Answers.Body: <p>This is a partial answer (or theory).<br>
  The moulds for most of the basic bricks have been changed over the years to use less plastic while (hopefully) retaining clutch.  </p>
  
  <p>2 x N bricks were given thinner walls with 'notches' for the studs. This may have slightly weakened clutch power.</p>
  
  <p><a href="https://i.sstatic.net/b6dQn.jpg" rel="noreferrer"><img src="https://i.sstatic.net/b6dQn.jpg" alt="2x4"></a>  </p>
  
  <p>1 x N bricks (and some plates) were given holes through the bottom tubes and had some supporting walls removed. Not sure how this might've affected clutch power though.</p>
  
  <p><a href="https://i.sstatic.net/estyC.jpg" rel="noreferrer"><img src="https://i.sstatic.net/estyC.jpg" alt="1x4"></a></p>
  
  <p><em>Photos taken from <a href="https://rebrickable.com/forum/index.php?/topic/2502-when-did-lego-changed-its-molds/" rel="noreferrer">here</a>.</em></p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-03-03T18:19:27.013Z
Answers.Text: I believe they gave up on the hollow tubes again.
Answers.UserDisplayName: Henrik supports the community
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Answers.CreationDate: 2020-03-27T09:03:51.933Z
Answers.Text: It seems like a limited selection of bricks follow this trend of being remodeled. Technic bricks haven't been affected by this, for example, however their clutch strength is changed over time.
Answers.UserDisplayName: Alex
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Answers.CreationDate: 2020-03-03T01:39:35.683Z
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Answers.UserDisplayName: Matthew Jensen
Answers.Body: <p>I may found a hint onto what's going on with old elements made of ABS on sister website - <a href="https://chemistry.stackexchange.com/questions/158584/what-causes-plastic-to-become-brittle-and-can-it-be-softened-again">Chemistry.SE</a>. That question discuss other problem with ABS plastic - brittleness, however answer provide some interesting facts:</p>
  <blockquote>
  <p>The original ABS substance is a copolymer made of acrylonitrile,
  butadiene and styrene. It is rather hard and brittle. To make it
  softer, some proportion of a plasticizer has to be added when it's hot
  and malleable. In the last century, the plasticizer was in general
  dinonylphthalate. It works well, but it is a bit volatile. So after a
  couple of years, the plasticizer gets evaporated, and the polymer
  becomes brittle again. This &quot;illness&quot; can only be cured by remelting
  the plastic and adding some new dinonylphthalate. Today better
  plasticizers have been discovered that are not so volatile.</p>
  </blockquote>
  <p>The &quot;old parts&quot; I had in mind are from early 90's or so, which fits the description. It also makes sense that ABS becomes less plastic when it looses its plasticizer, thus no longer being flexible enough to adjust to tiny deformations during assembly. This results in, say antistuds, no longer adjusting to studs once attached and now being tiny bit smaller causing greater clutch power.</p>
  
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Answers.CreationDate: 2021-10-11T08:28:02.513Z
Answers.LastActivityDate: 2021-10-11T08:28:02.513Z
Answers.UserDisplayName: Alex
Answers.Body: <p>New bricks (having cross support) are lighter, 2•25 grammes instead of 2•68 (from my own weighing). Fits to older Lego that don't hold together well better, but new bricks not hold to 1990's as well as those of then to their top. Must be changing sizes? The ribs inside squash? Also the yellow is a different shade, can shine a light through, &amp; the new ones light up, so there is a difference.</p>
  
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Answers.CreationDate: 2022-10-25T06:27:07.893Z
Answers.LastActivityDate: 2022-11-02T11:34:08.740Z
Answers.LastEditDate: 2022-11-02T11:34:08.740Z
Answers.UserDisplayName: Andrew Hodson
Body: <p>I have some pre-2000 (rough date to split the collection to old/new) System and Technic sets that are from different sources: some are from my childhood, while others have been acquired in &quot;used&quot; as well as &quot;new&quot; condition. They share a common property compared to newer sets - brick clutch power in older sets is a lot stronger. And this is something of a common observation in AFOL community.</p>
  <p>Take Technic 8880 set for example. You can feel greater power is required to assemble and take apart Technic bricks compared to what would modern same parts needed. They are not damaged or bent, and still look the same as new part. I've also noticed, when handling the assembled model, you can hear many connection points squeak, which isn't a case with modern sets.</p>
  <p>It is known TLG made a change from pre-colored plastic pellets to &quot;base + colored dye&quot; used in production these days. Newer bricks have slightly different properties too, like they doesn't yellow as much as old ones. So obviously, some changes were made to plastic formula, but it is still ABS plastic (question is about opaque colored bricks).</p>
  <p>So I wish to understand what's the reason behind this.</p>
  <ul>
  <li>Was the clutch power always like that for bricks of that era?</li>
  <li>Is it because of chemical nature where some elements within ABS plastic mixture cause clutch power to change?</li>
  <li>Maybe some physical nature like temperature or humidity causing plastic to degrade/shrink over time?</li>
  </ul>
  <p>Ideally I would like to see answers with facts, but keeping in mind TLG may be good at keeping their secrets I'm open to all the answers with some sort of proof of the statement.</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-03-25T20:33:54.033Z
Comments.Text: I don't have a source for this, but I heard that Lego considers the older, tighter bricks to be defective compared to the modern bricks, which clutch less but are easier for children to manipulate.
Comments.UserDisplayName: Mr. Shiny and New 安宇
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-03-27T09:00:40.657Z
Comments.Text: An interesting reason I have never heard of before. Would love to get more detail on this matter.
Comments.UserDisplayName: Alex
Tags: <lego-group><plastics><system>
Title: Why do older bricks have greater clutch power?
UserDisplayName: Alex
ThreadText: # Why do older bricks have greater clutch power?
  
  (Asked by: username_0 on 2020-03-02)
  
  I have some pre-2000 (rough date to split the collection to old/new) System and Technic sets that are from different sources: some are from my childhood, while others have been acquired in "used" as well as "new" condition. They share a common property compared to newer sets - brick clutch power in older sets is a lot stronger. And this is something of a common observation in AFOL community.
  
  Take Technic 8880 set for example. You can feel greater power is required to assemble and take apart Technic bricks compared to what would modern same parts needed. They are not damaged or bent, and still look the same as new part. I've also noticed, when handling the assembled model, you can hear many connection points squeak, which isn't a case with modern sets.
  
  It is known TLG made a change from pre-colored plastic pellets to "base + colored dye" used in production these days. Newer bricks have slightly different properties too, like they doesn't yellow as much as old ones. So obviously, some changes were made to plastic formula, but it is still ABS plastic (question is about opaque colored bricks).
  
  So I wish to understand what's the reason behind this.
  
  * Was the clutch power always like that for bricks of that era?
  * Is it because of chemical nature where some elements within ABS plastic mixture cause clutch power to change?
  * Maybe some physical nature like temperature or humidity causing plastic to degrade/shrink over time?
  
  Ideally I would like to see answers with facts, but keeping in mind TLG may be good at keeping their secrets I'm open to all the answers with some sort of proof of the statement.
  
  **Tags:** lego-group, plastics, system
  
  > **Comments:**
  > **username_1**: I don't have a source for this, but I heard that Lego considers the older, tighter bricks to be defective compared to the modern bricks, which clutch less but are easier for children to manipulate.  
  > **username_0**: An interesting reason I have never heard of before. Would love to get more detail on this matter.  
  
  ---
  
  ## 3 answers
  
  ### Answer by username_2 on 2020-03-03. Score: 9
  
  This is a partial answer (or theory).  
  The moulds for most of the basic bricks have been changed over the years to use less plastic while (hopefully) retaining clutch.
  
  2 x N bricks were given thinner walls with 'notches' for the studs. This may have slightly weakened clutch power.
  
  [![2x4](https://i.sstatic.net/b6dQn.jpg)](https://i.sstatic.net/b6dQn.jpg)
  
  1 x N bricks (and some plates) were given holes through the bottom tubes and had some supporting walls removed. Not sure how this might've affected clutch power though.
  
  [![1x4](https://i.sstatic.net/estyC.jpg)](https://i.sstatic.net/estyC.jpg)
  
  *Photos taken from [here](https://rebrickable.com/forum/index.php?/topic/2502-when-did-lego-changed-its-molds/).*
  
  > **Comments:**
  > **username_3**: I believe they gave up on the hollow tubes again.  
  > **username_0**: It seems like a limited selection of bricks follow this trend of being remodeled. Technic bricks haven't been affected by this, for example, however their clutch strength is changed over time.  
  
  ---
  
  ### Answer by username_0 on 2021-10-11. Score: 3
  
  I may found a hint onto what's going on with old elements made of ABS on sister website - [Chemistry.SE](https://chemistry.stackexchange.com/questions/158584/what-causes-plastic-to-become-brittle-and-can-it-be-softened-again). That question discuss other problem with ABS plastic - brittleness, however answer provide some interesting facts:
  
  > The original ABS substance is a copolymer made of acrylonitrile,
  > butadiene and styrene. It is rather hard and brittle. To make it
  > softer, some proportion of a plasticizer has to be added when it's hot
  > and malleable. In the last century, the plasticizer was in general
  > dinonylphthalate. It works well, but it is a bit volatile. So after a
  > couple of years, the plasticizer gets evaporated, and the polymer
  > becomes brittle again. This "illness" can only be cured by remelting
  > the plastic and adding some new dinonylphthalate. Today better
  > plasticizers have been discovered that are not so volatile.
  
  The "old parts" I had in mind are from early 90's or so, which fits the description. It also makes sense that ABS becomes less plastic when it looses its plasticizer, thus no longer being flexible enough to adjust to tiny deformations during assembly. This results in, say antistuds, no longer adjusting to studs once attached and now being tiny bit smaller causing greater clutch power.
  
  
  ---
  
  ### Answer by username_4 on 2022-10-25. Score: -1
  
  New bricks (having cross support) are lighter, 2•25 grammes instead of 2•68 (from my own weighing). Fits to older Lego that don't hold together well better, but new bricks not hold to 1990's as well as those of then to their top. Must be changing sizes? The ribs inside squash? Also the yellow is a different shade, can shine a light through, & the new ones light up, so there is a difference.
  
  
  ---
  
  