20 replies to this topic

[mikey8384]

I know what you all must be thinking right now, but I just wanted to get peoples opinion on an issue. Right now I have to replace both front floor panels, door steps, and oversills. My question is I am a Aircraft mechanic and repair panels on the planes, so we rivet all the panels on. I was wondering if I could do this to some of the panels on the mini? Mainly the floor and oversill, I would seal it down and shoot the rivets with sealant on them. Please all input is okay, I just want you all to know that this has not happened yet, just trying to get some input.

[Carlos W]

You would have to research local regulations, in the UK it wouldn't pass an MOT.

And avoid oversills

[Shifty]

No, it certainly wouldn't or shouldn't pass a UK Mot, not sure about the rules abroad.

Even if it were legal I certainly wouldn't want to be driving round with that underneath me.

[mikey8384]

Shifty, I understand what you are saying but alot of people don't understand that airplanes consist of 80% riveted parts and panels. haha

[Shifty]

Yes, but thats how they were designed, the mini wasn't.

[rally515]

I dont think this would be safe in unforeseen incidents such as a crash as the crumpeling resistence would be on the rivets which could shoot the panel off and possible risks your life.

Would be easy to replace rusty panels thou.

Regards
Clifford

[Old Bob]

It's the old conflict between should it flex or should it be rigid. I think the Chinese first wrote about 'The bamboo bows before the storm' and flexing certainly works for ship's masts, bridges and aircraft. Modern cars are generally intended to be completely rigid boxes with the necessary flexibility being provided by the external suspension units (think F1 carbon fibre tubs which are as stiff as possible).

The main objection to riveted panels on cars is that they are generally seen as a bodge (soft alloy rivets, overlarge holes a 'cover-up' coating to get them past an unknowing buyer or an MOT inspector). That said, many early cars had riveted bodies on solid chassis.

I don't doubt that using aircraft standard adhesives and engineering practices, panels could be replaced which would be as strong or even stronger than welded ones, but I don't believe they would be acceptable for a UK MOT inspection.

Bob

[mattbeddow]

I dont know about floor panels but i rivited in my new battery box as I dont have access to welding equipment and seeing as how it was spot welded to start with i figured it would be ok.
That said, a battery box doesnt have much structural purpose...

[Bungle]

don't know much about the make up for a plane but are the frames also riveted on or just the skins on the outside

[tiger99]

Rivetting a battery box, which is mostly held in by gravity, is structurally acceptable, but if the MOT tester spots it he may fail it, and in theory, as it is a modification to the monocoque, you could be required to have an IVA test, which there is no real chance of passing in a standard Mini. However, I doubt that most MOT testers are that mean, or stupid.

But there is NO, repeat, NO other panel on a Mini shell which can safely be rivetted. All are stressed parts of the monocoque.

There is very little similarity between rivetting aircraft and cars. The materials and stresses are very different. There are stresses in parts of the shell that could never be sustained by a rivetted aluminium alloy structure, at least not for very many fatigue cycles, whereas mild steel copes with fatigue very well. Aircraft alloy rivets would rapidly fail in a car.

Of course, you could, from the structural point of view, use old fashioned mild steel rivets, inserted red hot and shaped with suitable hammers, one where each spot weld would have been. It would still be an instant MOT fail.

There are a few places where a seam weld is used in a Mini (also compulsory for any patial panel replacements), and you could never replicate that by rivetting, so to do any serious body repairs a MIG welder is essential, amd far easier to use than rivetting anyway. No need to prepare exact size holes, for example.

[mattbeddow]

to be honest, its gotta be better than the rusty hole that was there before its also my understanding that an MOT inspector isnt alowed to remove anything on a car so as long as its covered up, they shoundt fail me for it (fingers crossed)
But yeah, rivited floor probably isnt a good idea

[Carlos W]

I dont know about floor panels but i rivited in my new battery box as I dont have access to welding equipment and seeing as how it was spot welded to start with i figured it would be ok.
That said, a battery box doesnt have much structural purpose...

What kind of rivets did you use?

[Bungle]

what about electrolysis between a alloy rivet and steel shell ?

just add winter salt water

[mike.]

You can get steel rivets too

[sonikk4]

The biggest problem you will have apart from the MOT aspect is do you use tension fasteners or shear. Then its down to strength. Normal Hi loks have a KSI rating of 95 which is a standard for aircraft fasteners.

Hi loks would be of no use on floor panels as you would have to overlap and then it would need to be a double row. So that then leads onto solid rivets. Now you will have to use Monel rivets and again a minimum of two rows but more than likely three. So if you were to go this route from a strength point of view you will to use 3/16 mush heads so tooling will need to be a 4x with a good heavy block. Compressor needed then.

Now i know exactly what you are on about with regards to strength using rivets, Hi loks, cherrys etc but a car monocoque is normally designed with all the various stress loadings passed through the structure via welded joints etc and this design is then signed off as being acceptable, the same as aircraft. A welded joint on a car has been designed that way and is the recognised way of joining all of the items together. By riveting you are deviating away from that accepted method and so without testing under the correct conditions then you cannot say just how well riveting will join the items together.

I wont wittle on about sphere of influence etc etc as although applicable on aircraft it would not be on a car as unless its been designed to be riveted together, so unless you are an aircraft engineer not many people will know what i'm on about.

So as far as you are concerned its welding and nothing else will be acceptable. If you do use rivets and then hide them with sealant you are running an unacceptable risk not only to yourself but to any passengers you may carry in your car. If a MOT tester sees something he finds suspicious then he will more than likely fail it. Is it worth the grief??