Friday, January 29, 2010

The Finish Line

When I'm in "the zone", it can be difficult to resist the desire to glue up a project before I add finish to inside pieces of a drawer or cabinet.

But you do yourself a favor if you finish first, assemble second. That's because trying to achieve a flat, brushed- or ragged-on finish when you're dealing with inside corners is next to impossible.

I fixed the drawer on my sawbuck table but, tempted as I was to glue it up, decided to first conduct a comparison study of different finishes on a practice piece to see which looks best.

The sawbuck table is made from curly cherry, a wood that's tricky to plane and tricky to finish, at least in my world.

My normal finishes of choice are shellac, Watco wipe-on poly, and boiled linseed oil (BLO). I never stray too far from them because I'm not an enthusiastic finisher and prefer to get the process done and dusted.

I consulted with friends and researched a few ideas and chose the following to try on a test piece, which was sanded to either 220 or 320 grit (I can't remember).

1. 2 coats of garnet shellac; 8 coats of blonde shellac; rubbed out with 0000 steel wool.

2. 1 coat of tung oil, thinned 30%, and dried for 24 hours; 2 coats of 100% tung oil, with 24 hours drying time in between.

3. 1 light coat of BLO, dried for 24 hours, then lightly sanded with 320 grit paper; 1 coat of garnet shellac; 6 coats of blonde shellac; rubbed out with 0000 steel wool.

4. 1 coat of BLO, dried for 24 hours, then lightly sanded with 320 grit paper; 1 coat of garnet shellac; 6 coats of blonde shellac; 1 coat of Watco wipe-on poly; rubbed out with 0000 steel wool; 1 coat of dark paste wax, rubbed out with a soft cloth.

Two woodworking buddies visited my shop last night and I asked their opinions. Neither one saw a difference between #3 and #4 (I thought #4 looked a little darker). Neither one liked the tung oil (nor did I). Both preferred the straight shellac (as did I).

#3 and #4 popped the figure the most and were darkest, although they did look a bit blotchy (maybe sanding to a higher grit would fix this?). I also thought they looked a little too shiny for a rustic piece, but they would look terrific on fine piece of furniture.

The tung oil looked dull and uninteresting and did not bring out the figure as I thought it would.

The shellac looked most natural and had a soft, buffed sheen. The figure did not pop as much (but there was not as much figure on the end of the board), however, it did not look at all blotchy.

I'm no finishing expert, so in the hands of someone else, all four finishes might look fabulous. But I've decided to stick with shellac. For this experiment, I applied more layers of shellac than I had ever done before, and I can say without hesitation, that the more layers, the better-looking the finish. I usually stop at four layers, but applied 10 to this sample. The result is beautiful.

Recently, there was discussion on the SAPFM forum regarding BLO and shellac. Two points that grabbed my attention: BLO will turn black over time, and shellac might peel if poly is applied on top of it.

One thing's for sure—if you're going to spend a lot of time building a project, it's worth it to invest the time in researching the best finish. Even if you end up using the same old standby.

29 comments:

Jonathan said...

I have tried pre-finishing before assembly, but the boards tend to move enough that glue-up is always a pain. I make sure that the wood is acclimated to my shop (hard to do in the Mid-Atlantic with the humidity always changing). Any other pointers?

George Beck said...

A wonderfully detailed post as always. One thing to keep in mind with finishes is preference. Some prefer a subtle dull wood look ,others prefer a shine. There are penetrating finishes and film build finishes. One is inside the wood not on the surface and the other is laying on top of the surface(like poly). Shellac is a film finish that is built up very slowly like lacquer. A combination of the two can be achieved with a oil/varnish mix like Minwax Antique Oil( or Watco Danish Oil) which contains linseed and tung oil. One can argue whether these are oils fortified with hardening agents(varnish) or varnished thinned with oils for penetration. The advantage is, among others, less coats. I might mention, I was with The Sherwin-Williams Company for 28 years, the makers of Minwax. Thanks for the always useful information.

John Cashman said...

I used to finish as you did in # 1, and still like the look. I never cared for oil only, as in # 2, and it degraded quickly. Yes, it's easy to fix -- but I don't want to have to "fix" a finish.

I now use # 4 for the most part, with a couple of minor changes. I don't stain cherry, but use an aniline dye on maple, especially figured maple. I then use BLO and garnet shellac. Instead of the blond shellac, I use Seal Coat, essentially a dewaxed shellac. You can put anything on top of that, and it won't peel. I also had problems putting other finishes on top of blond shellac, if it wasn't dewaxed. Instead of regular poly, I use water based poly. It is crystal clear, and doesn't darken the finish the way oil based poly will. I use the poly now because the shellac topcoat was prone to damage, especially from liquids. And because the water poly is so clear, you really can't tell the difference between it and shellac alone.

For tool handles, I like Minwax Antique Oil. The varnish adds protection, and it has an "old-timey" look.

Thanks for the experiment. It's always good to see a side-by-side comparison.

The Village Carpenter said...

Jonathan, if you prefer to finish the piece after glue-up, you can put blue painter's tape on the inside corners so that any glue that squeezes out will be on top of the tape instead of on the wood. You probably already heard that one before, though.

George, I figured I must have applied the tung oil incorrectly since the piece you showed me looked so nice. Finishes are totally subjective as you pointed out. Thanks for the advice--I've heard a number of people mention how much they like Minwax Antique Oil.

The Village Carpenter said...

John, have you ever put varnish on top of shellac? Is that as tough as poly? Thanks for the tips!

Ian W said...

I enjoy your site and really enjoyed this post on finishes.
Finishing is the down fall of my work. However, I have become a huge fan of shellac, the drying time means less dust in a dusty shop, it polishes well and I never liked the high gloss plastic look anyway.
Did you mix your own shellac or was it from a can?
cheers,
Ian W
walwoodwork.blogspot.com

Rob Bois said...

I've always been told that shellac is the ultimate universal seal coat. There is nothing you can't put on over shellac, so it serves as a good barrier between two incompatible finish layers. But the comments I'm seeing here seem to contradict my understanding. Anyone care to clear this up for me?

Bill Stankus said...

Shellac also ages and, with time, will darken. Museums often have dark, almost black looking furniture pieces ... because the shellac aged and changed. Typically with restored antiques w/shellac top coats, wax is the final application.

In the old days and ways there was common belief that furniture, especially chairs, would require occasional disassembly - and that was fairly straight forward since the "binding agents" were hide glue and shellac. So restoration was simple.

Today's glues make it impossible for simple disassembly and lacquers and polyurethane are glass-like and not easy to remove or repair.

Bob Easton said...

THANKS for the great photos Kari!

Your multi-photo compositions are always fabulous, and this post highlights how valuable they are. We have the pleasure of seeing multiple viewpoints at once. Wonderfully informative!

I too have found tung oil not so special. For me, it's just a pricier alternative to BLO, which is perfectly fine for woodworking tools, canoe oars, and other working objects ... but not for household furniture.

Gotta go get some shellac...

Dean Jansa said...

Bill,

The black finishes in the museum are likely due to BLO and other factors.

Shellac, from what I've been able to find reading, researching and listening to conservators, does not darken over time. UV damage can occur, but the results are not the darkening of the film.

Chris Friesen said...

I wonder if the comments at SAPFM also apply to the "tried and true" version of BLO, which they say has no heavy metal driers. Also, I wonder if BLO which is covered by a topcoat will go black over time.

This past year I tested shellac, shellac-over-blo, poly-over-blo, and poly alone on some red oak for a mirror frame. The shellac-over-blo was notably superior to the others in the way it highlighted the grain and the rays. The straight shellac just wasn't as nice.

The poly-over-blo looked basically identical to straight poly, leading to the possibility (which I haven't tried) of using a thinned coat of oil-based varnish instead of BLO under the shellac.

Extremely Average said...

I am really new to woodworking. This post and the comments, while informative, scared me to death. I really want to learn how to be good at finishing wood, but it seems it is a massive subject to understand.

I would like to start with one question. What is BLO?

badger said...

@Average

BLO - Boiled Linseed Oil

It's a finish that goes back a long way.

Frank Vucolo said...

Great information, Kari.

I'm a patient finisher, but not a very confident one. That is I never seem to have it 'for sure' in my head. So I take the approach you have and try several samples.

A recent project had several species (veneer) and some holly stringing and I was petrified about screwing it up with the finish.

I prepared several sample boards, laid up with the various veneers and stringing and experimented.

I really liked the shellac over BLO the best. I made several blends of garnet and blonde shellac and decided on blonde because it worked best with the holly contrast (though some blend of garnet/blonde would have been preferable without the holly.)
The final step was three coats of lacquer. In the end, I loved the results, but it's so sressful!

So, practicality, protection and the appearance of the finished piece aside, one of the things I love most about this craft is that stage where I get to take oil to painstaikenly prepared wood and watch it come to life as I rub in the oil.

Frank

Jeff said...

I have tried many finishes and have come narrowed in on Minwax Antique Oil because I can build a thin, non-plastic looking finish on the surface and not worry about dust, etc because one wipes off the excess (which leaves behind a thin smooth coat). After 2-3 coats, I knock off the gloss with 0000 steel wool and leave it as is if I want a satin finish. I apply wax if I want a nice mellow sheen.

You can make up your own version with a mixture of tung oil, BLO, and varnish. This is essentially the Sam Maloof finish.

Ray from Louisiana said...

Kari, well done as usual. Your timing is right on spot. A friend just gave me some AMAZING figured cherry. I understand how cherry can be a bear to keep from blotching. Because of this I've been doing lots of research on finishing methods.
It appears that great success has been found in reducing the dreaded blotching by "washing" the wood in a thin unwaxed shelac and spirits solution first to seal for base the finish. I believe the mix is 50/50. I plan to try it as soon as I get to using the cherry (I can hardly wait). BTW, anyone have a good contrasting wood for cherry other than maple, which is the front runner atm.
Thanks again and keep 'em coming.

The Village Carpenter said...

Ian, I do mix my own shellac as told to me by Bess Naylor from Olde Mill Cabinet Shoppe. She said to pour as many flakes as you want in a jar, then cover them with denatured alcohol, then add more alcohol so it is double that height. In other words, the flakes will reach half the height of the alcohol.

Rob, I read on one of the forums that you can put anything on top of dewaxed shellac, but not waxed shellac.

Bill, thanks for chiming in!

Bob, it seems (to me) like tung oil is very similar to BLO, but is a lot lighter and not as warm. It's a good alternative if you don't want to add too much amber color to your piece.

Thanks, Dean!

Chris, the shellac definitely did not highlight the grain as much as the BLO/shellac test. I've never worked with varnish, but would be curious to see what you discover with your experiment.

Brian, don't be scared! There are lots of recipes, but start small. Pick two or three to play with on different types of wood, save the samples, and write on the back of them what you did. Keep them on hand for your next project.

Thanks, Badger. ; )

Frank, did you spray on the lacquer? I've never used it. As much as I dislike finishing, it does bring the wood to life.

Jeff, I have to get some of that stuff. So many people have suggested it to me.

Ray, what is the contrasting wood being used for--string inlay or something larger? If stringing, then holly is a great choice. It's the lightest color wood you can get. You can also go the other side of the spectrum and use a super dark wood, like cocobolo or ziricote.

Jeff said...

Kari,

Am I remembering correctly that you have tried Waterlox Satin? That is another one that is pretty bullet proof. It just goes on a bit thicker than Minwax Antique Oil because it does not get wiped off, though I expect one could approach it in a similar fashion. I have never used the satin version but have heard others laud it because it is one of the few that gives you a true satin finish. It certainly does apply nicely with a fine cotton "rubber".

Frank Vucolo said...

Kari,

Yes, I sprayed the lacquer. I'm not set up for the real deal, so used aerosol cans I got from Woodcraft.Can't remember now if it was Watco or Bahlen. I'd used it on small items before with good results so tried it on a dressing table and was very happy with the finish over shellac and BLO.

It dries super fast, so you can get a few coats on in no time and dust doesn't stand a chance. You need plenty of ventalation, so I did it in good weather in a wide open garage.

A booth and real equipment would be nice, but if you can wait for a nice day, great results can be gotten with aerosol lacquer.

Pick up a can next time you're at Woodcraft and expriment.

Frank

John Cashman said...

Kari,

I have tried some varnishes, and like them a lot. They do generally add some yellowing, which can sometimes be desirable. I think I used it on a walnut cabinet a long while back, because it seemed to really bring out the color I wanted. I don't like stains or dyes on dark woods. I think Minwax had a wipe on varnish that I was partial to. I used to wipe on varnish and shellac, as it gave a texture to finishes that seemed appropriate to period furniture.

Someone had asked about other finishes on top of shellac. Yes, as Kari said, if it is dewaxed. Shellac with wax in it will cause topcoats to flake. Sealcoat is dewaxed, and good suppliers such as TFWW will say if shellac is dewaxed or not.

I've used Waterlox on turnings, and like it in that application.

The Village Carpenter said...

Jeff, I have not tried Waterlox, but a friend of mine swears by it. Thanks for the recommendation. I'll add that one to the list as well.

Thanks, Frank, I'll give it a try. I imagine that lacquer would be especially good for surfaces that get heavy traffic.

John, thanks for the info. I don't quite get the difference between varnish and poly, but plan to give it a try.

Grover said...

Great post. I will have to give this finishing process a try on one of my next projects.

Carl said...

I recently finished a curly cherry top, using simply three coats of GF Oil/Urethane, 220 grit between, then two coats of paste wax, 0000 between. Smooth as glass and the figure is mesmerizing and fiery. On the test piece I could not get a white ring from anything; hot plates, ice cold beer, or coffee mugs, and any fine scratches disappear with a sweep of my shirt sleeve. Can't think of a more beautiful finish or and easier one.

Woodbloke said...

Kari - a dark art, to be sure and in my view, one that should be kept as simple as possible. On my side of 'the big wet' there's a product called Osmo-PolyX (matt or satin) which is actually a flooring product. All you need do is to apply two very thin coats, leave to harden off and then buff with a soft duster. I usually apply some wax over the top of a matt finish which gives a softer sheen. The beauty of it is that it's easy to apply...and bullet proof!
I reckon there must be something similar available in the US of A...I strongly recommend that you source it and give it a go - Rob

Anonymous said...

Kari,

To be fair you did not really give tung oil a chance. You used 3 coats of tung oil vs. almost triple the amount of coats for all the other finishes. I personally have found polymerized tung oil (From lee valley) to be amazing and produce a durable, warm and grain popping finish.

http://lumberjocks.com/projects/13362

At the above link you can see the diningroom table I made with ~10 coats of tung oil(1 coat of raw, 9 coats of polymerized)

sorry for the rant. I am just a tung oil fanatic

Samuel said...

Hi Kari!

I read your blog on a regular basis and I'm struck by something when comparing to other woodworking blogs:

Your blog has a much higher degree of selfcriticism than the other sites I visit. I like it.

I used to write a blog about my first job as a pilot. I used the blog to improve myself and to evaluate my performance each day. I did this by openly criticising myself and admitting to mistakes and faults that originated from me.

A friend had a blog alongside mine about more or less the same thing, but her's was completely without open self critique. For me it was fun to read her blog, for a while. But then it was just the same thing over and over again.

A blog with open self criticism takes the whole thing to a new level, one can start to see trends in the posts and some sort of evolution within what is being discussed. That analytical element is what makes your blog so good.
Thanks and keep it up!

About the post itself: number 3 is the best in my view. And I don't find it blotchy at all, more of a draped velvety look... sweet!

Regards/ Sam

The Village Carpenter said...

Grover, it really helped to see different techniques side-by-side. Then, once you've done it, hang onto your samples so you always have reference. If you're impatient with finishing, like I am, it will save you lots of time with future projects.

Carl, thanks for the recommendation. I added it to my list of ones to try.

Rob, I'm all for keeping the process simple! :o)

Anon, thanks for your comment. I appreciate constructive criticism. That technique was suggested to me by a friend, since I've never used tung oil before. I'll put a few more coats on the sample to see if it makes a difference. Your table is beautiful!

Samuel, thanks! I'm all for self criticism. :o) It's possible that if I had sanded the cherry to a finer grit, no blotching would have occurred. I should have mentioned that it was my partner's favorite of the samples and she didn't think it looked blotchy at all. It would be a beautiful finish on a higher end piece, but the rustic nature of the sawbuck table really calls for something less flashy. I actually think it will look better to downplay the grain in this piece.

Anonymous said...

Hey Kari

Once again, very thoughtful post. I liked number 4 actually, really made that grain stand out!! Funny thing I was just reading Jeff Jewitts Finishing book and saw he does the same thing with with figured wood. I had no idea BLO made that big of a difference.

I will definately add this to my shellac repertoire!!

One question though, Jeff says in his book that shellac flakes have an almost limitless shelf life when stored in a cool dry place. I have always thought shellac flakes had a poor shelf life, any thoughts?

As always a great post, looking forward to the next one !!

Dave B

The Village Carpenter said...

Thanks, Dave. #3 and #4 came from Jeff Jewitt's book on finishing. The two others were suggestions from friends. I consulted other books, but Jeff's ideas appealed to me. I agree with him that shellac flakes, if stored in a cool, dry place, will last a long time, if not forever. I'm using flakes that are years old and they aren't sticky or clumped together at all. Once you mix the shellac, however, you have at most 6 months to use it. I only give it 3. If you've ever finished a piece with old shellac, you'll never do it again. The premixed shellac that you buy in a can lasts for one year after opening the lid.