it. I typically just apply shellac then buff with wax. Either method is not a durable finish for handling much.

 

[Dan Lambert]

Most shellac based sanding sealers are nothing more than the standard product cut with alcohol. I just use a 1 lb cut shellac for my sanding sealer and it works very well. Depending on the type of wood I'm working with, I may not even use a sanding sealer.

 

[Dean Center]

Al, my understanding is that the purpose of sanding sealer is to produce a super smooth finish by filling the pores in the wood. Some people consider their first coat of whatever they use for a finish is doing the same job. It all boils down to what you want in the end product. I'd suggest you take a couple of pieces from each of the most common woods you're going to use and do one with and one without sanding sealer to see how you like the results.

 

[Perry Hilbert]

I use Zinnser's Sanding Sealer, made with unwaxed shellac. Yes it is shellac cut with DNA. But it is also unwaxed. Some finishes will not adhere to waxed shellac. Which is why I purchased the Zinnsers. In addition, some sanding sealers on the market are water based and raise the grain a lot. Zinnser's made with DNA, does not raise the grain. I have been turning some red elm and it is a total SOB to sand. when I get to a certain grit, it seems to get whiskers raised and sticking out of the wood. If I use sanding sealer at that point, the next grit takes out those whiskers. But not is I don't use the sealer. I have never encountered that before with any other wood. It is like some fibers between grains stick up like wires.

 

[GRJensen]

I use Deft lacquer-based sanding sealer, cut 50/50 with lacquer thinner.

 

[John Walls]

I use Z. conditioner under alot of finishes if I can't immediately finish it. It's wax free thinned shellac. Sometimes I'll cut that 50/50 with DNA. but I don't know if that actually helps it penetrate deeper or a waste of DNA. After 10 minutes or so, I can apply straight shellac. I've started applying the cut conditioner when I get a lot of tear-out in punky wood. It helps some along with a freshy sharpened edge.

 

[Bill Boehme]

If I were painting a house for the first time then I would use sanding sealer. but for most everything else I think it is unnecessary.

 

[john lucas]

I dont use sanding sealer I just start my my finishing. Sanding sealer has Zinc Stearate in it to help with sanding in production environments. No harm in using sanding sealer I just never saw the need for it. If you want a glossy finish you simply have to apply enough finish to fill.thepores. A first coat.of sanding sealer helps but not sure it helps any more than a first coat of a y other finish.

 

[Roger Wiegand]

Here's a perspective from an expert on shellac as a sealer https://www.woodshopnews.com/columns-blogs/shellac-as-a-sealer-its-all-just-hype

I understand why a kitchen cabinet factory would use a thick, soft, stearated sanding sealer under their finishes, I don't know why I would do that in my shop. I want my finish to be as hard and durable as possible, so I'd just apply an extra coat or two of whatever my top finish is to take the place of the thick sanding sealer. I've tried sanding sealers but have not found a benefit that made me want to do it again.

I very often apply a first coat of shellac under water-borne finishes to improve the pop of the figure, but that usage is not as a sanding sealer. Shellac is, of course, invaluable as an intermediate coat between potentially incompatible finishes and to prevent bleed-through.

 

[Perry Hilbert]

Here's a perspective from an expert on shellac as a sealer https://www.woodshopnews.com/columns-blogs/shellac-as-a-sealer-its-all-just-hype

a thick, soft, stearated sanding sealer under their finishes, I don't know why I would do that in my shop.

I very often apply a first coat of shellac under water-borne finishes to improve the pop of the figure, but that usage is not as a sanding sealer. Shellac is, of course, invaluable as an intermediate coat between potentially incompatible finishes and to prevent bleed-through.

Zinnser's Sanding sealer is hardly thick. Are you speaking of grain filler? Grain filler is often quite thick.It is sometimes also called grain sealer. The sanding sealer I use is actually quite thin, even more so than normal shellac concentrations. I had to fill grain on a red oak T&G floor and used a grain filler that was nearly as thick as pudding. A pint can was more than enough for an entire room. and it contained no DNA. But that was not a sanding sealer. Similar product in ways, but totally different viscosity and composition.

 

[Roger Wiegand]

Here's a description quoted from Michael Dresdner that pretty well summarizes my understanding (to be honest, is probably the source of my understanding:

=============
Expert Answer from A. 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. Other woods, such as walnut and mahogany, require a good bit of sanding to level the pores even when pore filler is used. In both cases, the material of choice would be something that builds up quickly and is very easy to sand. Enter sanding sealer.

Sanding sealer is lacquer, or some other basic coating, with zinc stearate added. The stearate, which is a soft, fluffy soap, adds loft to the lacquer, making it build up and fill in pores much faster. It also makes the lacquer softer, and acts as a lubricant when sanding, so that sanding sealer powders off quickly and easily. These characteristics make it ideal for trimming both the number of coats and the amount of time spent sanding them. This is especially helpful when you are trying to build a perfectly flat, pore-free finish. It is useless, in fact, counterproductive, for the open pore "natural" look finishes more popular today.

A Word of Warning
A word of warning is in order. The stearates make sanding sealer rather soft. If you put a hard, brittle finish, like lacquer, over a thick, soft one, like sanding sealer, it is much more likely to chip and crack. For that reason, if you use sanding sealer, stick to one or two coats at the most, and plan to sand most of it back off. For the same reason, and because it tends to shrink as it cures, it is not advisable to use sanding sealer instead of pore filler.

 

[William Rogers]

I don’t think there is a clear cut answer as to if and when to use a sanding sealer. I use Zinsser dewaxed shellac sanding sealer. I am no expert, but feel dewaxed is better than straight shellac with wax. Normally I will use it on very oily exotic woods, woods that are open grain or soft when I am applying a lacquer or polyurethane finish. I will also use it to seal the insides of a hollow form. Another use is if I am dyeing just an area and not the entire piece I will use it to prevent the dye from appearing because of wood porosity in areas not dyed. I don’t use it on oil-based finishes such as walnut oil, danish oil, etc. I don’t know it will ever hurt to use it under any finish.

 

[Al Chavez]

Great feedback Everyone!
Thank you for all your replies. I may get some Zinnsler Sanding Sealer for future use on oily exotics or open grain woods. I will play around with building up coats of the oil/shellac/dna blend for now. On flatwork I typically use an oil based polyurethane blend with tung oil or b.l.o. and mineral spirits with a final coat of Trewax but I'm usually after a matte finish or a satin finish. With turned pieces I am thinking more of a gloss or high gloss finish. I will have to develop a style for my turned work.
Al

 

[Perry Hilbert]

I turn many items that will be painted. Turned normally from Yellow Poplar or Basswood. The paint cakes up and goes on very unevenly if I do not coat it first with Seal Coat or Wipe on Poly. If given a coat with Seal Coat or WOP first the paint goes nice and even and looks so much better.. Now that could have as much or more to do with the type of wood as anything. Both are dry porous woods.

 

[Doug Freeman]

Great feedback Everyone!
Thank you for all your replies. I may get some Zinnsler Sanding Sealer for future use on oily exotics or open grain woods. I will play around with building up coats of the oil/shellac/dna blend for now. On flatwork I typically use an oil based polyurethane blend with tung oil or b.l.o. and mineral spirits with a final coat of Trewax but I'm usually after a matte finish or a satin finish. With turned pieces I am thinking more of a gloss or high gloss finish. I will have to develop a style for my turned work.
Al

You dont need to limit yourself to just one “look” or “style” for turned pieces. I use several, depending on intended use and/or a particular look I’m after. They range from matte to hi gloss, utility use to “for looks only”. Also use several different types of finish, again depending on use and/or look. There are many choices available.

 

[Aaron Harris]

Though I'm new to bowl turning, I have used many different types of finishes on a variety of other wood projects over the years, so take that for what it's worth. I am also one who has been undecided whether or not I need sanding sealer without completely understanding its purpose, so this has been a big help. But just for a different perspective, one step I've often taken when finishing open-grained woods like walnut with probably my favorite finish, Birchwood Casey's Tru Oil gunstock finish, is to do a few sanding coats with 240 or 400 grit, working the sanding sludge into the pores, then flattening those coats with steel wool after they dry before applying further coats. I've gotten some beautiful finishes on turned walnut shaving brush handles, duck calls and also straight razor scales using that technique, though I haven't tried it on a bowl. It would probably be a bit labor intensive and impractical for bowls, as it takes several coats over several dry days to do well, and I suppose this is more of a pore-filler than it is a sealer.

But for spindle work on certain woods, Tru-Oil is a beautiful finish if you're willing to take the time to do it right. Just Google TruOil finished rifle stocks and you'll see.

Another technique I have had great success with recently on bowls is sanding to 400, then using Yorkshire Grit, the sanding paste that is supposed to be used over a sealer (though I eliminated the sealer without any apparent bad effects). I became enamored of this stuff from following several UK turners who use it and get beautiful finishes as the pumice and rottenstone break down; in fact, it leaves a beautiful finish all by itself, though I have no idea how durable it would be, as it's just a wax. I then turn in several coats of shine juice over that, and have been very pleased with the glossy finish.

I am always experimenting and trying new things. I try to learn or refine one new technique on every project, and just have always loved finishing fine wood. Thanks for all the tips and info. everyone including the OP. This forum has been an invaluable resource as I learn turning!

 

[Doug Freeman]

Aaron, I use the sanding sludge/pore filling technique on large pieces, works the same. I use wipe on poly , sometimes with blo added in.

 

[Glenn Lefley]

Though I'm new to bowl turning, I have used many different types of finishes on a variety of other wood projects over the years, so take that for what it's worth. I am also one who has been undecided whether or not I need sanding sealer without completely understanding its purpose, so this has been a big help. But just for a different perspective, one step I've often taken when finishing open-grained woods like walnut with probably my favorite finish, Birchwood Casey's Tru Oil gunstock finish, is to do a few sanding coats with 240 or 400 grit, working the sanding sludge into the pores, then flattening those coats with steel wool after they dry before applying further coats. I've gotten some beautiful finishes sanding sealer is just that a sealer so it on turned walnut shaving brush handles, duck calls and also straight razor scales using that technique, though I haven't tried it on a bowl. It would probably be a bit labor intensive and impractical for bowls, as it takes several coats over several dry days to do well, and I suppose this is more of a pore-filler than it is a sealer.

But for spindle work on certain woods, Tru-Oil is a beautiful finish if you're willing to take the time to do it right. Just Google TruOil finished rifle stocks and you'll see.

Another technique I have had great success with recently on bowls is sanding to 400, then using Yorkshire Grit, the sanding paste that is supposed to be used over a sealer (though I eliminated the sealer without any apparent bad effects). I became enamored of this stuff from following several UK turners who use it and get beautiful finishes as the pumice and rottenstone break down; in fact, it leaves a beautiful finish all by itself, though I have no idea how durable it would be, as it's just a wax. I then turn in several coats of shine juice over that, and have been very pleased with the glossy finish.

I am always experimenting and trying new things. I try to learn or refine one new technique on every project, and just have always loved finishing fine wood. Thanks for all the tips and info. everyone including the OP. This forum has been an invaluable resource as I learn turning!

Sanding sealer is just that. It seals everything up so grain will not raise any farther etc when it dries. Seals in the stain etc, and is cheap. It penetrates deeper into the wood then the finish coat, and is very easy to sand. Then you can put your more expensive finish of choice over it. On houses we sprayed one coat of cheap sanding sealer, sanded then a coat of lacquer. Sometimes two if they wanted depth to the wood.

also each finish system usually has a corresponding sealer they use. I would not recommend using one companies sanding sealer and another companies finish.they may not be compatible and cause orange peel etc. Also some of the new lacquers do not recommend sanding sealer, as they say it’s build into the product. Just spray two coats or more of the finish product.

but then again any product is really a sealer on first coat. The only time I’d recommend you must use a sealer is when you are restoring or refinishing old furniture. You will never get all the oils, silicone etc off furniture and the sealer, usually de waxed shellac, acts as a bonding coat. Between old finish and new poly or lacquer. That way you avoid any fish eye problems etc.

And from experience dewaxed shellac as a sealer can pretty well go on under any brand of final finish.

 

[Gerald Lawrence]

Sanding Sealer was developed by the furniture industry to speed finishing as the stearates makes sanding go faster and not to enhance the finish . If you are only concerned with sealing the wood just use a thinned coat of the finish you will use. This does not fill pores by will seal. As has been mentioned the SS is softer and will allow the finial finish to be more easily damaged. If it is pores you want to fill use a pore filler as doing it with any finish is a laborus proces.

 

[Roger Wiegand]

This thread is suffering from a vocabulary problem. "Sanding sealer" used to be a specific thing, defined by the addition of zinc stearate to a clear finish product, usually lacquer. Zinnser muddied the water substantially a number of years ago by rebranding their shellac as a sanding sealer even though it contains no zinc stearate. I use shellac all the time as a first coat under finishes as well as a final finish, and will frequently use it to allow me to harden and knock down difficult-to-sand fluffy grain. That doesn't turn it into "sanding dealer", both are different uses. It would be useful to distinguish in which sense one is using the term.

 

[Michael Lamka]

I use sanding sealer to get more even distribution of other liquid finishes, such as stains and paints, and especially in softer woods. If using a clear or friction finish, I don't bother with a sealer.

 

[Al Chavez]

General question, will using Zinnser "Sanding Sealer" or a thinned out shellac (1 pound cut?) as a sealer or first coat affect finish if an oil mix is used after the 1st coat? An oil mix like tung oil or b..l.o. mixed with an oil based poly and m.s. or oil and shellac with d.n.a.? Will the s.s. cause blotching or uneven absorption or of the oil blend? Will it prevent the oil from penetrating into the wood?
Thanks

 

[Gerald Lawrence]

Shellac will not affect color nor cause blotching. It is a "sealer" so yes it will affect the absorption of any oil finish. Sealers are used as a base for non penetrating finishes such as latex or other paint products. Some use it as a finish but the finish is soft and I would not recommend that. I do not use shellac under finishes such as tung oil or danish oil so I cannot tell you the effect it would have.

 

[Andrew Lindsay]

I'm a noob at turning, but I refinished quite a bit years ago. I used sanding sealer when I didn't want finishes to change (darken) the color of the wood. I'd apply the sealer, then remove visible sealer with steel wool and/or 400 grit sandpaper.