Friday, September 17, 2010

Electrolytic Rust Removal: Big Time!!!

Do you need an inspiration to start working on something? I usually do… Even worse, I need a REASON…

I was surfing the Internet last week, looking for paint options for my Elan. On one site I found a paint preparation guide, which mentioned Electrolytic Rust Removal (EER) as one of the ways to remove corrosion. No description, nothing… So, I goggled it. Started reading: it took a few seconds to realize – that’s what I need!!! To remove rust you need electricity, electrolyte (washing soda, AKA sodium carbonate, dissolved in water), bath, steel electrode and some wires. I searched some more, and here is the site (http://www.oldengine.org/members/orrin/rustdemo.htm) that I found very useful. No pictures, but very good description.
After some reading and thinking I got inspired to remove rust from Elan’s frame: it got a lot rusty areas with heavy pitting. It would take forever to remove by wire wheel. I can’t afford blasting service right now, so the ERR is the way to go!

So, I started my “need” list: first thing - power supply – checked. I have 50A 27DCV power supply, which just sits in the garage and collects dust – perfect for this job!
Second thing – the bath… Scratched my head: what to use?!? The answer came easy – large Toronto recycle container – perfect candidate for this job! Couple holes needed to be plugged, simple task. Third thing – washing soda… That was surprisingly hard to find! I got it from Grassroots Environmental Products – small store in downtown Toronto. Everything else was easy. I have plenty of steel pieces in the garage, so finding the waste electrode wasn’t a problem. I have plenty of wires to…
So, I cleaned the paint and gunk from the frame with wire wheel and made a set up. The container holds about 350L of water, so I used around 3lb of washing soda and it worked just fine. I started the process with one big waste electrode, but found that several small ones work better, because you can locate them closer to critical areas.
Anyway, I loaded the frame into the container, hooked the wires and turned the power on.

The process started right away, I had an average current about 30-35A. After some time the waste electrode collects a lot of rust on itself, so the current drops by 5-10A.


First signs of rust and grease appeared after on the top of the solution after half an hour of work.

Front of the sled was corroded the most, so I had plenty of rusty foam on the water. I collected it several times just to keep the solution clean. I started the process around 8 in the morning and had a few breaks during the day due to adding another electrodes, current drops or small problems like overloaded electrical breakers on the panel in the basement:) and left it alone until 21:00 when I switched the power off. I had to turn the work piece around in the tank to keep the rust removal under control:) I left the frame in the solution overnight (which is fine because solution is not corrosive to the metal) and turned the system on again in the morning. In the afternoon I fished the frame from the tank and cleaned black oxide flakes, which formed instead of rust. Not bad! Still some rust in the corners, but most of it was gone!






After cleaning with plastic brush I sprayed the first half with WD40 just to prevent surface rusting and dropped the frame in the tank again, now the rear portion went in. This time I had 4 waste electrodes in the container: one on the bottom, big one on the front and two on the sides. Current jumped to 40-45A, but after a few hours it dropped back to 30A. I played with electrodes positioning during the day and left the process overnight.


Next day I decided to locate waste electrodes close to corners along the tunnel and in engine compartment to remove remaining rust spots and installed them using tie wraps and hooks.

Worked wonders! Most of the rust was gone in no time.
I have to admit, that the process took a bit longer then I calculated, but I satisfied with result. Here are some pictures:










After getting some experience it’s much easier to set everything up correctly, so I don’t have to repeat the work again. Also, it’s hard to work with such big pieces of metal. It will be always a corner, which gets less treatment then others due to physics of the electrolytic process. You get best results in the areas where the distance between electrodes is the shortest. Anyway, I am happy with the final result. Now I can continue work on the frame and weld some patches and reinforcements.

0 comments:

Post a Comment