floor finishing

Ok, i got a dousing of BLO applied and wiped down on a new red oak floor. Now i need to know what is the best way (that is not spraying) to apply the wax free shellac sealer. I'm gonna start on this Thursday, and I am looking for ideas. I'm thinking a 2" brush like i did my stair treads with is probably not the best solution.

thanks!

Reply to
Steve Barker
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No, and no.

Boiled linseed oil is a drying oil. It's a relatively soft coating that's just not going to stand up well on a working surface like a floor.

Then, you're talking about rolling a shellac sealer onto that drying oil. Shellac is a natural material excreted from a particular kind of bug, and it's not nearly hard enough to stand up well on a floor.

In order for any coating to stand up well on a floor, it has to dry to a HARD film that will stick to the floor well. The harder the coating, the less dirt will get embedded in that coating underfoot (making the floor look dirty in the traffic lanes) and the less it'll be scratched up by people walking on it with shoes on (cuz grit gets embedded in the leather soles of footwear). So, the harder the coating you put over your hardwood floor, the longer it'll look new, and the slower it'll lose that "new" appearance.

What you need to do is go back in time and stain that red oak floor with an "oil based" or water based stain, (or leave it natural), and then go over that floor with a finish that dries to a HARD film that will stand up to foot traffic. That would be a conventional "oil based" polyurethane hardwood floor finish if you want to stay with tried and true technology from the 1950's, or if you want to go with one of the new isocyanurate based polyurethanes that'll give you a coating about three times as hard, "Traffic" by Bona or "Street Shoe" by Basic Coatings.

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Both Traffic and Street Shoe consist of a gallon of water based isocyanate prepolymer. When you add the small bottle of catalyst to the gallon jug and shake, the polymer forms as the water evaporates.

Both Traffic and Street Shoe are different from "oil based" polyurethane hardwood floor finishes in that the "oil based" stuff is essentially an alkyd resin with urethane groups inside it that act very much like the roll cage inside a race car. Those urethane groups link various parts of the alkyd resin together to make the resin harder (if you could squeeze it) and stiffer (if you could stretch it).

Neither Traffic no Street Shoe contain any alkyd resins. Instead, what you get is a water based slurry of prepolymer. The prepolymer consists of isocyanates already reacted with alcohols to make tiny plastic "blobs", and those blobs are suspended in water. When the catalyst is mixed into the jug, the jug shaken and the mixture spread on the floor, then as the water evaporates from the mixture, the catalyst concentration rises sufficiently to cause each of those "blobs" to cross link with all of their neighbors. So, the result is that the plastic that forms over you floor has very many more urethane groups in, making for a much harder film than you can ever get in any "oil based" polyurethane hardwood floor finish.

But, if I understand you correctly, you already have a coating of linseed oil on top of your oak, and it's never a good idea to put a harder coating over a softer one. That's because if the floor receives an impact, it'll have a tendency to "chip" as the soft linseed oil layer breaks, but the harder and stronger polyurethane above doesn't.

You might want to have a discussion with whomever told you to use boiled linseed oil on a hardwood floor, and to use shellac as a (presumably) "wear layer". Maybe see what his or her reasoning, if any, was.

Also, see if any of the hardwood floor finishing companies in your area have ever applied Traffic or Street Shoe over linseed oil, and what they're experience was with that installation.

Reply to
nestork

I will assume that you put on just enough BLO to enhance the wood's appearance and not so much as to try and form a significant coating.

The finish schedule you are using is traditional for both floors and furniture although shellac does not stand up to foot traffic as well as more modern finishes. That being said, I would thin the first coat of shellac maybe 50% with anhydrous alcohol and then use a lamb's wool applicator. These applicators fit on the end of a broom handle. Try to keep a wet edge but keep in mind that shellac dries more quickly than oil based finishes since the alcohol evaporates more quickly. You may want to do the floor in sections since later coats will melt into previous ones. You can buy retarders if needed.

Good Luck.

Reply to
Baron

Why shellac on a floor!!?? It is soft and absorbs moisture. Great for sealing, but seems a thinned varnish would do as well.

Reply to
Norminn

Now i need to know what is the best way (that is not spraying) to apply th= e wax free shellac sealer. I'm gonna start on this Thursday, and I am looki= ng for ideas. I'm thinking a 2" brush like i did my stair treads with is pr= obably not the best solution. thanks! -- Steve Barker remove the "not" from= my address to email

Start by abandoning the idea of using shellac and get some polyurethane. T= he traditional route is the oil based one but many have had good results wi= th the newer water based formulas. Which make clean up a lot easier and al= so do not yellow with age.

Reply to
jamesgang

Shellac is not a soft finish and it does not absorb moisture. One of the down sides to shellac is its brittleness. In fact, kayaks are traditionally finished with dewaxed shellac. Shellac is a traditional finish for floors and furniture. That is not to say that something more modern like varnish or polyurethane would hold up better but I think you would be surprised by how long a shellac finish will last.

Reply to
Baron

I felt it get sticky with moisture. Not too many things that moisture does not effect o some degree. Lacquer also is sensitive to moisture.

Greg

Reply to
gregz

Shellac gets white, cloudy stains from wet glasses. Still surprised to hear it is used as final finish on floors. I used shellac to refinish a piano....discovered the method used for a deep glassy finish was multiple coats of shellac and then final coats of varnish for moisture protection. Would be tough to use on a floor unless the place is wide open for ventillation.

Reply to
Norminn

If shellac were commonly used on hardwood floors, it would be common knowledge, and this is the first I've heard of anyone using shellac on a floor.

In 1956, Otto Bayer, founder of the company that still makes Aspirin, patented the first alkyd based "polyurethane", and it quickly became the clear coat of choice over hardwood floors because it was harder and more durable than the Carnauba wax finishes used on hardwood floors at the time.

Nowadays, we have isocyanate based polyurethanes like Traffic and Street Shoe that are three times as hard and durable as Otto's "urethane modified alkyds", and in 20 years it will be standard practice to use these isocyanate based polyurethanes as hardwood floor finishes as well as "varnish" for furniture.

So, why not have the benefit of modern chemistry and use the hardest and most durable clear coat available so that the hardwood floor

stays looking new longer and loses it's good looks slower?

The only thing I'm concerned about is this linseed oil the poster first put on the wood. While some of that oil will have been absorbed into the wood, I don't believe there isn't a coat of oil over the wood. And, the problem is that isocyanate based polyurethanes are very much harder and stronger than dried linseed oil, and so that linseed oil won't provide the support needed for those super hard clear coats to last as long as they should. I'd be concerned that the urethanes would tend to "chip", which is what happens when you put a hard coating over a softer one. The soft one breaks when it gets an impact, taking the hard coating off with it.

I'm nestork, and I approved this message.

Reply to
nestork

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you completely missed the question. but thanks for the novel i didn't read. The BLO is already on and I WILL be using the shellac.

Reply to
Steve Barker

thanks for the reply!

Reply to
Steve Barker

nestork wrote in news: snipped-for-privacy@diybanter.com:

Just a word of caution. Isocyanate is a rather reactive chemical group, one of the reasons it works so well in finishes. But it isn't really good for your health:

Reply to
Han

That's probably because you're only talking to people who are finishing new floors in (mainly) new houses. All of the (mostly parquet) floors other than kitchen and bathroom in my 4-story 110 year old brownstone had been finished with shellac when I moved in 30+ years ago, probably multiple times and probably interspersed with wax. The result predictably was authentic but dirty-looking floors. Being at the time gung-ho on polyurethane I sanded and refinished the floors with that chemical using a gloss coat followed by a satin finish coat. Although I'm not promoting the idea of museum-level restoration the result was clearly inappropriate for an aged building so after doing a few rooms I returned to the idea of shellac (orange shellac) which imparts a much more pleasant warm golden glow to the floors. Further, minor repairs to splintered pieces of parquet can be easily done and the area refinished invisibly.

Not only is the look great, shellac dries very quickly meaning that you can walk on it much more quickly than one of the newer chemical finishes. Further, if you screw up you can easily cover your mistake with another coat which will reliquify the base coat; try that with your plastic. If that wasn't enough, the smell of the finish is alcohol (the solvent) which is certainly less offensive than the god-only-knows-what solvent for the poly and successor finishes.

One further success story for shellac: I had a teak coffee table I wished to refinish. I sanded it then tried a wash coat of poly to seal it. Disaster. The poly coat wrinkled and failed to dry. Oops bad batch. Too old maybe? Re-sanded, new can, new attempt, same disaster. I tried sanding sealer, supposedly lacquer base. It didn't work either. At this stage I was pulling my hair out. I hadn't tried shellac because like you I believed it wasn't a good finish for a place where wet glasses might be put down but eventually I gave in and applied a full coat of non-dewaxed shellac. Success! I still put an overcoat of poly and it's held up to this day (15 years). Later, talking to an old-time furniture refinisher and he said, "Sure, everyone knows that teak is such an oily wood that the only finish possible is shellac!" According to him the bad-mouthing of shellac arose because the lacquer and later poly manufacturers were trying to gain market share; most of it was pure malicious fabrication.

Reply to
knuckle-dragger

thank you for that explanation. I wasn't going to bother telling them the truth. And the truth is, It looks better. That's the bottom line. What good is a (plastic) finish that lasts for years if it looks like shit? It takes 10 minutes to recoat a 11x15 room with shellac, it dries to walk on in an hour, so what's the problem? Even if it only lasted a month, i'd still do it.

Reply to
Steve Barker

If the customer is happy, then what I think doesn't matter.

Reply to
nestork

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