Removing dodgy liner from a pristine painted tank

[AshimotoK0]

I just sold my NOS CB500K1 Candy Custom Gold tank and nice matching side panels to member Sandyrob on here.
He showed me his original tank and side panels. They have been painted really nicely but the tank has been lined and the liner is breaking up with evidence of rust underneath. Why anyone would do such a superb paint job on a badly lined fuel tank is beyond belief. It also turned out that his bike is a K1 (he told me the frame starts with a 2) but the paintwork is definitely Candy Starlight Gold with the 'Made in Japan' emblems on the side panels plus the seat has the K0 style cover on it. Another clue that it's a K1 is the idiot light panel has not 'TURN'  not 'FLASH'.. although parts can have obviously been swapped.

He asked me if I know anyone who can remove his old tank liner (unknown type) without damaging the paint but it's a pretty tall order I reckon. Anyone on here done this or have any ideas? The only one I ever did , I chucked a load of caustic soda pellets into the tank and poured in really hot water via a length of garden hose/ funnel arrangement. There was a load of nasty fumes, gushing and gurgling but it sure removed the old liner (not that I suggesting in any way that Rob tries this on such a lovely painted tank).

I did wonder if you did the hydrolysis method for rust removal on it, it may somehow get under the liner  where there are patches of liner  already removed and loosen it. Acetone would definitely be out of the question.

I guess he is going to have a lovely set of Candy Starlight Gold side panels for sale. Whoever painted the bike made a cracking job ...pity about the liner !

[Skoti]

I'm watching this thread because I made the mistake of lining my (rusty but not leaking) tank about 10 years ago.

The lining is now starting to bubble up along the bottom of the tank (which was probably my fault for allowing too much pooling) but it's not actually broken up yet.

However I kept the old paint can and have been trying to find a solvent that will dissolve samples of the hardened liner, but so far no luck.

Be nice if it could be also removed without damaging the paint finish.


Let's see what happens here... 

[exvalvesetdabbler]

When I was cleaning up stuff for plating, electrolysis removed previous back paint on screws and the choke lever.  It has to work it's way in from edges so I would expect it to be a slow job for a wider surface area.

Regards
Dave

[K2-K6]

I don't know what this is Ash (could be acetone or similar) but looks to be specifically for removal  https://www.ebay.co.uk/itm/335608071954 perhaps an enquiry could produce more information.

[AshimotoK0]

I don't know what this is Ash (could be acetone or similar) but looks to be specifically for removal  https://www.ebay.co.uk/itm/335608071954 perhaps an enquiry could produce more information.

Evidently The product uses dioxolane (CAS: 646-06-0) to break down polymers.

[McCabe-Thiele (Ted)]

The product description does not mention anything about being an Epoxy Remover aside from on the tin itself.

It just reads like a repair product to me unless I'm missing something.

[AshimotoK0]

The product description does not mention anything about being an Epoxy Remover aside from on the tin itself.

It just reads like a repair product to me unless I'm missing something.

 I think they probably do liner coatings too Ted but this is their remover product. That chemical it contains is listed as a softener for epoxy etc.

It's related to tetrahydrofuran (THF), which I have used in the past to soften epoxy type potting of electronics assemblies.

[Skoti]

The product description does not mention anything about being an Epoxy Remover aside from on the tin itself.

It just reads like a repair product to me unless I'm missing something.

Ted,

I agree, looks like the ebay seller has attached the wrong details to the item description.


Here's the proper instructions from their website https://www.polyservice.nl/tank-cure/1-tank-cure-epoxy-remover-2613.html

 Product information
With Epoxy Remover you remove old coating and paint layers from metal moped or motorcycle tanks.

 

First, remove all gasoline from the tank and clean with water. Then pour the remover into the tank and close the filling opening. Shake the tank and turn it around and let the Remover work for at least a day. The coating will gradually soak and peel off the tank wall. After the Remover with coating residue has been removed, rinse the tank with water and Tank Cure Cleaner.

[AshimotoK0]

The product description does not mention anything about being an Epoxy Remover aside from on the tin itself.

It just reads like a repair product to me unless I'm missing something.

Ted,

I agree, looks like the ebay seller has attached the wrong details to the item description.

See previous post back to Ted. Looks pretty clear to me, and probably the chemical I would choose if hydrolysis doesn't work.

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[Skoti]

The product description does not mention anything about being an Epoxy Remover aside from on the tin itself.

It just reads like a repair product to me unless I'm missing something.

Ted,

I agree, looks like the ebay seller has attached the wrong details to the item description.

See previous post back to Ted. Looks pretty clear to me, and probably the chemical I would choose if hydrolysis doesn't work.

(Attachment Link)

Yes I agree it's sealant remover, but looks like the ebay seller has attached the wrong details to the item description.

Please see my previous edited post for the correct details.

[AshimotoK0]

The product description does not mention anything about being an Epoxy Remover aside from on the tin itself.

It just reads like a repair product to me unless I'm missing something.

Ted,

I agree, looks like the ebay seller has attached the wrong details to the item description.

See previous post back to Ted. Looks pretty clear to me, and probably the chemical I would choose if hydrolysis doesn't work.

(Attachment Link)

Yes I agree it's sealant remover, but looks like the ebay seller has attached the wrong details to the item description.

Please see my previous edited post for the correct details.

I see what you mean now ... but the product being sold does look like remover. I think I would start with hydrolysis with Rob's tank though, just in case the metal is perforated as that remover will definitely trash any paintwork.

[McCabe-Thiele (Ted)]

A solvent that can remove Tank sealant especially Epoxy Resin based ones will almost certainly remove paint I would have thought.

My first thought was to clean out the tank to remove any loose sealant, then fit extra in line filter(s) to catch what passes throught the standard filter arrangement, not a fix but it means you can ride the bike.

[AshimotoK0]

A solvent that can remove Tank sealant especially Epoxy Resin based ones will almost certainly remove paint I would have thought.

My first thought was to clean out the tank to remove any loose sealant, then fit extra in line filter(s) to catch what passes throught the standard filter arrangement, not a fix but it means you can ride the bike.

Rob has bought my  NOS K1 tank to use Ted and just wants to clean out his old tank to see if metal is intact .. then if not perforated, remove rust  with a view to selling. His tank was the wrong gold for a K1 anyway.

[AshimotoK0]

AI Overview
Yes, you can use electrolysis (often confused with hydrolysis) to break the bond between a failing tank liner and the steel, effectively removing it. Electrolysis works by using an electric current and an electrolyte solution (like baking soda and water) to turn rust into a "goo" that breaks the adhesive bond, allowing the liner to flake off.

YouTube
 +1
This method is generally most effective when the liner has already begun to delaminate or flake due to underlying rust.
When considering this process, it is important to be aware of several factors:
Process Duration: Electrolysis is often a slow process, sometimes requiring several hours or even days to sufficiently weaken the bond of the old liner.
Safety Precautions: Working with electricity and water requires careful setup to avoid short circuits. Additionally, the process can generate small amounts of hydrogen gas, so performing this in a well-ventilated area away from open flames or sparks is essential.

[Laverda Dave]

I have found the tank of the NC30 project to be thick rust inside with very large flakes present. The previous owner took it off the road because the rust kept getting through and into the carbs, stripping NC carbs isn't fun whatsoever.
My usual go-to would be Deox-C as it has been in the past but I know this tank is well beyond that and even if it does remove the rust (and it will take a few attempts) I know the rust will come straight back. I am loathe to use a liner having heard too many bad stories about flaking and being nigh on impossible to fully remove.
I have been in touch with a company I have used previously to remove a dent from the alloy tank of my Triton and who really are excellent called 'Motorcycle Dent Removal'. They have developed a process to remove the rust, prep the tank and to then nickel coat it. They give a lifetime guarantee for their work and the product.
The first question I was asked was is there a liner in the tank because if there was they wouldn't touch it.
I've sent the tank to them, they are located in Pickering, North Yorkshire.
I have asked them to let me know about the condition of the tank following the rust removal process and before they go any further.
I'll report back how it goes.