I received a very promising tip from a Mr Akagiyama, along with photos, on the troublesome and laborious job of removing rust. Apparently, Mr Akagiyama is in the process of restoring a Marubeni Yamaguchi, similar to one I restored several years ago.
This is his project, prior to starting the restoration.The bicycle itself is in fair condition, but the rims are heavily rusted. Since Araya stopped making stainless steel BE rims a few years back, the only options available now are to remove the rust from the old ones, hunt for NOS (new old stock), or, have the current ones re-chromed.
This is one of the badly rusted rims.
Step 1: Preparation
What you will need:
(2) Rubber gloves (Caution: Never touch the acidic solution with your bare hands!)
(3) Breathing mask and well ventilated area
(5) Hot water (not boiling)
(6) Wooden stick or other object to stir the solution
(6) Fine steel-wool (Grade 000 or 0000)
(7) Oxalic acid (20g per liter)
(8) Bicarbonate of soda (to neutralize the solution prior to disposing)
Now, small parts will fit into a bucket, but rims are a different story. Mr Akagiyama made use of a small inflatable pool.
Put on your goggles, rubber gloves and mask. Measure the oxalic acid and add to the bucket. Add hot water, not boiling. Note the oxalic acid will not dissolve if using cold water. As a reference mix in 20g of oxalic acid to every liter of hot water. Stir the solution until the oxalic acid is thoroughly dissolved. Immerse the items in the solution, remembering to never allow the acidic solution to come in contact with your skin or clothes.
The length that the items are left in the oxalic acid solution will vary depending on the severity of the rust; however, in Mr Akagiyama's case the rims were left in the solution for three days.
A yellow film will appear on the parts as the rust dissolves. The solution may not remove severely rusted spots, these spots may appear as black patches but can be later taken off with fine (000 or 0000 grade) steel-wool.
After removing from the oxalic solution thoroughly wash off the yellow film from the parts using dish washing liquid. Rinse and wipe off with a towel until dry. Depending on the item, may consider applying anti-rust solution to the parts.
BEFORE & AFTER
Using oxalic acid certainly appears to be a very effective and labor-saving method for the arduous task of rust removal. I have already purchased some oxalic acid and plan to try it out myself on a few smaller items.
A big thanks goes out to Mr Akagiyama, for sending in this useful tip on rust removal. If you have a tip or advice, pass it along so I can share it with other enthusiasts. firstname.lastname@example.org