{"id":11166,"date":"2026-02-14T17:50:36","date_gmt":"2026-02-14T16:50:36","guid":{"rendered":"https:\/\/yachtcentershop.com\/choosing-glue\/"},"modified":"2026-02-14T17:50:43","modified_gmt":"2026-02-14T16:50:43","slug":"choosing-glue","status":"publish","type":"post","link":"https:\/\/yachtcentershop.com\/en\/choosing-glue\/","title":{"rendered":"Choosing Glue!"},"content":{"rendered":"<ul>\n<li><a href=\"https:\/\/yachtcentershop.com\/izbor-ljepila\/rb-tallyho1030771x-768x967-jpg\/\" rel=\"attachment wp-att-11149\"><br \/>\n<\/a><\/p>\n<p style=\"font-weight: 400;\"><em>By Russell Brown<\/em><\/p>\n<p style=\"font-weight: 400;\">I was recently asked for help in choosing adhesives for a large spar-building project. This led to much thought and discussion with the wonderful\u00a0<a href=\"https:\/\/www.westsystem.com\/need-help\/\">WEST SYSTEM\u00ae Technical Advisors.<\/a>\u00a0The choices we made won\u2019t surprise anyone, but the reasons we made those choices are worth explanation.<\/p>\n<p style=\"font-weight: 400;\"><strong>The Materials<\/strong><\/p>\n<p style=\"font-weight: 400;\">We chose\u00a0<a href=\"https:\/\/www.westsystem.com\/products\/105-system\/\">WEST SYSTEM 105 Epoxy Resin\u00ae<\/a>\u00a0with\u00a0<a href=\"https:\/\/www.westsystem.com\/products\/205-fast-hardener\/\">205 Fast Hardener\u00ae<\/a>\u00a0(and\u00a0<a href=\"https:\/\/www.westsystem.com\/products\/206-slow-hardener\/\">206 Slow Hardener\u00ae<\/a>when we needed a little extra working time). We chose this route over pre-thickened adhesives for two important reasons:<\/p>\n<ul style=\"font-weight: 400;\">\n<li>The first was the ability to \u201cprime\u201d, or saturate the gluing surfaces with unthickened epoxy before applying the thickened epoxy. (It was the same epoxy combination, but fillers were added to create a thickened version.)<\/li>\n<li>The second was the ability to make the thickened epoxy relatively thin (lightly thickened). With our limited clamping pressure, it was important to be sure the parts weren\u2019t held too far apart by the thickness of the epoxy.<\/li>\n<\/ul>\n<p style=\"font-weight: 400;\">The spars (a 53\u2032 mast, 30\u2032 top mast, 34\u2033 boom, and a 26\u2033 gaff) are all built from Sitka spruce and are all built from eight staves (eight sided) before being shaped round. The individual staves for the mast needed scarf joints to make them long enough.<\/p>\n<p><a href=\"https:\/\/yachtcentershop.com\/izbor-ljepila\/rb-tallyho1030771x-768x967-jpg\/\" rel=\"attachment wp-att-11149\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-11149\" src=\"https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo1030771x-768x967.jpg-238x300.webp\" alt=\"\" width=\"238\" height=\"300\" srcset=\"https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo1030771x-768x967.jpg-238x300.webp 238w, https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo1030771x-768x967.jpg-600x755.webp 600w, https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo1030771x-768x967.jpg.webp 768w\" sizes=\"auto, (max-width: 238px) 100vw, 238px\" \/><\/a><\/li>\n<\/ul>\n<ul style=\"font-weight: 400;\">\n<li><a href=\"https:\/\/yachtcentershop.com\/izbor-ljepila\/rb-tallyho-2794x-1\/\" rel=\"attachment wp-att-11153\"><br \/>\n<\/a><\/p>\n<p style=\"font-weight: 400;\">The scarf joints are critical to the strength of the mast. Doing them right can be somewhat challenging because the end grain of a scarf joint can draw epoxy into the wood after the joint has been clamped. This leaves a dry, or starved joint, with a high filler to epoxy ratio. While fillers are essential for bonding wood, Gougeon Brothers\u2019 lab testing shows that a casting of epoxy with fillers is not as strong as a casting of neat epoxy.<\/p>\n<p style=\"font-weight: 400;\">Before selecting our fillers, we determined our approach to make the scarf joints as strong as possible:<\/p>\n<ol>\n<li>We used WEST SYSTEM 205 Fast Hardener. The epoxying was done in winter so the shop stayed around 60\u00b0F. With proper preparation, we had ample time to epoxy the individual joints. Our schedule required the joined parts to be moved the next day, which puts considerable stress on the joints. 205 Fast Hardener cured quickly enough to allow us to do so without any complications. The other benefit of using<\/li>\n<\/ol>\n<p><a href=\"https:\/\/yachtcentershop.com\/izbor-ljepila\/rb-tallyho-2794x-1\/\" rel=\"attachment wp-att-11153\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-11153\" src=\"https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo-2794x-1-300x205.jpg\" alt=\"\" width=\"300\" height=\"205\" srcset=\"https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo-2794x-1-300x205.jpg 300w, https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo-2794x-1-768x524.jpg 768w, https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo-2794x-1-600x410.jpg 600w, https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo-2794x-1.jpg 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>A test scarf joint. We encouraged it to soak up as much unthickened epoxy as possible before applying thickened epoxy.<\/li>\n<li>\n<p style=\"font-weight: 400;\">the 205 Fast Hardener is that the shorter cure time reduced the possibility of epoxy being drawn into the end grain, leaving a dry joint.<\/p>\n<ul style=\"font-weight: 400;\">\n<li>We pre-warmed the joints before priming them with unthickened epoxy. In the same way that warming wood will blow bubbles, cooling wood draws epoxy into the grain. We were encouraging penetration of unthickened, priming epoxy to fill up the grain before applying the thickened epoxy.<\/li>\n<\/ul>\n<p style=\"font-weight: 400;\">The fillers we chose were the 406 Colloidal Silica and 403 Microfibers. The 406 Colloidal Silica is an excellent thixotrope, meaning that it takes less filler to reach your desired consistency than using one of the other WEST SYSTEM Fillers. The wood was primed with unthickened epoxy immediately before applying the thickened epoxy. This allowed the epoxy to penetrate further into the end grain, without drawing it out of the thickened epoxy. The Microfibers were used because the thickness of the fibers helps keep all of the epoxy from being squeezed out of the joint when clamping, also helping to prevent a dry joint.<\/p>\n<p style=\"font-weight: 400;\"><strong>The Build Process<\/strong><\/p>\n<p style=\"font-weight: 400;\">Speed was essential while epoxying the staves together. We had multiple joints that were very long, and clamping was quite complicated, making the process time-consuming.<\/p>\n<p style=\"font-weight: 400;\">We started by liberally priming the staves with unthickened epoxy. Once the epoxy was fully mixed, we worked quickly to get the epoxy out of the roller pan and onto the staves with a 3\u2033 long foam roller. Once it was spread out, we returned to even out the coating. Epoxy left in mass cures much more quickly than when it\u2019s in a thin film. By spreading out the epoxy, it gave us more time to work.<\/p>\n<\/li>\n<\/ul>\n<p><a href=\"https:\/\/yachtcentershop.com\/izbor-ljepila\/rb-tallyho_2800x-1\/\" rel=\"attachment wp-att-11155\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-11155 size-medium\" src=\"https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo_2800x-1-300x218.jpg\" alt=\"\" width=\"300\" height=\"218\" srcset=\"https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo_2800x-1-300x218.jpg 300w, https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo_2800x-1-768x557.jpg 768w, https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo_2800x-1-600x435.jpg 600w, https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo_2800x-1.jpg 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n<p style=\"font-weight: 400;\">The thickened epoxy was poured onto the staves and then metered to an even quantity using an 809 notched spreader<\/p>\n<p style=\"font-weight: 400;\">For the thickened epoxy, we mixed less than a quart at a time. The mixed epoxy was poured onto a stave in a long bead before being spread with a 809 Notched Spreader. This type of spreader allowed us to meter the epoxy so we had a consistent thickness coverage over the whole bonding surface. Because of the limited clamping pressure, we were generous with our thickened epoxy. Our ample squeeze-out told us that we had sufficient epoxy in our bond lines.<\/p>\n<figure id=\"attachment_11157\" aria-describedby=\"caption-attachment-11157\" style=\"width: 300px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/yachtcentershop.com\/izbor-ljepila\/rb-tallyho-2726x\/\" rel=\"attachment wp-att-11157\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-11157 size-medium\" src=\"https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo-2726x-300x200.jpg\" alt=\"zalijepljene.\" width=\"300\" height=\"200\" srcset=\"https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo-2726x-300x200.jpg 300w, https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo-2726x-768x512.jpg 768w, https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo-2726x-600x400.jpg 600w, https:\/\/yachtcentershop.com\/wp-content\/uploads\/2026\/02\/RB-TallyHo-2726x.jpg 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-11157\" class=\"wp-caption-text\">The mast had solid blocking at both ends. Conduits for wires were installed before the two halves were glued together<\/figcaption><\/figure>\n<p style=\"font-weight: 400;\"><strong>Zaklju\u010dak i dodatne informacije<\/strong><\/p>\n<p style=\"font-weight: 400;\">These spars are for a century-old cutter named<\/p>\n<div><i>Tally Ho<\/i><\/div>\n<p style=\"font-weight: 400;\">, which won the Fastnet Race in 1927. The rebuilding of<\/p>\n<div><i>Tally Ho<\/i><\/div>\n<p style=\"font-weight: 400;\">\u00a0is being documented with a fantastic series of videos, which you can find at the Sampson Boat Co. channel on YouTube. Future videos will surely show these spars in action<\/p>\n<p style=\"font-weight: 400;\">\n","protected":false},"excerpt":{"rendered":"<p>By Russell Brown I was recently asked for help in choosing adhesives for a large spar-building project. This led to &#8230; <a class=\"cz_readmore\" href=\"https:\/\/yachtcentershop.com\/en\/choosing-glue\/\"><i class=\"fa fa-angle-right\" aria-hidden=\"true\"><\/i><span>Pro\u010ditaj vi\u0161e<\/span><\/a><\/p>\n","protected":false},"author":4,"featured_media":11145,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"none","_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","footnotes":""},"categories":[798],"tags":[],"class_list":["post-11166","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-expert-articles"],"acf":[],"_links":{"self":[{"href":"https:\/\/yachtcentershop.com\/en\/wp-json\/wp\/v2\/posts\/11166","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/yachtcentershop.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/yachtcentershop.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/yachtcentershop.com\/en\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/yachtcentershop.com\/en\/wp-json\/wp\/v2\/comments?post=11166"}],"version-history":[{"count":1,"href":"https:\/\/yachtcentershop.com\/en\/wp-json\/wp\/v2\/posts\/11166\/revisions"}],"predecessor-version":[{"id":11167,"href":"https:\/\/yachtcentershop.com\/en\/wp-json\/wp\/v2\/posts\/11166\/revisions\/11167"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/yachtcentershop.com\/en\/wp-json\/wp\/v2\/media\/11145"}],"wp:attachment":[{"href":"https:\/\/yachtcentershop.com\/en\/wp-json\/wp\/v2\/media?parent=11166"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/yachtcentershop.com\/en\/wp-json\/wp\/v2\/categories?post=11166"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/yachtcentershop.com\/en\/wp-json\/wp\/v2\/tags?post=11166"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}