Topic: Gas tank rust - opinions & testimonials needed

[Jay B]

I use The Works toilet bowl cleaner. Hydrogen chloride is the active ingrediant. Dump a $2 bottle in there and swish the tank around every few minutes for a half hour or so. I rinse with water a couple times, dry with compressed air, rinse again a couple times with gas, then dump about 1/2 qt of oil in the tank and turn it every which way to coat the inside to keep it from rusting till use. Works like a charm for very few $$$.

[Gin Rickey]

I've got a little bit of rust in the tank (enough you can feel with your finger tips) and I'm giving the phosphoric acid a go this afternoon.  Put an old petcock in to cover those holes, and plan on using a 2 mil. thick rubber sheet and hose clamp to cover the gas cap opening.  Keep your fingers crossed!

[pyro139]

my tank set up to electrolisys set up as i type, question will this also get rid of the laquar build up or will i need treat with a acid for that?

[Rhonda750F]

All this talk about rusty tanks has me worried.  I didn't think I had rust because when I looked down the hole, I only saw the channel where the frame sit under and it looks new.  The other day I too a real close look with a flashlight and I seem to have a uniform amount of surface rust that covers 1/3- 1/4 the bottom of the tank.  but it looks smooth. No flakes or chunks floating.  I normally run a inline filter, so should I be taking action or use as is
Thanks,
Paul Z.

[pyro139]

some one mentioned phospheic based toilet bowl cleaner would you use strait and coat tank? or dilute i have access to industrial grade stuff
and some one else said hydracloric, would this also work if used a hydracloric bowl sleaner and same question coat or dilute?

[pyro139]

my tank has very little rust the half inch of varnish build up has protected tank so electrolosyse aint realy helping much so may scoff a bottle acid at work tonight and try that, ill grab a hydrocloride and a phospheric just incase
btw industrial stainless steel polish helps remove surface rust from chrome

[Jonesy]

I just treated a tank with a couple pinholes using POR-15. I'll let you know how it turns out.

[smashedmelon]

I used a product called "Rusteco" because I was worried about the original paint on my tank being damaged. Its an eco-friendly product that actually worked. They told me I should buy 4 gallons of the stuff but instead I bought one (its expensive). I just kept shaking the tank and turning it upside down over a bucket and on its sides for three days. Came nice and clean. I didnt feel comfortable using a liner that may flake and didnt want to risk acid creating pinholes in my tank either. I guess I will just keep the tank topped off and that should keep the rust from re-forming.
Rusteco can be re-used and has a shelf life of 5 years, safe on paint, chrome etc. I dunked the rusty petcock screws and they came out spotless, and I'm sure there will be more uses for it as I slowly get my bike back into mint shape.

cheers

[paxtonpony]

The good and bad on molassess, because I've tried it twice and gotten completely different results.

The good: on a tank with light rust scale and no gas/varnish buildup it works great.  My Suzuki tank looked brand new when I got done with it.

The bad: my 750F tank had some varnish buildup, a ton of rust and some pinholes (discovered after sandblasting yesterday.  Didn't work at all on this tank.  In fact, I'd almost say it looks worse than before I started.  My next step is POR-15, it's got a few steps to it, hopefully they fix the problem.

[Master Ted]

Anubis Cycle goes straight to the hard stuff... Muratic Acid!

http://www.anubiscycle.com/gas-tank-cleaning.htm

I've been reading many boards/forums other than SOHC on Por-15 vrs. Kreem and the margin seems t/b about 3 to 1 in favor of Por-15.

[Gin Rickey]

One quart of phosphoric acid added to warm water and agitated for about 2 hours worked great.  I did it yesterday and I was very successful.  I followed up with the acteone wash and WD40 as suggested, and things look just fine (still a very fine film of rust that rubs to shiny metal with a finger rub).  I'm using a citrus-based biodegradeable paint stripper to take the (latex?) paint off the outside...with a little steel wool, today.  I'll let you know how things turn out.  Anyway, the phosphoric acid worked.

[Bodi]

Just personal opinions:
Mr. Honda left the tank inside bare steel. You have a 30 year old tank with some mild rust? Cleaning off the rust down to clean steel should be good for another few decades. A coating is not really needed. Note that current gasoline with ethanol added will absorb some water and you shouldn't get pooled water causing bottom rusting any more.
Coatings can and do degrade even if perfectly applied - maybe new gasoline formulas are to blame, I don't know. Kreem in particular has a bad reputation for failing. You must be super careful following the instructions and the most difficult part is getting the tank inside absolutely dry without letting much flash rust form.
If you have really bad flakey rust on the bottom the "good" steel is probably very thin. If you have pinholes then it's definitely very thin! Such a tank should be coated.
You can get phosphoric acid at hardware stores, it's sold as concrete etching solution to be used before applying epoxy floor paint. I've used Behr on concrete and for rust removal. Phosphoric acid leaves a black surface that doesn't flash rust as easily as the shiny metal you get with some cleaners.
DO NOT have a petcock in the tank with any acid cleaner, the aluminum alloy will disappear faster than you would imagine. Get a rubber stopper! Phosphoric acid is hardly nice to paint but it doesn't eat it away quickly, pour the acid in carefully with a funnel then rinse the outside off with plain water to get rid of any drips or splashes and it will be fine. Rust is pretty much dissolved, there's some grit in the used acid but not much. It doesn't attack good steel very quickly, I've left rusty bolts in it for days and they just come out rustless and black. I think leaving the acid in overnight would be safe.
Phosphoric acid is relatively safe, it will eat your clothes if not rinsed out but it's not like movies where your flesh smokes and dissolves if you touch it. Rubber gloves and goggles are recommended and have a garden hose at hand to flush off any spills. You can pour the "finished" acid down a drain and then flush it through with lots of water without damaging your plumbing.
Coca-cola and most soft drinks get their sharp taste from phosphoric acid by the way. Check the ingredients
If I had a tank with pinholes or severe bottom rust I would use POR-15, I've heard about enough Kreem troubles. I scrapped a CB350 twin tank because the Kreem coating was rotten, if it was a rarer tank I would have attempted to save it somehow.

[cafehonda]

Eastwood sells a product called oxysolve. It is reusable. I used thier tank coat kit and have had excellent results. Eastwood is an excellent source for all auto/bike restoration products.

[pyro139]

One quart of phosphoric acid added to warm water and agitated for about 2 hours worked great.  I did it yesterday and I was very successful.  I followed up with the acteone wash and WD40 as suggested, and things look just fine (still a very fine film of rust that rubs to shiny metal with a finger rub).  I'm using a citrus-based biodegradeable paint stripper to take the (latex?) paint off the outside...with a little steel wool, today.  I'll let you know how things turn out.  Anyway, the phosphoric acid worked.

how much water? i just diluted 1litre phospheric in entire tank of water, looks like going take alot more than 2 hours? i use to much water?

[Soos]

I used Kreem kit over the winter on mine.

For the phos. acid, i put it in my tank, topper her off with water, and let sit for about 36 hours.
Poured that solution into a 5 gal bucket, and rinsed with ... i think the kit had Metheyl Etheyl Keytone(SP.?) for the dryer.

Coated the tank in about 4 applications, a little at a time, and have a very durable (so far) tank liner.
I also waited... 2?3? weeks until i put gas into the tank.
I only did this due to hearing bad things about liners in general, and after talking to the company on the back of the KREEM bottle.
They mentioned the liner needs MINIMUM 36 hours to cure properly before placing gas back in the tank.
More time to cure cannot hurt, and probably helps IMO.


I have been pleased with Kreem SO FAR.
The liner has not come loose yet, and is still hard to the touch(still cannot dig a fingernail into it anyways).

If the POR-15 was locally available, i would have gone with that one, but the KREEM was readily available, and only 24.00 at a local dealership.

l8r

[BobbyR]

The good and bad on molassess, because I've tried it twice and gotten completely different results.

The good: on a tank with light rust scale and no gas/varnish buildup it works great.  My Suzuki tank looked brand new when I got done with it.

The bad: my 750F tank had some varnish buildup, a ton of rust and some pinholes (discovered after sandblasting yesterday.  Didn't work at all on this tank.  In fact, I'd almost say it looks worse than before I started.  My next step is POR-15, it's got a few steps to it, hopefully they fix the problem.

The Molasses will not dissolve the varnish. Molasses,binds to the rust. The varnish acts as an isulator. Simple Green really eats through varnish better than Gumout.

[Gin Rickey]

Pyro, this was my first try with anythinglike this...so I didn't mind the solution being a little weak. Like you, I filled the tank to the top (including the 1 quart of phosphoric acid) and in two hours I have so little a residue that I would think a gas rinse and the in-line fuel filter would catch it.  To take a step back, though, the rust in this tank was not big and flaked, more like a very coarse grade of sand paper.  In two hours, only a film of rust remained, and when I put my thumb to it (through the gas cap opening), it rubbed right down to shiny metal with one swipe.  Now, I can't get my thumb in far enough to clear the whole tank that way  but I'm guessing that I'm in the clear.  I suppose you could play with the strength of the solution and the duration of the soak, but things worked out well for me (a little luck helped).

[pyro139]

Pyro, this was my first try with anythinglike this...so I didn't mind the solution being a little weak. Like you, I filled the tank to the top (including the 1 quart of phosphoric acid) and in two hours I have so little a residue that I would think a gas rinse and the in-line fuel filter would catch it.  To take a step back, though, the rust in this tank was not big and flaked, more like a very coarse grade of sand paper.  In two hours, only a film of rust remained, and when I put my thumb to it (through the gas cap opening), it rubbed right down to shiny metal with one swipe.  Now, I can't get my thumb in far enough to clear the whole tank that way  but I'm guessing that I'm in the clear.  I suppose you could play with the strength of the solution and the duration of the soak, but things worked out well for me (a little luck helped).

im going try soaking for a day, varnish what i was able get free was about 1/8 inch thick
if doesnt work tuesday ill get tank acid flushed found a gas tank car and bike shop here in city that will cost 50$cdn to acid flush a tank like a hot dip but acid only flushed thru tank with preasure hoses till clean, so dont need repaint like hot dipping.

[paxtonpony]

POR-15 worked awesome.  I honestly didn't think the tank would get perfectly clean but it is.  With as bad as the rust was I was expecting at least some of the junk to be left but it came out like a brand new tank.  I had pinholes so I went ahead and did the coating too.  pretty easy stuff to use.  Looks good, hope it holds up.  Guess I'll find out when I gas up in a few days.

[chippyfive50]

I have used the Kreem too, but if the tank has no holes, I like Redcote.
It not gunky and chunky, and looks more professional.

[psykod]

I noticed these guys use something called Phenol Novalc Epoxy to coat their tanks, whatever that is...Looks like they do some pretty good tank repair as well.

http://www.empiregp.com/index.cfm?page=102

[.RJ]

I cleaned out my tank last night with the Kreem tank prep 'kit'.  There was only some minor rust in the tank but it turned out really well - I was pretty happy with the result, until today I went to look at the tank and the entire inside of it is covered in rust again, much much worse than before.  I read the directions and followed them to the letter, so where'd I go wrong?

[pyro139]

I cleaned out my tank last night with the Kreem tank prep 'kit'.  There was only some minor rust in the tank but it turned out really well - I was pretty happy with the result, until today I went to look at the tank and the entire inside of it is covered in rust again, much much worse than before.  I read the directions and followed them to the letter, so where'd I go wrong?

you didnt line tank so you got flash rust, if not going use tank liner should have atleast coated inside with oil.

[Master Ted]

I cleaned out my tank last night with the Kreem tank prep 'kit'.  There was only some minor rust in the tank but it turned out really well - I was pretty happy with the result, until today I went to look at the tank and the entire inside of it is covered in rust again, much much worse than before.  I read the directions and followed them to the letter, so where'd I go wrong?

To add to Pyro's comments... I recall reading Kreem squib where directions said to apply coating straight away and not to let tank dry b/4 application (unlike Por-15 which directs tank be bone dry). If you recovered your etch and metal prep it is fine to give it a second go.

[.RJ]

Argh...  I'll see if I can find something at the hardware store to use instead of the Kreem stuff - probably just phosphoric acid anyways.

What can I do to keep it from rusting striaght away?  Fill it with gas?