Radiator tag restoration

[z28z11]

After a couple of comments on the Originality section about recoring radiators, I decided to dig up the radiator tag for my Z11 L48 auto w/ A/C (UR code) and try to salvage it. Radiator tags are so extremely thin material, (you've probably noticed) that I was afarid to bead blast it without shredding it to pieces or blowing holes in it, plus removing too much material (see before pics). As I have not been able to find a repop UR tag yet, I tried something that really does work - electrolytic rust removal. A couple of hours in a plastic bucket hooked up to a battery charger can work miracles (as far as I'm concerned). Just thought I might share a few pics of before and after treatment - I have not bead blasted the tag, and may not, as a light coat of primer should finish this up before paint. Dirt cheap, and works surprisingly well, especially for tightwads like me with less-than-no-budget to work from. No holes, stamped number is plainly visible, traces of original paint remained in the crevices behind the rust.

Regards,
Steve

[69Z28-RS]

Hey steve,
..  That came out very nicely.. 

[69pace]

Steve - what did you use for the sacrificial rod?
I tried rebar but got inconsistent results reviving an oil pan but would like to try again since I have a ton of washing soda left over LOL

[Mike S]

 Personally, whenever possible, I would be more impressed looking at a restore part that may now have patina instead of a reproduction in perfect shape.
Patina shows there is history behind it. Something that is gone but the part retains its past existence through physical marks.
I'm glad to see you are using the original part. It sure came out great. I'm going to use your process when I have to restore mine.

Mike

[Steve68]

Steve - what did you use for the sacrificial rod?
I tried rebar but got inconsistent results reviving an oil pan but would like to try again since I have a ton of washing soda left over LOL

An iron rod (positive connection to battery charger).  Make sure you have a very good connection with the charger negative clip on the part.   This is critical to getting good results.  The battery clip should also be out of the solution.  If you don't the clip will suffer damage over time.

[Mike S]

I wonder if Evapo-Rust would have worked here too.
 
Mike

[z28z11]

Steve - what did you use for the sacrificial rod?
I tried rebar but got inconsistent results reviving an oil pan but would like to try again since I have a ton of washing soda left over LOL

I used a flat (thick) uncoated steel washer, suspended about 2 inches from the tag. I also used steel wire rather than copper (to make sure no contamination to the tag from free copper dissolved from the anode). Since the iron oxide replacement is more or less line-of-sight, for a large item you can rig several electrodes around the part (rebar is good; steel and usually uncoated, easy to rig). Your imagination can have a lot of leeway - just make sure you suspend the parts in the solution, submerge and try not to let them touch the bottom or the sides of the container (should be plastic, or nonconductive). And always make sure the negative cable is connected to the part you want to derust, otherwise it will eat it alive like it does the sacrificial steel part.

If you bought a big box of Arm and Hammer like I did, you probably have enough to do a couple of subframes and an engine block or 2. Just be careful when you mix water and electricity - use common sense. BTW - raising the pH to the alkaline level is the main thing - the residue is no more harmful than leftover washing machine rinse water. Don't do this indoors, as the electrolysis produces both hydrogen gas and pure oxygen, which can be explosive if not ventilated well. Great thing - it's just plain cool to watch the rust disappear from the part (and watch the sacrificial part dissolve). See the next response to Mike's statement as well -

[z28z11]

I wonder if Evapo-Rust would have worked here too.
 
Mike

Mike,

Probably does O.K. - the beauty part about electrolysis is replacement of the oxide with pure iron. This is not a plating process - it won't remove material from the part, it won't fill pits, and it won't add material like plating does. It will leave a black film on the part, which I scrubbed off during a clear water rinse with a nylon brush. I did "passivate" the part with a rust preventative after the rinse (this keeps it from rerusting when it dries, which it will do quickly). Any good bare steel prep like Ospho or Evaporust will work well - WD probably works too. Amazing thing - when the process starts, rust starts to float to the surface around the positive side of the connection, not around the part being derusted - very strange.

Regards,
Steve

[Petes L48]

Steve - what did you use for the sacrificial rod?
I tried rebar but got inconsistent results reviving an oil pan but would like to try again since I have a ton of washing soda left over LOL

I've had good results with rebar.  If the piece is big I'll use several rods around the perimeter and run a jumper wire across them.  I also clean off the rebar every so often.