Suggestions for tank cleaning (gone wrong...)

[wirelessguy]

Hi folks.

So it's mid June already and I'm only now finding enough downtime to start working on my old GS. I had attempted to strip and clean the inside of my gas tank and things didn't turn out as I planned.

I had purchased a POR-15 kit and thought I did a good job but things went off somewhere. The entire inside coating of POR bubbled and cracked and now I need to restart the process.

Question: (aside from throwing nuts & bolts into my tank) Does anyone have any suggestions for what to strip out the POR with and how to attempt this once again?


My theory is that I didn't let the tank dry for enough days before doing the coating and that perhaps water was underneath the POR layer and when I fired u p the hot engine of my 1100E I baked the whole thing causing it to bubble.

What would be used to strip the tank down with and then what rust inhibitor would one suggest I try?
I did see a video online for using Cider vinegar to remove rust but I'm not sure if that will strip paint as well. Thoughts?

Thanks.

[rustybronco]

People around here give me a wrath of $hit when I say this but...

And I say, teach a man to fish.

[BigD_83]

Once you have the POR-15 out, you'll still need to deal with the rust.

Depending on who you believe, Eavporust might be a good option for the rust problem, however, in my experience it doesn't actually remove the rust, but rather complexes with the outer surface to make it more or less inert, and then you coat over the top of that. It is pricey, but won't damage paint. You also don't need enough to completely fill the tank, but you do have to be willing to prep the tank in such a way to completely seal it, and then shake and turn it religiously while the Evaporust does it's chemistry. According to the company, there is no need to use an etchant afterwards. So far, I haven't had any problems and it's been a few years since I lined the last tank.

I like to use a weak solvent to aid the drying process, such as isopropryl alcohol, but I can source it cheaply. I use compressed air to blow out as much of the Evaporust as I can, give it a water rinse, blow out the water, add the isopropanol and swish it around, then repeat the blowdry, heat it up some, and seal.

[posplayr]

As I recall , if you simply let your tank air dry after fetus ting you will get a lot of surface rust.

one tank I did I used a tub from a waterfall kit do I had fill submersion of the entire tank in an acid bath. You have to be quick. After a few trials , I was able to get the tank out of the dip, flush it snd get some rubbing alcohol wash and then the heat gun to force air dry.

the phosphate wash Ed mentions helps a lot and is mandatory in my book.

[wirelessguy]

Thanks guys.

I removed as much gas as I could and then took out the fuel gauge and petcock. While shaking the tank upside down I managed to loosen a sheet of POR-15 which must have been up against the top of the tank. It was easily 4mm thick - I kid not. I had to go in with needle nosed pliers and keep cracking it until I removed it. Everything else in there is mostly a thin sheet that seems to peel away pretty easily. I filled the tank with about 1/2 gallon of distilled water and them dumped it out. Currently waiting for it to dry before I go to the next phase. I'm going to start with the paint stipper and see how well it does. If the tank looks clean enough I will move to a mix of distilled white vinegar and Cider vinegar to remove the rust (they did't have a massive jug of Cider vinegar or I've have just gone with that). I was told that baking soda should neutralize the vinegar and that if I use only distilled water to flush everything out I would hopefully not get any flash rusting. I'd end off with a quart of the phosphoric acid, a suggested so that there's good adhesion.

While it likely wasn't the fault of the POR-15 I'm going to consider something else as the coating. I've read some good reviews on Caswell tank sealer but I've yet to make a final decision. I believe I did try the heat gun drying method last time so this go around I'm going to opt for a high volume air fan and jury-rig something of a snoot to force the flow thru the tank for an extended period.

[wirelessguy]

Hi folks.

So far results have been poor.

I started with some Klean-Strip paint thinner and diluted just a bit with some water left for two days and then tried Klean-Strip Strip-X Paint stripper (which was really thick and gloopy but may have been better).

While both get some of the paint off I've still got sheets of POR-15 in the tank, so there's no way I can pour any vinegar or rust remover in just yet (at least I don't think so. Would Vinegar dissolve the POR-15???)

I'm considering getting a stronger paint thinner if I can locate one and perhaps I need to get it up higher in the tank too, which would take 4-5 gallons. I'm not relishing that.

The only other idea I can think of would be to soda blast the inside of the tank the best I could with the limited visibility I have. I've used baking soda before to blast paint and I was impressed with how well it worked. It's actually really easy to rig up an air gun to a feed tube and get enough baking soda. I hesitate though because I think it's basic and used to counteract acids like the stripper or vinegar so I don't want to go there unless I'm sure its a solution or I'll be doing a ton of tank flushing.

I've also been avoiding filling the tank with bolts as I don't have a great way to roll the tank and don't want to ruin the exterior paint job on it.

Thanks for reading and I always value your opinions.

[Guest]

I used Evaporust on mine. Poured a gallon in and propped up the tank at different angles for a few days, rotating it every few hours. Blew it out with the compressor, and wrung an old sheet through the tank to get whatever else was in there. Blew it out again, looked into it with a scope light and verified that all was clean. It takes patience and time as Evaporust is slow acting. You can also give it a light misting of engine fogger and wring the sheet through again if it will not be used for a month or so. The rust will return if it is not full of petrol soon after cleaning it out. I strained the evaporust through a coffee strainer afterwards and put it back in the can for reuse. It can be used several times. For vertical or difficult surfaces such as the underside of the tank, I simply soak some paper towel with evaporust and place it on the surface instead of trying to dip the item in. Re- soak the towel every few hours and the rust will be gone in a day. Evaporust uses a process called chelation to remove the rust and does not affect the steel. Someone I knww did the tank creme thing and within a year had it in his carbs and engine. Not good!

[Guest]

wireless guy,

The instructions for applying POR-15 clearly state that the excess should be drained from the tank, and not allowed to pool. POR is quite watery and will cover to a thickness of 0.5mm or so. I've just gone through the whole rust treatment/POR-15 drama myself. What I didn't know was that a previous owner had tried to simply cover the rust by pouring in a few litres of fibreglass resin. A real house of horrors. Of course the 3 step POR treatment didn't have a hope of working. The resin was only discovered when the bottom of the tank was cut out. Then light sandblasting removed all traces of rust and resin, and the lining process was successfully repeated.

There's no accounting for the actions of some PO's. Do you know what was in your tank before you started?

[wirelessguy]

Sorry to hear about your issues.

To add some insult to injury I was 1/2 smart about what I did (and half dumb, of course). I got my GS1100E is good shape but ugly color (the former owner went all Matte black). Rather than ruin a usable tank I went out and bought another on ebay which was in good physical condition. In retrospect, tryingto line the tank to begin with was prob worse than leaving it alone. At present, I'm trying to protect my own external paint job while stripping out the POR mess. Overall, I thought I did a respectable job when I coated the tank and I do think that I followed the instructions. I don't recall how liquid-y the POR was but I did try to turn the tank multiple times to ensure that everything was coated within. I'm guessing that I left it lying upside-down and the the accumulation was on the inner roof of the tank (which in a way is better than the alternative).

I bought a heavier stripper (Goof Off I Professional) from Home Depot and I'm going to pour it in and leave it over the weekend and see. Given what it cost me if it doesn't do the job I'll have no choice but to try the media blasting. If all fails I can pull out the original tank and consider if I want to paint he exterior there. The inside is VERY clean when I compare it to the mess the POR left me with. underneath the POR layer seems to be a thin flash rust which I'm hoping will come off with the Etch and vinegar after I'm past the paint woes. This is definitely one of those lessons on how less is more.

[jbird7262]

About to go on the same journey on an extra GS750E tank that has slight rust. Going to try Metal Rescue and see how it performs.

[wirelessguy]

Quick update...

@jbird if you're looking to strip off paint of the POR I can say that the can of Goof Off will likely be one of the better choices. On the down side, the stripper was so caustic that it actually ate through my oatley plastic stoppers. I was unable to seal all my holes well enough (especially the petcock and managed to get stripper on the outside paint job as well. While my loss was my own rattle can paint job I'm disappointing because I thought the tank really did look nice.

The inside still has some POR material there and while I may still try the etch and prep and vinegar, since they're both here already, but I'm going to guess that a media blasting is required too. As this point it's just a salvage job for me and I'm going to get the old gas tank from the shed and get it on the bike to see if she'll be ridable this season at all. No money on my end to continue painting this Frankenstein monster and I doubt I'd even be able to sell the whole bike this way.


I'm going to spend the rest of my day trying not to think about my bike. Happy 4th to everyone and hope your day is filled with the sounds of loud exhausts and the wind rushing by.

All the best.