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Sanding dust + glue repair drying too dark?

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Forum topic by daviddoria posted 12-16-2013 04:50 PM 2578 views 0 times favorited 9 replies Add to Favorites Watch
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daviddoria

66 posts in 1403 days


12-16-2013 04:50 PM

Topic tags/keywords: patch crack repair sanding dust glue

I have some small cracks that I am trying to repair. I’ve read that making a paste from sanding dust from the same wood + glue can do the trick. I’ve tried with both Titebond as well as CA glue, but in both cases (worse with the CA), the crack ends up much darker than the surrounding wood, even though the sanding dust was a perfect color. I’m not splitting hairs between shades of the same color – the wood is pretty light (it is Apple I believe) and the crack ends up pretty dark – it is very very visible.

Is there a different glue that will not make the sanding dust turn so dark when it is mixed? White glue perhaps? Any other suggestions?

Also, can anyone explain why this darkening happens? Is it the moisture in the glue that mixes with the dust (I’d bet the dust would turn the same color if I wet it) and then never has a chance to evaporate before the glue dries?

Thanks,

David


9 replies so far

View RandyinFlorida's profile

RandyinFlorida

181 posts in 1532 days


#1 posted 12-16-2013 05:37 PM

I used this same technique last night with a finger jointed cedar box I’m making. I used Titebond II. It looked great great after I sanded it. Not sure what it will look like when I put a finish it.

-- Randy in Crestview Florida, Wood Rocks!

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MalcolmLaurel

269 posts in 1087 days


#2 posted 12-16-2013 06:03 PM

I use this technique, but I don’t make a paste… I squirt some glue into the crack with a hypodermic syringe, then I sprinkle sawdust over that, press it in, sprinkle some more on, and gently blow the excess off. This way the surface has less glue and won’t be as dark.

It may take several shots as the glue shrinks a bit as it dries.

-- Malcolm Laurel - http://MalcolmLaurel.com

View pintodeluxe's profile

pintodeluxe

4856 posts in 2278 days


#3 posted 12-16-2013 06:08 PM

I have never had an acceptable repair with glue + sawdust. I usually just remake the part and avoid the headache.

Usually glue spots will not absorb stain as much as the surrounding wood, leaving a light spot.
Glue + sawdust slurries sometimes stain darker because the wood dust is porous, and not sanded to the same grit as your surrounding wood.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

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Rick M

7922 posts in 1844 days


#4 posted 12-16-2013 06:29 PM

PVA (yellow/white) glue shrinks as it dries and in my experience doesn’t look very good. Epoxy works but can look muddy if used with sawdust. CA glue is a good bet. I put some in the hole and press in sawdust then add a drop on top. It should blend in better once you apply a finish but glues won’t work if you are staining unless you stain or dye the glue first. An alternative is wood filler but I’ve never had good luck with them either. My advice is don’t try to blend the repair, just make it black, or dark brown, or a contrasting color.

-- http://thewoodknack.blogspot.com/

View oldnovice's profile

oldnovice

5730 posts in 2832 days


#5 posted 12-16-2013 06:54 PM

I haven’t tried I but last time I bought some Tightbond it was next to some Elmer’s that claimed to be stainable.

I have used Timber Mate with very good results for both grain filling and gap filling. It comes in various colors and can be blended; I have colored it with India ink and even water colors. There is no waste as any remaining material can be reconstituted with water but it cannot be used under water based finishes unless first covered with a protective coating. Thin it like heavy soup for grain filling keep it thick for gap filling.

It is available from a number of places including Amazon, Rocker …..!

............ END OF COMMERCIAL…........

A previous Lumberjock testimonial

-- "I never met a board I didn't like!"

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WibblyPig

168 posts in 2739 days


#6 posted 12-16-2013 07:45 PM

Hide glue plus sawdust. Hide glue takes stains (though in my opinion, if you want dark wood, why stain it dark – make it out of walnut), finishes, etc.

-- Steve, Webster Groves, MO "A society grows great when old men plant trees whose shade they know they shall never sit in."

View gfadvm's profile

gfadvm

14940 posts in 2154 days


#7 posted 12-17-2013 02:16 AM

I have had the same experience with the glue/sawdust “filler” every time I used it. Same results with shellac/sawdust filler.

I now use color matched Timbermate for all these tasks. It is inexpensive and very simple to use with almost zero chance to screw up! I get mine at Woodcraft.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View Jim Finn's profile

Jim Finn

2412 posts in 2386 days


#8 posted 12-17-2013 03:42 AM

I mix white glue and sanding powder. Yes it shrinks a little in voids over 1/6” wide so I sand it off and do several coats. Yellow glue does give a darker filler. Use more glue and less powder to get a lighter filler. Applying white glue and sprinkling powder on it and pressing it in place also works well. I never stain anything so that is not an issue for me. I like to use a credit card as a squeegee to force the mixture into the cracks.

-- "You may have your PHD but I have my GED and my DD 214"

View daviddoria's profile

daviddoria

66 posts in 1403 days


#9 posted 12-17-2013 05:33 PM

Thanks for the suggestions everyone.

@Jim Finn – those tips worked really well for me. I used Elmers white “School Glue” and kind of packed the dust on top of the glue. Some of my creacks disappeared almost entirely after a couple of rounds of doing this! I realize no method will ever be perfect, but this is a heck of a lot closer than my yellow glue mixed with dust method.

David

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