Mixing sanding dust w/epoxy?

[Royce Meritt]

While routing out the recess for the maple inlay on the top of my wooden gun case I ended up with a very small imperfection in the walnut that I will need to fill after gluing the inlay in place. I think mixing some fine walnut sanding dust with epoxy will give the least noticable fix. How much sanding dust does one need to mix with the epoxy? Do you want to mix it to a paste-like cosistancy like you would do when using regular wood glue and dust or just enough dust to color the epoxy? Thanks.

[Chris Padilla]

Royce,

It is best to experiment and it can depend on the epoxy. However, for imperfections on a pure esthetic base, you can mix in a "fair" amount of the sawdust.

However, I'm telling you to experiment ahead of time because you might be surprised by the color!! Maple dust mixed with epoxy actually turns a more brown color!!

[Allen Bookout]

I have mixed sawdust with epoxy (West System) quite a bit. I have found, at least for me, that I get good results by mixing it as thick as possible and still wet out the sawdust. Good Luck! Allen

[Jeff Sudmeier]

As Chris said test out your process as much as possible before you do it on your peice. The colors are drastically different then the actual dust.

I fill small gaps by putting some poly down and then sanding the poly wet. The dust created fills in the gap and you have a patch. You still don't end up with a perfect match this way.

[Marc Spagnuolo]

As mentioned above, epoxy and maple dust turn a few shades too dark to match the maple properly. Here is what I do. I use Durhams Water Putty. Its a maple colored powder that can help balance out the darker color. In some cases, the powder alone with the epoxy is good enough. Experiment with different proportions of powder and sawdust to find the perfect match.
On a related note, I will recommend against using too little sawdust or powder. There have been times when I didnt use enough of the material, and it doesnt look good when it dries. Sometimes you can actually see the particles in suspension an it looks funny. So I recommend mixing the material into a thick self-levelling putty.

After rereading the post, I just realized your problem is not with maple, but with the walnut. Honestly, thats the best case scenario. Its alot easier hiding a flaw in the darker wood. I think the walnut dust alone with the epoxy will be a good match.

[Royce Meritt]

After rereading the post, I just realized your problem is not with maple, but with the walnut. Honestly, thats the best case scenario. Its alot easier hiding a flaw in the darker wood. I think the walnut dust alone with the epoxy will be a good match.

Marc-
Glad you made the catch. I was just about to chime back in and re-explain that the flaw is in the WALNUT not in the maple. I evidently did not make that clear in my original post. Sorry for the confusion and thanks everyone for the input.

[Perry Holbrook]

Since lacquer is my top coat of choice, I've started mixing dust with the lacquer to get a very quick drying putty paste. It's going to turn the same color of any end grain once it's finished. In most species it works just fine.

Perry

[john whittaker]

Royce, Been there, done that... mix walnut dust with clear epoxy, as much as needed but still fluid enough to spread. "Push" fill the hole and get is fairly smooth but don't try to get it perfectly smooth while still wet. You can't work it very long. As soon as it dries it will sand down smooth very nicely. Good Luck.
John W

[Marcus Ward]

Mix it until it's like thick peanutbutter, you don't want it to flow out of the repair. I've been a west system user for years but a couple of years ago a tornado threw my 15' boat across my backyard and I become a west ninja after fixing that thing!

[Ian Barley]

One last tip - keep an eye on the mix and dont leave it in your shop unattended. Epoxy sets in an exothermic reacion (gives off heat) and in the right circumstances could burn when you add a lovely carbon based fuel like wooddust. I know about this bacause I have had this mix melt a plastic beaker and been too hot to touch if left "en masse". Whatever you don't use promptly should be spread thin and put somewhere safe until it has set.

[Chris Padilla]

One last tip - keep an eye on the mix and dont leave it in your shop unattended. Epoxy sets in an exothermic reacion (gives off heat) and in the right circumstances could burn when you add a lovely carbon based fuel like wooddust. I know about this bacause I have had this mix melt a plastic beaker and been too hot to touch if left "en masse". Whatever you don't use promptly should be spread thin and put somewhere safe until it has set.

Hmmm, that must be that *strange* English Epoxy you use over there... ;)

[Marcus Ward]

You'd have to have quite a chunk of it to get hot enough to burn or ignite wood. I think you're pretty safe if you're not mixing up quart at a time.

[Josh Goldsmith]

Does anyone have a close up pick of sawdust and epoxy. I have tried sawdust and different glues and never had any luck. I know that you are talking about epoxy but just want to be sure it works before i go out and buy some clear epoxy. Thanks Josh

[Steve Schoene]

I wouldn't go this route. Epoxy, or what ever, filled with sawdust is highly unlikely to take finish the same way as the walnut surrounding it, and doesn't give much flexibilty to tweak the color or grain.

I would hold off with the filling until I had gotten a coat or two of the final finish applied, and then I would use a burn in shellac stick. Colors can be mixed to get a very, very close match, at a point in the process when you know exactly how the wood is reacting to the top coat. You can even simulate the grain if you aren't going for a full filled finish.

[Frank Hagan]

I wouldn't go this route. Epoxy, or what ever, filled with sawdust is highly unlikely to take finish the same way as the walnut surrounding it, and doesn't give much flexibilty to tweak the color or grain.

I would hold off with the filling until I had gotten a coat or two of the final finish applied, and then I would use a burn in shellac stick. Colors can be mixed to get a very, very close match, at a point in the process when you know exactly how the wood is reacting to the top coat. You can even simulate the grain if you aren't going for a full filled finish.

I have to agree with this. I have used epoxy and maple wood flour as an adhesive for mahogany on boats (the maple wood flour turns the mix as dark as stained mahogany) but the joint is very noticable.

The exothermic reaction can happen with even small amounts of epoxy. I have had it happen with about 2 ounces when in a tall and narrow pill bottle ("hey, this looks like it would work for small batches!"). The most dramatic example I had was about 4 ounces in a measuring cup that "went off" when I mixed in inorganic material ... I dumped plastic fibers on top of the mix and insulated the top of the mix, where all the heat was dissipating. No fire, but it did smoke and melt the plastic container (not a wimpy one either; it was "dishwasher safe"). Drove me out of the garage in a flash. As long as you mix in a big enough container that the mix is spread out, and you allow the heat to dissipate, you won't see it. Some guys in hot areas will keep a cooler of ice around when mixing large batches, and the container gets set down on top of the ice.

[Ian Barley]

You'd have to have quite a chunk of it to get hot enough to burn or ignite wood. I think you're pretty safe if you're not mixing up quart at a time.
About an inch in the bottom of a plastic beaker. Hot enough to burn my fingertips when I picked it up. Having now gone through two house fires I may be getting over sensitive to the risk but feel that the warning is still valid.

Chris - it was West system epoxy.

[john whittaker]

Josh...You asked for pictures...I have attach a pic of a maple block with a paduk inlay. Did a poor job and had a gap that was filled with an epoxy paduk dust mixture. This is a worst case scenario in that paduk tend "color run" into lighter wood. Also, the light dark contrast will show the "fix" more than patching in the middle of a solid piece of walnut. This came out pretty well and I think a walnut patch would be much more concealed.

I made a walnut chopping block that had a piece about the size of a dime chip out. It was repaired using epoxy & walnut dust and you would have a hard time finding the spot.

[Carl Eyman]

I ,too, agree with Steve. If I'm finishing the walnut with a shellac (even though a topcoat may follow) I'll use some of the shellac flakes to burn into the gaps. Very satisfied with the results.

[Jay Knoll]

Chris

It happened to me as well, one hot FL day I was mixing some West System in a yoplait yogurt container, (narrow base, tall sides) finished the job and there was about 1/2" left in the container. I left it to "kick off" before I threw it in the trash, good thing I did, about 5 min later the whole thing was smoking! I dumped part of a glass of water into the container and that stopped the reaction.

Jay