Hardtop Restoration Rust Repair

Warren

Warren

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http://www.stovebolt.com/techtips/rust/electrolytic_derusting.htm

Have used this method before when doing motorcycle gas tanks. It is really wonderful for that.

Now, I have a kiddie pool filled with the washing soda solution as a hard top I bought looked great till it got off the car. As it sits bubbling in the solution it is hard to take a pic with a phone camera. No polarizing lens on the phone lots of reflected glare. The electrode a cut up angle iron from an old bed frame has produced a good amount of rust flakes.

I am only able to get one side at a time and the time in the directions is was understated gas tanks have taken a couple of days. Going on two days now for the worst of the two aft corners.

I will post some before and after, after I remember how to reduce resolution to post here..
 
Pics

The best thing is the process removes rust in the unseen spaces between the panels. The plan is to do both sides cut and remove badly damaged sections even though they are small and use my little gas welder to weld the patches in. In the past on inferior projects I used brazing rod but really do not care for the pain in the butt removing flux residue.
After the patches go in I will leave a small hole in which to pour some thinned primer and paint inside and then dry in the sun.

The pics show the bubbling oxygen from the process and the positive attached to the electrode and the 2 nd pic is the goop and bits of dislodged rust.

Not a project for someone in a hurry.... oh and the water was clean before. The process softens the baked hardend rubber and rusted in screws for easier removal as well.
 
Looks like you have a nice project on your hands. I spent 2 hours today installing rubbers on mine, I would love to say I am done but sadly nowhere close. I figure I have at least 2 months to work on it.
 
Small Parts Cleaning

Just did a couple of lic. plate holders and small parts and look at the size of the stalagmite of rust. I did not wait to complete the process on the parts that were easy to hit with the 4" Makita sander. The process is slow but can be increased with a higher amp battery charger. Wish I did not sell my big service station style charger that was a good battery boiler. There are a few black specs left on my trans tunnel access plate. The process is complete when it stops bubbling, so stay tuned. The next pic will be of a part that had nothing done to it but a drop in "the science project bath the Mrs, calls it". A set it and forget it mode of rust removal.
 
I have been using this method on a car I am currently rebuilding an it works extremely well. I found that by periodicaly cleaning the sacraficial electrode it speeds up the process, or as I have now done, use a peice of stainless angle for the pos electrode. Normally overnight is enough to clean most parts
 
hardtop

Warren said:
Just did a couple of lic. plate holders and small parts and look at the size of the stalagmite of rust. I did not wait to complete the process on the parts that were easy to hit with the 4" Makita sander. The process is slow but can be increased with a higher amp battery charger. Wish I did not sell my big service station style charger that was a good battery boiler. There are a few black specs left on my trans tunnel access plate. The process is complete when it stops bubbling, so stay tuned. The next pic will be of a part that had nothing done to it but a drop in "the science project bath the Mrs, calls it". A set it and forget it mode of rust removal.
Click to expand...

Warren I have cleaned rusted parts that way, it is a slow process.
I,m also restoring a hardtop no rust issues, but I now no why I don't weld much. I purchaced a hardtop project on ebay that was cut out for a sunroof. I have spot welded the new top in and now making repairs. Coming along nicely now. Kevin
 
Danger

The site says using Stainless steel as a anode releases toxic gas, Hexavalene. I have done motorcycle tanks with great results.
Kidz its D.C. no chance of a fatal shocking event.
 
speeding up the process

Hi Warren,
I use a Little elektronic DC converter that blows out 30A, can be found on Epay for LED lightstrips for around $50.
But with this much power you will Need a big surface Elektrode to be able to use it.
I have 2 rotten Hardtops waiting for surgery, should give em a try, geat idea with the kiddy-pool :)
 
Its not just for large items, my fan shroud came up as new. every small part I can fit in the garbage can is cleaned/refurbished. For the the anode I have large pieces of concrete reo steel welded together. works great.
When it becomes time to treat the front end and the rear end, I plan to use the big garbage bin as the container, still have to work out how I suspend the weights, maybe a 4x2 accross the top. :D
 
UK site

I have seen a very nice posting on the UK site, it is really worth a look. I have used coat hangers twisted up into spirals and just throw them away rather then cleaning them.

Vinreeb please post a link to the ebay DC converter. My pal told me stories of a whole car in the Sodium Carbonate solution, but he tells lots of stories.

Here is a couple of photos of the trans tunnel and the inspection door that got the treatment. Some pits remain but its rust free.
 
Results

Here is a picture from a clean gas tank.
My 64 VW bug convertible gas tank no coating but sat dry capped for 20 years.
Prepping car for sale .
Look at the crap that is attracted to the annode .
 

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Great tip - thanks

So for the inside of a gas tank, it seems that one would need only to fill the inside with the solution, and suspend the anode inside the tank?
Leaving the powder coated exterior untouched!

How much current?

Slosh around some Bill Hirsch tank liner and done!
 
10 amp

Exterior paint should be fine. Most every tank is bare steel . I've never bothered with any coating on the inside. There's a pile of online guides from motorcycle tanks tractor parts.
 
How do you know

It's working, see pic. Pardon the CT90 tank pictured cause it's on the mend.
 

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