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Discussion Starter #1
Ok, so, you see, I don't like polyurethane by itself. It either is too thin of a coat, or it feels too much like plastic if I put "enough" on. What I wanted to do, was instead, put on a coat of shellac, then use a spray-on polyurethane can to put a thin layer on to protect the shellac. This is going on a desk. The wood I'll be staining will be a half-inch piece of particle board glued to a half-inch piece of oak plywood (I have no idea how to build a rounded edge, so I assume it's easier if the wood is exactly one inch in thickness). I'm going to be staining the side that has the oak. If this is possible, what kind of shellac and what kind of polyurethane should I use?
 

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Ok, so, you see, I don't like polyurethane by itself. It either is too thin of a coat, or it feels too much like plastic if I put "enough" on. What I wanted to do, was instead, put on a coat of shellac, then use a spray-on polyurethane can to put a thin layer on to protect the shellac. This is going on a desk. The wood I'll be staining will be a half-inch piece of particle board glued to a half-inch piece of oak plywood (I have no idea how to build a rounded edge, so I assume it's easier if the wood is exactly one inch in thickness). I'm going to be staining the side that has the oak. If this is possible, what kind of shellac and what kind of polyurethane should I use?
Polyurethane won't adhere to standard shellac. If you want to seal with shellac you must use a de-waxed shellac such as Zinsser Sealcoat. Still the Sealcoat needs to be scuff sanded with 220 grit paper before topcoating.

You can use either a water based polyurethane or an oil based polyurethane however keep in mind if the color of stain you use is light the oil based will show yellow over time as it ambers as it ages. The sealcoat is also a good barrier coat for using a water based poly as the water based poly reacts badly to linseed oil which is in the stain.
 

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We have an introduction section where you can say a few words about yourself. If you fill out your profile in your "User Control Panel", you can list any hobbies, experience or other facts. You can also list your general geographical location which would be a help in answering some questions. In doing that your location will show under your username when you post.







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I'll suggest something for you to keep in mind for the next time: seek out a different varnish. Varnish is a resin cooked with a drying oil to form the compound. The most common resin are the urethanes, cooked with linseed oil. These are very good for scratch resistance (urethane's calling in life) but as you mentioned they look plastic to a good many of us. they have some other downsides as well, like adhesion (or lack of it) which is why a scuffinf is required. Anyway, consider using an alkyd resin varnish, very good and nonme of the plastic look. 2 I can think of if you can find them (the hardest part) would be Sherwin Williams Fast Dry Oil Varnish (alkyd resin/linseed oil) or (my favorite) Pratt and Lambert #38 (alkyd resin/soya oil). The P&L has a much lighter color than the SW, and yellows a lot less over time. Anyway, good luck with your project!
 

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:smile:
Ok, so, you see, I don't like polyurethane by itself. It either is too thin of a coat, or it feels too much like plastic if I put "enough" on. What I wanted to do, was instead, put on a coat of shellac, then use a spray-on polyurethane can to put a thin layer on to protect the shellac. This is going on a desk. The wood I'll be staining will be a half-inch piece of particle board glued to a half-inch piece of oak plywood (I have no idea how to build a rounded edge, so I assume it's easier if the wood is exactly one inch in thickness). I'm going to be staining the side that has the oak. If this is possible, what kind of shellac and what kind of polyurethane should I use?
I like your thinking to a degree. Take a scrap board, coat it with hot hide glue and wipe it off lightly leaving the pores filled. Let dry. Steelwool off raised grain. Here's what that accomplishes; the surface becomes VERY hard and grain is filled. You can now stain or top coat it with anything 'cept lacquer. Also IF you ever want to strip it's a lot easer. The hide glue will not interfere with ANY stain you might use. I wouldn't use more than two coats of THINNED poly wiped or brushed on. More than two coats of poly doesn't make it any more waterproof or tougher. I'm sorry if I seem such a zealot about finishing. I'm old school when it comes to this.
 

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Discussion Starter #8
Quick question, when people say a finish "fades", what are the effects of it fading, and how long until it fades? Is there a table somewhere that compares types finishes and stains on time until it fades? But, more specifically, how long will shellac and polyurethane last?
 

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Fading is something usually caused by UV exposure, whether it's in the finish or the wood itself. At times it's hard to distinguish between the 2. Stains typically have pigments for the coloring agent, and pigments don't fade, they are colorfast. But they sometimes also have dyes, and dyes will fade. Ad to this the fact that the top coat may be changing, usually it gets more of an amber cast to it, and it's easy to see there is no simple answer to your question. But shellac is color fast, it won't change. Varnishes not so much, especially the urethane formulas....they can get really dark over time; but it's usually years. As for the life, shellac has been used for hundreds of years and is till on some antiques. We don't have that much history with varnish, but in the proper conditions it will also last a very long time.
 

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Quick question, when people say a finish "fades", what are the effects of it fading, and how long until it fades? Is there a table somewhere that compares types finishes and stains on time until it fades? But, more specifically, how long will shellac and polyurethane last?
Fading would pertain to the stain rather than the finish. Some brands of wood stain are more colorfast than others. I have cabinets in my shop that were stained with Minwax stain which are less than 15 years old and are noticeably lighter then newly stained and finished wood. For this reason I switched brands to Sherwin Williams.

It would be difficult to say how long shellac or polyurethane would last. Like the stain different brands of polyurethane last better than others in different applications. If a project is set in a very sunny location where it gets radiant heat then it may last less than 10 years where if it was put in normal lighting last a half century before any noticeable change in the finish. Shellac on the other hand is a natural product and the durability would vary more by the freshness of the product on the shelf than the brand. Some folks buy shellac in flakes and mix their own in order to get a fresh batch. It just doesn't keep on a store shelf as well as polyurethane. Like poly the durability would depend on the environment however in my opinion it isn't a good product for something of high wear like a table top. It's softer and scratches easier. It is easier though to fix a scratch in the finish with shellac as you can just wet it with alcohol and it will re-liquefy.
 

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Discussion Starter #12
I went to go pick up the finish today, but there was only waxed shellac. I asked the guy there and he said I can just get Lacquer sanding seal if I was going to put something over it. I've heard it's not as strong when you mix polyurethane with another type of finish; how much weaker will the finish be?
 

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I wouldn't use polyurethane over lacquer sanding sealer. If you just can't get a de-waxed shellac I would apply the poly to the wood without any sealer. Polyurethane inherently has adhesion problems anyway and wouldn't adhere very well the stearates in lacquer sanding sealer.
 

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Discussion Starter #15
Home Depot and Lowes both sell de-waxed shellac such as Zinsser Sealcoat.:thumbsup:
I was actually looking for that, but they didn't have any. *sigh* I'm going to go to another Lowes tomorrow. Hopefully they have what I'm looking for.
 

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rrbrown said:
Home Depot and Lowes both sell de-waxed shellac such as Zinsser Sealcoat.:thumbsup:
Neither of them sell it here any more. I can get it at my local ace or true value though,
 

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Shellac is an excellent finish and there are many urban legends about it. The only real weakness is the fact that alcohol will dissolve it, making it a bad choice for use on a bar top. I would make my own shellac which gives you many more choices in types and color available and alcohol based dye stains readily dissolve into all of them making excellent toners. I recommend reading up on shellac at Shellac.net There is a ton of information there and you can buy from them as well.
 

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Neither of them sell it here any more. I can get it at my local ace or true value though,
I'm pretty sure I saw it recently at one of them. Might be a local thing, temp outrage in your area or new policy that has not reached my area yet. I guess I could also be crazy or seeing things who knows.
 
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