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Possibly messed up, patchy endgrain epoxy penetration

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Forum topic by coalcracker posted 11-14-2019 10:55 PM 915 views 0 times favorited 18 replies Add to Favorites Watch
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coalcracker

12 posts in 289 days


11-14-2019 10:55 PM

I’m a woodworking greenhorn making my first real project: a sycamore slab table from my own tree. After flattening, sanding and cleaning up the bark, I did multiple epoxy pours to fill in one large and DOZENS of smaller cracks. Following the end of those pours, probably 60% of the top surface was covered with epoxy.

Now, the problem.

As I’m sanding off the epoxy, I can see it’s penetrated into the wood to an unknown depth, and made those areas singificantly darker. As I see it, I have a few options:

1. Hours upon hours of sanding to take off some unknown thickness of the top (not realistic)
2. Take it to a lumberyard and run it thorough a large planer (again, problem with how much to take off. Plus what’s the fun in that?)
3. Use the router jig I made to take some off the top (not really thrilled to do this, but a realistic option)
4. Paint on a thin layer of epoxy to the raw areas of wood to help even out the grain

I’d really like to try #4 first, but don’t want to waste hours of my time if it’s unlikely to produce a nice result. Does anyone have opinions if this will result in a uniform finish after I apply it and sand it off?


18 replies so far

View Kazooman's profile

Kazooman

1386 posts in 2513 days


#1 posted 11-14-2019 11:30 PM

Hi Greenhorn:

First tell us how you treated the slab of sycamore from your own tree. How, and how long, did you dry it? No offense, but from the questions about your problem, I am not certain that you have gotten the sycamore slab really ready for any working or finish.

My first thought was to just go ahead and coat the entire surface with the epoxy to even everything out (your #4). However, that probably will not give you the final finish look you were hoping for.

Your #2 thought conjures up visions of the guy at the lumberyard yelling “you want me to run WHAT through my expensive planer?”. It could be done, and might not cause any problems, but not on my planer (fortunately mine is probably not wide enough).

Unfortunately, it is too late to offer suggestions to avoid the problem, but it is not too late to offer suggestions for the future. Without seeing the original piece it is hard to judge for certain, but could you have masked off the areas receiving the epoxy fill to avoid spreading it all over 60% of the surface? Blue painters tape (from the big box store) is great for this as well as masking areas prone to glue squeeze out, etc.

I am certain that many will suggest a card scraper, and that is sound advice. Lots of work, but it might work nicely.

https://en.wikipedia.org/wiki/Card_scraper

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Kazooman

1386 posts in 2513 days


#2 posted 11-14-2019 11:30 PM

Double post. Some day I will figure out the idiosyncrasies of this website.

View coalcracker's profile

coalcracker

12 posts in 289 days


#3 posted 11-14-2019 11:42 PM

Thanks Kazooman. The slab dried for over 2 years in my conditioned basement, and serial checks with a moisture meter over the last few months tell me that levels were stable and acceptable (in the 7-9% range throughout the slab).

Believe me I would have LOVED to keep that epoxy in the checks and cracks. The way it dried and shrank left dozens of small, narrow cracks (a few inches long, maybe 1/4 or 1/8” wide) scattered around much of the slab. It was near impossible to directly epoxy down into the cracks directly; I had to pour it on the surface and scrape it around to push it down.

If I could do it over, I would have probably just poured epoxy in the largest crack and left all the smaller cracks unfilled. Lesson learned!

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Kazooman

1386 posts in 2513 days


#4 posted 11-14-2019 11:54 PM

It sounds like you got the drying part done well. You are not the “greenhorn” you profess to be!

How about a picture? That might give someone an idea of a solution.

You can get what amount to plastic syringes (without the needle, of course) and they can give you more control with stuff like epoxy or glue. Actually, you can probably find a source of actual plastic syringes and very heavy gauge needles that you can cut the sharp point off of.

Try the card scraper.

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coalcracker

12 posts in 289 days


#5 posted 11-15-2019 12:07 AM

I’ll try to get a picture up later, don’t have a good one now.

I seem to have sanded through the surface epoxy down to the underlying wood in some spots, but it still looks much darker than the adjacent raw wood. I assume the epoxy penetrated through the end grain. Will a card scraper really help me clean this up? I feel like I would just be gouging the wood.

View wildwoodbybrianjohns's profile

wildwoodbybrianjohns

536 posts in 108 days


#6 posted 11-15-2019 12:26 AM

One way to isolate where the epoxy goes is to build dams with silicone around where you will pour. In some cases this is better than tape, as epoxy can seep under the tape.

Problem is, the silicone can also penetrate the wood and you might not notice theres teeny spots left after sanding prep for finish until you put the finish down.

I foresee that you will be doing alot of card-scrapering, if you go that route. A really sharp paint scraper could be more effective, perhaps. Pulling is more leverage than pushing. Or a belt sander with 60 to 80 grit.

Without seeing the surface, I cant really judge, but a float pour is probably the best option, should even everything out, like Kazooman said.

-- Wildwood by Brian Johns: It is wiser to find out, than to suppose (S. Clemens)

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LesB

2232 posts in 4004 days


#7 posted 11-15-2019 01:28 AM

Do you intend to put a finish on the wood? If so you may find that it darkens the wood about the same as the epoxy did. Give it a try on the underside or on a scrap to see if that works.

Also you could apply an undercoat finish like clear danish oil, or boiled linseed oil which will have a darkening affect that may blend in very similar to the epoxy. Let the oil finish dry/cure for several days. Then apply a top coat.

As often stated on this web site be sure to test the affect on a scrap before applying it to the whole project.

-- Les B, Oregon

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coalcracker

12 posts in 289 days


#8 posted 11-15-2019 01:44 AM

Here is a photo of one of sanded areas.

I do plan to finish with a few coats of Arm R Seal. I really wish I had a piece of scrap wood but unfortunately I only have the slab. I could give it a try on the undersurface.

View wildwoodbybrianjohns's profile

wildwoodbybrianjohns

536 posts in 108 days


#9 posted 11-15-2019 07:03 AM

I would hit it with a belt sander, little by little, see if that helps.

-- Wildwood by Brian Johns: It is wiser to find out, than to suppose (S. Clemens)

View Snipes's profile

Snipes

438 posts in 2805 days


#10 posted 11-15-2019 12:20 PM

Did you epoxy the whole thing? If not, I would thin some down and pour over the rest.

-- if it is to be it is up to me

View Kazooman's profile

Kazooman

1386 posts in 2513 days


#11 posted 11-15-2019 02:38 PM

That looks pretty bad. I think you should try your #4 remedy (Snipes agrees as well)

Then there is the “nuclear option”. What does the other face of the piece look like? You probably chose the best face to be up, but the other side might be better than what you are now dealing with.

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coalcracker

12 posts in 289 days


#12 posted 11-15-2019 02:46 PM

Thanks all.

I think I’d rather try my luck with a belt sander first. Some epoxy did get on the underside of the slab after a spill, so I can try sanding that first to see if it’s gonna work.

If it seems like a fool’s game after a while, I’ll switch to a thin coat of epoxy over everything. The epoxy was a PITA and I’d rather put it completely behind me than revisit.

View JayT's profile

JayT

6325 posts in 2772 days


#13 posted 11-15-2019 02:51 PM

Wipe the slab down with mineral spirits and see what it looks like. It won’t do anything about taking the epoxy away, but will give you a good idea of what the wood will look like with finish applied.

What I have found, in my admittedly limited experience, when using epoxy to fill cracks is that the coloration of the epoxied areas is the same as what it will look like if using an oil based natural finish and you can’t see the difference once the project is complete. Same as what Les B mentions. If you wipe it down with mineral spirits and the demarcation disappears, you are good to go. If not, then option #4 is viable.

-- https://www.jtplaneworks.com - In theory, there is no difference between theory and practice. In practice, there is.

View wildwoodbybrianjohns's profile

wildwoodbybrianjohns

536 posts in 108 days


#14 posted 11-15-2019 03:01 PM


The epoxy was a PITA and I d rather put it completely behind me than revisit.
- coalcracker

Exactly how I feel about epoxy now, after doing dumb stuff like what youve got here.

On a positive note, if you mix epoxy with pure talc powder until quite thick, you can then add tint to get colored filler for checks and whatnot; and I often use this filler. I use standard tint for paint, but there are various types thatll work, like RIT dye.

-- Wildwood by Brian Johns: It is wiser to find out, than to suppose (S. Clemens)

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OSU55

2450 posts in 2550 days


#15 posted 11-15-2019 03:23 PM

If you applied ars in sspots it would look very similar. Put some ars on the backside where you have some epoxy to see what it looks like. I use epoxy often in cracks of turned items, then poly over the top. Biggest issue is with a thin topcoat that does not fill the grain, the epoxied areas are somewhat noticeable because the grain is filled. If I do a fully filled finish, wb or solvent lacquer, the epoxied areas are invisible. If you build enough film thickness with the ars the epoxy will disappear, provided everything is leveled properly. A hand plane is much better for that vs a hand held sander of any type.

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