"RamblinRover Luxury-Yacht" (ramblininexile)
06/26/2015 at 14:40 • Filed to: None
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"RamblinRover Luxury-Yacht" (ramblininexile)
06/26/2015 at 14:40 • Filed to: None | 4
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Specifically,
!!!error: Indecipherable SUB-paragraph formatting!!!
on aluminum spot-welding research from the 70s. As it turns out, aluminum spot welds are shit unless you age the metal after cleaning, because otherwise a critical interface between the weld and the surrounding metal doesn’t reliably form.
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RamblinRover Luxury-Yacht
> RamblinRover Luxury-Yacht
06/26/2015 at 14:43 |
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This is relevant to my interests because aluminum spot welding = ALL LAND ROVER BODYWORK EVER.
Snuze: Needs another Swede
> RamblinRover Luxury-Yacht
06/26/2015 at 14:47 |
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I’ve never heard of “aging” but I do know that typically, aluminum welded pieces are heat treated if you want to maintain any kind of strength approaching that of the original piece(s).
Thats why the rage these days is glue ‘n screw, especially on large items. In fact that’s how Lotus puts the pieces Elise/Exige chassis together. They did this because heat treating an entire chassis would be prohibitively expensive, and modern aluminum epoxies are very strong and require less in terms of skilled labor, and less cure time vs. the heat treat process.
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RamblinRover Luxury-Yacht
> RamblinRover Luxury-Yacht
06/26/2015 at 14:47 |
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What’s weird is that people even today are pushing “clean your surfaces, make your welds consistent” when it isn’t the weld consistency itself that has much to do with strength. At all. Like these guys:
http://www.portablewelders.com/FAQRetrieve.as…
The plug can be 95% consistent, and still have wild variance in strength, according to literature on the books for the past 45 years. DURR
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RamblinRover Luxury-Yacht
> Snuze: Needs another Swede
06/26/2015 at 14:56 |
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Well, Rover didn’t care about nearness to original strength, as far as I know - otherwise they wouldn’t have been spot-welding things since the 40s. I’m not even sure they cleaned the chromate off pieces completely - but in some respects, the chromate may not have been a problem. Aging here would mean letting a surface oxidize for a while, because that apparently affects some aspects of the heat transfer during the weld - which is weird. Between 20 and 200 hours, a surface that has been sanded welds reliably - while surfaces that have been freshly sanded are a crapshoot.
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RamblinRover Luxury-Yacht
> Snuze: Needs another Swede
06/26/2015 at 15:02 |
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There’s also this:
http://www.autonews.com/article/201411…
Some aspects of using a smaller initial contact point and rings in the surface apparently help. I assume it’s because an electrode with a higher dome (electrodes have been curved since forever, that’s not new) probably allows more concentrated pressure at the center of the weld, so higher current. The circles being able to pierce oxide probably allows the benefits of aging the aluminum first - probably.
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RamblinRover Luxury-Yacht
> RamblinRover Luxury-Yacht
06/26/2015 at 15:03 |
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There’s also this:
http://www.autonews.com/article/201411…
Some aspects of using a smaller initial contact point and rings in the surface apparently help. I assume it’s because an electrode with a higher dome (electrodes have been curved since forever, that’s not new) probably allows more concentrated pressure at the center of the weld, so higher current. The circles being able to pierce oxide probably allows the benefits of aging the aluminum first - probably.
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Snuze: Needs another Swede
> RamblinRover Luxury-Yacht
06/26/2015 at 21:03 |
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Wow, that doesn’t make a lot of sense to me, runs contrary to everything I’ve ever heard. Sounds like you want a little oxidation, but not full oxidation. Weird.