Ebonite woes

[Blind_Squirrel]

I am working on a Patriot that I turned using ebonite. I can't get the ebonite to come out to a consistant finish; no matter what I do it turns out splotchy.

I searched the forums and tried both a natural finish (polished to 12000 MM) and CA (again polished to 12000 MM); both come out splotchy. It looks like it might be the ebonite itself. With both attempts I started out with 400 grit and worked my way up to the 12000 from there.

Any suggestions/tips on how to get it to a consistant finish i.e. either all glossy or all matte? Given my preference, I would like to go glossy.

Thanks.

 

[ctEaglesc]

Shoot an e-mail to DC bluesman
He works with the stuff a lot

 

[PenWorks]

Generally I do not put a finish on ebonite. It should sand & buff out very nice.
After your MM, I buff with tripole and then the white diamond and that's it.
I have put enduro over black ebonite, as it will keep the black from oxidizing.

 

[redfishsc]

Anthony, I'm a bit curious as to why you buff with something coarse like tripoli after you micromesh the wood. Tripoli is insanely more coarse than 12,000 micromesh, even white diamond isn't quite as fine grit---this seems like backtracking to me. Have you tried skipping the abrasive agents and just buffing with a carnauba wheel?


I know I'm speaking a bit out of inexperience, but it seems to me like you could save yourself time by either skipping the MM by going from 600 grit to the tripoli and white diamond, or by skipping the abrasive wheels and going from MM to buffng with a carnauba wheel.



As a side note, I'd like to guess that the CA isn't adhering very well to the ebonite b/c of the resin/glue content of the material combined with the very high polish the micromesh puts on it. I know this sounds like blasphemy to many of y'all but if you tried sanding no higher than 600-800 grit, I'm sure the CA would stick a lil better.

 

[DCBluesman]

Resin? Glue? Ebonite is vulcanized rubber. Just polish (Micro-mesh or buffing compounds) the heck out of it and slap on some lacquer.

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[RussFairfield]

The old question why a polishing compound that is coarser will leave a surface that has a higher gloss than the finer grit sanding medium.

Think of the sanded surface as a series of "U" shaped grooves with a peak between them. You can see these as scratches from coarse sanding, but you will need magnification to see them from the finer grits. The light you see reflected is from the bottoms of the U's.

Now use a polishing compound on a buffing wheel. The secret is the word "compound". You are using an abrasive with a viscous carrier. Typical carriers are tallow or wax. When applied with the buffing wheel, the carrier fills the bottoms of the U's and the abrasive flattens and rounds over the points between them. Voila, twice as many reflective surfaces, twice the light reflected towards you eye, and twice the gloss.

Tripoli is not really "insanely coarser" than 12,000 Micro-Mesh. The buffing compounds are not really much different from the MicroMesh grits. Comparing grit sizes, the 12k MicroMesh is about the same as 2000-grit sandpaper. The Tripoli is a jewelers rouge abrasive that is about 900-1000 grit on the same sandpaper scale. White Diamond is an 1800 grit particle size, and that is close enough to being the same as the 12k MicroMesh to call them the same. The difference is how they are used.

 

[bonefish]

Russ:

Buffing, if done at right angles to the sanding scratches, tends to smear the top ridges, making the surface smoother and more brilliant. At least it works that way on hardened steel.

Comparing MM 12K and 2000 grit silocon carbide wet or dry sandpaper, I find that, although the grit might be close to the same size, the MM gives a higher gloss. I use the 2000 grit, then the MM, then a paper towel.

Bonefish