Lessons In Wood Finishing 16 Years In The Making

elcoholic

Jet Fuel Genius
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Many of us refinish audio gear with whatever is handy and don't really give it a second thought. I offer these learnings in the hope to save some grief in our community.

16 years ago I was blessed beyond measure by the wood gods and obtained 3 large planks of Koa from a retiring cabinet maker. By large I mean immense 9 ft long x 2 ft wide x 2 in thick. He got them from a guy that brought them over from Hawaii in the 60s when you could still get it. He only wanted $300 making this the score of a lifetime. I used 2 of them to make my wife an 8 ft dining room table. These 2 boards had a retail value of at least $6,000 at the time. I don't say this to boast, only to point out that this is serious wood, it deserved my best and I came up way short.

I put my heart and soul into this table, it's mahogany base and a set of 8 mahogany chairs to go with it. The finish took weeks. Hand-rubbed BLO (Boiled Linseed Oil), a barrier coat of de-waxed shellac and several sprayed top coats of Enduro water-borne poly. It was absolutely stunning. The suite 'debuted' with the whole extended family over for our traditional spaghetti dinner before the candle light service at church. Much to the horror of all the warm moist paper plates stuck to the table and the finish was ruined.

Lesson 1 - Read The Label And Test In An Inconspicuous Place. I waxed the table with dark Briwax which I later learned uses toluene as its solvent. Toluene softens water-borne finishes. Had I tested the wax on the bottom and taken my time things would have been very different. The sticky mess required bagging the room in plastic and wet sanding with a pneumatic RO sander. I was so disgusted with myself I only stripped the top which brings me to ...

Lesson 2 - Always, Always Finish Both Sides Of Solid Wood Exactly The Same Way. Wood is dead as dead can be, it doesn't breath, but it does react with it's environment and takes on and releases moisture with changes in humidity. Unequal finishes affect the rate at which this occurs. More moisture content swells the fibers and less moisture constricts them. So I took a short cut and I refinished the top with a wiped oil/varnish blend. I though "close enough", but time wood tell (sorry). The top didn't have nearly the same atmospheric moisture resistance as the bottom so over the years the table top cupped - a whopping average of 7/32". That table was dead flat when I made it. After glue-up I took it to a shop and they ran it through a 48" wide belt sander. Nobody else noticed the cupping, but it's been chapping my hind-end at every meal for countless meals over the years.

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The straight edge is 2" wide.
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Today was the day to right this old wrong and take care of unfinished business. Armed with a couple of RO sanders, a Fein Dust Extractor and a bunch of sanding disks it got sanded down to bare wood. To further demonstrate the differences in the finishes the gentle Makita palm sander took the top down with (5) 320 disks.

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The poly finish on the bottom took the beast mode Bosch and the rest of these spent disks starting with 180 grit and followed with 220 before going back to the Makita with 320. Which is brings us to ...

Lesson 3A - Don't Skip Grits and 3B - Use Dust Extraction. More consistent scratch refinement, longer disk life and way less mess. I would not dream of sanding like this in the house.

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Lesson 4 - De-Waxed Shellac Is The Be All, End All When It Comes To Barrier Coats. BLO and water-borne top coats mix just like, err, well, oil and water. W/B top coats are far healthier to spray, but they leave the wood looking dull. BLO brings out the beauty of the wood, but W/B top coats won't stick to it. Bullseye Superblond Shellac is key to having your cake and eating it too. How good does it seal? This next picture blew my mind.
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I thought the dark spots in the middle were missed finish until I smeared them with my hand. WTF? That is 16 year old BLO weeping out of the end grain of the under bevel surface. Evidently BLO is classified as a non-drying oil for a very good reason. Even when cut 1:1 with mineral spirits and dosed with a couple shots of Japan Drier.

Lesson 5 - Working Wood Takes Great Patience - As Tom Petty said, the waiting is the hardest part. All I can (should) do now is give nature time to do it's thing and let the open wood acclimate and reach equilibrium. If it was thinner I could use a steam iron on the dry side to speed things up, but this is 1 5/8" of very dense wood and I have to follow Lesson 5 to the fullest. I'll know it's done when the table is flat again. Then I can open the can of Sam's oil/varnish blend and let the magic out.

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Nice write-up,and beautifully done!

You ain't kidding about that wood; I know a guitar maker and a cabinet maker who would be willing to make an ''anatomical sacrifice'' for that much Koa:rolleyes:
 
Thanks arts. That top weighs at least 150-175 lbs. Any one dude that can carry it out of here is welcome to it.
 
Meh,my lunchbox weighs that at least:biggrin:

Did you ever use the third plank? That grain would make for a really gorgeous turntable plinth...
 
Nice recovery and writeup. I have yet to try water borne finishes. Wipe on poly or spray lacquer are my go to's but I want to try WB finishes. It's great this forum has members that share experience beyond hifi.
thanks
 
Meh,my lunchbox weighs that at least:biggrin:

Did you ever use the third plank? That grain would make for a really gorgeous turntable plinth...

Yes. It's a live edge piece. I surfaced and finished one side, put a 4 ft French cleat on the other and hung it on the wall. I was planning to make a mahogany side board and use the slab it as a floating top. Well that hasn't happened yet and it's not likely given the dance Uncle Art(hritis) has been doing on my skeleton in recent years.

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It’s been almost 2 days and it looks flatter so I measured the cupping at each end. It’s moved much faster than expected. It’s now at 1/8” a avg which is 3/32” flatter. :banana:
 
A moisture meter was the best investment I made when trying to avoid excessive wood movement after completing a project. Even kiln-dried wood isn't necessarily dry or stable enough to work immediately, and a cheap meter can help you determine when the wood is acclimated and stable. I've made more mistakes with finishing than I can count, and almost every time a little more patience would have helped avoid a mistake.
 
Good tips and a good story!
Al I can think of is how many ukuleles are in that headboard slab, lol.

BTW, I added some splines to the undersides of a table and countertop I have that reside outside. Three splines in a four ft table. They seem to be holding the glue-board tops in good alignment.
 
I was a failure when I tried to make a living doing "fine" woodworking. I was a failure because my previous education and career caused me to get so fascinated with finishing that I COULDN'T FINISH ANYTHING!

As a college art major, I got pretty deep into pigments, vehicles, resins, oils and solvents. That led to a real job in the paint, coatings and printer's inks and adhesives industry, working in labs researching and formulating all sorts of interesting goo. When I started woodworking, I spent all my time fooling around with samples of mixtures and techniques. Just the world of waxes can keep me distracted for a lifetime. Polymers? OMG, don't get me started!
My wife, a degreed chemist, is convinced that all of these products should be based on pigeon poop, because that stuff is indestructable.
 
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Good tips and a good story!
Al I can think of is how many ukuleles are in that headboard slab, lol.

BTW, I added some splines to the undersides of a table and countertop I have that reside outside. Three splines in a four ft table. They seem to be holding the glue-board tops in good alignment.

Yeah that would make a bunch of ukuleles!

I was a failure when I tried to make a living doing "fine" woodworking. I was a failure because my previous education and career caused me to get so fascinated with finishing that I COULDN'T FINISH ANYTHING!

As a college art major, I got pretty deep into pigments, vehicles, resins, oils and solvents. That led to a real job in the paint, coatings and printer's inks and adhesives industry, working in labs researching and formulating all sorts of interesting goo. When I started woodworking, I spent all my time fooling around with samples of mixtures and techniques. Just the world of waxes can keep me distracted for a lifetime. Polymers? OMG, don't get me started!
My wife, a degreed chemist, is convinced that all of these products should be based on pigeon poop, because that stuff is indestructable.

In 2001 I took a shot as a high end custom furniture maker. I had a severance package from my engineering job equal to about 10 months of paydays. The commissions were good and not that I set out to be a chair maker, but I got to make a bunch of (30ish) chairs because that was the work that found. I failed because I couldn't do it all anywhere near fast enough all by my lonesome and I didn't want the headaches that come with employees. So back to engineering I went.

Pigeon poop might be kind of nasty on a dining table. The secretion of the humble lac bug is pretty durable in the absence of alcohol and is very repairable. Protein glues, fish and hide, are pretty strong and reversible if you can get past the smell. The old timers did pretty well with what they had, pigeon poop not withstanding :)

OK I just took another measurement and the cupping is down to 3/32" remaining. The rate of change has slowed way down, but that's to be expected as it gets closer to equilibrium.
 
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First, thanks to Elcholic for this fine writeup. That table is going to be magnificent.

Second, what's the story with Koa wood?? Why so expensive/rare?
 
First, thanks to Elcholic for this fine writeup. That table is going to be magnificent.

Second, what's the story with Koa wood?? Why so expensive/rare?

Thanks James. Koa has excellent working properties & tropical rot resistance, is also a tone wood for instrument making and only grows in Hawaii so it's always been scarce. It has also been protected for decades. Only dead trees can be logged. Most of it goes to veneer. Black acacia is the closest we have here on the main land.
 
oy,... wood working, finishing,....
I have two homes in Architectural Digest, one as a cover and feature. The other as a featured home. They were owned by a pair of brothers, and we built them from the ground up.
They have a boat that is capable of world cruising. In one of the adventures, they managed to bribe the right ifficials in a region of Asia with old growth teak forests. They were allowed to export many full teak tree stumps back to Washington where we milled them into useable lumber. From there we built two 15k sq.f.t homes, right on the beach in Laguna Beach. All of the wood trim in the house, we manufactured, and installed, and finished. We built a massive amount of the furniture as well, of solid old growth teak, and, with lots of decorative fantasy faux finishing as well.
We applied 7 coats of hand rubbed wax finishes to the teak ceilings , rubbed down int the thousands of grit fineness. The wood grain glowed magically after this many coats.
We also did other massive homes throughout Orange County. We had special dispensation from the state that allowed us to use in excess of the limit of 75 gallons of sprayed lacquer, daily.

Wood finishing?
ridiculous amounts of super high end.

we built and finished the stair pads, and handrail in this image. I also finished the stairs stringer with linear polyurethane, which in 1987 dollars was $250 gallon. The stair case was three stories tall, up through the center of the house.
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This is a small portion of one of our teak ceilings. This room felt as large as a football field, just huge!
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That's some beautiful finishing work!! I recently obtained a live edage walnut slab that I intend on making my desktop; what exactly was your finishing method? It looks like BLO, DW blond shellac and then WB poly. If it turns out half as astonishing as that 3rd slab of Koa I'd be ecstatic!!

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oy,... wood working, finishing,....
I have two homes in Architectural Digest, one as a cover and feature. The other as a featured home. They were owned by a pair of brothers, and we built them from the ground up.
They have a boat that is capable of world cruising. In one of the adventures, they managed to bribe the right ifficials in a region of Asia with old growth teak forests. They were allowed to export many full teak tree stumps back to Washington where we milled them into useable lumber. From there we built two 15k sq.f.t homes, right on the beach in Laguna Beach. All of the wood trim in the house, we manufactured, and installed, and finished. We built a massive amount of the furniture as well, of solid old growth teak, and, with lots of decorative fantasy faux finishing as well.
We applied 7 coats of hand rubbed wax finishes to the teak ceilings , rubbed down int the thousands of grit fineness. The wood grain glowed magically after this many coats.
We also did other massive homes throughout Orange County. We had special dispensation from the state that allowed us to use in excess of the limit of 75 gallons of sprayed lacquer, daily.

Wood finishing?
ridiculous amounts of super high end.

we built and finished the stair pads, and handrail in this image. I also finished the stairs stringer with linear polyurethane, which in 1987 dollars was $250 gallon. The stair case was three stories tall, up through the center of the house.
View attachment 1122678

This is a small portion of one of our teak ceilings. This room felt as large as a football field, just huge!
View attachment 1122679

Wow! Very great! And I love the water feature. How did you achieve that stone-look behind the pool?
Our house is a barn we converted. When we did my audio room, I ran a cold water pipe, a 20A device, and a drain pipe out to the area flanked by my elevator and stairs, so I could put an indoor pond and falling-water-over-rock deal in the future.

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Those mechanicals lie right under the easy chair.
I'd be interested in any info about your build that might be handy.

Also, in the old stalls below is my hangout/audio space. We used a lot of local Tulip Poplar that was cheap (all the stair treads, which were 1/2" thicker but we pulled them and planed them down-they looked too heavy, cost $300! The aquarium base and hood is also TP.
Downstairs, we took advantage of the fieldstone foundations and drilled 1" holes into it and pinned all the record shelves, etc onto the walls.
Which brings me to the table my gear sits on. We glued 3? 2x~12 planks together, then drilled them nearly fully through, hammered one inch steel rod into, and loaded the masonry holes with epoxy.
Then we put the table top into them, jigged it to level, and waited for everything to dry. Good luck pulling this out!!
I was a little scared to do this with the rods, but the top has stayed perfectly flat and un-checked for 10 years now.

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