Adventures in soap

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Blog entry by kaerlighedsbamsen posted 06-08-2014 11:41 AM 4492 reads 8 times favorited 10 comments Add to Favorites Watch

When making my Shop stool #2 I wanted to experiment with using soap flakes as a finish like in a lot of mid-century classics made from light colored wood, mainly beach, white oak, ash, birch and pine/fir.

The finish has some nice qualities:
- It is natural and can easily be removed
- It is the closest you can got to untreated wood and has a nice matte feel and shine
- It is easy to repair in case of damage and it can be done at home
- It does not darken/color the wood much loke oils and warnish does
- It dryes fast and can be handled in 30 minutes and used in a few hours

Despite being linked to scandinavian furniture and used quite commonly here in DK it is difficult to find knowledge about it. You can buy readymade products in the stores, like this one:

Like so many other aspects in our lives common knowledge have been lost and you now go to the store and buy a brand instead of the actual product you need. This happened to wood soap as well. I wanted to learn from this project and to know what i was doing so I had to get the real thing.

So spent an whole evening reading and searching on the topic. Turns out that the original soap used was not liquid but dry flakes made from lye and animal fat. This can still be bought from speciality dealers like this one (in danish):

In the stores flakes made from vegetable oil is still available and this is what i settled for:

The soap really is flakes and look like that expensive, english sea salt:

The flakes is mixed whith boiling water about 1 part soap to 2 parts water. Dont mix large quantityes as it goes a long way. At first it was watery and i almost poured it out to make another batch but after a while it turned stiff like frozen ice cream:

This was way too stiff so i thinned it again to about whiped cream consistency:

I wanted to make a test before using this treatment on something I have invested time in. Found a pieze of the most open and porous wood i had that i knew would be prone to attracting dirt and marks, in this case low grade construction timber (probably fir). Planed it and sanded to get as open a surface as possible. Here you see the untreatd wood beside the pieze that had 3 coats of soap with about 2 hours inbeween. There is a slight darkening of the wood but not much coloring:

I then lined up all the stuff i could quickly find that i knew would leave stains:

Placed a dot of each on the wood, rubbed it in a bit and left it there for about 20 minites. In order from left it is:
0: Permanent marker (small dot)
1: Red wine
2: Aceto Balsamico winegar
3: Black spray paint
4: Carpenters glue
5: Ketchup
6: Food color, green
7: Food color, blue
8: Engine oil
9: Jam from raspberries
10: Grass rubbed in

A closer look:

After a quick wipe off with a cloth, nothing more, the two piezes looked like this:

I did not expect the paint to be removable but the result impressed me. From a treatment that is so discreete I find this to be really great. Only the paint and food coloring left considerable marks. Here the paint closer up:

After a quick sanding with grit 220 after the wood was dry it all came of and a new layer of soap recreated the finish perfectly. (forgot to take pictures)

Will certainly be experimenting more with this and hope it was a usefull read.
Let me know what you think!

-- "Do or Do not. There is no try." - Yoda

10 comments so far

View leafherder's profile


1991 posts in 3291 days

#1 posted 06-08-2014 12:35 PM

Very interesting. I expected the paint to mar the finish and I would have guessed that the wine (with alcohol) and vinegar (with acid) would do more damage. Thanks for the information.

-- Leafherder

View Philip's profile


1277 posts in 3877 days

#2 posted 06-08-2014 12:38 PM

That is amazing, thanks for sharing. Sometimes it’s nice to have something look like there’s no finish.

-- I never finish anyth

View kaerlighedsbamsen's profile


1387 posts in 3052 days

#3 posted 06-08-2014 12:53 PM

Thank you both!
Leafherder: Yes i was impressed as well. Picked the wine with most alcohol and the winegar with most acid.

-- "Do or Do not. There is no try." - Yoda

View Buckethead's profile


3196 posts in 3207 days

#4 posted 06-08-2014 01:23 PM

I have been seeking a finish for my workbench (maple/walnut) that would not yellow or considerably darken the maple. It looks like I may have found it. Thanks for posting!

-- Support woodworking hand models. Buy me a sawstop.

View kaerlighedsbamsen's profile


1387 posts in 3052 days

#5 posted 06-08-2014 02:07 PM

Buckethead:Would love to hear how it turns out!

-- "Do or Do not. There is no try." - Yoda

View stefang's profile


17040 posts in 4673 days

#6 posted 06-08-2014 06:04 PM

I like your test, very revealing! It’s my understanding that soap finishes on pine will help keep it lighter instead of the usual darkening with time. We also use a lot of lute here in Norway which is a caustic soda mixture aka lye. It leaves a nice tone to the wood and also prevents darkening. We also use lute to make fish ‘Lutefisk’ strange stuff, but ok once a year around Christmas time.People used to make their own ‘lute’ from ashes, but I don’t know the recipe. I think soap is a great alternative and probably easier/safer to use too.

-- Mike, an American living in Norway.

View kaerlighedsbamsen's profile


1387 posts in 3052 days

#7 posted 06-08-2014 07:41 PM

Stefang: Thanks for your comment. My famly is norwegian so I have had lutefisk a few times. What the americans call “an aquired taste”..
As I understand it traditionally lute is made mixing ash from mainly birch with (nut much) water and then filter it.
Perhaps my next experiment could be to go all in and make my own soap as well..

-- "Do or Do not. There is no try." - Yoda

View lightweightladylefty's profile


3667 posts in 5051 days

#8 posted 06-09-2014 05:04 AM

This is really interesting and informative. We can learn a lot on LJs!


-- Voltaire: “Those Who Can Make You Believe Absurdities, Can Make You Commit Atrocities” There are 112 genders (not including male and female)

View mafe's profile


13694 posts in 4428 days

#9 posted 06-09-2014 10:08 PM

What a cool test you made there.
As a son of a architect and later a architect my self I grew up with this.
We used the ‘sæbespåner’ and mixed it with some ‘pibeler’ to give it whiteness, this was standard on all floors and some furniture’s of pine.
You can also use a mix with kalkvand or kaolin.
Sorry so much in Danish here…
Best thoughts,

-- MAD F, the fanatical rhykenologist and vintage architect.

View Roger Kimmel's profile

Roger Kimmel

36 posts in 2718 days

#10 posted 09-17-2014 01:52 AM

Thanks for posting. I have never heard of soap finish. I admire your experimental method. As an aside, I remember my mother making lye soap when I was very little. Wish I had paid more attention!

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