Gas tank revival

The little brother to the CA160 in our family of Hondas
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Biz
Posts: 21
Joined: Wed Jan 12, 2011 3:40 pm

Gas tank revival

Post by Biz »

Lots of newbies on the forum, I'm one of them. Working on my '64 CA95 which was given to me.

My biggest concern when I got it was the gas tank - it was dreadful inside, must have been stored with 1/2 tank of gas sometime in the '70's. About 1/2inch of rust/crud/solidified crap in the bottom, stuff caked on the sides. Didn't seem to have any rust holes, thankfully. Did a lot of research on the web on how to clean tanks, lots of different techniques out there, so here's what I tried.

Started off pouring in a couple handfuls of roofing nails and some diesel fuel, got about 1/2 cup of crap out after several rinsings, but still a lot remained.

Next I soaked in vinegar for a few days. Not effective.

I really didn't want to use any chemicals such as muriatic acid that were toxic and/or would harm the paint.

I had just about settled on either the POR-15 or phosphoric acid (or both), then I read about the electrolysis method and, since I am an electrical engineer, I had to try it. Bought a 10A charger, some Arm & Hammer Washing Soda, some 3/16" and 1/4" threaded steel rod, and some cable sleeving at an auto parts store. First I make a blockoff plate to put where petcock mounts. Ended up going with about 4 tablespoons per gallon of warm water, cut some threaded rod, inserted into the sleeving, stuck into tank. Charger + to rod, - to tank mounting bolt, 10A scale. Connected an ammeter to read current. The rod instantly started fizzing :)

After first day, solution was really rusty. Couldn't really tell if it was working, but rusty water means less rust in tank, so I kept going. Every day I replaced the dirty solution and cleaned rod. Usually after a few hours the current went to .1 amps or less which means it's time to change the solution.

After about 5 days I could see spot of metal showing on the botom of the tank. After 10 days it was 50% bare, then after about 14 days (today), the rust and all that 1/2" of crap is TOTALLY GONE! It's really amazing. Plus, it actually plates metal on the tank instead of removing stuff. Really cool. Not going to need any coating I think. So anyways, I'm thrilled with the results and thought I'd share them.

Now I need to figure out how to install the oil pump so that it doesn't wobble on the shaft... it's a very tight fit for some reason.

Biz
Smithers
Posts: 3176
Joined: Wed Feb 11, 2004 3:58 pm

Post by Smithers »

Wow good work! I would love to see some pictures of this action. I bought a small ultrasonic cleaning tank from Harbor Freight that works wonders. I can't put a fuel tank into it but a friend of mine has one at his work that I can! And I have a couple of tanks to try out with this method. I got a bunch of pictures I want to show here in a write up so I'll let you know when I get them online. Great to hear of a successful tank cleaning. This is a big issue for us restoration guys.
wwager
Posts: 11
Joined: Tue Feb 08, 2011 4:54 am

Post by wwager »

I am very interested in trying this on a rusty tank I inherited. Question is, why steel rod? wouldn't brass be better?? What is the chemical in arm and hammer washing soda - sodium bicarbonate?
Spokes
Posts: 1575
Joined: Sat Apr 25, 2009 9:40 pm

Post by Spokes »

Arm and Hammer washing soda is sodium carbonate.

The anode and the cathode have to be the same metals.
wwager
Posts: 11
Joined: Tue Feb 08, 2011 4:54 am

Thanks

Post by wwager »

Spokes,
Thanks for the information - I'll try your method. Any advice on finding a service manual?
Walt
Spokes
Posts: 1575
Joined: Sat Apr 25, 2009 9:40 pm

Post by Spokes »

Somewhere I have the manual on a pdf file. I bought a new computer and the files are somewhere on a back up disk. You should be able to find a hard print manual on eBay. Maybe other members can help out with this.

I do have the parts pic and list on a pdf file. You have to pm me with an email address.
comp_wiz101
Posts: 172
Joined: Tue Aug 31, 2010 8:33 pm

Post by comp_wiz101 »

I think you can get a copy from this thread: http://www.fourwheelforum.com/showthread.php?t=787
Otherwise, I can send you my copies of the C95 drivers manual, and the CA95 Parts and Service manuals.
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