Black Grain Filler Under EM6000?

[Trevor Healy]

I have a feeling that you might want to use something other than epoxy to do the black grain fill. Ideally, if you put it on raw wood, you’d want to sand it back so that only the black is left in the grain. But it seems risky on raw wood. I think sealing the wood first is a good way to go, even if it all gets sanded off again when you’re leveling the epoxy. I was also thinking you could potentially even use the Emtech Black 6600 as your pore filler. That stuff is thick and you could wipe it on and off, or squeegee, then scuff sand to remove excess. You’d have to experiment with dry time of course.

[Michael Bashkin Bashkin Guitars]

Hi: I think there is a risk using vinyl sealer under tinted epoxy. Some of the solvents in epoxy might eat into the sealer coat and expose the raw wood to the colored epoxy. I would seal with one light clear epoxy and after it cures use tinted epoxy on top of that. Just something to try.

[Karl Borum – Borum Acoustics]

Thanks Michael. I just watched your Epoxy Pore Filling demo today, what timing…

[Karl Borum – Borum Acoustics]

I have been using water based filler over sealer: sealer/ black filler/ sealer/ lacquer. I may just give that a test, (but with WB lacquer) but I would love to seal my purfling lines with epoxy. My last build was a nightmare with tiny “invisible” gaps that I couldn’t see until lacquer. I could barely see them afterward with a visor + loop. I would like to seal those almost invisible gaps before top coating (I know gaps shouldn’t be there in the first place, just coming clean……).

[Karl Borum – Borum Acoustics]

The EM-6000 WB topcoat and EM1000 sealer finally arrived; let the testing begin….

I’ve made a number of test panels for black grain filler under EM-6000 top coat and over Silver Tip Epoxy grain filler (including Michael Bashkin’s suggestion). I am going to update this thread with the results as the panels are completed. Materials are listed in the order applied.

The black filler, when done properly, accentuates the natural effect of dark shadow in the bottom of the grain, so there must be grain deep enough to accept the black filler, while the surface wood must be sealed such that dye from black filler will not discolor it. I had a killer method for nitro, but I’m moving away from nitro, hence the method testing.

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Panel #1 A and B (rejected; process not recommended) Honduran Mahogany:

1/2 the panel was grain raised with water then 320 sanded, the other half was not (A and B)

<b style=”background-color: var(–bb-content-background-color); font-family: inherit; font-size: inherit; letter-spacing: 0px;”>EMTECH EM1000 WB Universal Sanding Sealer

Silver Tip Grain Fill

Light scuff with red Scotch Bright

Rockler Wunderfill water-based Black Grain Filler

Final level sand with 320 on hard block

No top coat (yet)

RESULTS: The water-based sealer raised the grain, on both A side and B side, surprising given B side was grain raised. After the final “level sand” the surface was lumpy looking and uneven. A more rigorous flat sanding removed the black filler, down to a flat surface without grain.

Flat sanding the EM1000 sealer before epoxy would have likely sanded through the sealer due to the raised grain, I would rather not chase raised grain, so I reject this process. Another panel (#4) will have epoxy base with black filler directly over epoxy, then sealer. The #4 test case is drying and will be evaluated later.

Panel 1 might have been acceptable with 2 coats of sanding sealer with a flat sand in between but would have likely filled the grain to the point that the black grain filler was moot- that is, there would be insufficient grain depth to hold the black filler. The sanding sealer appears to fill grain very well, albeit it does raise the grain (damm it).

[Karl Borum – Borum Acoustics]

Black grain filler on mahogany, with Silver Tip Epoxy Grain Filler and EM6000 Top Coat:

What worked best, and what I went with:

1. Sliver Tip grain fill over bare wood.

2. Black StewMac water based grain filler; 2x

3. Final seal with another coat of Silver Tip Epoxy

4. Scuff sand 320 and topcoat with EM6000.

With all the methods, the black color in the grain filler did not bleed, which was a main part of the test panels. I do not like how much the EM1000 sealer raised the grain. Perhaps there is a work around but this case is closed, for now,