Lost Art Press

My First Time Using Soap Finish: Notes & Warnings

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One of my favorite stories is how the writers for “The Straight Dope” column sent a fake hand-lotion recipe to the “Hints from Heloise” column – mixing vegetable shortening and sugar. Heloise printed the recipe and added that she’d been using the concoction for years.

Go ahead. Go to the kitchen and try it. I’ll wait here.

I’ve been reading a lot about the Danish “soap finish” these last few months, plus the chemistry and history behind it. A lot of this research will be included in my forthcoming book (which, by the way, will have a new title, so I’ll call it “Formerly the Furniture of Necessity”).

This week I made and used a soap finish for the first time, applying it to an ash chair that also will be featured in the book. I like using the finish a lot. It’s basically an oil finish (from vegetable or animal oils) that leaves a waxy residue behind that can be buffed up. I’m going to put the chair into hard use in the house to see how it holds up and report back.

This post is to encourage you to give the soap finish a try, and to dispel some of the questionable advice I’ve collected on it.

First, on the sheen of the finish. While aged soap finishes I’ve seen on Hans Wegner chairs are indeed dead-flat, a new soap finish looks much more like a wax finish. I’d call it semi-gloss.

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Soap soup. From mixing one quart of boiling water with one cup of soap flakes.

Mixing the soap finish is easy. I recommend you make a very small batch to get a feel for the different results you get from mixing soap flakes and boiling water. You can get everything from a soup to a bowl of exploded jellyfish to a stiff paste. A stiff paste is what I was after.

For my first batch I used one cup of soap flakes and one quart of boiling water. This recipe was a cruel joke. It made a grey soup that was suitable for washing clothes, not finishing furniture. When I applied it to wood it mostly made the wood wet and not much else.

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Next I tried equal parts soap flakes and boiling water. This made the blown-up jellyfish parts (I hate jellyfish; I got one in my swimming trunks once and it burned my delicate parts). Even after I let this mixture cool, it didn’t make anything I was eager to apply to finish. It was too runny.

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So I took an approach that I recommend you try: Boil a cup of water and pour about half of it into a cup of soap flakes. Mix it and see what happens. If it’s too runny, add soap flakes. If all the flakes haven’t dissolved, add a little water.

The result should be stiff and meringue-like. After it cooled it became a little harder and less mushy.

How to apply it?

You can put it directly on the wood, but I found that to be messier than the process recommended by Caleb James. Essentially you make a rubber like you would for French polish. Take a dollop of the soap and put it in the middle of a soft cotton cloth. Wrap the soap and twist the “tail.” The soap soaks through the cloth as you press it against the wood, applying a nice film after a few minutes of work – your body heat from your hand and the friction soften the soap nicely.

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After the soap dries for a few minutes, buff it with a clean, soft cloth.

Some people have reported that the finish raises the grain. I didn’t find that. Perhaps they were using soap soup.

More on the soap finish as it develops.

— Christopher Schwarz

 

Where to buy soap flakes:

 

26 thoughts on “My First Time Using Soap Finish: Notes & Warnings”

  8. When I studied furniture design in Denmark in the late 90s soap was the only permitted finish for wood furniture, as it was considered “dogme”. (Dogme 95 was an en vogue set of rules for avant-garde cinema established by Danish film directors.) The description is rather apt, and soap does make for a pleasant enough finish, although furniture thusly treated smells vaguely of utility closets.

    I wonder if the instructors consider the finish “Noma” nowadays, as cuisine has overtaken filmmaking as the Danish cultural lodestone.

  9. By any chance did you drop one of those little baby Moon jellies down your trunks (just to see what would happen) or was it a viscious attack by a Portuguese man o’ war?

  10. I recently applied a soap finish to butternut (equal parts, blended in a small food processor, applied directly, not with a rubber as shown). I had an issue with the piece turning green in places where I applied it a little thick, especially on the end-grain. Perhaps this was a result of a reaction to the tannin in the wood or not wiping the piece well enough after sanding – I’m not sure. Next time I’ll use the rubber technique and work smaller areas.

  11. That sounds more like a soap polish compared to what I did. I have som Wegner chairs that I treated with soap flakes (and yes the quality is very important; a friend had problems with staining using a cheap brand). I got a recipe from the Danish Furniture Control (now Furn-tech.dk) through Getama, one of the Danish furniture manufacturers.

    It says to mix 1/4 deciliter soap flakes (2 spoons) with 1 liter of boiled water and you let it sit for 24 hours. Then you apply the mixture in a thick layer, the soap fat being the important ingredient not the water. After a short while you wipe of the excess. Don’t let it dry out.

    Here is a Youtube-video I found that basically shows the same process with a table. It’s in Danish but you can see the mixture and the use: https://www.youtube.com/watch?v=q5wqLF8JziY. They also use the mixture for the daily cleaning and recommend giving it the full treatment every month.

  12. So what’s the REAL scandinavian soap finish? everything I was able to find online until this was making a thick foam, like a shaving cream, by adding a small amount of water to soap flakes, including reports from people who claimed they lived in denmark, etc.
    I did this today to a piece and indeed it is more like wax than what you see on the scandinavian furniture. Not bad, but not what I expected.
    Mr. Schwarz, I’m curious, did you wait 24 hours for the soap soup to thicken?

  13. New shirt? “Dont forget to soap your ash”. Would go nice with that “stop looking at my chest” shirt.

  14. Chris, thank you and sorry for being so pompous.

    I did leave the mixture overnight myself and it did thicken to a jello-like consistency; it doesn’t flow anymore, it’s really viscous. All this from two tablespoons of soap in 1 liter of water. So, my piece had already received 3 layers of the other Danish finish, the “porridge” consistency one, and it was indeed half-glossy. As the piece was a little scruffed due to my incompetency in installing it (it is a radiator mask), I sanded lightly and reapplied the thickened soap soup, which looked very much like what the guy in the youtube link posted by simonkahr did. If you agitate this jello a bit it will foam, and it’s this foam that you have to apply, I think. This was about 6 hours ago, and the finish already starts to resemble what I thought Danish soap finish should be – a matte, very soft at touch and quite special. I think it needs a couple more coatings and I’m getting there.
    ANyway, last night I ran a search for ‘sæbebehandlet”, which is danish for “soap finish”. There are a number of sites from furniture manufacturers or soap makers; some instruct to make a thick “porridge”, with a lot of soap to a little water, others instruct the opposite, the “soap soup”. As google translations has obvious limitations I may be missing a lot here, but it may be possible that one style is used for floors and the other for furniture.

  15. I’m very curious about this. Are these soap flakes zwitterionic, cationic or anionic? How long is the alkyl chain of the counter ion?

  16. If all you want is lye and oil, maybe you could just start there and make the soap yourself? It’s not hard, a friend used to make fancy soaps for our local farmer’s market. Depending on the type of oil you use, and how much excess there is after the lye eats some and turns it to soap, you could bury yourself in a whole new range of variables on the quest for the best nearly-useless traditional finish!

    Seriously, though… Olive oil, tallow, jojoba oil, linseed oil? Different alkalis? I’m guessing wood ashes and lard is the ultimate old-school recipe, but maybe I’ll substitute bacon fat. My dining table’s finish may not hold up to a damp napkin, but the food will always be delicious.

      1. Right?! It’s not my fault. I live in Portland.

        The Colonial Williamsburg store sells something called “Historic Area Wash Balls”. Just thought I’d throw that out there.

  17. OK, I’m not a chemist but…
    If soap is made from food oils… then wouldn’t they eventually go rancid? Or does the saponification process convert (the fatty chains or something) to a different type of oil?
    I have a liquid soap concentrate made from Coconut oil we have used for decades… I’ll have to try that.

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