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Protecting surrounding wood surface from epoxy while filling powder post beetle holes in a slab?

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Forum topic by chris_d posted 05-31-2016 09:46 PM 2093 views 0 times favorited 19 replies Add to Favorites Watch
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chris_d

9 posts in 193 days


05-31-2016 09:46 PM

Topic tags/keywords: claro walnut slab epoxy filling voids

In thicknessing a couple of large claro walnut slabs I discovered that the sap wood in the slabs in peppered with what I assume to be powder post beetle burrows. Whatever they are, they range from a tiny hole every few feet to sections of the surface that are a maze of burrows. I’d like to fill these with epoxy (system 3 with medium-speed hardener) but am concerned about getting the epoxy on the surrounding wood.

My final finish will be sam maloof poly/oil. My worry is that the areas that have epoxy overflow on them will look different than the areas that did not, because if the porosity of the wood. Would it be a good idea to apply a very light coat of the poly/oil before filling the holes with epoxy? If I didn’t, how much sanding would i be looking at to clean the overflow areas of any sign of the epoxy having been there?

Also, any suggestions on adding pigment or wood powder to the epoxy? I don’t mind their appearance one way or the other.

Smallest holes (for reference, the hole is 1mm in diameter):

Most concentrated areas of burrowing (these burrows are about 1mm wide each):

Front and back of both slabs:

Slab 1 top:

Slab 1 bottom (note sticker shadows):

Slab 2 top:

Slab 2 bottom:

Having never done this before, I’m open to any advice and intend to practice on scraps before pulling the trigger on any specific approach.

Thanks in advance.


19 replies so far

View runswithscissors's profile

runswithscissors

2192 posts in 1492 days


#1 posted 06-02-2016 04:20 AM

I fear the oil would not be compatible with the epoxy, so I’d avoid using oil first. To keep epoxy from spreading beyond the patch, you can punch holes in masking tape to isolate the area of the hole. As for the wormy channels, I wouldn’t bother to try. Just mix up your epoxy with a small amount of wood flour (like from a sander), and scrape/plane/sand it smooth after the epoxy cures. I use epoxy + wood flour all the time to fix flaws and also my own blunders (which are a kind of flaw).

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

View AZWoody's profile

AZWoody

700 posts in 691 days


#2 posted 06-02-2016 05:23 AM

I read recently smoeone said they use wax to protect the area around the hole but then, whatever final finish would have a different where the wax was.

When I use epoxy, I just run it through the drum sander whenever everything is dried and filled how I want.
That way, any excess is removed and all the wood is clean and ready to be finished. If you do not have one, and this is a one time project like this, then you can always ask a cabinet shop to run it through the drum sander.

You can also use a planer if you have good sharp blades. I have run epoxied boards through my planer with no problems. It just took a little extra sanding.

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runswithscissors

2192 posts in 1492 days


#3 posted 06-02-2016 07:13 AM

Drum sander or planer for that slab would be a pretty impressive piece of machinery.

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

View rhett's profile

rhett

734 posts in 3134 days


#4 posted 06-02-2016 11:31 AM

That is a beautiful chunk of wood. For precision epoxy work, I buy the 5 minute syringe type, self mixing epoxy they sell at BORG. Point it where you want and squeeze. It isn’t cost effective for large areas but should work well in your application.

I have only had issue with epoxy showing up during finish when staining, since it works as a resist. Oils and clear coats don’t really show any bleed over since the epoxy makes the wood the same color oil does. Either way, be clean and as exact as possible. Grain filling is a bigger problem with open pore woods.

Don’t forget to have fun.

-- Doubt kills more dreams than failure.

View chris_d's profile

chris_d

9 posts in 193 days


#5 posted 06-02-2016 03:53 PM

I ran a test yesterday by filling the burrows on a scrap of the wood that was cut off the end of one of the slabs. Unfortunately, the piece was so small that i’m worried it’s not indicative of what the broader piece will look like. Here’s a (bad) picture of that:

While I think i need to try this on (maybe the underside of) one of the slabs to really get an idea of what it’s going to look like, I was pleased to confirm that the epoxy doesn’t really soak into the wood very much. A light sanding with the belt sander followed by 120 grit on the R.O.S. leveled the epoxy and the maloof poly/oil didn’t look any different in the epoxy overflow areas than it did on the wood that was completely bare.

I saved a good bit of wood flour from sanding one of the slabs with 120 grit on the r.o.s. and will try @runswithscissors’s epoxy/wood flour mix. My concern here is that it will really make the burrows stand out on the larger slab, where the clear epoxy shows them up somewhat, but not in a dramatic fashion.

This is fun, but it would be more fun if the stakes weren’t so high. Ha!

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chris_d

9 posts in 193 days


#6 posted 06-02-2016 03:57 PM



...For precision epoxy work, I buy the 5 minute syringe type, self mixing epoxy they sell at BORG. Point it where you want and squeeze. It isn t cost effective for large areas but should work well in your application…

- rhett

That’s an excellent idea, but I’m afraid I’d bankrupt myself buying enough syringes of epoxy to handle the number of burrows these slabs have in them. :) Also, it’s probably not a bid deal, but i’ll be filling some voids and checks with system 3 standard epoxy…would the two epoxies have a different hue?

View Aj2's profile

Aj2

692 posts in 1265 days


#7 posted 06-02-2016 04:25 PM

I think you’ll be fine with with epoxy in the tunneled areas. One trick for the single holes is to sharpen a piece of walnut scraps in a pencil sharpener and drive in the hole with some pva glue. Do this when your close to your final thickness.

Nice slabs.

Aj

View CharlesA's profile

CharlesA

3025 posts in 1265 days


#8 posted 06-02-2016 04:29 PM

You are doing more extensive filling than I have done, but I’ll give you my experience.

1. I use the two 4 oz bottle sets of 5 minutes epoxy. They last a long time and not that expensive.

2. It depends on what I am filling on how I use it. Sometimes I just use it straight and it usually looks like a darker streak in the wood. On cedar and in some other applications I have mixed it with sawdust from the wood. The potential downside to that is that if your finish darkens the wood, this may stand out as lighter (the color of the bare, sanded wood). On knots that are dark/black, I’ve mixed a little black stain or dye with it and it shows as solid black.

3. The other technique I have used is to fill the holes with straight epoxy and than sand them down when they are about 50-75% dry, so that the sawdust from the sanding kind of seamlessly bonds with the epoxy. Again, this may show up as a little lighter after finish (might not, though).

4. I usually mask tape around the holes so I don’t have that much to clean up afterward. I use a ROS or sanding block to clean them up.

-- "Man is the only animal which devours his own, for I can apply no milder term to the general prey of the rich on the poor." ~Thomas Jefferson

View RogerM's profile

RogerM

764 posts in 1866 days


#9 posted 06-02-2016 04:33 PM

Work with the problem by tinting epoxy with lamp black and filling the holes. Black filler tends to compliment the voids.

-- Roger M, Aiken, SC

View runswithscissors's profile

runswithscissors

2192 posts in 1492 days


#10 posted 06-02-2016 06:32 PM

An excellent black tint for epoxy uses powdered graphite. WEST epoxy company sells it. A pint can of it will go a heck of a long ways. Takes 2 coats to be completely opaque, unless you put a lot in the mix.

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

View bondogaposis's profile

bondogaposis

4037 posts in 1818 days


#11 posted 06-02-2016 06:45 PM

I have never had a problem with epoxy soaking into the wood so that it affects the finish. I would just fill, sand flush, then move on to your regular finishing schedule.

-- Bondo Gaposis

View chris_d's profile

chris_d

9 posts in 193 days


#12 posted 06-02-2016 11:19 PM

thanks for all the feedback. I’ll be doing a larger test area on the underside of one of these slabs tonight.

Another question; what level of deformation do people normally consider acceptable for a slab that’s going to be a dining table top? One of these slabs has remained pool-table flat since I router-planed it a few days ago. The other developed some warps almost immediately that reflect the wavy warping that the slab displayed before i planed it, only less severe. At the worst spot, a straight-edge held across the 48-inch width of the slab reveals warping of about 1/4 inch that is centered between the center of the heartwood and the sapwood on either side.

I’m tempted to give it another pass with the router planer, but am thinking i might be chasing an unnecessary level of flatness, and risking further thinning the slab only to have it warp again. These tables are for my own house, so it’s not like i’ll have an angry client.

Thoughts?

View Aj2's profile

Aj2

692 posts in 1265 days


#13 posted 06-02-2016 11:31 PM

The slab that is misbehaving is probably going to warp more the thinner it gets.That is a clear message I sometime get from slabs.So you are on the right track leave it alone!
At the most a few shaving on the high spot with a nicely cambered hand plane just before your finish.

Nice looking wood

Aj

View chris_d's profile

chris_d

9 posts in 193 days


#14 posted 06-05-2016 05:14 PM

Reporting back. I chose the worst of four sides (which will become the bottom of the coffee table) and filled the burrows with epoxy. The next morning I went over them again to catch the ones that has “soaked” in below the finished surface. I let that cure for a day and a half just to be on the safe side (System 3 actually calls for 2-3 days for a complete cure). This morning i went over it with an old 60-grit belt on the belt sander, then a fresh 120 grit belt, followed by 120 grit on the ROS, then hit the whole surface with another pass with 220 grit on the ROS. I dusted it a little then wiped on a coat of the Maloof Poly/Oil. I was pretty pleased with the results. Here’s a picture:

Another:

Despite the sticker shadow, saw marks, and general surface flaws (I decided to save thickness rather than get a perfect surface on the bottom of this slab), I’m really excited about these slabs and can’t wait to see what the other three surfaces reveal.

My plan is to let this first coat dry overnight while I finish surfacing the other slab and laying out the butterflies, then tomorrow fill the burrows on the other side of this slab so I can get the other side finished.

Then I need to research the best mortise and tenon setup for cutting the thin end off this slab to stand it up as the support on one end of the slab, “waterfall” style, I suppose. That wasn’t my plan, but this thing is way too long to serve as a coffee table in our small living room.

Here’s a short flyover video of the slab with the first coat of finish.

https://youtu.be/BzLCKlz-Di8

View CharlesA's profile

CharlesA

3025 posts in 1265 days


#15 posted 06-05-2016 05:20 PM

There are a number of ways to join a waterfall leg. Here’s how I did it, in case it is helpful:

http://lumberjocks.com/CharlesA/blog/41934
http://lumberjocks.com/CharlesA/blog/41937
http://lumberjocks.com/CharlesA/blog/41957
http://lumberjocks.com/CharlesA/blog/41984
http://lumberjocks.com/CharlesA/blog/42001
http://lumberjocks.com/CharlesA/blog/42038

-- "Man is the only animal which devours his own, for I can apply no milder term to the general prey of the rich on the poor." ~Thomas Jefferson

showing 1 through 15 of 19 replies

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