Wood Filler Basics
posted on May 2, 2008 by Rockler

wunderfilWood filler, grain filler, wood putty – what’s it all mean? Judging by the raft of questions we field on the subject, filling wood is a source of general confusion.  Here’s a little clarification.

Wood filling can be devided into two basic tasks: filling voids – such as nail holes, chips and dents – and filling the pores of “open grained” woods, like oak and mahogany.  Fillers designed strictly for filling voids are thicker, and for one reason or another may not work well for filling grain pores – they may contain particles too large to work into miniscule grain openings, or may not be easily thinned down to a viscosity suitable for the task. Fillers designed strictly for filling grain are thinner, with a consistency often compared to pancake batter. They simply lack the “body” to fill larger voids. Some fillers can be used for both - they are thick enough to span a void, and can be thinned to fill grain pores in an entire wood surface.

For filling voids, many woodworkers swear by fillers composed of a nitrocellulose lacquer binder and wood flour (very fine wood particles). Famowood is an example – and a product that truly lives up to its name. It dries quickly, shrinks minimally, comes in a variety common wood species, and earns customer reviews like this:

“There is no substitute when it comes to the best of the best. That’s what Famo is all about. You simply will not find a better wood filler. Its ability to basically become invisible is what sets it apart from everything on the market. Nail holes vanish, slight imperfections in a mitered joint seam together...”

Wunderfil, another favorite, is a dual purpose filler. It comes in putty form, suitable for filling voids, and can be thinned with water to a consistency that works well for filling grain. It cleans up easily with water and is available in a number of colors, which can be mixed together or custom tinted to produce a perfect color match. Wunderfil is also heartily endorsed in our customer reviews:

"The absolute best filler I have used. I have only used this for damage repair so far but will be starting a project soon and using it as a grain filler. Have confidence it will work well. Nearly undetectable after being stained."

"I recently build a desk for my wife using 5/4 oak for the top. I've never used a woodgrain filler before and couldn't find any on the store shelves. Got it from Rockler, followed the directions and was very happy with the results. Showed it at my woodworkers club, Woodworkers of El Paso and was highly praised for it...thanks Rockler."

"Unquestionably the easiest filler to apply and sand I have ever used. "

(etc.)

Products designed strictly for filling grain come in two varieties: oil/varnish based and water based. Bartley Paste Wood Filler is a classic oil based grain filler, and a top choice for filling grain under oil based wood finishes. It comes in three shades and when used as correctly, will produce the perfectly flat surface necessary for a “glass-smooth” finished product. Crystalac is a water-borne grain filler, cleans up easily, works under any type of film finish, and has a unique and often desirable property: it dries water-clear.

bartley paste fillerFilling grain requires something of a “knack”, and seems to be the source of the most wood-filling confusion. But it’s not beyond the reach of anyone with average woodworking skills. As with any advanced finishing technique, a little knowledge and a practice run or two can go a long way. If you’ve never filled grain, advice from a pro – such as that found in a wood finishing book or DVD - can really flatten out the learning curve. Bob Flexner’s Understanding Wood Finishing, for example, contains a thorough discussion of various grain filling techniques that can help you choose the best method, and apply it successfully on your first try.

posted on May 2, 2008 by Rockler
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Comments

16 thoughts on “Wood Filler Basics”

  • David Thornton
    David Thornton July 4, 2008 at 12:11 am

    I have up and down wooden garage doors with horizontal cracks in the wood panels.<br />I am looking for a filler that will withstand the day to day impact of the doors opening and closing.

  • Blog Editor

    You might try an epoxy filler, like <a href="http://www.rockler.com/product.cfm?Offerings_ID=2358" rel="nofollow">Quickwood Epoxy Putty</a>. It's quick, easy to use, and should wear like iron.

  • Jonas Grumby

    I plan to paint over my old oak kitchen cabinets white. I would like a very smooth glass-like finish where I can't see or feel the wood grain texture. There's no Rockler store close to my area and I'd rather buy where convenient which is locally. Are wood grain fillers available in regular hardware stores like Home Depot, Lowe's, OSH, or Ace Hardware? I've read about Behlen's Pore-O-Pac Paste Wood Grain Filler in paste or liquid form. I've also heard of Briwax, J.E. Mosers, Famowood and Timbermate used for floors. I prefer to work with a water-based grain filler.

  • Rockler Blog Team
    Rockler Blog Team December 30, 2009 at 7:16 am

    Thanks for the comment, Jonas. True grain filler is something of a specialty item and you may have trouble finding it in hardware and big box stores. Since you are painting the cabinets, and aren't concerned with the look of the filler, you might try a standard water-based filler. Various water-based fillers are available in most hardware stores, and most can be thinned down a little to make them more suitable for filling grain. They aren't terribly expensive, so you might buy the smallest quantity available of a couple brands and test them both for ease of application and sandability once they're dry.

  • Charlene

    I have a pine table that has patching with wood putty. Will it pick up stain, or will I need to paint it to cover the putty?

  • Rockler Blog Team
    Rockler Blog Team March 8, 2010 at 11:02 am

    Thanks for the comment, Charlene. Unfortunately, wood filler, unless it happens to be very close in color to the stain, tends to stick out like a sore thumb once it's stained. You could try a small area to see for yourself and then wipe it off before it dries with spirits if you don't like it. You would still be able to paint the table as a "plan B."

  • Faye Jasmin

    I have treate wood deck with 2x6 deck boards. The nails have
    been removed and have left holes that ned filling. What can I use
    that will not shrink and can be painted o make my deck look
    great again? Thanks for your help!

  • Rockler Blog Team
    Rockler Blog Team April 20, 2010 at 4:12 pm

    Thanks for the comment. You could use just about any exterior-rated filler. The problem with outdoor projects - those directly exposed to the elements - is that wood changes dimension with changes in moisture content and (for practical purposes) filler doesn't, which can cause the filler to work its way out of the hole. That said, if the area you need to cover isn't all that large, consider an epoxy filler like "Quickwood" (http://www.rockler.com/product.cfm?page=2358). It's a little more work to use but definitely stands the test of time.

  • Angie

    Can I drill into a wood filler hole? I made a mistake putting together dressers and i have to fill old holes with wood filler.

  • Rockler Blog Team
    Rockler Blog Team January 25, 2011 at 5:50 am

    Sorry to hear about the mishap, Angie. You can drill into wood filler, but the resulting hole isn't likely to hold a screw very well. If the area is hidden from view, you would be better off patching it with wood, such as drilling an over-sized hole and gluing in a piece of wood dowel. If that's not an option, you'll get better results with a filler that uses actual wood particles in a binder, such a Famowood (see above). Good luck!

  • Marie

    I have a table with a very rough and un-even surface and a design routed into the top. I am looking for a clear product (maybe lacquer or lacquer-like...I've seen it, but do not know the name...often used to fill the natural voids in mesquite wood) that will fill the the design as well as add enough layer to the top of my table for it to be flush and smooth. I do not want to cover, mask, or take away the look of the table, but I would like the surface to be more usable/flat/consistent.
    Does anyone have any suggestions which product type to use? Which product is best? What is easiest (for someone who has never done anything like this before)?

  • pat

    I have a chocolate lab puppy who loves to chew. He has knawed at
    the wood on the baseboard. How do I correct damage he has
    done(without pulling all his teeth out haha)

  • Rockler Blog Team
    Rockler Blog Team November 15, 2011 at 1:15 pm

    Thanks for the question Pat. We agree - tooth pulling, while effective, is too drastic. The best and possibly only way to completely right the situation is to replace the trim (and then perhaps coat it with that flavored stuff that dogs don't like). Short of that, you could try filling it with a filler that's as close in color to the molding as possible. Wunderfil would work. Then you'll need to reapply a clear top coat. You may need to custom tint the filler to get the best match. Depending on the color match and wood grain type, you may not be able to achieve the look you want, so you might try a small area to see how it looks. Best of luck!

  • Danny

    Hi- How do I tint the filler to match my spice colored bamboo wood floor? I have a few cracks and surface nail holes to fill. Thanks for the help.

  • Bret Combest Jr
    Bret Combest Jr May 20, 2013 at 8:06 am

    Danny I'm with you on the trying to fill in my spice bamboo (lowes). We just got about half the floor down today and have some cracks I would like to fill in also.
    Thanks
    Bret

  • Annika

    I am looking to paint unfinished oak cabinets. I know its easier to paint over finished cabinets but what is a good filler to get a smooth look.

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