Using epoxy to fill knot holes

[Eric McMillan]

I'm looking at using epoxy to fill some knot holes in a knotty alder kitchen bench I'm making. At what point should I fill the holes? If I fill them before it is stained, then any light colored areas will not take stain, but if I fill them after staining I will probably sand though the stain when leveling the epoxy. Any suggestions from someone who's done this before will be appreciated.

[Steve Clardy]

Never used epoxy. I always use regular Famowood filler, or a home brew of sawdust and lacquer.

Steve

[Don Abele]

Eric, when I fill knot holes I use epoxy colored with charcoal before I do anything else to the board. It makes it jet black which accentuates the presence of the knot, rather than try to hide it. If I want to hide it, I don't use that piece of the board :p

Be well,

Doc

[Donnie Raines]

The staingin part is what makes this a bit more of an issue. I would use the epoxy prior to staining....and I would maybe reconsider staing if you can. However, you could mix the epoxy to match the color of the stain...or at least very close. I use epoxy on burls and highyl figured boards to fill voids. I normally tint them black or brown...but I finish my projects "natural" when useing the epoxy.

[Todd Burch]

I just made two cherry blanket chests that received about 3 quarts of epoxy in all to fill every known wood defect to man.

I surface planed the bare wood, then thicknessed the wood to a point thicker (20mm) than my final thickness (19mm). Then, I got out the epoxy. I poured it on, many times having to back up the opposite side of the wood with masking tape due to through holes. After the epoxy cured, I might have to repour two or three times more if any voids were left, or I got too many bubbles that I didn't get around to popping at the right stage in curing. Once this first side of the board was done, I removed the masking tape from the opposite side, ROS'ed any epoxy than made it through to the backside of the board, and then replaned to 20mm. After that, I then repeated the procedure on the backside of the board to fil any voids there.

Once all the epoxying was complete, I thickness planed to 19mm, taking 1/2mm per side.

It took a long time. Todd

[Eric McMillan]

Thanks everyone. I've planed the boards and glued up the panel, but I haven't surfaced it from there. As a result I have a some thickness to work with. I think I'll go ahead and fill the knots with a dark brown epoxy and then bring it down to final thickness with a belt sander and ROS. I would plane it down, but the panel is 15 1/2" wide and won't fit in my 13" planer.

[Warren White]

I am reading this thread with interest. I have wondered about doing this, but never knew just what type of epoxy to use. Do you need something just for woodworking, or will any old two part expoxy work? What do you use for coloring the epoxy?

Thanks. I love this place!!!

Warren

[Steve Cox]

Warren, there are a number of things you can use to tint the epoxy. Artists dry pigments are one thing as is sawdust. The thing with sawdust is that it must be DUST like something out of your ROS. It also will get much darker in the epoxy. Think something like maple dust for cherry etc.

[Todd Burch]

Several years ago, I invested (note the word "invested" - it's not cheap) in West System Epoxy. They have a whole regiment of fillers/additives/techniques for using epoxy in different manners. Their product manuals are good and filled with instruction for using epoxy effectively.

I have only tinted with graphite to make epoxy repairs black. There are oodles of materials that can be used to tint. I have a friend that even used metal shavings in his epoxy once to make it magnetic. It worked great.

Todd

[Chris Padilla]

I use epoxy products from www.raka.com (http://www.raka.com) as they are a boating supply company in Florida. They have many kinds of epoxies and I think you'll find their prices very good.

They sell you maple flour and pine flour to mix with epoxy. The maple will turn a chocolate brown and pine a little lighter than that. By mixing in this wood flour (yes, it is literally flour consistency...powder), you have the chance to get a stain to work on the epoxy/wood mixure because as you sand the epoxy/wood mixture, you will expose wood that will stain.

[Don Abele]

Warren, I use just plain ol' 2-part epoxy and tint it with artists charcoal. Works great and is cheap and easy.

Be well,

Doc