Tech: How to salvage your original, rusty gas tank

How to salvage your original, rusty gas tank<o>

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The Scenario: You just dragged home your beauty of a barn find. For the past few hours you&#8217;ve been trouble-shooting your fuel starvation problem. It leads you all the way back to the fuel pick up tube/gas tank. You open it up and pull out your pick up tube. The thing you&#8217;re staring at looks like an ancient, rusty artifact you just uncovered from the Titanic. Where do you go from here? You don&#8217;t want to pay a shop $100 so they can spend a week cleaning your gas tank do you? You want that sweet ride on the road!<o></o>

This job doesn&#8217;t take long or break the bank. You just need $10 and a few hours of time.<o></o>

Supplies:<o></o>
<!--[if !supportLists]-->-<!--[endif]-->Go to your local hardware/pool supply store and get a few gallons of Muriatic Acid<o></o>
<!--[if !supportLists]-->-<!--[endif]-->Baking soda powder<o></o>
<!--[if !supportLists]-->-<!--[endif]-->Rubber gloves<o></o>

Safety and disposal:<o>
</o> <!--[if !supportLists]-->-<!--[endif]-->Be real careful with Muriatic Acid. Wear gloves because it will burn your skin, don&#8217;t breath in the vapors and make sure non splashes into your eyes (you may even want to wear glasses when you pour the acid into the tank)<o></o>
<!--[if !supportLists]-->-<!--[endif]-->Baking soda will neutralize the acid. You could also just take the acid down to a hazardous materials drop off.

First, you&#8217;re going to have to drop your tank and take off any sending units, pick up tubes or filler tubes. Once you&#8217;ve dropped your tank take it over to your yard or gravel driveway; somewhere that you can dump a lot of water.<o></o>

For this next step I used a pressure washer but a garden hose with a high pressure nozzle will work as well. Get in that tank with your hose/pressure washer and blast as much of the scale/grime out of the tank as you can. You&#8217;ll probably have to alternate between blasting then dumping the water/debris out. As you&#8217;ll soon find out there is only so much rust you&#8217;re able to get out of the tank with the hose. It is hard to get at every corner of the tank and you&#8217;re still going to have rust left. Here is where the acid comes into play.

This is a picture of some of the rust that was left after blasting (much of the tank looked like this):


Heres the acid that I ended up buying:


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Pour the acid into the tank. The concentration is up to you. I just used it straight out of the container without diluting the acid. Any concentration will work, it will just take longer the more you dilute your solution.

I poured in a gallon of the Muriatic Acid at 15% concentration (as it came in the container). I sloshed the tank back and forth and I rotated the tank every so often to make sure that I was getting every inch of the tank. If you look inside the tank at this point you&#8217;re going to see flakes of rust and other sediment starting to come off.

Once you&#8217;ve done a thorough job of sloshing the acid around in the tank (I spent around 30 minutes sloshing the acid around) pour the acid out of the tank (you can use baking soda powder to neutralize the acid). Then give it another thorough run through with the pressure washer followed by a rinse with the garden hose to make sure all the sediment was out of the tank. Try to dump out as much of the water as you can. You should now have a nice clean gas tank.

Here is that same spot that I showed above after the acid:

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Finally, lay the tank down in your garage overnight with a fan blowing into the openings of the tank. I used a small computer fan and laid it on top of one of the openings. By morning you should have a nice, dry gas tank. As I found you may get some "flash" rust, caused by air drying wet steel. This a extremely thin layer of rust. I would then seal the tank with a Por 15 product or some other tank sealant.

Heres my fan set up for drying the tank:



I hope this will be useful for someone in the same situation. Let me know what you think and ask any questions you may have.

- Scott

 

I'll be doing this, this weekend. I'll post up some before and after pics.

Thanks for the write up Scott.

 

I've been considering this for my Model A tank. Except I was going to use phosphoric acid. I think it is less aggressive over the long term.

I wonder if there is a need to neutralize the tank surface to stop the acid from eating clean through. Where's a chemist when you need one???

 

haha a computer fan, great idea!!

 

CJ Steak - Nice man. I'm glad my article was helpful. Be sure to post those before after pics. You won't be disappointed.

Wildfire - The acid is MUCH more reactive to rust. The acid come in a plastic container, I don't think its too aggressive. So I wouldn't be worried about using the Muriatic acid (which is dirt cheap) but if you use the Phosphoric acid post up here and tell use how well it worked.

Another thing I forgot to add is don't be worried if it doesn't seem to be working. I was expecting it to fizz are at least show physically that it was doing something. It doesn't fizz or boil or anything...the rust just starts coming off.

 

I have used that in the past also, but on the realy bad ones I add a length of chain and slosh it around to get in the corners. If you dont seal it now you will be doing it again in the near future, how do I know !!!

 

What do you do with the acid when you take it out of the tank?

 

I believe the proper procedure is to pour it down the storm drain at the end of the block.

...or put it in your pump-up sprayer and take care of that neighbor's tree that constantly dumps leaves and berries and other crap in your yuard all year long.

...or clean up your chain-link fence.

...or clean up your driveway where all those old cars have left those interesting black/brown/orange/ and whatever stains all these years.

 

LOL! ~

 

When I cleaned out an old tank I dumped a few handfuls of bluestone gravel and half a gallon of kero into it and sloshed it around until the gravel chewed out all the rust and the kero dissolved the orange crud that had once been petrol.

Cheers, Glen.

 

Well technically you should either neutralize it with the baking soda or pour it into a container and take it to a hazardous materials drop off.

 

I did that procedure with two tanks. Unfortunately I found that the tanks were originally plated, and with the plating gone, the tanks would rust within days of being filled with gas.
Then I went to Gas-Tank-Renu.
Cosmo

 

Hmm... I might have to try this sometime.

 

Better yet is to fill your tank with hot water and use powdered Draino and some gravel or old bolts, then roll it around for 15 minutes or so. Then you can just pour it down the drain. Cleans your tank and your drains as well

 

I only have two things to add to this thread. First of all, Muriatic acid will disolve galvinization from a gas tank, or anything else. Secondly, the fumes are extremely volitile; NO NOT SMOKE WHILE DOING THIS, you may blow yourself up. Butch/56sedandelivery.

 

And the fan could spark an explosion............plus most of those sealers are CRAP with modern, blended fuels. Only to get worse.

 

You can rinse it out with regular old rubbing alcohol - it will remove most of the water as well & dry much quicker.

I wouldn't use any of the tank sealers. I'd just do another rinse with phosphoric acid alone. Then another rinse with alcohol. Done.

Phosphoric acid is much less aggressive, but will work. You're best to rinse it thoroughly, drain excess, then dry. I'd follow up with an alcohol rinse.

Yep - the baking soda will neutralize most of it. I'd still be leery of just dumping it though...

True, true, true! I don't have any faith in any sealers. I've seen everything begin to peel over time. I prefer the muriatic acid, neutralize, alcohol rinse, dry, phosphoric acid, drain/dry, alcohol rinse. Works every time - even on new tanks I'll do the phosphoric acid rinse, alcohol rinse..

 

I had an interesting problem while doing the original tank in my '54 Buick. There were some baffles in it. I did the acid, and pulled out wads of the shellac that were the approximate size of dead squirrels. Big dead squirrels. Once the crud was out, I did one of those at-home gas tank sealant kits because the tank had some pinholes.

Turned out the acid weakened the spot welds that held the baffles in place. They eventually fell over, and then every time I went around a corner, came to a stop, or started quickly, the metal baffles would slosh around the tank, digging up ribbons of that sealant as they scraped across the floor of the tank. It was miserable--thin strips of sealant in the lines and plugging the filter.

Never again. Next one gets sent out to a professional.

Also, use it in a VERY well ventilated area, with a fan blowing across you. I did it outside in front of my garage, and I still breathed in too many acid fumes. Didn't feel good for a few days.

It also wrecked a pair of jeans, and it dissolved the little metal fingers on my Craftsman mechanic's grabbers.

-Brad

 

In theory, you should only use just enough acid to fully coat the inside of the tank for the acid to do its job. You should not put enough acid in the tank to worry about disposable. Of course, in practicality that perfect amount is impossible to acheive, but you should have very minimal overage. Use sparingly!

 

You should always pour acid into water not water into acid. About 10% to 20% (swimming pool acid) acid to water. I mix it in a 5 gallon plastic bucket. Then into tank. Good to take rust off old blocks. You MUST neutralize the acid with baking soda or vinegar or it will keep eating away at the metal .
John

 

I don't think vinegar will neutralize acid...it being an acid itself...