Replies

1. 
   scubadiddle | Mar 09, 2010 09:39pm | #1

   Hi George, I am a hardwood flooring company owner/ part time furniture maker. My company does many reclaimed barnwood floors, mostly oak. On some of the larger holes, especially in traffic areas, I will use the technique you are inquiring about. I had found that the dye in the epoxy ( I mix my own)will  dye the wood fairly bad to where you have to sand it pretty good to get it out. I came up with the technique of covering the knothole and a few inches around with blue tape. I then take an exacto knife after rubbing the tape for an outline, and cut out the exact edge of the hole. I then fill with epoxy. Usually takes two coats w/ 30 min. epoxy. If I fill it flush I have found that it's just about perfect to where you wont have to sand much. I pull up what tape will come up and then sand the rest off. I have also used "scrap knots" to inset into the epoxy to get a more natural look, and I find it works well. Just make sure the epoxy is very well set up. This technique keeps the dye from getting on (in) the wood. Hope this helps, Rex

1. 
   Joe Sullivan | Mar 10, 2010 09:08pm | #2

   Agree that epoxy works well, and am glad to hear the blue tape trick.

   However, I am at a loss to know why you guys build up using thin layers.  Epoxy cures faster (sometimes better ) when more of its exothermic heat is retained.  The heat accelerated the chemical reaction.  Air is not necessary. 

   I just go for the whole thing at once, starting with a lump that seems the right size.  I only go back for a second layer if I misjudge the first.

   NOTE:  I extensively restored a log house with epoxy in addition to to the odd knot-filling task, so am pretty familiar with its foibles.

1. 
   scubadiddle | Mar 10, 2010 09:23pm | #3

   On a solid table you may be able to do it in one pass, as I use this technique on flooring however, I cannot have access to the undersides of the boards, so I have no idea exactly how much I would be filling ,taking into account potential small voids concaved underneath the boards. In the past when I have tried to fill in one pass, many of the knots would just keep sucking epoxy (expensive epoxy if you get my drift), so to keep down on the waste I would let the first "fill" set up, and then do another pass, this would almost always work and keep my costs reasonable. However I will agree that in this particular situation, he should be able to see the extent of the void and one pass could potentially take care of it.  Rex

1. 
   Joe Sullivan | Mar 10, 2010 10:35pm | #4

   Rex:

   Put that way, it makes perfect sense.

   J

1. 
   davcefai | Mar 11, 2010 12:56am | #5

   If the hole is deep is it not possible that the heat generated by the curing epoxy could vapourise some water and weaken the epoxy-wood bond?

2. 
   Joe Sullivan | Mar 13, 2010 08:36pm | #6

   I can't make an authoritative statement about  whether or not the epoxy heat can affect water somehow, but can tell you for sure that even at its hottest, you can handle it in your bare hands.  Therefore, it is so far below the boiling point of water that I can't see how it would have much effect.

   As a matter of fact, if the epoxy gets too hot, it will bubble.  I learned this while repairing a door in the summer Texas sun.

   Joe

2. 
   stantheman | Mar 14, 2010 11:09am | #7

   George, I don't know how large the knothole is, but I would think a black hole in a tabletop would be noticeable.  Joe mentioned inserting a  knot to fill the hole  or you could cut out the hole and make a plug with some scrap wood that has similar grain to surrounding area. 

3. 
   user-1119323979 | Mar 15, 2010 08:56pm | #8

   I built a huge table with one piece of 12' by 4' by 2" thick curly Sapele.  It was smack dab the middle of the tree, so there were voids and pith and knots, worm holes etc..  The larger holes I filled with trans tint dyed 5 min. epoxy.After I filled the void pretty well up, I would insert a piece of cut off, or figured veneer that matched while the epoxy was still wet, using the blue tape trick mentioned above to keep the clean up under control.  Then I scraped and sanded, being careful to not sand though the veneer.

   Dollyb