<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>hwillis</author><text>They are not going to weld castings except maybe for very small cracks and even then it&amp;#x27;s very unlikely.  The casting is not in a place that could be repaired if it were steel, though.  It&amp;#x27;s the main structural member, located behind the rear seats.  If you needed to weld there you&amp;#x27;d need to take the car practically down to its frame.&lt;p&gt;Even if it were in a place that was accessible and subject to repairable damage, you would not see it welded or cut.  First off a lot of it isn&amp;#x27;t physically possible to weld; it&amp;#x27;s in very deep (6&amp;quot;) pockets and you&amp;#x27;d have a huge amount of difficulty getting penetration.  Second, welding aluminum is not super easy.  Anyone can weld steel, aluminum isn&amp;#x27;t the worst but it is much trickier.  Third, aluminum welds create a weakness in the aluminum around the weld, because it gets hot but isn&amp;#x27;t properly tempered as it cools.  It&amp;#x27;s still strong, but the loss is significant- temper is responsible for ~70% of the strength of common aluminum alloys.  Fourth, the weld and the surrounding area are very weak (&amp;lt;40% strength) for several days after the repair.  It&amp;#x27;s a huge pain in the ass and you probably can&amp;#x27;t just let somebody drive off on it.</text><parent_chain><item><author>Aeolun</author><text>It seems to me that cutting out, and welding or glueing in a new part had a serious effect on the structural integrity of the vehicle.</text></item><item><author>andrewmunsell</author><text>For everyone concerned about repairs-- this isn&amp;#x27;t exactly a new concept.&lt;p&gt;The BMW i3 has a carbon fiber frame that, as far as I know, they do not sell in sections (&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.cnet.com&amp;#x2F;roadshow&amp;#x2F;news&amp;#x2F;crash-your-carbon-fiber-i3-ev-heres-how-bmw-will-fix-it&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.cnet.com&amp;#x2F;roadshow&amp;#x2F;news&amp;#x2F;crash-your-carbon-fiber-i...&lt;/a&gt;). This means during an accident, the damaged portion is cut out and a new section is glued in, though the repair would likely involve purchasing an entirely new frame unless the shop has one leftover from a previous repair.&lt;p&gt;With the Y, it&amp;#x27;d be the same thing-- the shop would either have a spare, partial casting from a previous repair or need to order a new one, and it would be cut and welded into place.&lt;p&gt;The repair itself shouldn&amp;#x27;t be any more difficult than any other car, it&amp;#x27;s just purchasing the part that becomes more expensive if you have to purchase a new entire casting for damage in one area of the car. That, however, is entirely fixable through some clever supply chain fixes and may be something Tesla can support through savings on the single casting.</text></item></parent_chain></comment><story><title>Tesla Fremont to Soon Activate World’s Largest Unibody Casting Machine</title><url>https://www.tesmanian.com/blogs/tesmanian-blog/tesla-model-y-from-fremont-will-soon-use-the-biggest-casting-machine-for-mass-production</url></story>
<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>markstos</author><text>From the internet: &amp;quot;assuming your joint is designed properly and you have an experienced welder performing the work, your welded joint will be as strong as the base materials it is joining.&amp;quot;&lt;p&gt;Welds are key to most bicycle frames and they are not known as the part that&amp;#x27;s likely to fail.</text><parent_chain><item><author>Aeolun</author><text>It seems to me that cutting out, and welding or glueing in a new part had a serious effect on the structural integrity of the vehicle.</text></item><item><author>andrewmunsell</author><text>For everyone concerned about repairs-- this isn&amp;#x27;t exactly a new concept.&lt;p&gt;The BMW i3 has a carbon fiber frame that, as far as I know, they do not sell in sections (&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.cnet.com&amp;#x2F;roadshow&amp;#x2F;news&amp;#x2F;crash-your-carbon-fiber-i3-ev-heres-how-bmw-will-fix-it&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.cnet.com&amp;#x2F;roadshow&amp;#x2F;news&amp;#x2F;crash-your-carbon-fiber-i...&lt;/a&gt;). This means during an accident, the damaged portion is cut out and a new section is glued in, though the repair would likely involve purchasing an entirely new frame unless the shop has one leftover from a previous repair.&lt;p&gt;With the Y, it&amp;#x27;d be the same thing-- the shop would either have a spare, partial casting from a previous repair or need to order a new one, and it would be cut and welded into place.&lt;p&gt;The repair itself shouldn&amp;#x27;t be any more difficult than any other car, it&amp;#x27;s just purchasing the part that becomes more expensive if you have to purchase a new entire casting for damage in one area of the car. That, however, is entirely fixable through some clever supply chain fixes and may be something Tesla can support through savings on the single casting.</text></item></parent_chain></comment><story><title>Tesla Fremont to Soon Activate World’s Largest Unibody Casting Machine</title><url>https://www.tesmanian.com/blogs/tesmanian-blog/tesla-model-y-from-fremont-will-soon-use-the-biggest-casting-machine-for-mass-production</url></story>