First degrease:
soak them in a 5 gallon bucket of pinesol for a week in a basket which is suspended off the bottom about 2 inches as all the crud will be at the bottom. Shaking it all up or put the bucket on the washing machine so it vibrates and shimmys alot.
You can reuse this degreasing mix like 20 times.
Or get a couple gallons of concentrated degreaser from Lowes and use that for taking off tar, undercoat and paint (submerge for a week or two).
Then pull all the parts out and wash them with water. Repeat degrease soak if needed but its unlikely.
Once the parts are totally grease free and rinced, submerge them in a 5 gallon bucket of a 3 gallons of OSPHO and 1 gallon of water. You can reuse this "vat" for a super long time too.
They will rust free between 10 minutes and over night depending on how thick the rust is.
Rince and either tumble or you can blacken them or paint them.
You can get a large vibratory tumbler from harbor freight for a good price (not easwood cause theirs is wayyyy overpriced for what it is) and tumble them.
When you pull them out, rinse with laquer thinner and paint or coat with oil immediately as they will likely flash rust quickly if left bare.
Keep parts submerged under antifreeze after the ospho if you dont want them to flash rust prior to coating
Parts in pics were either super thick rusty and or caked with layers of oil and years of crud.
Overall they all looked like rusty goopy hell and I soaked in pine sol, rinsed, soaked in OSPHO. The little grinder reamer things, I tested in the rain for 1 month during winter.
The general parts in the last picture were sitting in a plastic bucket full of tree leaves, grease and rust and water for 10 years so I tested the process on them too. Some pieces were caked with piles of rust and some looked like they were covered in tar. After the process, I let them sit in a bucket of used antifreeze for a couple months and they slowly got light surface corrosion.
Like said in other posts, nothing beats manual labor of wire wheels and sand blasters but wire wheels will not get in half the crevices and sand blasting off grease and heavy rust is very time consuming, messy and ruins your blasting media in your cabinet super fast.
I wanted to have a system that would prep the parts for sand blasting so it would be really quick and not so messy to blast for the last step: Caswell electroless nickel plating.
Recycle waste products according to local regulations.
