{"id":538,"date":"2025-12-22T15:00:37","date_gmt":"2025-12-22T15:00:37","guid":{"rendered":"https:\/\/pole-lathe.com\/?p=538"},"modified":"2025-12-22T15:02:37","modified_gmt":"2025-12-22T15:02:37","slug":"finishing","status":"publish","type":"post","link":"https:\/\/pole-lathe.com\/index.php\/en\/2025\/12\/22\/finishing\/","title":{"rendered":"Finishing"},"content":{"rendered":"\n

A chilly winter day, and therefore a good time to look at the finishing touches on all the bowls and cups we’ve made (and a chemistry lesson). One of the things we generally do is oiling. This should be done with a hardening oil, such as linseed oil or walnut oil. In other words, it should be an oil with a high omega-3 content, as this fatty acid can form a polymer with many cross-links due to the many double bonds in the fatty acid chain, for those interested. Most types of oil, such as sunflower or olive oil, have a very low omega-3 content and therefore don’t harden, but at most become somewhat thicker and sticky.
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Bonds formed between a number of linseed oil molecules (source: bcachemistry.wordpress.com)<\/pre>\n\n\n\n
But beyond the technical aspects, you can also make oil paint with this type of oil by adding pigments. Traditionally, this is done with linseed oil. We’ve experimented with this paint and also with milk paint. This is another type of paint, based on proteins. Different types of proteins can be used. Traditionally, these are proteins from milk, hence the name milk paint. The paint is often made by mixing, for example, quark with lime and pigments. The paint we used was based on pea protein. The proteins adhere to each other and to the wood. The lime provides the right acidity and opacity, and the pigments, of course, provide the colour.<\/p>\n\n\n\n
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On the left two bowls with oil paint test and on the right a cup with milk paint<\/pre>\n\n\n\n
Sometimes wood splits. There are a few options. You can leave the split as is, have some extra firewood, or you can repair it. An elegant way to repair it is with copper wire. First, drill a few small holes where you want to fix the wood and then weave copper wire through them.<\/p>\n\n\n\n
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Drill holes to repair the tear and a plate with iron acetate<\/pre>\n\n\n\n
In the photo above, you also see a plate that has been stained black (ebonised) with iron acetate. Adding iron to vinegar dissolves it, creating a so-called iron acetate solution. This solution is clear and colourless. The real magic (chemistry) happens when you apply this solution to wood that contains a lot of tannic acid, like that chestnut plate. The dissolved iron then penetrates the wood and reacts with the tannic acid, forming a black complex.<\/p>\n\n\n\n
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The formation of the iron-tannic acid complex (bron: https:\/\/www.researchgate.net\/figure\/Complex-formation-between-tannin-and-ironIII-47-48_fig3_363357873)<\/pre>\n\n\n\n
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A chilly winter day, and therefore a good time to look at the finishing touches on all the bowls and cups we’ve made (and a chemistry lesson). One of the things we generally do is oiling. This should be done with a hardening oil, such as linseed oil or walnut oil. In other words, it […]<\/p>\n","protected":false},"author":2,"featured_media":533,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[],"class_list":["post-538","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-meetings"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/pole-lathe.com\/index.php\/wp-json\/wp\/v2\/posts\/538","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pole-lathe.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pole-lathe.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pole-lathe.com\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/pole-lathe.com\/index.php\/wp-json\/wp\/v2\/comments?post=538"}],"version-history":[{"count":2,"href":"https:\/\/pole-lathe.com\/index.php\/wp-json\/wp\/v2\/posts\/538\/revisions"}],"predecessor-version":[{"id":540,"href":"https:\/\/pole-lathe.com\/index.php\/wp-json\/wp\/v2\/posts\/538\/revisions\/540"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pole-lathe.com\/index.php\/wp-json\/wp\/v2\/media\/533"}],"wp:attachment":[{"href":"https:\/\/pole-lathe.com\/index.php\/wp-json\/wp\/v2\/media?parent=538"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pole-lathe.com\/index.php\/wp-json\/wp\/v2\/categories?post=538"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pole-lathe.com\/index.php\/wp-json\/wp\/v2\/tags?post=538"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}