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Does walnut sapwood not take finishes?

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Forum topic by MrDan posted 12-01-2017 02:25 AM 1074 views 0 times favorited 11 replies Add to Favorites Watch
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MrDan

205 posts in 3128 days


12-01-2017 02:25 AM

Topic tags/keywords: walnut sapwood finishing shellac

Question about walnut sapwood: I have a shelf made of air dried walnut that i just finished making & now I’m trying to finish it but things are not going so well.

My shellac wasn’t coating the lighter sapwood, so I switched to an acrylic finish but that’s not working either. It looks as though the sapwood is unfinished while the dark heartwood is very glossy. The whole thing has about 6 coats already, but the sapwood looks unfinished still.

(The entire shelf was sanded to 220 and wiped clean prior to finishing.)

Has this happened to anyone else? Any ideas?


11 replies so far

View EarlS's profile

EarlS

612 posts in 2188 days


#1 posted 12-01-2017 02:35 AM

Did you seal it first? I’ve never seen walnut sapwood not take finish but I have seen it soak up polyurethane like a sponge.

-- Earl "I'm a pessamist - generally that increases the chance that things will turn out better than expected"

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MrDan

205 posts in 3128 days


#2 posted 12-01-2017 03:27 AM

I put 2 coats of shellac on it before i started with the acrylic coats but that didn’t help much. Maybe it’s just way more thirsty? Strange. I’ve never experienced this with any other wood.

View TheFridge's profile

TheFridge

8336 posts in 1326 days


#3 posted 12-01-2017 06:51 AM

Cypress does this as well.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

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Loren

9639 posts in 3488 days


#4 posted 12-01-2017 06:59 AM

It’s “pithy” I think, or can be.

View Firewood's profile

Firewood

168 posts in 1474 days


#5 posted 12-01-2017 01:46 PM

I just finished some walnut beds. I put on about 4 coats of waterlox (no sealer) and noticed no issues with the sapwood.

-- Mike - Waukesha, WI

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MrDan

205 posts in 3128 days


#6 posted 12-02-2017 05:02 PM

Bump. Anyone else have a way around this?Additional coats don’t seem to do anything.
Thanks

View OnhillWW's profile

OnhillWW

112 posts in 1072 days


#7 posted 12-02-2017 06:01 PM

It can be a bugger. I use primarily Waterlox as well and my routine is to spend 20+ minutes making top wash applications. I concentrate on areas where it soaks in – sapwood, sometimes crotches and busy grain, keep applying for 20 – 30 minutes concentration on the dryer looking regions. Thirsty sapwood may not look like it has reached the same saturation point as the heartwood but if you have made at least a handful or so of flooding coats it will be fine. I wipe off the entire piece, not to the point of dryness but getting 95% of the finish off and let it sit for 24Hrs. 2nd and 3d coats will now look good in the thirsty areas despite how they looked at the end of the first coat wipe off. I light sand with 600 grit every 2nd coat as well.

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MrDan

205 posts in 3128 days


#8 posted 12-02-2017 07:40 PM

Thanks OnhillWW. I suppose I’ll have to change my process when it comes to sapwood. I prefer to spray everything but I’ll try you suggestion next time prior to spraying.

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EricTwice

230 posts in 373 days


#9 posted 12-02-2017 08:05 PM

Walnut heartwood is hard, and rot resistant. Sometimes the sapwood is a little punky and will absorb a load of finish before it starts to get glossy. OnHillWW is correct with his method. You can do the same process with shellac. This will also harden the wood making it more durable.

-- nice recovery, They should pay extra for that mistake, Eric E.

View Loren's profile

Loren

9639 posts in 3488 days


#10 posted 12-03-2017 12:05 AM

Shellac is great for working up to a surface
build because it dries so fast. I know it’s
frustrating to hear it, but it probably just needs
more coats to get a build on the soft area.

The cut edge of a piece of MDF can drink up
an awful lot of shellac I think, for example.
But it will seal and build eventually.

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MrDan

205 posts in 3128 days


#11 posted 12-03-2017 12:49 AM

Thanks a lot for all the input guys, much appreciated!

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