A few weeks back I was looking at the various finishes that had been applied to the sills that I'd bought for the Saloon over the last few months - a hard black coating on the OE N/S inner sill, a softer black coating on the OE N/S outer sill, a soft brown coating on the O/S repro inner sill and rust on the OE N/S middle sill. I decided that in the interests of longevity I wanted to get these items back to bare metal so that I could get modern primer on them before fitting them.
A little bit of research unearthed a media blasting/surface treatment specialist - Abercorn Media Blasting - just down the road from Livingston in Winchburgh. I explained to them what I wanted to do and they couldn't have been more keen to help - in fact the managing director I spoke to, would you believe it, is also restoring a 2000 Saloon!
They collected the sills a couple of weeks ago and delivered them back this afternoon. They've done a fantastic job. The painted sills have gone from looking like this:
to looking like this:
The two inner sills and outer sill were blasted with soda media and the middle sill was blasted with glass media. The middle sill in particular has cleaned up beautifully.
It turns out that there was evidence of corrosion, mostly minor surface pitting, under the coatings on all of the finished sills so I reckon it was worthwhile doing.
The inners and middle sill will now be painted with Electrox primer - a very high zinc content galvanising-type primer. The inside surfaces of the outer sills will also be painted with Electrox while the outside surfaces of the outer sills will be painted with etch primer. The Electrox will obviously need to be cleaned off as required when welding the sills but it'll be reapplied after the welds have been cleaned up.
Top coat will also be applied wherever possible and no doubt copious amounts of cavity wax will also be consumed!
So hopefully, when I get the car back on the road, the sills won't rust out within seven years or so the way they did back in the day.
I'll probably do the same thing with the front wings when they're due to be fitted.