I’m ready to finish a solid walnut table that I’ve built. I’d like to prevent it from fading. Are there any disadvantages to using Spar Urethane instead of regular Polyurethane in a wipe on mix of 1pt urethane .5 pt Min. spirits, .25 tung oil?
Other than exterioor use and UV protection what are the differences between the two?
Replies
The walnut table won't fade.
Wipe on is thinner than reg. poly, thus requires more coats. Spar is more flexible- designed for coating the spar(s) of boats.
Thanks! That's very intresting, It's flexible. It makes total sense! All this time I thought Spar was a chemical in the urethane, not the part of a boat. But Jackplane, what exactly is a spar? My great-grandfather use to build boats on Long Island, but no longer answers any questions.
I'll go with my original mix, unless you have any other suggestions to try. I'm stuck in this wipe on rut, It's always worked for me. Would there be any benefit in waxing it after it's final (7th) coat? It's something I've always done, but don't know if it's really all that necessary since the wood is sealed instead of simply tung-oiled.
Spars are the masts and booms on a sailboat. Spar varnish is made to cure soft & flexible so it won't crack as the wood expands and contracts from the extreme changes in environment you see on a boat. It has little abrasion resistance and really doesn't have much place in furniture finishing, either indoors or out. Oil/varnish mixes like yours are also somewhat soft. You can't get much build with them, although they build better than straight oil.
I generally use BLO/poly/MS wipe on for much of my furniture & always apply wax with 0000 steel wool to ensure a smooth, "touchable" finish with a nice sheen. It's best to wait a few weeks before waxing.
You are exactly correct about spars and spar varnish. It's a very soft finish with little abrasion resistance. It is not intended to withstan being walked on, sat on or worked on. It has little application for almost all furniture coating applications.The best varnish or poly varnish to use is that designed for interior use. It will have the most resin solids giving the most durable finish. For exterior use, use an exterior varnish. Poly additives to exterior varnish decrease the durability. Polyurethane quickly begins to deteriorate when exposed to UV. It is never used in true marine exterior finishes.Howie.........
Howie, where do you think I learned about spar varnish? :)
Thanks a lot for the poly info! This really clairifys things.
About the waxing... What do you prefer to use? I've been using Johnson's paste on top of this poly wipe on. Usually two coats. Is that overkill? It's kind of streaky after I buff it... must be overkill.
Also with the BLO, which I understand has no curing resin, is this better than tung in the mix even though there is resin in the poly? Also I've learned that the tung oil I've been using is a "finish" (BEHR-Home dpt) and not 100% pure. It hasn't been a problem in the past, but is this counter-productive?
And finally, is there a clear pore filler available, or should I sand everything down and build up again?
Obviously I'm experimenting here, and the answers to my questions are extremely valuable. I am very greatful for the advice. Thanks so much!
There should be no need for waxing. However, if you do wax, give the finish time to fully cure otherwise the off-gasing can soften the wax. Wait 3-4 weeks for a varnish finish. One coat of wax applied per the directions on the can is enough. The solvents in wax dissolve the prior coat and you just end up with a somewhat gummy surface. That's what you are seeing when you wax.Howie.........
Johnson's is good stuff, I've used it quite a bit. The most common mistakes made with waxing are (a) using too much and (b) letting it get too hard before buffing.
I learned from a book by Bruce Johnson (paraphrased here):
Apply a thin coat in small, light circles, working into any open pores. Work on one section at a time.
No more than 5 minutes later, buff lightly in a circular motion, removing only the excess wax
Wait about 10 more minutes, then buff again, more vigorously and only in the direction of the grain.
At the end of an hour, do the vigorous final buffing with the grain.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
How long do you wait between coats when you use your BLO/Ploy/Spirits mix?
Do you sand with an ultrafine grit, steel wool, or not at all?
Would you mind sharing your process?
Thanks!
The first two applications are absorbed pretty thouroughly. You can get them on the first day, and usually apply a third. After that, I wait until the surface is no longer tacky, which can take a full day for the later applications. I will rub out the surface with 0000 steel wool if it feels rough, which normally happens only if you don't wipe the surface completely after each application. I generally use 6 or 8 applications applied over a 4 or 5 day period. I apply wax with 0000 steel wool a couple of weeks after the last application of finish to get a silky feel and nice sheen. I've used this finish on coffee tables and end tables, but I wouldn't use this for a table regularly used for eating and drinking.
Should I just use straight poly for this table that will be used for eating and drinking?
I've applied the first two coats of this mix already. When I did, I noticed some absolutely striking curl in the walnut. Now it has penetrated and is somewhat flat.
Straight gloss poly is the most durable finish I have used and is perfect for a "working table". You can always lower the gloss by rubbing it with steel wool and wax after it cures, if that's the look you like. I usually apply poly by wiping after thinning 1:1 with MS. Takes twice the applications as full strength applied with a brush for the same build, but it's much easier to do than brushing.
This is an interesting topic to me, so I would like to say a few things. More personal observations that any kind of advice. Garret Hack wrote an article in FWW several years ago in which he gave the recipe for a spar varnish and tung oil mixture. I used it several times and liked it allot. But I wouldn't use it for a table top. Beheln's Rock Hard Table Top Finish is what I use there. I also wouldn't use wax on a table top, glasses with the least amount of moisture on the sides or bottoms will leave rings.
Bill
Never heard of the Behlen's finish before. Where do you get it?
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