Fuel tank sealants

[Rat]

I searched the forum first and literally nothing relevant came up, so this should probably help quite a few people down the line.

There are many fuel tank sealants out there for steel tanks whether it is to seal over rust, plug pinholes and seal over rust, or sealing a new raw tank to prevent rust from forming, gasoline, and diesel.

The ones I recognise by name what they are would be... Kreem, Red-Kote, and Por 15.

While the tank on my Mule is solid and without pinholes doing an edescopy on it revealed it has a fair bit of rust in the lower half. It's appears to be only surface rust.

I need recommendations of what the best option is for sealing tank that really can't be cleaned out due to design. It seems to have some sort of divider, maybe a reserve partition below the E on the gauge, idk. It is a relatively large tank as well.

 

[chaznaster]

I searched first and literally nothing relevant came up.
There are many fuel tank sealants out there for steel tanks whether it is to seal over rust, plug pinholes and seal over rust, or sealing a new raw tank to prevent rust from forming, gasoline, and diesel.

The ones I recognise by name what they are would be... Kreem, Red Coat, and Por 15.

While the tank on my Mule is solid and without pinholes doing an edescopy on it revealed it has a fair bit of rust in the lower half. It's appears to be only surface rust.

I need recommendations of what the best option is for sealing tank that really can't be cleaned out due to design. It seems to have some sort of divider, maybe a reserve partition below the E on the gauge, idk. It is a relatively large tank as well.

I used the POR-15 gas tank treatment/sealant on a car about 6 years ago. Have the tank out this winter and looked all over with a 'scope. It still looks pretty good.

 

[Denny]

Put some POR15 metal ready in the tank (about 3 cups) and some BBs or old nuts. Give it a good shake and keep doing it for as long as it takes to do all sides. Letting it sit for an hour on each side to soak.
Drain, the metal will now have a good phosphoric coat in the metal. Rinse and neutralize with baking soda and very hot water. Let dry in the sun for a day or 2 or lightly warm with a torch or heat gun to quicken the process. I’ve used Kreem and POR15 tank sealers before and they both work equally as well.

 

[Rat]

I used the POR-15 gas tank treatment/sealant on a car about 6 years ago. Have the tank out this winter and looked all over with a 'scope. It still looks pretty good.

That is one of the top 2 I've always hear by name when referencing a crusty tank... close second is always Red Kote.

My thing is that there are warnings that it won't adhere to fuel varnish... I don't see any varnishing that I can tell, but even if I did there's no real way to clean this tank out by design.

I've dropped automotive fuel tanks full of sludge and cleaned them out, totally different animal considering with the fuel pump out I could shove my whole arm in them.

I've done motorcycle tanks by dropping a couple fistfuls of drywall screws, a bit of water, and shaking the everluvin hell out of them. Dump, fish out screws with a tethered magnet, rinse, check, and repeat as needed.

I have never had to seal one, the cars were plastic tanks, the motorcycles were steel but they were never an issue after cleaning

 

[Rat]

Put some POR15 metal ready in the tank (about 3 cups) and some BBs or old nuts. Give it a good shake and keep doing it for as long as it takes to do all sides. Letting it sit for an hour on each side to soak.
Drain, the metal will now have a good phosphoric coat in the metal. Rinse and neutralize with baking soda and very hot water. Let dry in the sun for a day or 2 or lightly warm with a torch or heat gun to quicken the process. I’ve used Kreem and POR15 tank sealers before and they both work equally as well.

Wait... what the point of the bb's or nuts? We talking 2 stage stuff (like 2 part epoxy)?

 

[Denny]

BBs or nuts, drywall screws, nails they all do the same thing and help scour while the phosphoric acid does it’s job.

 

[Rat]

BBs or nuts, drywall screws, nails they all do the same thing and help scour while the phosphoric acid does it’s job.

I missed that you were talking about cleaning THEN coating

I always dried with a borrowed hair dryer on high heat high fan for 20 minute cycles (to not defore plastic fuel tanks or burn up hair dryer) with automotive tanks it takes wrapping in a towel and jamming it in the fuel pump port venting the induced pressure out the filler neck stub. Motorcycle tanks were done similarly and vented from the petcock bung.

Doing the Mule tank it would get vented through the fuel gauge port

 

[Rat]

If I didn't care about it being $500 I could just get a shiny new one

I'm irritated enough that 4 tires at 75-150 each is too much.

I am debating switching the 10" for 12" because the price difference is insignificant and 12" is more common. Finding the 10x8.5 wheels with a 4/137 bolt pattern is like trying to get tires for Buick 15.5 wheels. In this case tires are not the issue, and while the rims stopped leaking I'd rather update and replace them to make tires more available later on

 

[Rat]

I'm not even sure all of it is actually rust... looking at the pics I got with the 'scope it looks a lit more like varnish than rust. I don't want to use anything that's going to eat the paint off the outside if exposed.
So no lacquer thinner.

 

[Whitetrashrocker]

Try a stronger solvent? Will laquor thinner cut it? Maybe. MEK?

 

[Rat]

Try a stronger solvent? Will laquor thinner cut it? Maybe. MEK?

I haven't done anything to try cleaning this tank out just yet.

All I have done was dump out some watered down gas
(dumped it I to a big pan and hit it with a torch to see how bad... it would light and only burn for a second or two unassisted)
and fished out a chunk of debris from some sort of flap that used to be riveted in.

I'm not even sure what to use (preferably something that I have on hand or dirt cheap) in the event it is almost all varnish.

I've been scouring the web and apparently PineSol will eat the varnish as well so I may start there... I'm on a septic tank, and don't want to deal with anything extremely volatile or corrosive that I can't dump down a drain or driveway. Acetone is out because I'm not about to try repainting the tank...I've got enough Sh!t on that thing to repaint already as is

 

[Denny]

Pine-Sol will work if you can put it in an ultrasonic cleaner big enough to put the tank in. I don’t see that happening. The only thing I can see cutting that sludge is laquer thinner or MEK. Sorry, I know it’s not what you wanted to hear. You could maybe try some Formula 409? Just dump in a bottle with your screws, BBs, nuts and bolts then start sloshing around. If you have a cement mixer you could strap the tank to for a few hours that would be even better yet! Then treat like I said above with the metal ready to kill the rust.

 

[Rat]

Pine-Sol will work if you can put it in an ultrasonic cleaner big enough to put the tank in. I don’t see that happening. The only thing I can see cutting that sludge is laquer thinner or MEK. Sorry, I know it’s not what you wanted to hear. You could maybe try some Formula 409? Just dump in a bottle with your screws, BBs, nuts and bolts then start sloshing around. If you have a cement mixer you could strap the tank to for a few hours that would be even better yet! Then treat like I said above with the metal ready to kill the rust.

I don't have a cement mixer... but

I do have 4 jackstands, a lot if bungee cords, and about a dozen ratchet straps.

Could maybe strap it to a tire, toss it in gear, and run the idle screw in a quarter turn after filling an plugging it.

Nothing I've read on using Pine-Sol indicated more than it being a slow process... certainly nothing about needing ultrasonic. Most of what I saw on it was specifically really old steel gas tanks like 1940's-1960's stuff.

I have no full pump so there's no rush at all. It could take a month or two to work and that would be fine by me IF IT WORKS.

I have all the patience of a Saint for THINGS, but people FUGGITABOUDIT!

 

[Thepartsguy]

Not really what your looking for but nothing works better then this for holes in the tank.

 

[Rat]

Not really what your looking for but nothing works better then this for holes in the tank. View attachment 146529

Well there are no holes, just crud.

Some of that might have been great to have a year and a half ago when I first started messing with an old Briggs engine... steel tank was full (of not much gas) and didn't leak until I cleaned it with a fistful of drywall screws and extremely hot water. Bottom and one corner started leaking with more pinholes than a dish sponge and the cleaner it got the worse it leaked. It was rusted badly but ironically had no varnish.

I bailed on that briggs, it sits on a shelf now

 

[Rat]

Closer inspection via the fuel gage opening... the divider is vertical not horizontal... must be structural to keep the straps from collapsing it when cranked down

 

[Rat]

I filled it completely overflowing with BOILING water... it loosened a fair bit (far from effective) but it rinsed just enough sludge to show the tank is in fact in great condition internally.

I think I might go the acetone route afterall, probably end up painting the tank Red with a Brake caliper paint.

If rattle can ceramic Brake paint it is Chem resistant enough to prevent Dot3/4 from eating it off (when cleaned up quickly) calipers then it should handle the less caustic nature of gasoline right?

 

[Rat]

The official call is Berryman's B-12 which specifically states "REMOVES PAINT-DO NOT SPILL ON PAINTED SURFACES"

I will do the obligatory before/after pics... someone, somewhere, will appreciate this $5 varnish fix.

Oh and I've got the fuel pump and gauge ordered.

 

[Rat]

BEFORE

 

[Whitetrashrocker]

That's what fuel filters are for...