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Oil first or epoxy fill first?

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Forum topic by AllanK posted 12-20-2018 04:07 PM 988 views 0 times favorited 31 replies Add to Favorites Watch
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AllanK

55 posts in 4500 days


12-20-2018 04:07 PM

Topic tags/keywords: english walnut question finishing epoxy fill danish oil

I’m working on a piece of English walnut that has some deep cracks going all the way through. I’m going to fill them with West System 105/206 epoxy, and finish the piece with Danish oil. I have a question about the sequence of operations:

Do I finish the piece completely, oil it, and then fill the cracks, or, fill the cracks, then sand/finish the piece and then oil it? I’m wondering whether the epoxy around the cracks will prevent the oil from being absorbed.

Here are pics of the cracks:

And on the other side:

-- "Stupidity is forever, but ignorance can be fixed."


31 replies so far

View OSU55's profile

OSU55

2363 posts in 2412 days


#1 posted 12-20-2018 04:15 PM

The epoxy will prevent the oil from being absorbed but…. you will flatten the surface after epoxy. The thin line left isnt noticeable to me. For turning bowls I epoxy then turn flat then finish. Since you are using danish oil You might find this an interesting read.

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ocean

164 posts in 1256 days


#2 posted 12-20-2018 04:24 PM

Epoxy first – oil will interfere with epoxy bond.

-- Bob, FL Keys

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pottz

5570 posts in 1407 days


#3 posted 12-20-2018 05:40 PM

definitely epoxy first as bob stated.

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

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AllanK

55 posts in 4500 days


#4 posted 12-20-2018 06:22 PM

Thanks, I suspected as much. I’m going to try to put wax along the edges of the crack, do you think that will help, in case I get a bit clumsy with the pour?

-- "Stupidity is forever, but ignorance can be fixed."

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avsmusic1

442 posts in 1108 days


#5 posted 12-20-2018 07:09 PM

are you coloring the epoxy?

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AllanK

55 posts in 4500 days


#6 posted 12-20-2018 07:11 PM

No, leaving it clear.

-- "Stupidity is forever, but ignorance can be fixed."

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Andybb

1932 posts in 1026 days


#7 posted 12-20-2018 07:53 PM

Epoxy 1st. The epoxy becomes a structural component of the wood. The oil is a finish. This is assuming that the slab and cracks are stable and don’t need butterflies. If that crack in the picture is on the outside as it appears that would be a candidate for a butterfly. The epoxy is a great filler and adhesive but not strong enough to prevent further cracking on its own.

I’d stay away from the wax. You’re going to need to sand it down to bare wood anyway. You don’t want any trace of the wax on there when you apply whatever finish you’re gonna use.

Don’t know if this is your first epoxy pour so I’ll say to make sure you pour in stages. Seal it very well with the tape. The epoxy will bubble and heat up and melt the glue on the tape if you pour too much at one time. For that crack seal the end and bottom and pour a little in from the top and let it harden then add more epoxy.

-- Andy - Seattle USA

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ocean

164 posts in 1256 days


#8 posted 12-20-2018 08:12 PM

Not a bad idea to tape off the surfaces near your epoxy pours to try and keep it off the surrounding wood. If your cracks are real loose you may need to inlay a bow tie/butterfly or two. Depends on how strong you need it to be. Epoxy many time is not strong enough of prevent farther cracking. Just a thought.

-- Bob, FL Keys

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AllanK

55 posts in 4500 days


#9 posted 12-20-2018 09:44 PM

Andy, yes, it’s my first pour, and I just experimented on a scrap piece of the same walnut. The stuff goes everywhere! This is an art piece, not structural, so butterflies are not desirable. I’ve had the slab for over a year in my shop and the cracks have not changed at all. I just want to give it some support, otherwise I would leave it as is with the cracks.

When you say pour a little and let it harden, so you mean really harden for the full curing period?

Bob, I will be taping the back and side with 3M metallic tape.

-- "Stupidity is forever, but ignorance can be fixed."

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Andybb

1932 posts in 1026 days


#10 posted 12-20-2018 10:21 PM


When you say pour a little and let it harden, so you mean really harden for the full curing period?

- AllanK

Yes, or at least overnight. If not, then you’ve got to really seal the bottom. It goes all over the place because the epoxy heats up and the glue on the tape melts. If you only use a little to just give it a hard base then the rest of the epoxy will sit on that and not leak out. If the bottom is really flat you can also put a flat board under the crack and tape and clamp it down to keep it from leaking. The more epoxy you use the hotter it gets. as it’s an exothermic reaction.

Seams like Bob mentioned the metallic tape. Definitely an improvement over plain packing tape.

-- Andy - Seattle USA

View Phil32's profile

Phil32

589 posts in 326 days


#11 posted 12-20-2018 11:21 PM

Good advice given. Just remember, when you need penetration and bonding, bare wood is best. When you want to prevent penetration, a sealer is best over bare wood. When you’re ready for the final finish, oil may be best.

-- Phil Allin - There are mountain climbers and people who talk about climbing mountains. The climbers have "selfies" at the summit!

View Gene Howe's profile

Gene Howe

11638 posts in 3851 days


#12 posted 12-20-2018 11:45 PM

I use a sanding sealer before the pour. If you can get it in the cracks, so much the better. You’d be surprised at how the wood on either side of the crack will soak up the epoxy.
A good tape along the edges is much better than any thing else. Wax residue will interfere with the finish.

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

View Aj2's profile

Aj2

2321 posts in 2221 days


#13 posted 12-20-2018 11:56 PM

That’s a nice piece of English . I’m a bit concerned that the west system epoxy will close the wood cells around the crack and prevent the oil from absorbing. It might create as shinier look around the crack.
So I’m going to suggest oil first. As long as it doesn’t run down in the crack the epoxy will bond.
Keep the show side up.
Good luck

-- Aj

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AllanK

55 posts in 4500 days


#14 posted 12-21-2018 01:42 AM

Gene, are suggesting a sanding sealer over the whole piece before the pour, or just in the cracks?

-- "Stupidity is forever, but ignorance can be fixed."

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Aj2

2321 posts in 2221 days


#15 posted 12-21-2018 01:57 AM

I don’t agree with Gene.
You don’t need sanding sealer plus you want the oil to go deep into the walnut to get the nice rich look.
Some sanding sealers are something like liquid vinyl. Yuck :(

-- Aj

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