How far should I go to cover rusty sills for tech?

Thanks - good answer for me. I have extra sheet metal...

I still have to find jack points on this. Where I've been lifting it (to change two tires) has been a little crunchy. I haven't yet looked far enough underneath to see how rusty it is for a state inspection, so this is still one of my build candidates, instead I might turn it into a dd.

I hope I don't get into 'too rusty to cage'.

unless the rust somehow makes the car unsafe, I wouldn't worry about it. #$500carmyass#

More good suggestions - thanks!

   Bc: I understand using tape at times, like your door; but trying to keep it attached to an already "crunchy" underside is a losing battle. Like in my pic: not sure if you can see it, but I have clear plastic shipping tape over the 'pried up' edge of the sunroof to try to keep rainwater out. I just removed the ragged tarp from the winter; a new one goes on shortly. And you might be able to see a couple rust shakes on the ground (one with red paint) under the sill plate; I stomped the rest back into iron oxide after I pulled the jack from under that corner lift. And all that rust was there _before_ I broke the window to get into the "auction" car.

   Mr.Y: yes, the extent of the rust is what I'm concerned about. #$350carwithauctionreceiptrunsanddrives#  ;-)

   DR: Brilliant! I'll look into that some more.

   Years ago, I found a roll of 'aluminum flashing'-like metal in a cardboard box in a drainage ditch; or maybe it's gutter material(?) - dunno - I picked it up. Regardless, it's thin enough to bend but thick enough to be fairly sturdy, and I know someone with a metal brake. So I can cover the rusty areas, but I think a jack would punch right through it.

   Reinforcement idea is great.

I don't know yet, but the two corners I lifted crumbled pretty badly. I taped the sunroof after the auction, and covered the broken window with heavy plastic, and the interior stays pretty dry; no condensation on the inside, and no mold. I'm hopeful about a dd for a while, but again, I haven't had it up long enough to look underneath. I'm guessing I'll do some sheet metal, regardless.

I just stripped the interior (except for the dash, so far) from another build candidate with standing water in the bottom, but that's a flood car; clear biohazard, but conveniently, very little rust showing, and I've got plenty of bleach and a spray bottle. That'll definitely be a driveline swap, but it's a good platform. Likely penalty laps; though not that I'd care.

I have too many candidates...

Ooops, I wasn't clear:

BMW, crusty rusty underneath; _possibly_ able to be inspected, but I don't know. Runs and drives. Front end is really pretty tight, accelerates nicely and stops straight. My first experience driving a BMW, but has only been in a parking lot, not on the road. I kind like it a bit. If it's not too rusty to inspect here in PA, I'll PA title and register it, so that's my decision point. I'll just have to get at it.

Other candidate is _not_ a BMW, flood car (fresh water), now stripped of most of the interior other than the dash. Some of the _mechanical_ is rusty, but the body - not so much. No electrical function via the key in the ignition cylinder. The dash will come out and I'll set it for defrost function after reconfiguring, unless it's too dirty to salvage; that's what pick-n-pull fans and switches are for. I think ecoboost or K swap, based on previous input here. Maybe diesel, but that would require a fuel system swap also. Second build likely; first if I daily the BMW. I did save the seat mounts.