Topic: Best solution for light rust inside tank?

[RAFster122s]

Pewe, the tyre workshop was glad I came to collect those balancer leads, but I'm sure you can find lead in another form more handy. Make sure to protect your hands when you deal with lead and/or diesel and after having had lead in your hands, wash them. BTW, it's not the same kind of lead that used to be in gasoline. There's some good info on that in Wikipedia. Scientists today look back at that era as the greatest mass poisoning ever in history.

IN THE USA...
most wheel weights are now made of steel, zinc, and other non-lead materials – and the risk to our drinking water is greatly reduced...
It is a Environmental Protection issue for drinking water and poisoning of animals and people. Some states have outlawed the use of lead wheel weights on cars from/in those states.

Much of the hunting shot is also not lead, in fact it is difficult to buy lead shot for bird shot as it is nearly outlawed in most any area to have bird shot load shotgun shells with lead pellets.
FWIW, YMMV

[mrbreeze]

I used the Prep & Etch method. It was something like $16 a gallon at Home Depot. I did it on 2 tanks......one was very rusted and I didn't think it would survive but it did. It also leaves a protective coating behind. After a thorough rinse with warm water I ran some alcohol through and blew it out with compressed air.

[Imago]

I used the Prep & Etch method. It was something like $16 a gallon at Home Depot. I did it on 2 tanks......one was very rusted and I didn't think it would survive but it did. It also leaves a protective coating behind. After a thorough rinse with warm water I ran some alcohol through and blew it out with compressed air.

I wish we could buy this in Canada, hence my apple cider vinegar method.

[RAFster122s]

Can you buy Naval Jelly, a Phosphoric Acid paste?

Then it is matter of finding an alcohol or chemical to thin it and change the Naval Jelly into a liquid rather than a paste.
Denatured Alcohol might do it (Methanol). Acetone would likely render it too liquid and it eats paint like no tomorrow too.

If it were light rust I would be tempted to give it a quick acid wash.

Oxalic Acid works too, wood bleach. It is faster than Evaporust which needs to be warm to work well.
Citric Acid crystals are very slow but very safe to deal with...
Muriatic acid, brick acid, works but is is aggressive and it eats rust and metal readily and most of the acids will attack the pot metal in a petcock. Muriatic acid very aggressively.

If it is merely surface rust and no scale you could run it and just keep the tank filled with pure gas with a stabilizer if you don't use the bike a lot.

VInegar works...just shake frequently and maybe toss a heavy rag in to serve to wash the tank insides a bit so any film that is built up will come off without emptying and rinsing the tank. FLUSH the vinegar out with a lot of water and follow with an acetone wash or a denatured alcohol wash. Acetone if you intend to repaint the tank, denatured alcohol will damage lacquer paint but not most others that are typically used if you rinse paint off with water.  Rinse it twice and then dry the tank with warm air from a hair dryer for a couple hours to make it bone dry.

Since you can't get Prep N Etch, then several ounces of 2 stroke oil coating the tank will stop any rust and be gas friendly with some smoke...
Keep your tank full and don't use ethanol fuel, especially if you aren't going to be running the tank empty...as a get by until you can get to a no ethanol station. The ethanol and water suspension will settle in the bottom of the tank rotting the seam of the tank even before it does a full phase separation.

Does the Apple Cider vinegar have greater acid concentration? It is generally much more expensive than white vinegar; here at least that is very true...

[sixthwisconsin]

Hi folks, I've got some light rust inside my '77 model CB550 tank. It's getting through to the (stock) carby's and occasionally the float bowls get stuck. I want to fix the cause and not keep treating the symptom.

What's the best way to deal with it?
ank inner with some sort of Marine epoxy (seems the more expensive route)

I have used "the works" toilet bowl cleaner with good results. I use this before using the KBS kit. You will need to reline the tank in any case but this will dissolve all the rust. Dump a couple of bottles in and slosh it around for a couple of hours. It will remove the rust as a pre treatment to the KBS three part treatment that includes a liner coat.

[flybox1]

the works is great but it leaves bare metal.
how fast did it flash rust? 

Prep-n-etch leaves a phosporous coating...prevents flash rusting.

[sixthwisconsin]

If you are not going to coat it, Prep & Etch is the way to go. I used the works before the KBS kit just to get the big stuff out. The kit contains a de-ruster, a rust blast that leaves the phosphorus coating, and then the sealer.

[RAFster122s]

With the commercial Prep N Etch not being available in Canada and in other countries those wanting to NOT line the tank or to even if they line the tank (if they do not use a kit that leaves the phosphorus coating...both the Caswell's and POR-15 kits do)  will need to find some other product that will leave the phosphorus coating.  Reminder of the Caswell's site wide 20% discount with coupon code XMAS2018...until that sale is over...would be nice if it runs until 12/31 but I doubt it will.