When two cars bump into each other, there’s often paint from the first car on the second car, and vice-versa.

How is paint swapped like that?

Spiny Norman said:

When two cars bump into each other, there’s often paint from the first car on the second car, and vice-versa.

How is paint swapped like that?

Energy from the impact fragmenting pieces onto the parts that make contact maybe

Cymek said:

Spiny Norman said:

When two cars bump into each other, there’s often paint from the first car on the second car, and vice-versa.

How is paint swapped like that?

Energy from the impact fragmenting pieces onto the parts that make contact maybe

Physics. Everything is physics. Friction?

buffy said:

Cymek said:

Spiny Norman said:

When two cars bump into each other, there’s often paint from the first car on the second car, and vice-versa.

How is paint swapped like that?

Energy from the impact fragmenting pieces onto the parts that make contact maybe

Physics. Everything is physics. Friction?

I suppose friction comes into it, but I’d say the main cause was conservation of momentum and the second law of motion.

Locard’s exchange principle.. every contact leaves a trace.. “with contact between two items, there will be an exchange.”

but I suspect you mean for a physic perspective.. car paint is in layers, so the catching of one layer on another might result in transferral of paint chips/shards.. then rubbing would also cause some exchange at the fragment level… like a smear

you mean like how a rubber will pick up pencil from paper but also leave rubber on paper

that’s the general vibe of Locard’s principle… it’s used mainly in forensic investigation, but it’s applicable to all manner of circumstances.

Arts said:

that’s the general vibe of Locard’s principle… it’s used mainly in forensic investigation, but it’s applicable to all manner of circumstances.

For the benefit of the less forensically knowledgeable amongst us:

“Locard’s principle holds that the perpetrator of a crime will bring something into the crime scene and leave with something from it, and that both can be used as forensic evidence.”

oops again.

I should probably read a couple of posts up, before posting valuable new information.

The Rev Dodgson said:

The Rev Dodgson said:

Arts said:

that’s the general vibe of Locard’s principle… it’s used mainly in forensic investigation, but it’s applicable to all manner of circumstances.

For the benefit of the less forensically knowledgeable amongst us:

“Locard’s principle holds that the perpetrator of a crime will bring something into the crime scene and leave with something from it, and that both can be used as forensic evidence.”

oops again.

I should probably read a couple of posts up, before posting valuable new information.

but surely this is a mere instance of the general principle of quantum mechanics, whereby any agent of an interaction will introduce information to a system, and simultaneously extract information from the system, and both can (must in concert) be used as scientific evidence

The Rev Dodgson said:

I should probably read a couple of posts up, before posting valuable new information.

Doing that now. I agree with Cymek that cracking and fragmentation is the dominant mechanism, followed in importance by friction and gouging. But depending on the impact angle it could be the other way around.

I was removing a top layer of paint from powder-coated metal yesterday, and brittle cracking and fragmentation using a scraper was a much easier way to get the paint off than sandpapering.

mollwollfumble said:

The Rev Dodgson said:

I should probably read a couple of posts up, before posting valuable new information.

Doing that now. I agree with Cymek that cracking and fragmentation is the dominant mechanism, followed in importance by friction and gouging. But depending on the impact angle it could be the other way around.

I was removing a top layer of paint from powder-coated metal yesterday, and brittle cracking and fragmentation using a scraper was a much easier way to get the paint off than sandpapering.

I think that there’s a couple of episodes in the various ‘CSI’ series that cover this topic. :)

captain_spalding said:

mollwollfumble said:

The Rev Dodgson said:

I should probably read a couple of posts up, before posting valuable new information.

Doing that now. I agree with Cymek that cracking and fragmentation is the dominant mechanism, followed in importance by friction and gouging. But depending on the impact angle it could be the other way around.

I was removing a top layer of paint from powder-coated metal yesterday, and brittle cracking and fragmentation using a scraper was a much easier way to get the paint off than sandpapering.

I think that there’s a couple of episodes in the various ‘CSI’ series that cover this topic. :)

Yes they zoomed in and enhanced from a reflection of a reflection in a puddle

Cymek said:

captain_spalding said:

mollwollfumble said:

Doing that now. I agree with Cymek that cracking and fragmentation is the dominant mechanism, followed in importance by friction and gouging. But depending on the impact angle it could be the other way around.

I was removing a top layer of paint from powder-coated metal yesterday, and brittle cracking and fragmentation using a scraper was a much easier way to get the paint off than sandpapering.

I think that there’s a couple of episodes in the various ‘CSI’ series that cover this topic. :)

Yes they zoomed in and enhanced from a reflection of a reflection in a puddle

don’t get me started.

Arts said:

Cymek said:

captain_spalding said:

I think that there’s a couple of episodes in the various ‘CSI’ series that cover this topic. :)

Yes they zoomed in and enhanced from a reflection of a reflection in a puddle

don’t get me started.

Why not? You get better as you warm up.

roughbarked said:

Arts said:

Cymek said:

Yes they zoomed in and enhanced from a reflection of a reflection in a puddle

don’t get me started.

Why not? You get better as you warm up.

dude.. seriously?

Arts said:

roughbarked said:

Arts said:

don’t get me started.

Why not? You get better as you warm up.

dude.. seriously?

Of course not.

Arts said:

Cymek said:

captain_spalding said:

I think that there’s a couple of episodes in the various ‘CSI’ series that cover this topic. :)

Yes they zoomed in and enhanced from a reflection of a reflection in a puddle

don’t get me started.

Could you post the science and technology behind it please, it sounds interesting, magical almost

Cymek said:

Arts said:

Cymek said:

Yes they zoomed in and enhanced from a reflection of a reflection in a puddle

don’t get me started.

Could you post the science and technology behind it please, it sounds interesting, magical almost

yes: it’s bullshit.

Arts said:

Cymek said:

Arts said:

don’t get me started.

Could you post the science and technology behind it please, it sounds interesting, magical almost

yes: it’s bullshit.

I know I’m being cheeky

Arts said:

Cymek said:

Arts said:

don’t get me started.

Could you post the science and technology behind it please, it sounds interesting, magical almost

yes: it’s bullshit.

Your just jealous cos you don’t have fancy machines with the coloured lights!

Bogsnorkler said:

Arts said:

Cymek said:

Could you post the science and technology behind it please, it sounds interesting, magical almost

yes: it’s bullshit.

Your just jealous cos you don’t have fancy machines with the coloured lights!

ping

Bogsnorkler said:

Arts said:

Cymek said:

Could you post the science and technology behind it please, it sounds interesting, magical almost

yes: it’s bullshit.

Your just jealous cos you don’t have fancy machines with the coloured lights!

imagine how great it would be if we could solve shit in an hour and with machines that go ping…

Arts said:

Bogsnorkler said:

Arts said:

yes: it’s bullshit.

Your just jealous cos you don’t have fancy machines with the coloured lights!

imagine how great it would be if we could solve shit in an hour and with machines that go ping…

You need the World’s Experts in everything.

mollwollfumble said:

The Rev Dodgson said:

I should probably read a couple of posts up, before posting valuable new information.

Doing that now. I agree with Cymek that cracking and fragmentation is the dominant mechanism, followed in importance by friction and gouging. But depending on the impact angle it could be the other way around.

I was removing a top layer of paint from powder-coated metal yesterday, and brittle cracking and fragmentation using a scraper was a much easier way to get the paint off than sandpapering.

I was of the impression that the “damage” was no worse than “a paint exchange”
so I left you to argue the mechanics of said transfer without stating what I thought was obvious:
A superficial kiss of the top clear & top coat could be easily RUBBED AWAY by using
Rubbing Compound.
https://www.turtlewax.com/products/rubbing-compound-heavy-duty-cleaner-105fl-oz

depending upon the depth of the damage (scratches) more steps may need to be employed:
https://www.wikihow.com/Use-a-Rubbing-Compound

NOTE: RUBBING Compound is Different from POLISHING Compound

Arts said:

but I suspect you mean for a physic perspective.. car paint is in layers, so the catching of one layer on another might result in transferral of paint chips/shards.. then rubbing would also cause some exchange at the fragment level… like a smear

That’s more what I’m asking, thanks.
I also thought that perhaps the paint on one car might get hotter than the paint on the contact patch of the other car and so leave a streak of (say) red paint on the (say) other white car. Then at some point the other car’s paint gets hotter and starts leaving a trail on the other car. Repeat as long as there’s contact.

Spiny Norman said:

Arts said:

but I suspect you mean for a physic perspective.. car paint is in layers, so the catching of one layer on another might result in transferral of paint chips/shards.. then rubbing would also cause some exchange at the fragment level… like a smear

That’s more what I’m asking, thanks.
I also thought that perhaps the paint on one car might get hotter than the paint on the contact patch of the other car and so leave a streak of (say) red paint on the (say) other white car. Then at some point the other car’s paint gets hotter and starts leaving a trail on the other car. Repeat as long as there’s contact.

Auto-Motive STD

I’m going to call it ‘Friction stir’, after the welding technique of the same name.

(did it to a corner of the Rulemobile on a yellow post the other morning. Felt the weight of the forum’s reputation for being excellent drivers crashing down upon me. Not happy)

Rule 303 said:

I’m going to call it ‘Friction stir’, after the welding technique of the same name.

(did it to a corner of the Rulemobile on a yellow post the other morning. Felt the weight of the forum’s reputation for being excellent drivers crashing down upon me. Not happy)

It was obviously the post’s fault, not yours. It should not have tried to emulate those roadside trees that jump out and grab cars. (Yes, too long living with an ambo…)

buffy said:

Rule 303 said:

I’m going to call it ‘Friction stir’, after the welding technique of the same name.

(did it to a corner of the Rulemobile on a yellow post the other morning. Felt the weight of the forum’s reputation for being excellent drivers crashing down upon me. Not happy)

It was obviously the post’s fault, not yours. It should not have tried to emulate those roadside trees that jump out and grab cars. (Yes, too long living with an ambo…)

Richard Brautigan wrote of such things
I’m still looking for that book so I can copy the prose.

buffy said:

Rule 303 said:

I’m going to call it ‘Friction stir’, after the welding technique of the same name.

(did it to a corner of the Rulemobile on a yellow post the other morning. Felt the weight of the forum’s reputation for being excellent drivers crashing down upon me. Not happy)

It was obviously the post’s fault, not yours. It should not have tried to emulate those roadside trees that jump out and grab cars. (Yes, too long living with an ambo…)

Don’t mean to sound like I’m pouting, but I have complained about this particular facility multiple times that entering and leaving three side-by-side vehicle bays through one narrow door is guaranteed to cause low-speed maneuvering crashes. Yep.

surely anyone who has acquired gravel rash knows that the gravel also acquires flesh rash