Topic: Clean that rusty gas tank!

[BeSeeingYou]

I'm planning on using the salt water method followed by an ATF coat this weekend on my CB350F tank, I hope it works, but the tank has some bad rust along the bottom.  Gonna cross my fingers and see what I can do.

The amount of salt in the water will have a bearing on the amperage level.  Try about 1 tablespoon per gallon to start.  It may be best to keep the level somewhere in the 2-5 amp range.  It could take several hours and you may find that you will have to pull the electrode every hour or so to clean it off. 

[Sparked]

I'm planning on using the salt water method followed by an ATF coat this weekend on my CB350F tank, I hope it works, but the tank has some bad rust along the bottom.  Gonna cross my fingers and see what I can do.

The amount of salt in the water will have a bearing on the amperage level.  Try about 1 tablespoon per gallon to start.  It may be best to keep the level somewhere in the 2-5 amp range.  It could take several hours and you may find that you will have to pull the electrode every hour or so to clean it off. 

Ok, I have my tank full of water with about 15-20 ounces of salt in it. set the battery charger to the manual 10 amp setting and nothing happened.  Negitive is connected to the tank, and Positive to my 1/2" steel rod.  Nothing is happening, so am I missing something??

[Sparked]

OK I got it working, ended up putting a deep cycle battery inbetween the charger and the tank, it's pulling 7 amps and the tank is making lots and lots of green bubbles.

[BeSeeingYou]

It will bubble less with a lower amperage and take a little longer.  I think what is happening is that when the current is too high it breaks down the water into it's components and it is the hydrogen that is causing the excess bubbles.  Your electrode may also be eaten up at a faster rate so keep an eye on it.  Remember it's line of sight so if you have the rod on one side you may have to put it on the other side to get that area.  When I did mine I made an electrode that went down each side and had one leg running down the center ridge of the tank.  It was three separate pieces that had cork feet and screwed together at the ends that stuck out of the tank.  When you are done rinsing out the tank try doing a rinse with denatured alcohol to get the rest of the water out. Let us know how it goes.

[Sparked]

7 amps was the lowest I could get it to work, maybe I had too much salt in the mix.   Anyways it cleaned up really really well, and there was only a minor amount of flash rust inside.  I've coated it with ATF and so far so good.  & amps was defiantly too much though, I had it in for 3 hours, moving the electrode around a few times to get both sides.  It really ate up the electrode though. Here is what the 1/2" steel rod looked like when all done. (The 1/2 wide parts of the rod is where I had wrapped electrical tape to keep it from contacting the inside of the tank)

[David]

How does this method compare to using Kreem or POR-15?

[BeSeeingYou]

Less destructive as the electrolysis only affects the corrosion.  The acid cleaning method will take a small bit of good metal as well as the corrosion.

[BeSeeingYou]

When using an acid to clean the tank rinse with a mixture of baking soda and water to neutralize the acid.  Get as much water out then rinse with alcohol. This will help keep the flash rust to a minimum.  I tried the electrolysis method with salt on another tank and it flash rusted much more than using sodium carbonate.  I ended up using a diluted mixture of CLR to clean out the flash rust and after the baking soda rinse no problem.

[leekellerking]

When using an acid to clean the tank rinse with a mixture of baking soda and water to neutralize the acid.  Get as much water out then rinse with alcohol. This will help keep the flash rust to a minimum.  I tried the electrolysis method with salt on another tank and it flash rusted much more than using sodium carbonate.  I ended up using a diluted mixture of CLR to clean out the flash rust and after the baking soda rinse no problem.

Two questions:

1. Has anyone used CLR to strip their tank (including stripping out the old Kreem liner that is coming apart); and
2. What type of alcohol would you use?

I was going to use POR-15 to do my tank but a buddy is using CLR on his renovation and I thought I'd try that first.

Okay, make than three questions:

3. If I use ATF for the "lining" (I can't want 96 hours for the POR-15 type stuff to cure), how do I do it?

Thanks,

Lee

[BeSeeingYou]

I have not had to strip a tank liner.  Do a search on gas tank liner and you will see mixed results using MEK, The Works, or acetone.  A product called aircraft stripper seems to work well.  I think CLR is similar to The Works, a toilet bowl cleaner.

If there is heavy corrosion in the tank I like the electrolysis method as it does not affect the good metal.  For light corrosion or flash rust CLR or something similar works well and it does not have to remain in the tank long enough to damage the good metal.  I just used a quart and sloshed it around the tank for ten minutes.  The time will depend on how bad the corrosion is.

I used denatured alcohol.

The tranny fluid is just a temporary coating to prevent corrosion if you will not be using the tank for awhile.  I just put in a cupful and slosh it around to get the whole tank coated.

[leekellerking]

No heavy corrosion, but the old Kreem liner is starting to come off the walls of the tank. I'm afraid that if I leave it there it will eventually come off and clog my tank.

Of course, I'd rather ride that work on the bike so it may take me a few weeks to get to it.   

It will also give me an opportunity to measure the tank bung so I can figure out what petcocks will fit my tank.

POR=15 makes a stripper for about $11.00 a quart, but I'm looking for something I don't have to mail order.  And that does not have quite as scarey an MSDS. 

http://www.actiocms.com/MsdsDisplaycode_adm_australian.cfm?msds_id=613693&dbname=actioauthor1&Language=1&CFID=1016238&CFTOKEN=62733302

Then, sometime in the future, I may do the POR-15 clean, prep and seal thing (when I have an extra 96 hours for the tank to cure).


Lee

I have not had to strip a tank liner.  Do a search on gas tank liner and you will see mixed results using MEK, The Works, or acetone.  A product called aircraft stripper seems to work well.  I think CLR is similar to The Works, a toilet bowl cleaner.

If there is heavy corrosion in the tank I like the electrolysis method as it does not affect the good metal.  For light corrosion or flash rust CLR or something similar works well and it does not have to remain in the tank long enough to damage the good metal.  I just used a quart and sloshed it around the tank for ten minutes.  The time will depend on how bad the corrosion is.

I used denatured alcohol.

The tranny fluid is just a temporary coating to prevent corrosion if you will not be using the tank for awhile.  I just put in a cupful and slosh it around to get the whole tank coated.

[OldSkool]

Used this electrolysis method today with amazing results. Unfortunately I was unable to document the process but my tank had a fair amount of light surface rust after sitting in storage for almost 30 years. I used 1/3 cup of Arm & Hammer washing soda and a 10 amp charger. Went to the local hardware store and purchased a 3' steel rod (Non coated or stainless). Fashioned a wood fixture to hold the sacrificial anodes (I cut the 1/8" steel bar in two pieces and then folded one end on each a couple of times) hooked everything up and right away started to see bubbles coming up to the tank filler hole. Two and a half hours later there was a significant amount of gunk in the filler hole. I disconnected everything, emptied the tank and 90% of the rust was gone. As soon as I flushed the tank out the remaining 10% of surface corrosion just came right off and left the tank looking brand new. I was going to use a POR-15 kit I purchased but have decided to just coat the tank with some ATF fluid and leave it be since it looks so pristine. (If anyone is interested in the POR15 kit I'd be willing to sell it)

A couple of notes: The gauge on the charger never went above 2amps even though I am 100% sure it is working correctly. I was going to plug the holes for the petcock but couldn't find anything small enough to plug them. I wound up using a piece of duct tape over the petcock area and it held the whole time without leaking a single drop. (I did clean the area with a brake cleaner soaked paper towel prior to adhering the tape)


This was a pretty cool process although I am sure some of my neighbors wondered why there was a motorcycle gas tank in my driveway with some wires coming out of it. Given the neighborhood watch that takes place here I'm really surprised I didn't wind up with the bomb squad on my front lawn.

Thanks to the OP (Even though the procedure is listed backwards and the positive lead should be hooked to the sacrificial anode and the negative lead should be connected to the tank)

[BeSeeingYou]

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.

[jhelly]

Hi,I have a 76 cb750f ss it sat for 19 years, in a garage the tank looks perfect outside but was really bad looking in the cap hole, I was going to use the kreem method but I have read some bad results. When I read your post I ran out to home depot and bought a 3/8 piece og rolled steel and put it to the test. My tank has piping in the cap hole so i flipped it over and put the bar in the petcock hole using duct tape at the bottem of the bar and the area whereit would contact the petcock hole, I was unable to see any gas rising from the hole, I did remove the bar twice in 3 hours but there was nothing on the bar,I then drained the tank and what came out was all black. I have flushed the tank and letting it dry overnight tomorrow I will coat it with tranny fluid and see how it looks.

[jhelly]

I tried this today on my 76cb750ss. this tank has internal piping so i went in thru the petcock hole using full container 26oz salt in 4 gals water, I connected the pos clamp to tank and the neg clamp to rod,the battery charger showed about 9 amp, I pulled rod 2x in three hours and did not see anything on the rod,when i emptied the tank the solution was black, I flushed the tank several times until the water was clear. is the polarity correct.other posts mention gases and bubbling which i did not experience.

[BeSeeingYou]

I tried this today on my 76cb750ss. this tank has internal piping so i went in thru the petcock hole using full container 26oz salt in 4 gals water, I connected the pos clamp to tank and the neg clamp to rod,the battery charger showed about 9 amp, I pulled rod 2x in three hours and did not see anything on the rod,when i emptied the tank the solution was black, I flushed the tank several times until the water was clear. is the polarity correct.other posts mention gases and bubbling which i did not experience.

The initial post is wrong.  Negative to the tank, positive to the metal rod is the correct way.  That is to much salt also.  It will lead to too  high an amperage, excessive gassing, and will eat up the electrode quickly.  Washing soda works as well and does not flash rust as bad as salt.  I used a product called Oxo Brite.  If using washing soda I found it best to let the mixture sit overnight before using to let the suds dissipate though it is not necessary.  Going thru the petcock hole will only clean one side as it operates on line of sight.  You also need to use a degreaser on the tank to remove any varnish from the old gas as the electrolysis will not remove this.  Some use Simple Green for this, I used Zep Industrial Purple.  I have the same tank and here is a picture of the electrode I made.  It is three separate pieces with four cork feet to keep it from contacting the tank.  The two feet on the long center piece sit on the hump running down the centerline of the tank.   Not shown is a small pvc collar cut from a piece of 1 inch pipe that sits under the c clamp to insulate it from contact at the gass hole. You can also see some blue and purple electrical tape at the bend for insulation.  It slips into the tank in pieces and then the c clamp holds it all together.  Probably a little overkill, others have just used a rod and moved it from side to side.  I followed this with a quick three to four minute bath of a quart of diluted CLR sloshed around to get any last little bit of corrosion/flash rust.  The petcock spigot makes a good place to clamp on the negative lead from the charger.  I don't know what to say about tank liners.  It seems for everyone that has good luck there is another where it fails.  If the tank is solid after cleaning I see no reason to use one, after all they were uncoated from the factory.  If the tank is weakened by severe corrosion than you may have to use one.

You can also take an easier route and use The Works toilet bowl cleaner.  I have not used this but others report good luck with it.  I have used CLR, a similar product with good results for light corrosion/flash rust.  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.

[David]

SRust58, very interesting.  What did you use for the electrode?

David

[BeSeeingYou]

It is a piece of 3 foot steel flat bar 1/2 x1/8 that I cut into three pieces.

[brett_bike]

Anyone heard of this stuff.  http://ridrust.com/  Seems too good to be true.

[MCRider]

Anyone heard of this stuff.  http://ridrust.com/  Seems too good to be true.

Its just another brand name for the same stuff marketed many ways. There is the non-acidic and there is the acidic, primarily phosphoric acid.

Both do pretty much what they say they will. Each has plusses and minusses. Eastwood,
http://www.eastwoodco.com/jump.jsp?itemType=CATEGORY&itemID=380
even Yamaha has a branded product for rust removal. Just do a Google on rust removers and you'll be flooded. Same stuffs, different names mostly.

Electrolysis is becoming very popular though. It leads the findings when you google Rust Remover. Hard to do on a car body or iron fence.

[Magpie]

If you have patience, Molasses will work, diluted about 1 part to 3 parts water. I've done this some time ago, filled the tank and let it sit, checking it daily. It seemed to take a week or 10 days, easy to clean, easy to get rid of, biodegradable, smells good. I bought it at a local grocery store. The stuff for horses is much stronger but smells like very ripe chicken s**t apparently.
Cheers,
Cliff.

[leekellerking]

If you have patience, Molasses will work, diluted about 1 part to 3 parts water. I've done this some time ago, filled the tank and let it sit, checking it daily. It seemed to take a week or 10 days, easy to clean, easy to get rid of, biodegradable, smells good. I bought it at a local grocery store. The stuff for horses is much stronger but smells like very ripe chicken s**t apparently.
Cheers,
Cliff.

Sweet!   


Lee
(Sorry, couldn't resist)

[Magpie]

Too easy!

[camelman]

Okay, this might be a stretch, but here's my plan.  Please chime in if you have any helpful advice.

I have an old 350F tank that is in perfect condition, except for light internal rust, and light external rust where the sun has baked the paint away.  I want to remove all of the rust and put on a coating of copper.  I then plan to clear coat over the copper.  My steps are:

1) prepare salt solution and remove rust from internal and external surfaces of tank,
2) remove electrodes,
3) quickly (so as not to accumulate flash rust) place tank in new container of copper sulfate for copper plating and attach power leads accordingly,
4) move electrode around the tank to ensure complete coverage,
5) remove from solution, dry, and clear coat immediately.

I want to do this because of the pattern of paint remaining on the surface of the tank.  It is a red tank, but only in places.  Much of the top of the tank is only speckled with white primer and the red paint just slowly fades in the further down the tank you go.  I am hoping the copper deposits between the good paint/primer for a multi-colored fade.  Also, the decals are still on the bike, so I am hoping the existing paint underneath will remain to provide a red paint "decal" when I am done.

Any advice/suggestions will be appreciated... unless you are my father... mother... brother... sister... or girlfriend.  ;-)

Thanks,
Camelman

[BeSeeingYou]

Okay, this might be a stretch, but here's my plan.  Please chime in if you have any helpful advice.

I have an old 350F tank that is in perfect condition, except for light internal rust, and light external rust where the sun has baked the paint away.  I want to remove all of the rust and put on a coating of copper.  I then plan to clear coat over the copper.  My steps are:

1) prepare salt solution and remove rust from internal and external surfaces of tank,
2) remove electrodes,
3) quickly (so as not to accumulate flash rust) place tank in new container of copper sulfate for copper plating and attach power leads accordingly,
4) move electrode around the tank to ensure complete coverage,
5) remove from solution, dry, and clear coat immediately.

I want to do this because of the pattern of paint remaining on the surface of the tank.  It is a red tank, but only in places.  Much of the top of the tank is only speckled with white primer and the red paint just slowly fades in the further down the tank you go.  I am hoping the copper deposits between the good paint/primer for a multi-colored fade.  Also, the decals are still on the bike, so I am hoping the existing paint underneath will remain to provide a red paint "decal" when I am done.

Any advice/suggestions will be appreciated... unless you are my father... mother... brother... sister... or girlfriend.  ;-)

Thanks,
Camelman

I don't think this will work.  Real copper plating is a much more exacting process especially internally.  Just immersing the tank in a copper sulfate solution gives the illusion of a copper coating but it can be it can be easily scratched off and I am unsure of the longevity of it.  So it is easy to be fooled and think you really have something.  I mean it even looks good but...

I have no idea how it would react on a painted surface.