# Oil first or epoxy fill first?



## AllanK (Mar 28, 2007)

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:


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## OSU55 (Dec 14, 2012)

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 (Feb 13, 2016)

Epoxy first - oil will interfere with epoxy bond.


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## pottz (Sep 15, 2015)

definitely epoxy first as bob stated.


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## AllanK (Mar 28, 2007)

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?


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## avsmusic1 (Jul 10, 2016)

are you coloring the epoxy?


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## AllanK (Mar 28, 2007)

No, leaving it clear.


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## Andybb (Sep 30, 2016)

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.


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## ocean (Feb 13, 2016)

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.


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## AllanK (Mar 28, 2007)

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.


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## Andybb (Sep 30, 2016)

> 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.


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## Phil32 (Aug 31, 2018)

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.


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## Gene01 (Jan 5, 2009)

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.


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## Unknowncraftsman (Jun 23, 2013)

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


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## AllanK (Mar 28, 2007)

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


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## Unknowncraftsman (Jun 23, 2013)

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


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## runswithscissors (Nov 8, 2012)

I'd suggest mixing a small amount of very fine sanding dust from your walnut into the epoxy. It will absorb the oil and leave the epoxy a dark walnut color. I believe the sawdust also strengthens the epoxy and its bond with the wood.


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## AllanK (Mar 28, 2007)

Research continues. After mining YouTube, I found a few examples of the use of non-wax shellac (SealCoat) on the whole piece before the pour. Claim was that it makes the epoxy overflow easier to remove. On the videos the results seem good. Others simply taped around the cracks, others just sanded the result.

In hindsight, I should have done the pour before machining the wood down to its final thickness… next time.

I experimented with a scrap of the same wood, filled a few holes, sanded, then applied the Danish oil. Seems like I can still make out the edges of the sanded overflow… now considering using a syringe to minimize the mess for the smaller pours…

Also, the boss now wants to fill with a turquoise, flecked look (she has a cutting board that she likes that has this effect). Anyone have experience with Jacquard Pearl EX powdered pigments? Specifically Duo Blue-Green?

PS runswithscissors: good idea for the smaller fills, where the turqouise would be kinda hokey.


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## kelvancra (May 4, 2010)

As others said, oil after epoxy is just a messy waste of time.

Depending on the wood, much of the epoxy can soak in, or not.

As to the oil, if before, I presume you are talking a hardening oil, otherwise it would be a disaster akin to putting the wood in a zip lock.

I've, literally, poured gallons of epoxy over photos and things that I sealed first. Usually, I used poly. One reason I like to seal before epoxy is, it stops the wood from releasing air into the resin.

Before I took up the habit of sealing wood before pouring epoxy, I noticed air kept appear. Took me a shot or two to figure out it was coming from the wood.


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## AllanK (Mar 28, 2007)

Kelly, I am only using epoxy in the cracks to stabilize them. The piece wil be oiled when done. Do you still recommend sealing the whole piece first?


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## pottz (Sep 15, 2015)

> Kelly, I am only using epoxy in the cracks to stabilize them. The piece wil be oiled when done. Do you still recommend sealing the whole piece first?
> 
> - AllanK


allank I love your sig line and it applies to Kelly,please ignore whatever the hell he's talking about.wood releasing air or who knows what? I think you've got enough info to make a educated decision,good luck with it.also Im not sure if I agree with scissors assessment that wood dust strengthens epoxy? im kinda doubting that theory,maybe he has some scientific data he can share!


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## kelvancra (May 4, 2010)

Allan, Pottzi would do well to revisit your tag line, rather than trying to present as an ass.

While I do not know everything there is to know about resin and wood, I first started using it in quantity back around 75, when I began buying it in five gallon buckets (five of A and five of B).

There are many types of epoxy resin. I have not used them all, but have used at least fifty or so gallons, so have more first hand experience than most. Probably more than Putz.

The things I mentioned I learned early on using resin. They may or may not apply to every application, but the knowledge can save someone a lot of trouble, depending on the circumstances of their pour.

One of the common problems with resin pours is removing air from the poured resin. This is done using heat or, if practical, vacuum or air pressure.

Avoiding air in the first place is the first step and is no less important than removing it.

To avoid adding air, stir slowly. Don't whisk. Too, warm your resin. When it's around seventy-five degrees (in other words, warm), it'll be more fluid. If more fluid, it'll give up the air trapped in it easier.

Obviously, air in epoxy that will be visible is problematic. The bubbles will be visible and, in quantity, will result in a cloudy, rather than a clear pour.

The problem I mention reduce with the thickness of the pour.

If you were applying resin to a surface and it soaked in so you only ended up with a shiny surface, the bubble problem would be minimal, if any. However, if you were applying the resin to, for example, a table top, though the resin only equated to about fifty coats of poly, you would do well to seal the wood before applying the resin.

The reason for sealing is, if you apply heat, such as with a heat gun or propane torch, the heat can and will draw air from the wood.

_

Now, back to the oil. I will assume you are talking of hardening oil, like tung, walnut or boiled linseed oil to bring out the grain.

If you are going to cover the table in resin, I would suggest a daub of hardening oil on a inconspicuous spot (e.g., the underside of the table), and near by, put a daub of resin. When the oil is hard, apply a bit of resin over it and the other epoxy spot (build coats). I don't think you're going to see enough difference in end appearance to justify the oil.

Again, if you put the epoxy on, you will not be able to use oil over it, but can wipe it off with paint thinner.

If you want to use oil before the epoxy, the epoxy will still work. It just will soak in less than it, otherwise, would.

I like the idea of the epoxy soaking into the wood in the cracks (you'll have to sit on it, because it will soak in a bit and you'll have to add some).

It's going to be hard to limit the epoxy to just the cracks, so if you really want the oil, go there first.



> Kelly, I am only using epoxy in the cracks to stabilize them. The piece wil be oiled when done. Do you still recommend sealing the whole piece first?
> 
> - AllanK
> 
> ...


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## bd1886 (Jul 2, 2018)

People here are right. Epoxy has to bond by absorbing into the wood to bridge that gap securely. Taping it off with a tape that flexes down into the wood's shapes, applying epoxy and pulling the tape just before the full kick of the epoxy (is the right path for sure). 
I work my way through finishing processes a lot and it takes a lot of different concepts and rules. (Epoxy and clean surfaces for bonding are a primary rule best followed.)


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## Peteybadboy (Jan 23, 2013)

Allen, good luck with this project. I like all the advise you are getting. Please post which advice you will use and a few pictures of the process/Finish if you can.

Thanks for starting this discussion


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## Redoak49 (Dec 15, 2012)

I guess I will be different. I had a number of cracks in my Claro Walnut Maloof Rocker.

I used Tung Oil and put on one coat carefully first and up close to but not into a crack. I then filled cracks with System Three T88 epoxy. This epoxy is slow setting and hardening. Putting the oil on first makes for much easier clean up. I tried the tape method but it did not work well.

Of course, you do not want to get the oil into the crack.


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## AllanK (Mar 28, 2007)

Happy New Year to all.

I've been experimenting using pieces of the same English slab to make bookends for the grandkids. They have many cracks so I've been filling those. I bought a bunch of disposable syringes, and that worked quite well to control the flow, although if you don't control the plunger carefully, you get sudden blobs of epoxy spurting out.

One thing I find is that the stuff is a bit too viscous, so it's taking a long time to penetrate into the cracks, and if they are deep, I run out of pot time constantly topping up the crack.

Question: I read somewhere that heating the mixture a bit (to ~75°F) makes it flow more easily. Any comments on this? And if it works, what's best way to heat the mixture - just put the container in a pan of hot water?


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## kelvancra (May 4, 2010)

A pan of hot water will work fine, but wipe the water off so it doesn't get in your pour mix.

If you have a low watt bulb (e.g., 40 watts), you could hang it in a cardboard box [with a lid] big enough to hold the resin and large enough to be certain the bulb doesn't touch the resin containers or the box. The heat should be enough to warm the mix.

I'm guessing, you could take the heat up to eighty-five and still be safe. Run a search on the resin and it should tell you.


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## AllanK (Mar 28, 2007)

When all else fails, read the instructions - this from the WestSystem instruction manual:

"There is a better solution to get good penetration without losing strength or moisture resistance. We recommend moderate heating (up to 120°F) of the project area with a heat gun or heat lamp before applying epoxy. On contact with the warmed substrate, the epoxy will thin out, penetrating cavities and pores, and will be drawn even deeper into pores as the substrate cools. Although the working life of the epoxy will be considerably shortened, slower hardeners (206, 207, 209) will have a longer working life and should penetrate more than 205 Hardener before they begin to gel. When the epoxy cures it will retain all of its strength and effectiveness as a moisture barrier, which we feel more than offsets any advantages gained by adding solvents to the epoxy."


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## AllanK (Mar 28, 2007)

Just completed the 6 bookends made from the off-cuts from the original English walnut slab. Practiced my epoxy pouring on them, good results, but ended up with a few bubbles. Applied medium walnut Watco Danish Oil and the epoxied areas all turned black, even though I used untinted epoxy. Looks good though. For the tongue at the bottom I used 3×5 tie plates from Home Depot, painted black, and recessed them in the base using a template and a bottom-cleaning bit. Countersunk the holes for the screws, so the heads would be a tad below the surface.

The pictures make the wood look all yucky, but they really turned out nicely.


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## kelvancra (May 4, 2010)

Looks like they're well on the way.

Sounds like, for the application, the darkness from the oil will just go invisible to all who visit the home of the shelves.


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## BroncoBrian (Jan 14, 2013)

Allan,

The bubbles can be seen before the epxoy cures. A heat gun (with care) will pull the bubbles up and out.

Lots of advice here, most of it in agreement. Epoxy overflow is fine, I always flatted after and you can sand it right off. I would use T88 and darken the epoxy if it were mine. Either way, do not put anything on the wood until you fill and sand/flatten the board. Finishing is last. The epoxy will shrink (especially in that volume) so you will need to add it a few times.


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## Dustyjobs (Dec 24, 2018)

Wicked awesome thread. Great info

Thank you for posting


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