To be fair a āwelded repairā on my 96 lasted 6 years before āproper restorationā was done, and even then, it was only done because I was feeling picky.
Since the 2017 repairs, its not been mollycuddled, and everything around the repairs looks fine, though elsewhere, I need to attend to the underseal (though more precisely, someone else will be
2009, before any repairs
Repair (whole car was repainted)after 12 months. Oh.
The horror, 18 months after the repair (early 2011). You can see the plate.
So naturally, stormed off the the bodyshop who did this, who came up with excuses, but put ārightā the repair.
I didnāt photo this repair, but in 2017 it looked like this:
It felt pretty solid to touch. There is an obvious rust bubble developing. But I opted for have the whole lot and the arch to be replaced, as the upper arch lip was looking a bit suss and starting to balloon
When cut away, the sill itself wasnāt too bad; the repair you see was done during the arch repair, so despite the grmness of 2011, the sill survived. What was grim was the inner arch lip, which had to be built up (never welded before, 1996 Roadster, imported 2000).
So, cheap and cheerful patch repairs will only last 12-24 months. They are not necessarily the harbingers of doom. But a cheap patch is cheap; Ā£100 or so.
Cheap repairs masquerading as more expensive repairs will only last 12-24 months, and might cost hundreds. These repairs are scams.
A good localised repair to a sill will last at least 6 years. The repair itself might last longer, but its the rest of the car that is starting to crumble. It doesnāt make any sense toreplace an arch, but not an older welded outer sill panel, given that the patch panels are sill plus arch. Iām expecting this repair to last at least 6 years, but I know elsewhere on the car will likely need some repair.
Garaging a car can be a killer. If garaged, leave the boot open to allow air to circulate.
Of the cars I have had for significant periods:
1991 S-Spec, imported 1997, never garaged, lived by the sea. Sold in 2005, not a shred of rust. I note though by 2016, someone had to make repairs to it.
1993 S-Limited: Imported 2003, one owner to 2009, who garaged the car, mollycuddled it, dinitrol box sections when imported, hardly used, 2009-2013 used as a daily drive, not garaged, 2013-owned by me, 100% garaged, when acquired, the sills were starting to degrade, as were the front wings. 2018; two sills and one arch were needed, jacking points on one side had collapsed
1996 S-Spec 2: The workshorse. Imported 2000 by Mazda UK, couple of London owners then me from 2005. 2005-2013; never garaged, no additional undersealiong, clocked on 100k+ miles during this period. Repair to sill needed in 2009, redone in 2011, By 2015, other rear sill was starting to show rust. Full repairs in 2017. Remarkably, I have never had a rust advisory, let along fail on this car. Underside is starting to look a bit shabby now, so will be attended to. During the 2017 repairs, I also needed repairs to the passenger door frame; unusual, but I think related to door skin repairs by Mazda back in 2002-2003.
My first Roadster, SAZ9826, was torched in 2000, so doesnāt count. My M2-1002; despite being in shabby condition, and used as a farmyard hack, had no issues whatsoever with the sills.
My conclusions? So called best in class rust treatment did nothng to prevent rusting of a well looked after car over a 13 year period. Maybe that is to do with how it was applied, who knows. TGhe critical area is none-draining and difficult to access. Even if it can be accessed, it is essentially impossible to demonstrate effective coverage here. Whether a car is garaged or not, does not affect speed of rusting, per se. How the car is used might do, ie. if you never use the car, its probably not going to have a problem, rustwise. Long term storage outdoors might affect paint apeparance, but that is cosmetic/superficial really. Modern waxes and sealants I think largely mitigate this.
Our view of how to regard rusty examples of Mk1s is largely driven by the fact that there were always plenty of cheap rust free alternatives; if the different between a ārust freeā and a ārustyā (including obviously cheaply repaired cars) was less than Ā£1000 (the cost of sills and arches, plus paint), then it always made sense to reject the rusty car. But thats no longer the case. Sub-Ā£1000 cars are still available, though they probably have lots of other problems. There are good numbers of cars at Ā£1000-1500, generally well looked after, except for dodgy sills. Byut now, concours quality cars are reliably achieving Ā£8-10,000, and very good cars Ā£5-8000. Tidy presentable cars, with few obvious issues (and probably a history of decent repairs) are Ā£3-5000. So there is a yawing gap between Ā£1500 and Ā£3000, making decent repairs much more economic. The cars in between are questionable, as they will be a mix of some bargains, and some real heartbreakers.
So, set your budget high enough to exclude these questionable cars (and this budget I suggest will be fluid), or, set it low, and look for those well looked after, but rusted cars; the ones that have good tyres (no mixed brands), a recent hood, evidence of mechanical upkeep, but now the owner is facing a Ā£1000 bill on a car he perceives as worth only Ā£1000, but he needs a car for work. At least one member of this forum went this route; a car with scruffy sill repairs, but otherwise honest, and is getting great fun out of it, without sweating whether the sills are misleading. If he likes the car enough, I am confident that the car will be more than worthwhile enough to properly repair.
Of course there is a limit. Rotted front wings add to the costs, repairs to the main sills and floorpan add. But, at the moment, these are relatively rare. Those cars with rusting in the rear sills; that is a very easily budgeted repair.