Blackwood *^)(!#$@@!

[ngeb528]

Hi all,

Need some advice. I'm making a pen & pencil set for a graduation present and I'm having some trouble with the CA finish on the Blackwood portion on the first of the two blanks.

It starts out ok, but around the 4-5th coat, I get some areas that look great and some that are hazy or dull.

Tried thin CA on 1st try, let it sit for a while then tried to put ren wax on it. It almost looked like the ren wax removed some of the CA in areas.

Sanded it back and tried medium CA on the 2nd try and a combination of the two on the 3rd try. Can't get it right for some reason.

The top - Redheart - finished beautifully.

Is Blackwood oily? It didn't feel that way but what do I know.

This thing is kicking my butt. Help :frown:

 

[mick]

Nancy, Blackwood is a rosewood and is oily. If you have some accelerator wipe the blank down with it first to get rid of the surface oils. Then apply your CA finish....no BLO.

 

[GodofBiscuits]

Yeah it's oily. I've found wiping the blank down with acetone first then applying an even coat of BLO before applying finish helps to even it out. You can also try wiping it down and using the CA only. I personally will be going to a lacquer finish for woods like these.

 

[bradh]

Like the others have said, wipe it down.
The dull patches don't always show up right away. The reason the patches did not show up until the 4th layer is it too that long for the oil in the wood to start reacting with the finish.
Many people here have tried different finishing methods with Blackwood and wiping off the oil with a strong solvent is the only thing that seems to work consistently.

 

[RussFairfield]

It is a fact of life that oils that are in or applied to the wood and not polymerized into a solid will dull the gloss of a finish. The oil can be removed for long enough that a gloss finish can be applied. However, the oil in the wood will eventually migrate back to the surface of the wood, and it will then migrate through to the surface of the finish because all finishes are porous. The only difference between the various oils and finishes is in how long it will take for the finish to lose its gloss.

Also, some woods have more oil than others. You mentioned the difference between Redheart and Blackwood. Be aware thaty the Redheart is one of those that will also lose its gloss over time. It just takes longer than Blackwood, but in a few months to a couple years they will have the same matte finish.

Many will disagree with this, but that's only because they haven't waited long enough. I have several pens in old inventory that were made from oily woods like Blackwood, Cocobolo, Ebony, and such that have never been used. They had a high gloss when new, and it lasted for a few months to a couple years, depending on what finish was on them, and the wood. Five to ten years later, they are all a dull flat matte finish. The finishes are still the same. Only the gloss is gone. Other pens from woods like Maple still have the same high gloss as when they were new.

If 2 years is an acceptable life for the gloss, then use CA glue because it is the least porous of all normal finishes, and will last that long. If you want longer than 2 years, I would suggest you learn how to use a plexiglass coating because it is not a porous coating and it is unlikely there will be any loss of the gloss with time. Either way, remove the surface oil with acetone.

Other than that there are two low gloss possibilities. You can use a no finish finish that is just polished wood that will keep whatever gloss it gets from finger abrasion during use. The other option is to cut back the surface with 0000-steel wool to something far less than a high gloss to start with. Either way, there will be no high gloss to be destroyed by the oil.

You might be surprised how many people prefer the low gloss or matte finish.

 

[jamiller99]

Russ,

I have seen exactly the same phenomenon that you are discussing with every pen I have made using oily woods finished with CA's and BLO/CA's. Eventually they develop the dull patches described in this thread. Do you have experience with the long-term durability of the Plexiglass (PMMA, polymethyl methacylate) finish on oily woods? I am trying to learn more about this finish technique exactly because of the dulling issue with CA's. So far, my attempts with PMMA have yielded middling results at best in terms of finish characteristics (generally slightly milky appearance). However, I have big concerns over the long-term stability. Rates of diffusion of the wood oils through PMMA and polycyanoacrylates (CA) are likely to be very similar. (All of the film-forming finishes are nonporous, including CA, PMMA, and lacquers, but all are permeable to various materials, such as wood oils, via diffusion to varying degrees).

As an aside, I am looking into other transparent plastics that might have high diffusion barrier properties to wood oils. The idea would be to use a coat or two of such a material as a barrier to the diffusion, effectively sealing in the oils. The last several coats could be virtually anything, CA, PMMA, whatever. Diffusion isn't always directly related to solubility, but I have a few ideas. The leading candidates at this point are ploystyrene and polyethylene terephthalate glycol (PETG), a copolyester. PETG is not so easy to dissolve....but that's good. Problem is, the best solvent I have found is hot methylene chloride, not a great choice...... PETG also has the advantage of being about 30% harder than either CA or PMMA, so if I can make it work (safely), it may be the next great finishing choice. Lot of work left though.....

Thanks,

John

 

[Kaspar]

Has anyone tried turning a difficult wood down to slightly below the bushings, then casting it, and turning it down again? I realize the time involved in two turn downs would be an annoyance, but it seems to me that would be a kind of ultimate finish.

 

[RussFairfield]

Kaspar, good idea, but I'll bet that Snakewood would still crack.

 

[Kaspar]

Kaspar, good idea, but I'll bet that Snakewood would still crack.

Yes, the three things in life that are certain: death, taxes, and Snakewood going "crack." Although this guy seems to have solved the problem.