Sanding Sealer process order

[Josepi]

I have finished a few pieces of furniture and other projects in red oak up to a few years ago. I was with other interests for quite a few years, now. I need some input on finishing a new staircase in red oak.

I have always liked a darker stained red oak colour like special walnut or dark walnut and have always stained my oak projects with darker colours. The darker stains are a bitch for wood scratches and end grain staining unevenly and I have been told by many professionals and polished (pun intended) amateurs to use a sanding sealer first.

With Internet research I see the crowd is well split about using a sanding sealer before the stain coats). Some state the stain will not absorb (that would be the point to a certain extent) and others say it is the only way to do it so you don't sand after staining and "distress" the stained finish look. The wood finishing product companies recommend "wood conditioner" before stain so I have purchased some for experimentation. Many seasoned (pun intended) woodworkers recommend thinned out shellac based products before staining.

Anybody have any experiences with this? I would appreciate experienced input. I have never pre-sealed before staining and this appeals to obscure some sanding laziness, with a dark stain, and surprise wood blotchiness.

TIA

[dadiOH]

1. Sealing won't necessarily avoid stain catching in residual sanding scratches so sand properly. No scratches should show with or without stain. Sand properly means... (a) sand LOTS with whatever coarse grit you start with to get the wood level/flat/smooth (b) sand with progressively finer grits to remove scratch marks from the previous grit; again, you need to sand more with each grit than you probably think you do. Work up to at least 180, maybe 240 or finer, depends on the wood.
2. The end grain of red oak sucks up anything like a sponge. If you want the end grain to remotely resemble the rest, that end grain has to be sealed or conditioned. That is true of any wood, especially red oak. Hell, I don't know if it is even possible to seal red oak end grain, I avoid that wood as much as possible; glue size maybe...
3. Red oak doesn't blotch when stained; at least, it never has for me.
4. I have never heard of anyone sanding after staining unless they left too much stain on or were striving for a special effect; normally, wipe stain on, let set, wipe off. That's oil stain. If the wood has been sealed/"conditioned" lots more will wipe off, ergo lighter color.

[SonomaProducts.com]

...

You need to be careful with terms. "Sanding Sealer" and "Pre-stain Conditioner" are not exactly the same thing and you are talking about a conditioner.

Red Oak won't benefit much from pre-stain conditioner. Even-handed sanding is your best bet for avoiding any unevenness. If you want the end grain to be less absorbent you can use either conditioner or sanding sealer. Or even just do a thinned shellac painted on the end grain first. Do some tests for how much thinning but zinsser bulls eye seal coat thinned about in half with alcohol should do the trick. Really soak it into the end grain and let it dry a day. Shellac dries in 10 minutes but when it wicks into the wood it will take longer.

Sanding sealer is a thinned film finish meant to lay down thin and to be softer that the real finish to let you do one final surface sanding \flattening before subsequent coats of a film finish like lacquer or poly. It can act like a stain pre-conditioner but not exactly the same and might seal the wood completly if layed down too thick.

Finally, you might experiement with gel stain. Especially if you are trying to darken Oak. Just a hint.

[Josepi]

What type of alcohol would you thin the shellac with?

I have never used gel stain. Does it avoid some of the open grain darkness had with the darker stains on open grains in oak?

Finally, you might experiement with gel stain. Especially if you are trying to darken Oak. Just a hint.

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[Swingman]

I usually use a 99% anhydrous isopropyl alcohol to cut shellac when spraying in this Gulf Coast climate humidity, but denatured alcohol from the BORG works just as well most of the time.

Not in my experience ... although the difference may be less obvious, gel stain itself does not necessarily avoid a noticeably darker end grain when staining.

It does seem to help, however, with woods that have a tendency to blotch, like maple; and woods like poplar, with strong sapwood and heartwood differences in absorption.

[dadiOH]

To do that, fill and seal the wood so that the open grain doesn't fill up with stain. You can sand lightly afterward to remove sealer from the non-open areas if they don't absorb as much stain as you want.

[SonomaProducts.com]

Any alcohol really. Most common usage would be denatured alcohol, sold at home depot along side mineral spirits, turpentine, paint thinner, etc. However, isopropyl alcohol also works and dries a little slower. I have also seen guys use grain alcohol so if you see a bottle of Everclear in a wood shop it may have a dual purpose.

Not that denatured alcohol can absorb moisture and the water can give some problems (I have heard, never experienced). A fresh can won't have the problem. I buy the pint cans so it never gets too old even though a gallon is super cheap too.

End grain will still super absorb gel stain. My recommendation for gel stain is to avoid blotchness and to build darker color easier. Gel stain is oil stain suspended in poly. So you can easily build it up to a darker color, not relying on absorbtion.

[Ed Pawlowski]

"SonomaProducts.com" wrote

End grain will still super absorb gel stain. My recommendation for gel stain is to avoid blotchness and to build darker color easier. Gel stain is oil stain suspended in poly. So you can easily build it up to a darker color, not relying on absorbtion.

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What I've done with end grain is to burnish it first. Not a perfect solution, but it helps.

[Josepi]

I would assume that hydrogen peroxide would not work though. There are so many types of alcohol. I have to assume isopropyl of some type without the water and oils used to dilute medical "rubbing" alcohol.

I found a can of "zinsser bulls eye seal coat" today. Funny thing is is states "do not thin" and "do not use under polyurethane finishes....yikes! I noticed the same statements on another can of shellac...I think it was.

Not that denatured alcohol can absorb moisture and the water can give some problems (I have heard, never experienced). A fresh can won't have the problem. I buy the pint cans so it never gets too old even though a gallon is super cheap too.

End grain will still super absorb gel stain. My recommendation for gel stain is to avoid blotchness and to build darker color easier. Gel stain is oil stain suspended in poly. So you can easily build it up to a darker color, not relying on absorbtion.

[dadiOH]

You assume correctly. The reason is that H2O2 (hydrogen peroxide) isn't alcohol.

dadiOH _________________

[Scott Lurndal]

Not sure that I'd consider USD16/gal "super cheap", myself.

scott

[Josepi]

That's why it tastes so bad in Coke!

dadiOH _________________

Josepi wrote:

[SonomaProducts.com]

Kind of strange. The very language of shellac is discussing the "cut" or pounds of shellac flakes to gallons of alcohol. So the seal coat is like 2 or 3 pount cut. I suppose if it will perform as described on the can as an undercoat sealant that will block stains, mold, etc. then using it as mixed is required. But thinning it for other purposes is surely OK. Zinnser is just a simpler way of getting shellac than mixing your own flakes. I think they add something besides alcohol to enhance shelf life too.

Not sure why they would say not under poly. Shellac is the worlds best undercoat and many of the top finishing guys say to use shellac under anything. I guess maybe their shelf extender might have some lacquer type properties and lacquer cannot go under poly but I use zinnser under poly all the time and have never seen any problem. Not sure what to say. The seal coat is dewaxed and works great for me.

[Nova]

I suggest you re-read the instructions.

From Zinsser's Technical Data Sheet for SealCoat

"Pre-Stain Conditioner - SealCoat is ideal for preventing uneven stain penetration over softwoods such as pine. Thin product by adding 3 parts alcohol to 2 parts SealCoat."

"Application Requirements ? Do not thin product when using as a sealer or bond/barrier coat." ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

"Sanding Sealer - May be used as an undercoat to prepare all new or previously finished interior wood surfaces for oil-based and acrylic polyurethanes, varnish and lacquer topcoats."

[Josepi]

Thanx!

That looks like the exact product I would be looking for. Trouble is the can I had in my hands at Lowe's says not to dilute and not to be used under oil Based polyurethane finishes.

My guess is Canada has a different product or the product has been changed and they have old stock. The store is only a few years old so the old stock thing is unlikely. Looks like the same product name and very similar can too???? This may be a restricted product in Canada. We have stricker restrictions on some chemical products.

Got involved in WD-40 arguments, years ago, and it turns out the labelling is different here. USA label states "lubricates" but not in Canuckistan.

Will be in Buffalo area in a few months but need to move faster on this. My oak staircase is drying out.

From Zinsser's Technical Data Sheet for SealCoat

"Pre-Stain Conditioner - SealCoat is ideal for preventing uneven stain penetration over softwoods such as pine. Thin product by adding 3 parts alcohol to 2 parts SealCoat."

"Application Requirements ? Do not thin product when using as a sealer or bond/barrier coat." ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

"Sanding Sealer - May be used as an undercoat to prepare all new or previously finished interior wood surfaces for oil-based and acrylic polyurethanes, varnish and lacquer topcoats."

[SonomaProducts.com]

My guess is exact same product with different labeling requirements. With lacquers it is very common for them to say "Do not thin". But the reason for this is with a higher percentage of solvent thay then have a higher vox (volitile chemicals) rating and the gubment don't wnat ya to be gassing off so much. I suppose the same might be true for shellac in a PC world. Frankly Canada could benefit from a little global warming and it might open up a whole bunch of new northern territory. I think in preperation they created anew province just for that purpose a few years back didn't they?

[Dave Balderstone]

Territory, "Nunavut", not a full province.

[Josepi]

LOL

Interesting part is in Zinsser's search engine, Canada always shows up in Buttfuck, Nebraska, no matter what provonce or city you search for. Also if you select that product in other suppliers, they state they cannot ship to Canada or California, unless the companies don't know the difference between Ca and Ca.

I suspect this product is bad for our environment but some states don't care or want to test Obama's new healthcare system.

Looks like a road trip!

[SonomaProducts.com]

Well if alcohol is bad for the environment than we better cut down every green thing with sugars in it that can possibly rot. Ever heard of pruno? Jail hooch made from any kind of fruit or grain you can get your hands on.

[Father Haskell]

Chemists' shorthand for an alcohol is R-OH, a hydrocarbon radical with an OH branch.