collision bros!

[Craizie]

Post 23...

Where it says the roof bows and upper inner roof rails?


Edit, nvm. I see the secondary part now.

[Ruffdaddy]

Where it says the roof bows and upper inner roof rails?

Keep reading....you're almost there.

[Scott Mc]

Oh, this shit makes so much more sense now. Beers on me and you can tell me how shit works brotha. So where is your information from?

[jammeejamm]

most door skins are fold over and glued on the outside perimeter and then spot welded along the belt line to the door shell, much like a roof skin(with the exception of folding over). there is nothing connecting either skin near the center to create more rigid unitized structure. instead of a cap, think them more like a flimsy lid on tupperware. all they do is cover something, and absorb very little energy in a collision.

in addition, the door shell holds the intrusion beam. the beam is most definitely considered primary structure in a collision, and the skin is glued("tied") to it. without the beam a unitized vehicle would fold up like a suitcase in a hard front or rear collision. that is why i brought it up.

and now i see you said you are an engineer. make sure you bring that up first if or when you drop your vehicle off at a collision center.

[Ruffdaddy]

most door skins are fold over and glued on the outside perimeter and then spot welded along the belt line to the door shell, much like a roof skin(with the exception of folding over). there is nothing connecting either skin near the center to create more rigid unitized structure. instead of a cap, think them more like a flimsy lid on tupperware. all they do is cover something, and absorb very little energy in a collision.

in addition, the door shell holds the intrusion beam. the beam is most definitely considered primary structure in a collision, and the skin is glued("tied") to it. without the beam a unitized vehicle would fold up like a suitcase in a hard front or rear collision. that is why i brought it up.

and now i see you said you are an engineer. make sure you bring that up first if or when you drop your vehicle off at a collision center.

This whole wall of text deserves deflection of the year award. Running away from The fact that the roof is structural and you are flat wrong.

When I say primary structure...i mean the actual body structure:

https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.repairerdrivennews.com/wp-content/uploads/2015/09/2016-honda-fit-body-information.pdf&ved=0ahUKEwi-0qC71q7VAhXLqlQKHaDoB78QFgisATAa&usg=AFQjCNFyh_5I26ffiNkitMvlFobGvIjHRg

The design of a roof isn't anything like that of a door so again...why are you even bringing it up in this thread? It's just a deflection. You are running away from your pile of shit and covering it with febreeze.

I sure hope that when you repair someone's car you make sure to tell them that you think you know better than the OEM engineers and are going to take the easy way out. I hope you also notify insurance of this as well as any licensing/certification commitees.

It is surprising and sad to see multiple people admit to ignoring OEM requirements for safe repair and actually justifying it. And going a step further to post about it on a public forum. Let that sink in...

Dunning and Kruger have an excellent study on why you genuinely think you know better. You can't possibly know what you don't know. So a bunch of repair techs that want to take the easy way out way over estimate their ability to understand structural engineering.

[Ruffdaddy]

Oh, this shit makes so much more sense now. Beers on me and you can tell me how shit works brotha. So where is your information from?

I would genuinely sit down and have a beer with you if it meant you would stop half assing repairs that impact the public's safety. I would spend as much time as needed running through simulations and analyses on my laptop to demonstrate how much of an impact thin panels can have.

Just because a thin sheet is weak in the face normal load case doesn't mean it doesn't make a big difference. Load that same sheet in tension and tell me it's weak.

[svauto-erotic855]

They should have tacked the 4 corners but it is a ok to use panel bond in that way. The issue of this accident had nothing to do with the roof, they are just fishing for a lawsuit when they should just be glad to be breathing. A roof skin is not a part of a cars structure, and carfax is a scam. All the news is doing is fear mongering like usual with inaccurate info.

You can not make a blanket statement saying that the roof skin is not part of a cars structure. Every design is different but engineers rarely pass on an opportunity to add structural rigidity and a skin installed as a stressed panel adds buckets of strength. The windshield is a stressed member in many designs.

Carfax is a bunch of lying mothers fuckers. You will never get any disagreement from me over that.

I hate Carfax!! They're liars half the damn time. They're whole business model is based on the general public's ignorance.

Roofs should be tacked but as far as I know Panel bond has been used for at least a decade and was tested to be as strong as welds.

But also, we are talking a small low end Honda that had the shit knocked out of it....

I have no doubt that they are just looking for a payday to help with expenses related to their injuries. You are correct that gluing a panel makes for a strong joint but there is no way on earth I would pass on welding if the manufacture says that something must be welded. I prefer both gluing and welding if it is an option. Mazda made several sportsman versions of the second gen RX-7s that were glued at every seam and had extra and over sized spot welds. The difference in structural strength was very noticeable even though 2nd gen RX-7s were very stiff cars to begin with.

have you ever seen a new roof skin? have you ever seen how one is installed?

even if one was welded around the entire perimeter, it is still just a very thin piece of sheet metal resting on foam on top of flimsy cross-members. the front and rear cross members are actual structure that give strength.

you think a door skin is actually structure?

A very thin panel can add a lot of strength to a structure if the structure was designed with that panel being a stressed panel. Jumbo jets are made this way.

[svauto-erotic855]

I know of a guy that was killed when his late 80s Firebird Formula broke in half while driving it down 35 in Lewisville. The car had been repaired by Jim's Auto Body or Velvet Hammer Auto Body and their welds were such shit that they came apart a few weeks after the car got out of the shop. At the time it was a valuable car that was worth fixing even though it had sustained major damage and he was very happy to have gotten his car back.

[Shaggin Wagon]

I have no doubt that they are just looking for a payday to help with expenses related to their injuries. You are correct that gluing a panel makes for a strong joint. I prefer both gluing and welding if it is an option. Mazda made several sportsman versions of the second gen RX-7s that were glued at every seam and had extra and over sized spot welds.

I do want to clarify my statement. Roof panels need to be tack welded in conjunction with panel bonded, not panel bonded only. I was just stating that panel bond is to be as strong as welds. You should not just panel bond only. Kinda like seat belts, they're good, but airbags and belts are great.

[svauto-erotic855]

I do want to clarify my statement. Roof panels need to be tack welded in conjunction with panel bonded, not panel bonded only. I was just stating that panel bond is to be as strong as welds. You should not just panel bond only. Kinda like seat belts, they're good, but airbags and belts are great.

I edited my post before you quoted it basically saying exactly what you just said. I am good at welding and go crazy on every seam on my own cars but I do not do body work for a living and can afford to take my time.

[Blackout]

They should have tacked the 4 corners but it is a ok to use panel bond in that way. The issue of this accident had nothing to do with the roof, they are just fishing for a lawsuit when they should just be glad to be breathing. A roof skin is not a structural part of a cars structure, and carfax is a scam. All the news is doing is fear mongering like usual with inaccurate info.

This 100% we can't replicate the laser welds the factory puts on it just doesn't happen. Most roof panel replacements are welded on. Hell I've done a quarter on a BMW the was welded in factory but the repair requires it to be glued on. Panel bond will hold it just find. It's not even HHS. These people are just looking to pass the blame. Sad part it they will probably win in court.


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[Ruffdaddy]

I do want to clarify my statement. Roof panels need to be tack welded in conjunction with panel bonded, not panel bonded only. I was just stating that panel bond is to be as strong as welds. You should not just panel bond only. Kinda like seat belts, they're good, but airbags and belts are great.

Define strength.

[svauto-erotic855]

This 100% we can't replicate the laser welds the factory puts on it just doesn't happen. Most roof panel replacements are welded on. Hell I've done a quarter on a BMW the was welded in factory but the repair requires it to be glued on. Panel bond will hold it just find. It's not even HHS. These people are just looking to pass the blame. Sad part it they will probably win in court.

Does BMW say to glue the panel on as an approved repair method? If so I would take their word for it and go about my business.

In the case being discussed here the cars manufacture very clearly said that the panel must be welded in and failure to do so could cause a fatality or injury.

Even if the bad repair had nothing to do with the injuries caused in the crash the repair shop is fucked on this deal. This is just another example of why you should follow published instructions even if you think you know better.

[Shaggin Wagon]

Define strength.

Definition of strength
plural strengthsplay \ˈstreŋ(k)ths, ˈstren(t)ths, ˈstreŋks\
1
: the quality or state of being strong : capacity for exertion or endurance
2
: power to resist force : solidity, toughness
3
: power of resisting attack : impregnability
4
: degree of potency of effect or of concentration

[svauto-erotic855]

Definition of strength
plural strengthsplay \ˈstreŋ(k)ths, ˈstren(t)ths, ˈstreŋks\
1
: the quality or state of being strong : capacity for exertion or endurance
2
: power to resist force : solidity, toughness
3
: power of resisting attack : impregnability
4
: degree of potency of effect or of concentration

In engineering terms there are many types of strength. Yield and shear strength are what I believe matter in this case.