Routers, Epoxy and repairs, Oh my!

[Ben Fleis]

I have a small repair that I have "figured out", but am curious if anybody has done something similar. Basically I already routed out a Soss hinge mortise, and the deepest part is only 1/64" from what will be the back side. (Error in design.) Basically, I routed about 3/32" deeper than needed, so my thinking is thus: fill the bottom w/ 1/8"+ of sawdust filled 5-minute epoxy. Let sit for ~30 minutes (the point between too soft and too brittle), and then re-route the deepest mortises as conservatively as will fit. The new layer will make sure that in my final piece, that 1/64" thickness turns into at least 5/64", and if by chance I sand/plane through, it will maintain the color of the material via the sawdust.

Has anybody run a router bit through epoxy? It's a very light cut, but in very thin-walled space, where burning or router jumpiness could tear through the wall and force a remake of the hinged piece.

Thanks,

-b

[Lex Boegen]

Do you have any leftover material that you can test your repair method with? It sounds plausible to me, but I've never routed epoxy. Another option would be to route out a dutchman and glue it in place, then re-machine the mortise from scratch.

[Rob Young]

I'd be more inclined to make the pocket deeper and inlay a dutchman. Then after the glue dries clean it up and then go back to re-mill the pocket.

You can route the epoxy + sawdust mixture but give it 24 hours to cure at room temperature. Especially if you have any volume present. It will take a while before you have something other than a gooey center. While routing it, go slow and take light passes. I've had it chip out but that was re-routing an edge profile where I patched a knot (dumb move not to plan around the knot but too late). Lucky for me the chipping wasn't too deep and the final skim pass cleaned it up.

[Jim Terrill]

I've never routed through 5 minute epoxy, but I have routed and drilled through the slow setting epoxy, and man that is a beast. Dulled my bits like crazy, I would avoid it if possible.

[Ben Fleis]

Just for future reference, I went ahead with it as described. I waited about 30m after application before routing out the 5-minute epoxy. It was hard to the touch, and cut cleanly with a chisel (left some out to check). When routing it created a "gum dust" kind of stuff -- not actually dust, since a vacuum wouldn't pick it up, but I could scrape it out with not too much work. The cutting was smooth and easy, although it was a nearly new bit. The hardest part was scraping the epoxy gum off the bit itself, but otherwise all is well.

Thanks again!

-b