Hi All,
I am nearing the finishing stage of a sofa table that I have been working on for several months now. I used spalted pecan for the top and black walnut for the “body.” Once it is finished, I promise to post pictures as I want to hear constructive criticism.
In the meantime, my goal is to achieve a fairly durable, satin finish. In the past, I have primarily used polyurethane for “lesser” projects. However, I would like to expand my horizons. Therefore, when I was in Home Depot, I purchased some Flecto Varathane (oil-based). I have applied some with a rag to some samples of wood that were sanded to 220 and left them in the house to dry (about 70 degrees inside). After several days and a couple different samples, I am having serious doubts with this finish because it feels very oily to the touch. I know the finish is dry but it seems very tacky. I realize that I should sand between applications of the finish, but I am very nervous that the result will still feel very oily (and not as nice to the touch as the natural wood).
1) Has anyone experience with Flecto Varathane or similar products?
2) What other types of finishes might I try? I don’t have the equipment to even attempt varnish unless excellent results could be obtained w/ a high-quality brush.
3) In lay-mans terms, what is the difference between urethane and spar urethane?
Thanks for any help.
Z
Replies
Z,
A urethane varnish will give you a very durable coating, but urethanes are not very easy to rub out to a smooth satin or gloss which is usually the goal when finishing a fine piece of furniture. Urethanes are great for high traffic floors or a table top that is going to get a lot of abuse.
In all varnish formulations, urethane or alkyd, spar varnish is formulated to never completely harden. Its intended use is in a marine environment where flexibility of the film is necessary and it is anticipated that frequent re-varnishing is a standard activity. Some spars may feel hard and dry but are still more flexible than non-spar types. Others actually feel tacky for their entire life.
Behlen's Rock Hard is one of the best finish varnishes for furniture. It is very durable and rubs out very well. Scuff lightly between coats and let it cure for at least 2 weeks, if not a month before final rubbing with steel wool, 600 grit, rubbing compound and or polishing compound to your liking.
Rich
Varnish is resin and oil and solvent plus other stuff that's added like flattening agents and UV inhibitors. It's easiest to think of it in terms of being just oil and resin. Resin by itself is too hard and brittle and rigid to make a decent finish. Oil is added to resin to make it more flexible. Spar has more oil than interior varnishes because it needs to move more due to sun, shade, hot and cold weather. Spar is softer than interior varnishes due to this higher proportion of oil.
Oils in varnishes are tung or linseed generally. Resins can be synthetic, like urethane, polyurethane, varathane, etc., or natural resins extracted from linseed oil or tung oil through a process using acid and alcohol and these resins are called alkyd, named for the process of extraction.
The resins used in finishes can be very hard, like polyurethane or a bit softer, like alkyds. The harder the resin the more scratch resistant the finish. But, polyurethane is cold and hard to the touch and a true bear to apply well. Alkyds are much warmer and softer to the touch but are a bit softer. A good quality alkyd is a pleasure to work with. Application characteristics are levelling, bridging, open times and viscosity. Synthetics really suck at this, alkyds are much easier to apply. I've been using alkyds on my work for two decades and would never consider synthetics for fine furniture. Give them a try.
Oh, because of clean air standards recently enacted volatiles have been lessened in varnishes. Oil was added to make up the difference. Because of this it's quite important to thin the first coat 15% or so with solvent. This will make that first coat that gets sucked into dry wood harden much more quickly. After the wood is sealed by that first coat go full strength for subsequent coats uless you're spraying.
Lee
First, Flecto Varathane is just Flecto's brand name for their polyurethane varnish. In other words, it's just a rather plain poly varnish little or no different from any other manufacturer's poly varnish. Like most of today's varnishes, it handles and flows out better if thinned about 10-15% with mineral spirits.
"Spar Urethane" is another brand name used by Minwax for a rather poor exterior finish. True spar varnish is a finish designed to be very soft and flexible so it maintains its integrity when used on wooden "spars" or masts on sailboats. It is soft so it is not a good finish to use where there will be any abrasion. Spar varnishes are never used for areas that will get any abrasion. Also, no true spar varnish will contain polyurethane as urethanes rapidly deteriorate when exposed to the UV from the sun. There is very few situations where a spar varnish should be used as a furniture coating.
The best furniture varnish is an interior varnish. It has the most solids and will be the hardest and most durable.
Z,
Like others have mentioned the varathane (at least used to) has tung oil within and it takes forever to dry. I used the ext varathane years ago for cedar chairs. When it finally did dry it was very hard and very durable for the first two years (being in all weather). After that period of time, the varathane starts peeling off which may also be because of the natural oils in the cedar. Anyway I stopped using the varathane.
The past few years I have been experimenting with water based poly's and thus far really like Muralo's "Ceramithane" sold by Highland Hardware. I'm still brushing my finishes.
Bill
I greatly appreciate everyone's comments, insight, and suggestions. I have a good reason now (like I ever needed one) to go to my local woodworking store.
Thanks again!!!
Z
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