Bubinga cookie slab filling

Photos always help get better responses.

Pre-finish with shellac?
Maybe try a different brand of epoxy?

I really have no clue, but maybe one of these works (?)

I bet if you wiped the slab with water or alcohol, it would turn black until the liquid evaporated, then it would return to … blah. So the epoxy is having the same effect, except that it doesn’t evaporate.

The only thing you can do now is sand it out. Don’t be shy, start with 60 grit.

I think it’s the end grain absorbing. If Yiu have more to do, I would try BC’s suggestion about shellac. I often tape off cracks just to limit the amount of mess to remove. You can also make a template by rubbing a pencil along the edge of the crack then cut out the profile.

I've got about 30 more cookie cut slabs to go... I'm going to put this one back on the flatting jig and route off a 16th and start over. I've got a second one flattened, shellac-ed, and epoxy poured. I will update once it sets and I get started sanding. Thank yall for the replies. My intended finish is Rubio monocoat.

End grain of a porous species, same thing happened on the red elm cookie I did. I ended up buying a syringe and blunt needle set on Amazon and "surgically" filled the cracks and voids. I still had some shadowing as trying to sand it out was taking off too much material. Once the finish was on it wasn't noticeable. A thick/clear finish though would amplify the shadowing.

Are you sure thats bubinga? i make a lot of boxes from bubinga and I havent seen any that pale and that open grain.

I looked again. If that was a reality tv show, or a youtube video, they would fill the crack with some brightly colored epoxy and call it a feature. And double the price.

rbashley said:

I've got about 30 more cookie cut slabs to go... I'm going to put this one back on the flatting jig and route off a 16th and start over. I've got a second one flattened, shellac-ed, and epoxy poured. I will update once it sets and I get started sanding. Thank yall for the replies. My intended finish is Rubio monocoat.

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i finished some end grain slabs with rubio and it was a total pain in the butt, the rubio doesn't go far on end grain. it was very frustrating. i would consider other options if i were to do another end grain table. if someone has a good tip please chime in, i am by no means an expert. just wanted to forewarn you

rbashley said:

I'm working with some bubinga cookie cut slabs and when I try to fill voids with epoxy (west systems), it is staining the lumber black anywhere the epoxy touches!! I HAVE to come up with some sort of solution.
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I see that you level the slab with a router sled. I have had the same issue with epoxy fills. One solution that usually works is to carefully mask off everything but what is to be filled with a tight sticking masking tape. I think a better solution would be to level the slab after you do the fills.

sunnybob said:

Are you sure thats bubinga? i make a lot of boxes from bubinga and I havent seen any that pale and that open grain.

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That's what the bill of laden from the mill in brazil says...

sunnybob said:

Are you sure thats bubinga? i make a lot of boxes from bubinga and I havent seen any that pale and that open grain.

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I haven't worked with it, but this says "Sapwood is a pale straw color and is clearly demarcated from the heartwood. "

Looks like you already have the solution but I follow Blacktail Studio on YouTube and one of his solutions to this problem is to pre-finish with a clear coat of something that doesn't penetrate. Another which he details in this video is to use charcoal as his pigment (and it looks like he's actually using it with West Systems epoxy as well).

Dbolick said:

i finished some end grain slabs with rubio and it was a total pain in the butt, the rubio doesn't go far on end grain. it was very frustrating. i would consider other options if i were to do another end grain table. if someone has a good tip please chime in, i am by no means an expert. just wanted to forewarn you

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going off a little more from what i previously said, if i was doing another end grain slab, i think i would put a coat of clear epoxy and sand it down after it cured so now the epoxy has filled in the pores and then apply the rubio. i've not tried this myself but i have seen it done in videos and it seemed to work well

That’s really weird. It looks like there’s something in the wood that is reacting with the epoxy because it looks like the epoxy is turning black. Am I seeing that right?

As others have suggested, I’d seal with shellac, then fill, then use a film finish over that.

I think Rubio needs to go on raw wood and so it won’t work over shellac.

Dbolick said:

i finished some end grain slabs with rubio and it was a total pain in the butt, the rubio doesn't go far on end grain. it was very frustrating. i would consider other options if i were to do another end grain table. if someone has a good tip please chime in, i am by no means an expert. just wanted to forewarn you

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I finished mine with Rubio, no issue, I honestly didn't think that little can was going to do front and back. I had left over and coated several times.

what was your final grit on sanding prior to Rubio?

shoot summ said:

I finished mine with Rubio, no issue, I honestly didn't think that little can was going to do front and back. I had left over and coated several times.

what was your final grit on sanding prior to Rubio?

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the final grit i had used was 150 on an oak cookie and walnut cookie

shoot summ said:

I went to 320 on a red elm slice, 350ml Rubio, had to work to use it all up, coated several times, even "wet sanded" to 600 grit with it.

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that's beautiful! Yeah I would definitely sand to a higher grit if I were to do it again. I was hesitant since the directions say to only go up to 120 or so