Hi, I have a DIY project with rustic grade (#2) red oak and I'm trying to find a suitable filler for sections where the flooring was face nailed. I'm using Osmo Polyx Oil (hardwax oil), which is an oil-based penetrating finish.

I've been experimenting with different wood fillers that I can get locally to get a feel for what'll color-match to the wood once it's finished and I'm finding that the fillers that match the color of the raw wood most closely turn much darker when I apply the Osmo finish.

I've tried Famowood Oak and Maple colors, PL oak, Elmers golden oak & red oak, and stainable wood glue mixed with sawdust from my dust collector. I expected the sawdust/glue mix to be very close, since it's from the same wood, but it turned out to be the darkest of the lot after I put the finish on it. So far the closest match has been the Famowood Maple, which is significantly lighter then the flooring boards before the finish is applied, but even that is fairly visible.

I presume this darkening is normal when using an oil-based finish like this? Do you have any recommendations for fillers that will match better?

Thanks,
Greg

I'm still testing fillers, but there are some of the frequently recommended ones (Timbermate, Woodwise) which I can't get locally and would like to understand better how to color match the filler and the floor under this oil-based finish. I presume the problem would be the same using oil-based polyurethane, so I don't think I'm in strange territory here.

So far, the smoothest filler I've tried (best fill) was Durhams, but the color is way too light. The best color match (after finishing) so far has been Famowood Maple, but it didn't fill very smooth (may need to be thinned, but I didn't have any acetone when I was doing my test).

I don't want to have to spend a small fortune buying a bunch of different colors of wood filler and having them shipped here only to find none of them are right for my floor.

If I was to tint a light/neutral filler like Timbermate, what products do you use for the pigments? Liquid wood stain? Paints from the hobby store?

Thanks,
Greg

Greg, We installed, sanded and finished this ¾” x 1 ½” #2 red oak with a little #2 white oak mixed in and trowel filled with Pro Parks full-trowel wood filler, red oak color. You can see how the filler blends in with the verity of color after the finish goes on. I have not used the Hardwax oil but I would think it would color the filler just like the oil-based sealer we used on this floor.

We normally use Woodwise filler on a job like this but we were out of it so instead of driving 75 miles to the wood floor distributor we bought the Pro Parks filler from Home Depot. It is not as thick as the Woodwise and required filling twice but is similar and looked great.

You could buy a small container of the Parks and try it on a small test area; it looked
good on our #2 red oak.

That #2 looks good Buddy. I wish more folks around here liked it but they typically do not. I like to see some of the unusual figure that is often present. In your opinion, do you think #2 is more dent resistant than say select or clear? Or maybe that they show less because of the figuring? Anyway, looks good.

ghouse - I've been finishing my floors with OSMO one room at a time now for the last couple of months. To fill gaps, I've had success with mixing some of the OSMO with the dust from my sander. I mix it until it is fairly thick and then trowel it into the gaps. I'll do this after I've put down the 2nd coat and then wipe off the excess. If you try it any time before the 2nd coat is down, you'll likely brush it out of the gaps as you are working the OSMO into the wood.

That's a great idea, Ted. I wouldn't have thought of that. Thanks, I'll definitely give that a try!

re: BuddyJ

So you found the red oak colored Parks filler matched your wood pretty well? Or does it contrast? I could see using a contrasting filler for a trowel fill, but I wouldn't want that when filling nail holes.

What finish were you using in that photo? Looks great!

I'm thinking about filling the larger imperfections with black, to match color in the surrounding wood. I think I can get Timbermate in black, so I'll probably try it for that. I like the fact that you can rejuvenate the stuff by adding water, and that it isn't sensitive to storage conditions (you can freeze it, etc)

re: Gary

I totally agree, #2 is beautiful. I absolutely love the look.

Greg

Gary, The dark brown and red strips with the irregular grain are very dense but the lighter strips are soft, not as soft as pine or some of the other soft woods. Most select or clear we see does not have these light soft strips that can dent fairly easily.



Greg, The finish is Bona DriFast Sealer then we applied two coats of Lenmar oil-based Poly.

I tried tedh98's recommendation of using a mixture of sanding dust and Osmo finish, but I wasn't too happy with the results. Once again, it came out very dark looking, very similar in look to the results I got from mixing sawdust with wood glue.

I haven't tried the Parks trowel filler, but there is a Home Depot nearby, so it wouldn't be too difficult to do that. I ordered some Timbermate in maple finish (and ebony, for the knotholes).

If those don't do it, perhaps I can tint it. What do you guys use when you tint filler?

Greg

Quick followup.

After trying a bunch of stuff, my favorite fill for this floor (#2 red oak, lots of variation) is Timbermate in Red Oak color. It blends in with most of the wood well, and it doesn't darken significantly (from the color in the can) when I put the Osmo finish on it.

I've found that the trick as far as predicting color is to compare the color of the filler when WET. If I compare the color of the filler after it's dried, then the oil-based Osmo finish darkens it up too much for my taste.

Close 2nd on the match was the Parks trowel filler in white oak. It's a nice color, but the consistency is runny, so it'd be better for a trowel fill then spot filling. I'm spot filling just the nail holes. I like the smoothness of the Timbermate and the way you can add water to vary the consistency.

Thanks for all the advice,
Greg

Timbermate is becoming the favorite of pro finishers.

I can see why, it's very pleasant to work with. Low odor, nice smooth texture. Seems to sand out nice on the tests I've done too.

Greg