Author Topic: Clean that rusty gas tank!  (Read 126213 times)

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Offline pinnacle

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Re: Clean that rusty gas tank!
« Reply #100 on: May 16, 2009, 03:49:55 PM »
i am trying the process described and have a couple of questions.1 which way are the probes conected because the first enrty says positive on tank and negative on probe and the article that was mentioned later on says negative on tank and positive on the probe.2 my charger keeps cycling on and off is this normal it has a few settings normal charge /deep cycle,  charge /start,  70 amp start/12 amp charge/2amp and 12 amp for 6 volt.I have put three electrodes in the tub and completly submerged the tank.
1974 cb550, 1978 cb550, 1984 honda shadow vt750

Offline BeSeeingYou

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Re: Clean that rusty gas tank!
« Reply #101 on: May 16, 2009, 07:28:31 PM »
i am trying the process described and have a couple of questions.1 which way are the probes conected because the first enrty says positive on tank and negative on probe and the article that was mentioned later on says negative on tank and positive on the probe.2 my charger keeps cycling on and off is this normal it has a few settings normal charge /deep cycle,  charge /start,  70 amp start/12 amp charge/2amp and 12 amp for 6 volt.I have put three electrodes in the tub and completly submerged the tank.

read from pages 6-7 it's all there.  Negative to the tank positive to the electrode.  Use the 12 or 2 amp charge setting.  The concentration of your solution will determine amperage.  If you are cleaning the inside of the tank there is no reason to submerge it in a tub.  It operates on line of sight so the electrodes need to be inside the tank.

Offline seat cover man

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Re: Clean that rusty gas tank!
« Reply #102 on: May 16, 2009, 10:11:04 PM »
WOW!!!!!!!! this is amazing...just did my tank and saved my self 50 bucks! Thanks!!!!!
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Offline MosquitoJones

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Re: Clean that rusty gas tank!
« Reply #103 on: May 19, 2009, 09:43:31 AM »
I just bought a 65 Superhawk, came with a spare tank.  Both are horrid inside.  I was planning on doing the electrolysis on the tank currently on the bike.  The spare is in better condition, but it has a small hole in the bottom, maybe 1/8" x 1/4".  Is this repairable by welding?  I'm guessing I could probably shove some JBWeld Stik in there and have it hold long enough to electro the tank, but that's not a permanent fix (is it?).
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Offline BeSeeingYou

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Re: Clean that rusty gas tank!
« Reply #104 on: May 20, 2009, 09:40:00 AM »
Just a few thoughts to add to what I have learned after doing several tanks.  It is very hard to make an electrode with enough surface area to do this really efficiently.  The smaller the surface area of the electrode the more often it has to be removed for cleaning so try and make it as large as possible.  Using a coat hanger bent back and forth for one tank required removal about every 15-20 minutes for cleaning.  The flat bar electrode in an earlier post would go about 60 minutes.  Also the corrosion is of two types, the red flaky stuff(ferric oxide) and the black rust underneath this.  The red is loosely attached and non-conductive so it comes of easy but the black is conductive and is harder to remove.  Given enough time (24-48 hours)this will also come off but then the small electrode surface comes into play because of the frequent need for cleaning.  I have usually let the process run for 6-10 hours and then use the shortcut of the acid bath to get any remaining black rust out.  It is somewhat loosened by the process and using a bit of rag tied to the end of a coat hanger I am able to scrub around the inside of the tank with a quart of acid and it comes out fairly easy.  If you have just lite surface corrosion/flash rust I think the acid bath is all that is needed to clean it up the electrolysis being better to use for heavier corrosion.
« Last Edit: May 20, 2009, 10:33:17 AM by srust58 »

Offline BeSeeingYou

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Re: Clean that rusty gas tank!
« Reply #105 on: May 20, 2009, 09:46:58 AM »
I just bought a 65 Superhawk, came with a spare tank.  Both are horrid inside.  I was planning on doing the electrolysis on the tank currently on the bike.  The spare is in better condition, but it has a small hole in the bottom, maybe 1/8" x 1/4".  Is this repairable by welding?  I'm guessing I could probably shove some JBWeld Stik in there and have it hold long enough to electro the tank, but that's not a permanent fix (is it?).

I never thought much of that stuff in the stick form.  I doubt it would work long term but am sure it would be fine for the cleaning process.  But just a piece of duct tape or some other temporary patch may be easier to remove.  However you repair the hole there are probably other weak spots in the tank.  Maybe this tank is a candidate for a tank liner product after you have the hole/holes patched.  I think you are going about this the right way.  Plug that hole temporarily and clean the tank, other leaks may show up.  Then proceed to fix them permanently.
« Last Edit: May 20, 2009, 09:48:36 AM by srust58 »

Offline brett_bike

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Re: Clean that rusty gas tank!
« Reply #106 on: May 21, 2009, 02:44:28 PM »
Ok everyone, I've read this post many times.  I did the electrolysis today and it turned out well, but I can't figure out how to clean the left side of the tank.  My gas cap is offset to the right and the inside of the tank doesn't allow very much room to squeeze a rod over there (ha...squeeze a rod).  Help.

Offline BeSeeingYou

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Re: Clean that rusty gas tank!
« Reply #107 on: May 21, 2009, 03:46:36 PM »
I had the same problem with my XS650 tank.  While I am not proud of this and it ain't pretty it worked and can be bent to conform to the contours of the tank.

Offline Dave-and-his-550

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Re: Clean that rusty gas tank!
« Reply #108 on: May 25, 2009, 06:50:48 PM »
The amperage level is controlled by the amount of washing soda in the water more than the size of the charger.  2-3 amps is the best level to use so you were right on.

I'm trying this method again and I am not having much luck. I have a 10 amp auto/manual charger. I am using 4 gallons of water with half a cup of super washing soda. My electrode is a steel rebarb that is bent in a U shape inside the tank. After about 15 minutes the amperage goes from 4 to under 2...No matter how clean the electrode is. Maybe I should use a new piece of steel? Maybe less washing soda?

I've had this going for 15+ hours over the last two days, cleaned the electrode off about four times, and the rust is gone, BUT like you mentioned in another post, there is this black pitted rust still in the tank.

I might try making a new electrode like the one you had pictured on the other page, the black rust does not seem to come off. I had it running overnite, and in the morning there was NO difference (I got all the brown rust off the first day) but the black stuff was still there.

Do you recommend using some acid to get this black stuff off instead? Or maybe should I fashion a new electrode and use less washing soda?

Last time I tried acid...My tank still rusted. I used acid, rinsed with warm water and detergent, used acetone to get the water out, coated it with marvels mystery oil, then filled it with fuel. It STILL got rusty again after a few weeks...

What kind of advice can you give me now after all the experience you have cleaning the tanks?

Offline BeSeeingYou

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Re: Clean that rusty gas tank!
« Reply #109 on: May 25, 2009, 10:26:17 PM »
Dave
Is it possible that some of the black stuff you are seeing is varnish or some type of deposit from old gas?  I had these black deposits in the bottom perimeter seam of the tank that were like little blobs of charcoal.  Nothing would take it out.  I took a stiff coat hanger bent it straight and put a 90 degree bend in the last 3/4 inch and sharpened the tip like a chisel point and used it to scrape this stuff out of the seam area.  If it is the black rust I have had good luck with CLR and a rag/scrubbing pad tied to a coat hanger to scrub this stuff loose.  I take the hanger and double it back on itself, twist it a few times to lock it together and make a loop in the end to tie the rag to.  The CLR is about $5 for a quart and it is not hard on the hands if you get some on you but rinse it off anyway. It only takes 5 or 10 minutes and it does not seem to be overly aggressive like muratic acid.  I bend the wire scrubber so I can scrub top, bottom, and sides, keeping it all wet throughout the process.  Don't let any surface become dry.  Do a quick rinse with 1/2 gallon of water and then you HAVE to rinse with baking soda and water, just a couple of table spoons in a quart of water, to neutralize the acid.  Shake it all around so all surfaces get rinsed.  Even if you only let the acid sit in the bottom of the tank the fumes will leave an acid deposit on other surfaces and lead to flash rust.  If you did not do this it may be why your tank rusted again.  It has been almost two months now and my tank is still spotless.  It has been sitting nearly empty for a week as I have been to busy to ride. :(   I am also wondering about the rebar.  Is it truly mild steel or is it some type of specialty steel like Corten which I believe develops it's own "oxide" coating to protect it from corrosion?  I thought most rebar was made from this and it may have some effect.
« Last Edit: May 25, 2009, 11:32:30 PM by srust58 »

Offline Dave-and-his-550

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Re: Clean that rusty gas tank!
« Reply #110 on: May 26, 2009, 03:51:59 PM »
Is this what you're talking about?



The black stuff is mostly at the top (By the filler neck I guess) and along the center (Along the inside center curve of the tank) But not so much at the very bottom of the tank. I tried scraping the stuff off at the top with an exacto knife and it didn't come off...

I made a new electrode out of mild, untreated steel and I turned it on just now. I'll let it sit for 4-6 hours and see how it turns out. If it still hasn't removed the #$%*, then I guess I'll try the CLR stuff.

Is ANY of this necessary though, if I decide to use POR15?



The starter kit has marine clean, metal ready, and POR15. But, POR15 ISN'T what goes on the inside of the tank right? I would need their other cycle tank repair kit?


Which has U.S Standard tank sealer, so this cycle kit doesn't even include POR15 as the sealer for the tank, I thought POR15 WAS the sealer u use in ur tank  ???

Offline BeSeeingYou

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Re: Clean that rusty gas tank!
« Reply #111 on: May 26, 2009, 05:52:39 PM »
The CLR I use comes in a bottle like this.  The stuff in the squirt bottle may be a diluted version.  I suppose if you are going to line the tank this process may not be necessary but I have also heard that the metal prep in these kits does not do a real good job on getting the corrosion out.  And then some say the liner sticks better to a surface with some corrosion on it.  I am skeptical about that but then again I don't buy into the whole tank liner thing.  I have not used them so I can't really advise you about them.  The stuff in the cans is the sealer the others being the degreaser and the metal etcher which would be some form of mild acid.

Offline Dave-and-his-550

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Re: Clean that rusty gas tank!
« Reply #112 on: May 26, 2009, 08:56:57 PM »
Well I'm really losing my patience now! I made a new electrode, filled up my tank with 4 gallons of water, a cup of washing soda, let it sit for 5 hours and the tank still isn't lookin better, but look at all the gunk on my electrode! Here are some pics:







So what do you think of that black stuff that aint comin off? I still got a gallon of muriatic acid, and I'm thinking of diluting it down and just using that tomorrow instead.

You have to neutralize any acid product with a baking soda and water rinse or it will flash rust faster than you can dry it.  I still prefer the electrolysis method for severe corrosion as it is less destructive to good metal than acid.

Last year when I used The Works, I used warm water and powdered laundry detergent to neutralize the acid, then I dried it out with compressed air, coated it with oil, filled with fuel and it rusted again. So was the detergent wrong? Did I not rinse it out long enough and let it sit with the detergent? You recommend using Baking Soda, so NOT Super Washing Soda to neutralize?

Sorry if I'm making you repeat yourself lol, I'm just at odds here  :-\

One thing I should mention, I'm doing this again over night because its wet out, and I don't want it to rust as it sits...SO this time I used two cups (16 oz) of washing soda to the four gallons, and when I turned it on, it jumped up to 10 amps opposed to 4 last time when I started. Hopefully the added amperage should remove it.
« Last Edit: May 26, 2009, 09:36:02 PM by Dave-and-his-550 »

Offline BeSeeingYou

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Re: Clean that rusty gas tank!
« Reply #113 on: May 26, 2009, 10:06:30 PM »
The washing soda is only used to make the water more conductive.  It has no cleaning purpose and will not neutralize the acid regardless of how much you rinse it.  That's the job of the baking soda rinse.   The black residue does not look like the typical black rust that I have seen in my tanks that is somewhat soft and easy to scrub off after that much treatment.  Could it be the remnants of some type of coating or rust converter that was applied at one time?  I guess the acid will tell as if it is black rust it will come off.  Muratic acid will flash rust extremely quickly so do the rinse ASAP and like I said before make sure you rinse all surfaces even if they had no contact with the acid.  I tried some muratic acid on one tank and it does work fast but that's I when I learned about the fumes leaving a residue.  I only had the acid covering the bottom of the tank and then only rinsed the bottom.  By the time I had the tank dry the top and sides where brown with flash rust.  I used a quick swab with CLR and then a proper rinse and it cleaned right up.

Offline Dave-and-his-550

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Re: Clean that rusty gas tank!
« Reply #114 on: May 28, 2009, 12:53:34 PM »
I think I'll try the CLR instead and just give up on the other method. I'm having my tank bead blasted and once I get that back I'll finish up on the inside. Once that's done, I'll have my tank painted grey metallic. Getting rid of the faded orange finally! Yay!

Offline Dave-and-his-550

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Re: Clean that rusty gas tank!
« Reply #115 on: June 09, 2009, 11:40:34 AM »
Quick question, when trying to neutralize the acid, wouldn't it be a good idea to use alkaline water rather then neutral/slightly acidic tap water mixed with the baking soda?
« Last Edit: June 09, 2009, 11:42:58 AM by Dave-and-his-550 »

Offline razor02097

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Re: Clean that rusty gas tank!
« Reply #116 on: June 09, 2009, 11:56:05 AM »
Tap water is closer to neutral.  Besides you don't want to go the opposite extreme bases will eat metal as fast as acid will.
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Offline Dave-and-his-550

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Re: Clean that rusty gas tank!
« Reply #117 on: June 09, 2009, 05:02:32 PM »
well the CLR worked ok. I still have small black pits, and streaks of black going down the sides. When I look close at my tank on the inside, it is very pitted. And when I touch it, it is very rough. I think I've tried cleaning it one to many times.

I used simple green to hopefully neutralize any fuel that was left in there. I'll rinse that out and try this electrolysis method one more time.

Offline BeSeeingYou

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Re: Clean that rusty gas tank!
« Reply #118 on: June 09, 2009, 08:36:39 PM »
The electrolysis should not hurt the tank so that pitting must be from corrosion.  That black stuff should be somewhat loosened and could be scrubbed off with the coat hanger and rag/scrub pad device.  The stuff in the pits may be a bit tougher to get at depending on how deep they are.

Offline Frankencake

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Re: Clean that rusty gas tank!
« Reply #119 on: June 09, 2009, 09:15:57 PM »
It is my understanding that the black left behind after washing soda is iron phosphate; like parkerizing on a gun.  I tried the electrolysis method this weekend and I love it.  I have a few more tanks to do and I can't wait.
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Offline Dave-and-his-550

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Re: Clean that rusty gas tank!
« Reply #120 on: June 11, 2009, 04:49:23 PM »
Well thats that. I went ahead and used a bottle of The Works again. Tank is perfectly clean of rust. I washed it out with two gallons of water + cup of baking soda. And I think I might wash it out again with another gallon & baking soda.

What should I do after that? Air dry it? Get out as much water as I can and maybe put in a cup of engine oil? Marvels mystery oil? WD40?

It's going to get painted so I don't wanna fill it up with gas.

Help! I don't want it flash rusting again like last time!!


Offline razor02097

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Re: Clean that rusty gas tank!
« Reply #121 on: June 14, 2009, 06:32:05 PM »
I've heard of guys filling paint cans with argon or an inert gas then sealing it so the paint doesn't dry, you could do that..... or you could just use WD-40 its cheaper  :P
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Chippy569

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Re: Clean that rusty gas tank!
« Reply #122 on: June 16, 2009, 11:20:24 PM »
noob question time, how does one go about blocking the petcock/sending unit holes? (photos greatly appreciated!)

Offline razor02097

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Re: Clean that rusty gas tank!
« Reply #123 on: June 17, 2009, 04:24:03 AM »
noob question time, how does one go about blocking the petcock/sending unit holes? (photos greatly appreciated!)

be creative man   ;D

Since you aren't using a caustic nasty chemical here you can let your imagination take over...old fuel valve, pipe cap, foil n' tape, rubber stopper, bottle cap n' tape... I'm sure there are another hundred ways
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Chippy569

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Re: Clean that rusty gas tank!
« Reply #124 on: June 17, 2009, 11:27:22 AM »
... i think i'm a little bit more noob than you assume I am, lol. Do I need to remove the petcock from the tank? and if so, how do I go about that?

I got the little ball part off the bottom and it was very gummed up, but I'm not sure how to remove the rest.