daviddoria

Avoiding "puddles" of dyed epoxy

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Hi guys,

I am filling some checks and small cracks in a walnut slab. I am using West Systems (105 + 205 (fast)), and a few drops of black India Ink. I applied the epoxy (kind of just dropped it on with a toothpick), let it cure, then used a card scraper to scrape it smooth. This filled the crack perfectly, but about 1/4" around the crack there is a black "stain" from where the epoxy puddled/pooled before it cured. How do you prevent this / what do I do about it now? I can keep scraping and scraping and the problem seems to get better (presumably the dye hasn't penetrated THAT far into the wood), but I'm going to make a huge divot (and it's also hard to remove that much material on crotch figure, etc.).

Surprisingly I also filled some cracks in the end grain and it seems to sand right off (I was expecting that it would have pulled much farther into the end grain (capillary action, etc.).

Any tips or thoughts would be appreciated!

David

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Good question, I've dealt with this a bit as well. Curious to see what others have to say. 

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Minnesota Steve, then you'd just make the curved outlines of the puddles become straight edges. The nature of most cracks doesn't lend them well to being taped - I feel like no matter how many tiny edges of tape you tried to use to make a boundary you'd still have this problem.

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This won't help you now, but in the future just use clear epoxy. Once you put a finish on it blends right in.

I wonder if you can tint the finish the same way you tinted the epoxy. Maybe it will blend in. You might try it on some scrap.

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31 minutes ago, daviddoria said:

Minnesota Steve, then you'd just make the curved outlines of the puddles become straight edges. The nature of most cracks doesn't lend them well to being taped - I feel like no matter how many tiny edges of tape you tried to use to make a boundary you'd still have this problem.

Cut the tape with the contour. 

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Practice taping, get better at using tape and use a good masking tape, use a razor blade for cutting around the "details".  Devil is in the details, pre, prep ,prep!!

Or remove more wood, you shouldn't have a divot, you should be taking/sanding wood from all around the repair, just not around the repair. Also, are you repairing on rough flat sawn surfaces or is the surface already processed?

 

-Ace-

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The surface was already sanded basically flat from the mill where I bought the slab. So any local card scraping I do makes it "not flat" (even if the epoxy is 1" and I scrape around like 6", you can still feel a 6" "dip" when you run your hand on the surface, ya know?)

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It's better to fill over wood that has been processed and sanded to about 120 grit. The tape will stick better the color won't be absorbed as deep, should any get under the tape. 

 

-Ace-

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Here is something to try: apply a coat of the finish that you will later use on the entire top to the area around the unfilled defect.  If this is done with a [very] short-nap small roller it should allow for applying some finish on the top but NOT into the defect.  When you sand the top you will likely remove all the finish around the defect and then..........well, proceed normally.

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6 hours ago, daviddoria said:

Minnesota Steve, then you'd just make the curved outlines of the puddles become straight edges. The nature of most cracks doesn't lend them well to being taped - I feel like no matter how many tiny edges of tape you tried to use to make a boundary you'd still have this problem.

So you ask a question, are given the answer and return that he's wrong and you know better.. why even ask?

If you can't tape close to the crack, you need practice taping, not a different answer. I find green frog tape lays very well and does seal the edge a bit which isn't needed when you tape very close to the crack.

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Tape is the best suggestion, but I have found sanding with a ROS at 120 grit works better than scraping. Sand the whole slab, not just the repair to avoid divots. If you already have the divot, you need to scrape/sand amuch larger area to taper out the depression so it isn’t visable. 

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Not helpful this time, but in the future, use powdered pigments. Little to no absorbtion into the wood.

For tiny cracks, clear is fine. Larger cracks, sanding dust from the same wood. Knots and inclusions, dust and dry coffee grounds.

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I agree with 1) sealing the wood around the area with finish or clear shellac sealer and 2) try a powdered pigment.  Good luck.

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