cross-posted from: https://lemmy.crimedad.work/post/542998
“It does suck, because everybody kind of makes fun of the Cybertruck. To the outside person, it’s kind of weird, it’s ugly, whatever. Once you actually get in it, drive it, you realize it’s pretty frickin’ cool,” he says. “It’s kind of been sad, because I’ve been trying to prove to people that it’s a really awesome truck that’s not falling apart, and then mine starts to fall apart, so it’s just… Yeah, it’s kind of unfortunate and sad.”
(X) to doubt
Adhesives can be incredibly strong.
But never a weld.
MEK welds styrene. Cynocrylate forms a mechanical bond. MEK will be stronger in tension, cyno stronger in shear.
Good ole methyl ethyl ketone.
Dropped a rubber boot in a vat of it once to see what would happen.
No idea why, but it came out much larger/expanded.
Fun fact, you can shrink barbie doll heads in acetone.
I don’t even know the name of the adhesive they used. I do know that it was made by 3M and that it’s orange.
Well, OK. So maybe that adhesive is stronger than a weld on that particular plastic. Of course, if you’re talking about adhering a plastic to a metal you cannot weld it so Elmer’s would be “stronger than a weld”. But whatever’s going on it’s not adequate.
E: and actually welding plastic together typically isn’t that strong, a mechanical bond can easily be stronger than melting the plastic to weld it.
Epoxy bonding on body panels is super common on many cars now. And it’s the only way to bond incompatible materials like aluminum and high strength steel.
Even steel body panels can’t be welded to high strength steel because the heat affected zone will be weakened by the weld and will crack just outside the weld.
Adhesives to create a mechanical bond, and the 3M body adhesives include glass microbeads that prevent you from squishing the joint too tightly, which makes the bond more effective.
Now using it in dirty or coated stainless steel clearly isn’t working, and the design of thin strips of shiny steel that will grow and shrink a lot, mostly in one direction on a design that was done by a 7 year old in a hurry to draw a truck is another issue.
Good points.
Why aren’t they using fasteners? Cost or weight?
Probably cost, via speed of assembly, robots are really good at depositing glue, also design and safety, since the glue can remove intrusive hard points in a car. Also rigidity could be improved since the glue is continuous vs spot welds or fasteners.
I recently glued the roof skin on a classic car I’m restoring and the reason for replacement was that the 60 year old seam sealer had failed 20 years ago and the rust had crept in between the spot welds. I used 3M panel bond, partly because spot welds were difficult to do in position and it would likely be more reliable and water tight long term.
I probably won’t be around to find out if it fails, at any rate.