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Cocobolo finishing

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Forum topic by DevinT posted 12-08-2021 04:12 PM 695 views 0 times favorited 40 replies Add to Favorites Watch
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DevinT

2384 posts in 299 days


12-08-2021 04:12 PM

Topic tags/keywords: cocobolo

I have these cocobolo feet for a plaque I am making.

I planed one side, sanded the other side to 400, and burnished the bottom to 3k grit and then used polishing compound.

Now here is my question, but bare with me. I think I have a shortcoming in knowledge when it comes to “furniture grade” and what that means. I am looking to increase my knowledge of fine finishing.

ASIDE: Not quite yet to the level where some of you all are doing French polishing, but my question is much more specific than just exploring finish technique.

I had been admiring the natural qualities of this wood and so far to date in my woodworking experience when it comes to finishing, I had been admiring the “pores” of a wood that look almost like the dimples on pig skin leather. But this Cocobolo is really pronounced. I was looking at photos and zooming in:

Is this what grain filler products are for? Do they fill those holes? Should I fill the holes?

OK, so now I was planning on doing one of two things to this wood:

1. Drench it in acetone and then quickly flood it with Danish Oil then wipe clean and hand rub for about an hour, sit for a day (occasionally wiping), and apply furniture wax — a process that has worked well for teak, walnut, and other woods I have worked

or

2. Just some dark paste wax (I read that the paste wax will get into those little holes and you want dark paste wax to keep from forming contrasting dots). Maybe some furniture wax over the paste wax.

So, fill the holes? With what? Which finish approach would you use? Other recommendations?

-- Devin, SF, CA


40 replies so far

View Dave Polaschek's profile

Dave Polaschek

9309 posts in 1915 days


#1 posted 12-08-2021 07:03 PM

Grain filler will fill those holes in the grain.

An alternative is French polishing, where you’re using an abrasive (pumice) to remove a very small amount of the wood and use that to fill the grain, gluing it in place with shellac and linseed oil.

I use grain fillers more when I’m looking for a contrasting color, because I can buy or make all sorts of crazy colored grain fillers. I use French polishing more when I want to avoid the contrast. And sometimes I skip the pumice entirely, either because I’ve sanded fine enough to clog the pores with sanding dust created by sandpaper, or I decide that the pores are fine enough that they can be filled just with shellac.

Dark paste wax will work, but it will be a temporary finish. Set the piece in the sunshine, and it may thin enough that it will no longer fill all the pores. Or clean the piece and the wax will be gone.

For a rosewood (dalbergia) like cocobolo, I think I would French polish for a flat piece, or grain-fill and then sand for curved surfaces where I would have trouble padding the pumice around to use the wood to fill itself. But I have the benefit of having shellac and linseed oil, plus a well-used pad and pumice all on hand. No shopping required!

Yet another alternative would be making your own grain-filler. Buy something like the clear Goodfilla and mix it with your fine sanding dust from the pieces to get a color that will be as good of a match as French Polish without needing the elbow grease. When the Goodfilla sets, it’s nice and hard, but still sandable, and you can get a decent color match if you get the ratio of filler and sawdust right. I would try that if I was having problems getting a good color from French polishing.

-- Dave - Santa Fe

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DevinT

2384 posts in 299 days


#2 posted 12-08-2021 08:39 PM

Luck would have it, I saved about a quarter pound of dust from surfacing it. Hmmm.

-- Devin, SF, CA

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SMP

5056 posts in 1238 days


#3 posted 12-08-2021 09:22 PM

Is that endgrain?

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pottz

22280 posts in 2317 days


#4 posted 12-08-2021 10:14 PM

ive worked with cocobolo many times but never noticed holes like that.ill look at mt stash and see if that is the same with what ive got.dave have you ever noticed that on any youve worked with ?

-- working with my hands is a joy,it gives me a sense of fulfillment,somthing so many seek and so few find.-SAM MALOOF.

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Aj2

4221 posts in 3131 days


#5 posted 12-08-2021 10:18 PM

I would spray them with deft rattle can lacquer. Stunning looking wood
Good Luck

-- Aj

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DevinT

2384 posts in 299 days


#6 posted 12-08-2021 10:18 PM

Yes it is end grain

-- Devin, SF, CA

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pottz

22280 posts in 2317 days


#7 posted 12-09-2021 01:09 AM

dev i looked at the coco i have and no tiny holes like that at all,just smooth soild wood.as for finishing ive always just used an oil finish,coco will polish up to a high luster very well.

-- working with my hands is a joy,it gives me a sense of fulfillment,somthing so many seek and so few find.-SAM MALOOF.

View Mario's profile

Mario

206 posts in 4729 days


#8 posted 12-09-2021 01:27 AM

Why go through all that trouble?....a couple applications of sanding sealer and topcoating with your favorite finish is all you need, still have to level the finish at the end so avoid yourself all that needless suffering…..imho

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therealSteveN

9383 posts in 1907 days


#9 posted 12-09-2021 02:38 AM

I’ve seen those tiny holes on wood that was heavily waxed when green, like the chunks turners use. I don’t believe it’s a “wood” feature.

-- Think safe, be safe

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DevinT

2384 posts in 299 days


#10 posted 12-09-2021 03:32 AM

It was heavily waxed after being rough sawn. Has been sitting in a bin in the rafters at MacBeath for decades. Super aged.

-- Devin, SF, CA

View Lazyman's profile

Lazyman

8781 posts in 2720 days


#11 posted 12-09-2021 03:58 AM

The pores look pretty much like the cocobolo end grain pictures on Wood_Database which says they are medium to very large (50-200 microns across).

Grain fillers are most commonly used on open pored side train like mahogany or walnut to get to a super smooth surface before you apply a finish. Unless the pores are detracting from the appearance, I wouldn’t worry about them, especially if you are not shooting for a French polish look.

I would guess that just trying to fill the pores with oil is a bad idea. If the oil does fill the pores it may take weeks to cure. I have never tried it but I have often seen Aqua Coat clear grain filler recommended for filling grainy wood in preparation for a high gloss finish.

I tried a technique once where you use BLO and abrasive pad or wet/dry sand paper to create a slurry with the oil and sawdust to fill grain. It was a lot of work and really didn’t make that much difference—probably because I needed to spend a few more hours at it.

EDIT to add: This probably goes without saying but try any new finishing technique on a cutoff/scrap first.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

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DevinT

2384 posts in 299 days


#12 posted 12-09-2021 02:03 PM

So apparently mixing dust with finish is a thing in fine woodworking I am learning.

Going to give it a try.

-- Devin, SF, CA

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HokieKen

20636 posts in 2471 days


#13 posted 12-09-2021 02:43 PM

I would ignore the pores. I’ve seen them but have to really look for them. They won’t affect finish at all in my experience. For French polishing, you would want to fill the grain but that is moreso to level the surface rather than to fill any pores.

-- I collect hobbies. There is no sense in limiting yourself (Don W) - - - - - - - - Kenny in SW VA

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SMP

5056 posts in 1238 days


#14 posted 12-09-2021 03:24 PM


So apparently mixing dust with finish is a thing in fine woodworking I am learning.

Going to give it a try.

- DevinT

Absolutely. We have a local master chairmaker here who teaches various classes etc. the feel of his chairs and other stuff he makes is amazing. He uses Liberon Finishing oil as it dries quickly. Oils with longer dry times dont work as well as Lazyman noticed. The key is to create a slurry of finer and finer wood dust and hardening oil to push into the pores/grain. Here is the method my local chairmaker uses:

https://russfilbeck.com/866-2/

https://www.woodmagazine.com/woodworking-how-to/finishes-finishing/russ-filbeck-s-award-winning-oil-finish

View EarlS's profile

EarlS

4983 posts in 3681 days


#15 posted 12-09-2021 05:28 PM

+1 – sander sealer to seal the holes then finish like you normally. You might want to wipe it down with some alcohol or acetone, or whatever you can get in CA that works a solvent, to remove any surface oils. I’ve had problems getting finish to cure on exotics and others recommended that approach and it seems to work.

-- Earl "I'm a pessamist - generally that increases the chance that things will turn out better than expected"

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