Every once in a while I come across a bike that has been left to the elements. Most of the time these are only worth saving parts from. On a few occasions however the bike deserves to be saved. So how do you safely remove rust from a bike while preserving as much paint (and decals) as possible? The product I use is called oxalic acid. Oxalic acid (OA) is a very mild acid that is particularly good at attacking rust while leaving paint and decals alone. OA is sometimes referred to as wood bleach as it is used in the wood pulp industry as well as a wood and deck cleaner. OA is a naturally occurring acid and is found in most vegetables. It comes in a crystalline form and as long as you aren’t ingesting or playing with the crystals with your bare hands it is relatively safe. You can buy large bags from EBay or Amazon which include mixing directions. A 5lb bag on EBay is about $20 with free shipping and would last a long time.
I use a kiddie pool that I bought at Walmart for about $15.00
OA works best when both the water and outside temperature are warm or hot. Use is pretty simple. You can follow the directions or simply add a cup or so to the pool and stir. The amount is not critical but you don’t want the solution too weak. The worst I’ve seen happen by adding too much is getting a stronger yellow film which washes off anyway. I’ve used bare hands to move parts but you should probably wear rubber gloves to be safe. You may also want to place this in an area where animal can’t get to it and accidently drink from it. When you’re finished you can pour it in the yard and there are no environmental concerns.
The first bike I ever used oxalic acid on was a 1934 Huffman camelback. While not worth a lot of money it is probably one of the rarest bikes I own. This thing came in a wonderful rust brown color and it didn’t look to hopeful. My dad was a body man for 50 years and when he first saw it declared there was no paint worth saving. Here are a few pics as received.
You can see there was some evidence of original paint but this thing was pretty crusty. I completely disassembled the bike and began putting parts I the pool starting with the frame and fork. After only a few hours the original colors started showing through—my dad and I were amazed! I left the parts in the pool overnight although I think the acid had did most of its job in the first six hours. The next day I took the parts out and gave them a good (gentle) soap and water bath to remove any residue. After this I used compressed air to dry the parts as much as possible and let them set out in the hot Georgia sun to make sure they were dry. To preserve the finish I used Johnsons paste wax. Some automotive waxes tend to leave a white film in the recesses. Some folks like to use Linseed oil. I personally don’t like coating with any kind of oils because it attracts dust and dirt as well as giving the finish and unnatural sheen. So I put the bike back together and here is what I came out with.
While not a show piece I did preserve the paint enough to be presentable. Here is a 1923 Columbia motorbike that I did as well. Before…
This one came out pretty nice as well. As you can see the decals were unaffected by the OA. Using other methods such as rubbing compounds, or very fine steel wool will normally damage old decals as well as remove pinstripes or thin paint such as secondary colors.
So the next time you run across a bike that you think is a hopeless case give OA a try and see if you can save another relic. Enjoy the ride!
Razin
Mike Di Vito