[TheForge] stubborn rivets

[CGRAF]

   I was thinking more of concentrating the heat on the rivet and then 
stretching it along the axis of the role displacing the central portion 
out the far end.

Actually just heating it and allowing it to cool might loosen it up.

Mike Graf

  On 8/9/2016 1:44 PM, Mike Spencer wrote:
>
>> my 2nd least desired solution is to use a welding tip on the torch
>> and heat the surround metal to allow the rivet body to fall out.
>>
>> Option #2 would have been my first choice .
>
> Not sure that would work as you think.  If you heat a ring, it gets
> bigger in diameter beause the ring material gets longer linearly.
>
> But if you heat a small region of the truck frame around the rivet
> hole, it's surrounded and constrained by cold metal so I think the
> hole would get smaller, thus tighter.  That could be good because
> after cooling, the hole might be a tiny bit enlarged from crushing.
> But it will be hard to heat uniformly all around the rivet, expecially
> if, as I imagine, the mating flange of the bracket is hard up against
> the frame.
>
> I haven't used oxy-propane but if you have a welding tip that can
> quickly heat the rivet itself to red heat, the rivet will try to
> expand but will be restrained by the surrounding cold(er) hole. As the
> rivet gets to (even dull) red heat, the force or the constraining hole
> will crush the rivet a tiny amount, making it smaller.  It will also
> crush any oxide between the rivet and the hole and, as rust isn't
> malleable at a dull red heat, it wil tend to crumble and loosen.
>
>> suggestions welcomed.
>
> That, FWIW, is mine.  Good luck.
>
>
> - Mike
>