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



## chris_d (May 31, 2016)

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.


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## runswithscissors (Nov 8, 2012)

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).


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## AZWoody (Jan 18, 2015)

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 (Nov 8, 2012)

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


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## rhett (May 11, 2008)

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.


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## chris_d (May 31, 2016)

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 (May 31, 2016)

> ...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?


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## Unknowncraftsman (Jun 23, 2013)

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


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## CharlesA (Jun 24, 2013)

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.


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## RogerM (Oct 31, 2011)

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


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## runswithscissors (Nov 8, 2012)

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.


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## bondogaposis (Dec 18, 2011)

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.


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## chris_d (May 31, 2016)

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?


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## Unknowncraftsman (Jun 23, 2013)

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


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## chris_d (May 31, 2016)

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.


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## CharlesA (Jun 24, 2013)

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


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## chris_d (May 31, 2016)

Thanks, Charles.

Funny story; I spent a lot of time picking the guy's brain who I bought these slabs from. One idea i bounced off him was cutting a 45-degree miter like you did on your slab. He looked at me like I was a fool or a lunatic for a few seconds before advising me against it. His reasoning was "you'll spend a lifetime driving yourself insane trying to get it perfect and in the end you'll never really get there." His advice was to just cut it at a 90-degree angle and stand it up. "People will see that the grain continues from the top to the support. They'll get it."

Ha!

The narrow part of the slab I'll be cutting for the waterfall piece is still 30 inches across. Aside from building a pretty elaborate balsa wood model airplane as a teenager (which never flew, BTW), this is my first woodworking project. I've dabbled in lots of other materials (stone, steel, concrete, plastic) but not wood. So I'm taking it really slow and trying to keep it simple. I'm afraid that a 45-degree miter blind mortise like that is something I'd have to shop out, and I was hoping to do this all myself.

I am,now, however, looking for a copy of that book you posted photos of in your blog.


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## AlaskaGuy (Jan 29, 2012)

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


No problem.
These guy have a 67'' widebelt sander and they'' do it for you for 300 dollars an hour.

http://www.hearnehardwoods.com/wood_facilities/wood_shop/millwork.html


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## CharlesA (Jun 24, 2013)

A mitered waterfall leg would be a pretty ambitious first project. I'd i were going the 90 route, I'd inset the leg a bit instead of a faux waterfall. Good luck. I spent 2 weeks planning/l, making the jig, planning the cut, etc., bc I really wanted that look.


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## chris_d (May 31, 2016)

Just a final update on this for anyone who might find this looking for the answers I was looking for. I found that there was really no need to protect surrounding surfaces from the epoxy I was using to fill the voids in the slab. The bug burrows are the best example of this…there were just hundreds of them. In the interest of time, I just poured and spread the epoxy all over the whole area, then once it set and had at least partially cured (at least 24 hours later) I sanded it down with a belt sander (*carefully* with 80 grit, then 120) then once I got down to the surrounding wood, switched to the ROS with 120 then 220 grit. That was good enough for me. I don't want people to be able to see through the epoxy, so a finer grit wasn't merited.

I found that (like a poster above advised) the epoxy didn't soak into the wood appreciably. A torch drew out the bubbles in all but the thickest applications. In most cases, I needed a second round of touch-up. Easy. Here's some pictures of the finished tables.

The densest bug burrows, filled:










Many of the checks in this picture, and the center of the knot, are filled with epoxy.










I decided not to fill the large check on the dining table slab, since I liked it, and put butterfly splines in to stabilize it instead. Two on top:










One underneath:










Despite a good bit of practice on scrap, i didn't get the mortises and splines matched perfectly, and I filled a couple of tiny gaps with epoxy, which was probably a mistake, since they were almost invisible, but the epoxy created a dark contrast that draws the eye on a very close inspection. Still basically invisible from a distance.

The finished dining table:










A good view of the support (and Wu):










There were far fewer voids to fill on the coffee table slab, but here's a couple of shots:

The biggest checks in this slab were in the crotch sapwood. Not the greatest shot, but this is what the fill looked like:










The overall surface:










I love these sharp edges, but one has already fallen victim to the wife's vacuum cleaner wielding 










You can see the vacuum cleaner chip in this one, and the very simple support i fabricated for this table:










Anyway, I wanted to say that the epoxy work was very low-stress, and to thank everyone who posted here. Helped to give me the confidence to just have at it with the somewhat intimidating slabs. My wife and I saw some furniture at Urban Hardwoods on a visit to Seattle a couple of years ago and I thought "heck, i can do that." Turned out to be the case, and I'd encourage anyone else with a little general handiness to give it a try! Some more pictures of the finished tables can be found here.

I know that above I said I was planning to do a "waterfall" end on one end of the coffee table. In the end, despite the slab being way too big for our tiny living room, I chickened out. Figure I can always go back and do it later if I want. 

Thanks!


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