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post #1 of 14 Old 10-28-2008, 12:28 AM Thread Starter
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Finishing help


I am in the process of refinishing a 1920-1930 time frame quarter sawn oak center post kitchen table and chairs. The origional finish I'm pretty shure was shellac. I want a durable finish but I do not want to use poly type finishes. Since we will be using this table I don't think going back with shellac is a good idea. I am leaning toward varnish. I need to know if this is a good idea and what would be the best varnish product to use. I would also like to know if I can spray the varnish. I have both high pressure and HVLP systems.
What do you guys think?
Thanks, Keith

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post #2 of 14 Old 10-28-2008, 04:51 AM
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You can spray oil base varnishes in either of those guns. Depending on the brand, they may have to be thinned. Several thin coats finish better than trying to lay on heavy coats. It stays wet fairly long and will run if you're not careful.

Sherwin Williams carries many excellent varnishes, including some fast dry, and conversion varnishes that are very durable.






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post #3 of 14 Old 10-28-2008, 11:30 AM
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Shellac has been on the table for about eighty years and you don't think it is durable?. If you want a durable varnish try Waterlox Original Varnish. It is made with a phenolic resin and tung oil and was originally sold as gym floor finish. I have used it for many years in some applications.

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post #4 of 14 Old 10-28-2008, 12:02 PM
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Quote:
Originally Posted by jerry View Post
Shellac has been on the table for about eighty years and you don't think it is durable?. If you want a durable varnish try Waterlox Original Varnish. It is made with a phenolic resin and tung oil and was originally sold as gym floor finish. I have used it for many years in some applications.

Regards

Jerry
Shellac scratches easily and is just as easily damaged by water. Not a good finish for a table that will be in use.

The varnish is better in this case but still suseptable to water rings whereas the poly is more durable yet and not so prone to water damage.

I too, prefer the varnish over the poly in most situations, but a table top isn't one of them.

Just my .02
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post #5 of 14 Old 10-28-2008, 01:19 PM
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If you have striped the old finnish...And you have spray equipment...I would stick with (Old School) spray Laquer with a matched sanding sealer. Rick

Never... I mean always... never mind Rick
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post #6 of 14 Old 10-30-2008, 11:43 AM
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Quote:
Originally Posted by Tweegs View Post
Shellac scratches easily and is just as easily damaged by water. Not a good finish for a table that will be in use.

The varnish is better in this case but still suseptable to water rings whereas the poly is more durable yet and not so prone to water damage.

I too, prefer the varnish over the poly in most situations, but a table top isn't one of them.

Just my .02

" Poly " is varnish - the one part polyurethane varnishes are made with alkd resin with a little urethane resin added and are no more water resistant than the varnishes without the urethane resin. Waterlox Original or Behlen's Bar Top are made with phenolic resin and either linseed oil or tung oil and are both harder than polyurethane varnish. I have a dining roon table that has a shellac finish that has been there over thirty years. While it doesn't get the wear of a kitchen table with a little care shellac is a great finish.

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post #7 of 14 Old 10-31-2008, 10:59 AM
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Quote:
Originally Posted by jerry View Post
" Poly " is varnish - the one part polyurethane varnishes are made with alkd resin with a little urethane resin added and are no more water resistant than the varnishes without the urethane resin. Waterlox Original or Behlen's Bar Top are made with phenolic resin and either linseed oil or tung oil and are both harder than polyurethane varnish. I have a dining roon table that has a shellac finish that has been there over thirty years. While it doesn't get the wear of a kitchen table with a little care shellac is a great finish.

Regards
Jerry
True, Poly is a varnish. Suffice to say that old school varnish uses natural resins while poly uses synthetic.
I use shellac quite a bit, usually as a washcoat but have, on occasion, used it as a top coat on things that don't see a ton of use. i.e. a book case, fire place mantel. Easy to work with and I like the results, but never thought it hard enough for more extreme use.

I have to disagree on the hardness and water resistance of poly, respectfully, of course.

Here is what wiki has to say on the subject:

Polyurethane materials are commonly formulated as paints and varnishes for finishing coats to protect or seal wood. This use results in a hard, abrasion-resistant, and durable coating that is popular for hardwood floors, but considered by some to be difficult or unsuitable for finishing furniture or other detailed pieces. Relative to oil or shellac varnishes, polyurethane varnish forms a harder film which tends to de-laminate if subjected to heat or shock, fracturing the film and leaving white patches. This tendency increases when it is applied over softer woods like pine. This is also in part due to polyurethane's lesser penetration into the wood. Various priming techniques are employed to overcome this problem, including the use of certain oil varnishes, specified "dewaxed" shellac, clear penetrating epoxy, or "oil-modified" polyurethane designed for the purpose. Polyurethane varnish may also lack the "hand-rubbed" lustre of drying oils such as linseed or tung oil; in contrast, however, it is capable of a much faster and higher "build" of film, accomplishing in two coats what may require multiple applications of oil. Polyurethane may also be applied over a straight oil finish, but because of the relatively slow curing time of oils, the presence of volatile byproducts of curing, and the need for extended exposure of the oil to oxygen, care must be taken that the oils are sufficiently cured to accept the polyurethane.
Unlike drying oils and alkyds which cure, after evaporation of the solvent, upon reaction with oxygen from the air, polyurethane coatings cure after evaporation of the solvent by a variety of reactions of chemicals within the original mix, or by reaction with moisture from the air. Certain products are "hybrids" and combine different aspects of their parent components. "Oil-modified" polyurethanes, whether water-borne or solvent-borne, are currently the most widely used wood floor finishes.
Exterior use of polyurethane varnish may be problematic due to its susceptibility to deterioration through ultra-violet light exposure. It must be noted, however, that all clear or transluscent varnishes, and indeed all film-polymer coatings (i.e.paint, stain, epoxy, synthetic plastic, etc.) are susceptible to this damage in varying degrees. Pigments in paints and stains protect against UV damage, while UV-absorbers are added to polyurethane and other varnishes (in particular "spar" varnish) to work against UV damage. Polyurethanes are typically the most resistant to water exposure, high humidity, temperature extremes, and fungus or mildew, which also adversely affect varnish and paint performance.
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post #8 of 14 Old 10-31-2008, 11:08 AM
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Polyurethane varnish gets its slightly more abrasion resistance because it is softer. Both lacquer and shellac are harder than polyurethane varnish. By the way commercially available varnishes haven't been made with natural resins for at least fifty years.

Jerry
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post #9 of 14 Old 10-31-2008, 08:50 PM
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That's what I love about this place.
There is always an oppertunity to learn and sometimes find out a long held belief isn't always correct.

When the advise I give is questioned the first thing I do is some research, I realize there is always the possibility that I am wrong.

This seems to be one of those times.
Thanks Jerry, for prompting me to do some necessary research.
Seems quite some time ago I was given some bad advise myself concerning the composition of varnish and the make up of poly.
I stand corrected.
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post #10 of 14 Old 11-01-2008, 10:16 AM
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Tweegs:
I hope you were not offended by my remarks ,they were not meant that way. I live in Mi. also -Garden City-

Regards

Jerry
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post #11 of 14 Old 11-01-2008, 04:19 PM
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Not at all.
You taught me something and I appreciate it.
Mama raised me with the notion that I didn't always have to be right.
I learned early on that the moment I found I had my foot in my mouth was an oppertune time to pull it out.

Never cared much for that corn chip taste anyway.

There is usually a good WW show at the Novi expo sometime before Christmas each year, or is it in the spring? Be a good time to meet up, us and some of the other Michiganders here on the boards.
Keep an eye open for it. As the time draws near we can start a thread and try to put something together.
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post #12 of 14 Old 11-01-2008, 06:34 PM
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I'm a big fan of oil base Poly. As was mentioned, I believe it's very durable, such as in water resistance without fogging up, and it's soft enough that if dented, the finish goes with the dent instead of chiping off in most cases. I use to refinish floors, and allways thought that if it's tough enough for a floor, it's good enough for anything I refinish or make for myself. I know it's not fast drying, but who cares ? I'm doing it for myself. If I was makeing things and selling them, well then thats another story, I'd want something that dries fast like laquer. All the other finishes I could really careless about, I like to keep it simple.

Last edited by user4178; 11-01-2008 at 06:36 PM.
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post #13 of 14 Old 11-08-2008, 03:10 PM
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Dont believe Wiki

It is a poor substitute for a real encyclopedia. Anyone and I mean anyone can go in there right now and remove an article and replace it with their own name.
If I wanted to be a jerk, I can go into Wiki tight niow and remove Tweegs article and replace it with "Howdy All" if I wanted to.
At least that was easy to do only a few months ago.
Someone did that to my article. LOL
Anyway, you can post anything you want in there.

Tony B



Retired woodworker, amongst other things, Sold full time cruising boat and now full time cruising in RV. Currently in Somerville, Tx
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post #14 of 14 Old 11-09-2008, 09:17 PM
 
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my expernce has been that the relitive hardness of finishes goes some thing like this regular nitrocellious lacquer, PRe-Cat Lacquer, Water based lacquers, Conversion varnish, ( that being a different animal than regular varnish) and then the polyurethanes being at the top of the hardness ladder. There are a number of different qualities to the different brands and in fact I have gone to automotive polyurethanes when I wanted a realy high polished hard finsih that was UV resistant and had some flext to it

Greg
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