de rust a petrol tank

[mickwinf]

my 500 has got lots of crud getting through to the carbs causing blockages. I have cleaned tank and it is pretty good inside except for the seams and the odd spot of rust. I have read that vinegar will dissolve rust but is this true? or any other method that is proven to work. I don't think it is bad enough to need a sealant so look forward to your ideas.

[hairygit]

A cheap brand of cola drink in the tank and left overnight. It contains phosphoric acid, which converts iron oxide (rust) into iron phosphate, a hard black inert material, it's basically the main ingredient in organic rust killers such as Jenolite, but much cheaper!

[JustcallmeMrT]

I rigged up an electrolysis unit to clear the rust from my tank, and it worked a treat.  Might not be worth it for a small quantity of rust though, but worth considering.  Google electrolysis petrol tank and you should get a load of hits

[mickwinf]

I like the idea of cheap cola Hairygit, as the rust is mainly in the bottom seam it might lead to a leak if the rust was completely removed by the electrolysis method.

[Lobo]

Hi Mick,

http://www.sohc.co.uk/index.php/topic,6985.msg39684.html#msg39684

Within this post open up the Internet reference & you'll see a number of 'recommended' ways to remove rust. Don't remember cola being one of them though... Tom400 tried it with apparently little success (see link below)

The electrolysis method will ONLY remove rust, and not good material, which is the beauty of it versus (eg) abrasives or some chemicals. If you're implying that a certain amount of rust is needed to stem any leaks (!) then it can only be a (short) matter of time before you're back to square #1 and doing some sort of other major job on it. How's about a full rust removal, and then lining the tank with eg POR 15, which Tom400 has fully detailed elsewhere here....

http://www.sohc.co.uk/index.php/topic,4758.msg21866.html#msg21866

Yes, POR in tanks is not for some, but perhaps you have little option?

Simon

PS: Electrolysis is cheap too... only 3 tablespoons of the wife's baking soda.. And if I was to do it again I'd rig something better / more surface area than an old crushed can... thinking a steel ruler (raid the kids school bags...)

[AshimotoK0]

Wonderful stuff baking soda apart from the tank electrolytic cleaning and blasting uses. Try a little bit with cyanoacrylate adhesive (superglue). It cures up instantly and also 'gap fills' which superglue is normally useless for. My mum once rescued a child with severe burns from falling onto an open fire by treating the burns with a paste of bicarb ( need Nurse Julie to confirm if this is a known method) !

I don't think Coke has sufficient concentration of phosphoric acid to convert the rust quickly. I would try something like this. Diluted of course.

http://www.ebay.co.uk/itm/Phosphoric-Acid-1-Litre-81-48-hour-delivery-Best-Price-on-Ebay-/231316778500?pt=UK_BOI_Medical_Lab_Equipment_Lab_Supplies_ET&hash=item35db8dee04   plus a bag of sharp screws etc to slosh around with it.

On the electrolytic method I saw someone on one of the forums ( probably SOOC) using an electrode made out of a plastic pipe with lots of holes in it and the electrode wire passing down the bore of the tube. That way you never get shorting out of the power supply and ignition of any gases produced . Need to try this method myself sometime on a spare CB250K0 tank I have.

Cheers ... Ash

[bike-pusher]

hairygit - I tried Coke.  Trust me - it doesn't work.

[Green1]

What would you recommend for a tank with fine rust spots on the tunnel.

Mick

[mickwinf]

Thanks for all the replys but now more confused about what to do, I have a rusty bolt soaking in vinegar to see how it works!

[AshimotoK0]

Thanks for all the replys but now more confused about what to do, I have a rusty bolt soaking in vinegar to see how it works!

Use either proper concentration of phosphoric acid (see my earlier eBay link)  ( this is often supplied along with tank lining kits). Not Coke , as it's not strong enough. Or use the electrolysis method. Neither will remove good metal and if its the rust that's preventing a leak then it's a leak waiting to happen after an expensive (or time consuming) paint job. 

See this link for electrolytic cleaning,

http://cb750sandcastonly.com/smf_forum/index.php?topic=1323.0


Cheers ... Ash

[bike-pusher]

Not Coke , as it's not strong enough.

As I discovered     That said, I did use 13 litres of Lidl cola, rather than The Real Thing (sic).....

So what we need is a scientific test of the leading colas on the market, to determine which (if any) works best...

[tom400f]

I tried Tesco own brand. And diet, not with sugar.

But it didn't work so...

[Nurse Julie]

Hi All
Yes to Soda Bic for Ash's Mum's remedy for burns. Good old fshioned remedy but not allowed as a treatment now due to Health and Safety and COSHH regs.It works by taking the heat out of the burns. Don't know if it would work on a rusty tank but Caustic Soda works well on my old sink pipes, so should work well on the inside of a tank. (just make sure you wear a mask and gloves as very caustic and fumes get right in your lungs)

Nurse Julie

[AshimotoK0]

Hi All
Yes to Soda Bic for Ash's Mum's remedy for burns. Good old fshioned remedy but not allowed as a treatment now due to Health and Safety and COSHH regs.It works by taking the heat out of the burns. Don't know if it would work on a rusty tank but Caustic Soda works well on my old sink pipes, so should work well on the inside of a tank. (just make sure you wear a mask and gloves as very caustic and fumes get right in your lungs)

Nurse Julie

Sounds like she was correct in her prompt actions then. Sadly passed away when I was 17 to bigC    . Never wanted me to have a bike said they were death traps but thought scooters were OK.    I am not sure about caustic soda for tank though Julie, I think you need something acidic or electrlytic. Heard of people using molasses too though.

Cheers ..  Ash ...  Welcome back BTW we need more gals on here!

[Nurse Julie]

Hi Ash
There is a really good article in Real Classic Bike Mag  about de rusting petrol tanks, they suggest Caustic Soda and Spirits of Salts.Really good article with all the instructions on how to do it etc
Hopefully this link will take you there
www.realclassic.co.uk › Tech › Insider Info

Nurse Julie