Does anyone know how to dimple box section steel?

Let me explain, I've gotten hold of 3 sheets of 0.6mm ally for the sides and back of my car. I wish to paint the car,so countersunk rivets are needed.

The alloy thickness is too thin to countersink, but should pull (self dimple) into the box section.

I don't want to countersink the box section as it will only leave 0.6-0.8 mm of material under the rivets, leaving a weakened box section.

So, I'm left with dimpling the steel, Any ideas out there? I have one but want to get other opinions first.

Here's what I mean.




Regards Dan.

[Edited on 26/1/14 by scutter]

Bond the panels on with Sikaflex, but only if you don't want them removable I have to say that 0.6 is very thin, it will dent
very easily.

You get almost countersunk rivnut's in steel. You can fill a rivnut with resin and flatten off the panel. If you made up a counter bore drill the same size as the rivnut head and thus could be made to be flat as the head of a steel rivnut is very thin.


Alternatively you could make a punch and mandrel to the exact shape as per your drawing, then apply an alloy countersink rivet.

I'll run the risk of the thin metal, it was free.

The countersunk rivinuts would remove as much steel and countersinking normal rivets.

I was thinking of using something like what is attached to this G clamps screwthread.




Regards Dan.

i would advise against doing it. it will make the chassis very weak in compression loads e.g a crash.

think of a length of tube compress it from both ends until its at the point of almost buckling under the pressure. then do it again with a small dent in the tube. it will take less than half the pressure to make it fold!

Thanks for that Ash, I'm currently reading up on the effects of dimpling and dents on steel structures (the winter nights do indeed fly by)

I can understand your concerns, but isn't a similar weakening to drilling rivet spacing? i.e. a calculated risk.

ATB Dan.

quote:

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Originally posted by scutter
Thanks for that Ash, I'm currently reading up on the effects of dimpling and dents on steel structures (the winter nights do indeed fly by)

I can understand your concerns, but isn't a similar weakening to drilling rivet spacing? i.e. a calculated risk.

ATB Dan.

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Looks like dome rivets for me then.

Many thanks to everyone. Regards Dan.

I understand what has been said but I'm curious about something. I thought swaging a panel added strength. how does the idea of dimpling differ?

Why not just buy thicker alloy and countersink it.? Seems a false economy to use something thats not going to allow you to what you want just because you have it.

Ive been countersinking mind for areas I plan on vinyl wrapping.

http://www.locostbuilders.co.uk/viewthread.php?fid=37&tid=150452