Over winter break Dad and I (mostly Dad) restored almost 30 pieces of cast iron. We were spurred on when a family friend showed us his 'collection' of 20 rusty pieces that had been passed down or acquired from yard sales over the years. Combining my knowledge of metallurgy and chemistry (i'm a materials science major),Dad's hands on gusto, and information from the internet, we ran a few trials and worked out our system for turning rust buckets into absolutely stellar cookware.
We have 3 tubs, a lye solution, a vinegar solution, and an electrolysis setup.
The lye solution is an 18oz can mixed with 5 gallons of water
The vinegar solution is a 50/50 mix of distilled white vinegar and water
and we set up the electrolysis with a 40 amp battery charger and information that can be found here (http://www.wag-society.org/Electrolys...)
We would start with an overnight soak in the lye solution. In the morning rinse with hot water and a scour pad. then a quick (<15min) rinse in the vinegar solution. From there it goes into the electrolysis tub from anywhere to 4-8 hours depending on the corrosion level and responsiveness. some pans just seem to shed the gunk quicker. finally a last rinse in the vinegar solution and then hot water before it gets its first seasoning coat.
In short Lye->Vinegar->Electrolysis->Vinegar->Season
Seasoning is a highly debated subject, but I don't think that there is necessarily a wrong way. We used the method described here (http://sherylcanter.com/wordpress/201...) using 5-7 thin coats of grape seed oil because that's what we had. for some pieces we used a more traditional method of 2 thin coasts of crisco.
The pans have turned out beautifully taking on a bronze like sheen. attached are photos of 2 block logo griswold number 7's one before and one after restoration.