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How best to fill scar (crack) in walnut panel

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Forum topic by DannyW posted 10-17-2019 07:49 PM 716 views 0 times favorited 11 replies Add to Favorites Watch
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DannyW

197 posts in 333 days


10-17-2019 07:49 PM

Topic tags/keywords: walnut finishing question

I am finishing up on the walnut top for an entry bench but the side that I want to use for the top has a scar about 2” long (but not deep) that I like (gives it character) but how should I fill it before finishing (or should I even try)? I have attached photos of the top and the scar. I am planning on finishing with 3 coats of Danish oil followed by 3-4 coats of Arm-R-Seal. The bench frame is red oak with walnut accents and I will be attaching the top with wood clips that I have made. I am asking the advice of the fine folks here with way more experience than I have; the top is just beautiful and I really don’t want to mess it up.

-- DannyW


11 replies so far

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Snowbeast

114 posts in 1873 days


#1 posted 10-17-2019 08:05 PM

I would pack it full of fine sanding dust and then drizzle with thin CA glue. Sand it flush and finish as you wish. It will look like that knot is just a nice solid piece.

Just make sure you post the finished product!

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CaptainKlutz

1939 posts in 2030 days


#2 posted 10-17-2019 08:30 PM

+1 saw dust and thin CA

For a seat on bench, I would use some 30 min epoxy mixed with saw dust. But it will be thicker, and have to use putty knife and work it into the crack. The epoxy is stronger than CA, and has better flexibility for when that 350lb uncle visits.

Probably need two applications regardless of adhesive used; as 1st will sag into crack slightly as it cures.

Might want to put some masking tape on bottom side to prevent the glue from running out and all over the bottom?
Be sure to give adhesive time to cure, or you can/will drag gummy residue across surrounding area as you sand.

Best Luck.

-- I'm an engineer not a woodworker, but I can randomly find useful tools and furniture inside a pile of lumber!

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Rich

5001 posts in 1125 days


#3 posted 10-17-2019 09:46 PM

Given the already blackish color of that, the easiest fix would be ebony colored Timbermate. It will look dull when it dries, but the finish will seal it and you’ll have a perfectly smooth area. Just spread it with a putty knife, being sure to push it in firmly. Leave the surface slightly proud and sand it when it dries. You’ll want to give it a few hours or overnight to be sure that it’s fully dried down in the void before you sand.

If I were doing it, I would do a more involved repair using a burn-in knife and hard fill, but that takes special tools, materials and a lot of practice.

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pottz

6639 posts in 1520 days


#4 posted 10-17-2019 10:13 PM

id just fill it with dark brown or black epoxy then sand smooth and finish as you stated.

-- sawdust the bigger the pile the bigger my smile-larry,so cal.

View DannyW's profile

DannyW

197 posts in 333 days


#5 posted 10-18-2019 12:16 AM

Thanks for the suggestions everybody, they are much appreciated. I think I will go with the walnut sanding dust followed by CA glue. And yes I will be sure to post pictures of the finished product!

-- DannyW

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LesB

2216 posts in 3978 days


#6 posted 10-18-2019 12:23 AM



Thanks for the suggestions everybody, they are much appreciated. I think I will go with the walnut sanding dust followed by CA glue. And yes I will be sure to post pictures of the finished product!

- DannyW

That works well but I would also use medium CA glue immediately after applying the thin CA….before it sets up. That way the thin glue wets the filler and wicks the thick glue in making a solider filling. I have done that many times so I know it works. Pack the filler as tight as you can before adding the glues.

I would suggest collecting a dark colored sawdust (even dark roast coffee grounds would work) to fill this particular crack. A light contrasting color that is lighter than the area around the crack probably won’t look good.

-- Les B, Oregon

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runswithscissors

3080 posts in 2560 days


#7 posted 10-18-2019 01:01 AM

My method would be to use epoxy (5 minute would work fine in a small crack like that), mixed with walnut sanding dust. You can try leveling it before fully cured with a sharp chisel. In any case, sand it smooth. The Danish oil will turn the walnut dust in the epoxy a nice dark brown. Epoxy has the advantage that it will penetrate to the bottom of the crevice very readily.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

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Lazyman

4080 posts in 1923 days


#8 posted 10-18-2019 11:49 AM

I have used epoxy with various fillers or dyes to fill voids and that is my prefered method. Just be sure you sand all of the epoxy off the surrounding surfaces or it will block the finish and could make the defect more, not less visible. A card scraper can be a good way to remove the epoxy on the surface. If you don’t have one you need one. :-)

I’ve used CA too but be careful with the thin CA. It soaks in to porous woods and can permanently discolor the area surrounding the void and for that reason, I personally would not risk it here. It is worse on light colored wood but can affect dark ones too.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

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OSU55

2437 posts in 2525 days


#9 posted 10-18-2019 04:27 PM

+1 for not using ca due to soaking in the surrounding wood. I do a lot of this with turnings and flat wood. Epoxy or timbermate are much better. For epoxy I use a dab of artists oil paint. Saw dust or shavings mixed in do not take much if any color because they saturate with epoxy. Dark brown or black will look good in this situation. Card scraper or plane can flatten out the repair.

You dont need DO unless for color – the ars will provide plenty of chatoyance. For color I would mix dye directly into the ars. Colored DO is tinted with pigment, not dye. I much prefer the look of dye in the wood vs pigment on the wood. Some minwax dark walnut stain, letting the pigment settle and using the dye on top, mixed with poly – ars – looks very good on walnut and oak. Thin the ars about 1:1 with ms, add dye to the intensity desired and apply like DO, ie wipe off. 2 coats, then finish with ars any way you want. Test to get the intensity desired.

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DannyW

197 posts in 333 days


#10 posted 10-18-2019 08:28 PM

I thought I had some medium CA glue but it was hard as a rock, so I tried the thin CA glue and sanding dust approach on a hole that was on the underside and it worked beautifully. I will be doing the same with the knot crack on the topside. I have some seams to fill in the red oak frame so it may not be appropriate there; this is my first time doing mortise and tenon joinery, and some of the joints left visible seams where the stretchers meet their mating leg. I read somewhere to make a paste using sawdust and linseed oil and fill the seam with the paste; I have never tried this so will try it on some scrap first.

-- DannyW

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LesB

2216 posts in 3978 days


#11 posted 10-20-2019 05:33 PM

I read somewhere to make a paste using sawdust and linseed oil and fill the seam with the paste; I have never tried this so will try it on some scrap first.

- DannyW

This will give you a similar potential for a color change in the adjacent wood but will work, taking a lot more time to cure than a color matched commercial wood patch (water based) which might work better. The draw back of the CA is that it is impermeable so it won’t take a stain and unless top coated with a hard finish like poly it can appear as a “shiny” spot for instance if just an oil type finish was used as the final coat.

Also “3 coats” of Danish oil will take quite a while to cure depending on conditions before you can apply the Arm R Seal. Anywhere from a few days to two weeks. One coat of oil should be enough to make the grain “pop” is that is what you are looking for and should cure in a couple of days.

-- Les B, Oregon

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