Are gas tanks coated with anything?

[postoak_imp]

I mean when they leave the factory?

I was reading a post on another forum by a guy who had had the rusty inside of his tank lined, and then down the road he had trouble with the lining peeling and it occurred to me that if factory tanks are not coated then why not just come up with a way to sand blast the inside of old tanks?

[Ulvetanna_imp]

no you are expected to keep adequate fuel in the tank to prevent corrosion

during layup you are to fill the tank

do not line a rusting tank unless it has been very thoroughly cleaned with chemical and mechanical means

better to just replace the tank

[postoak_imp]

If not coated, then it seems like having a sand-blasting nozzle on a wand -- one that would throw out sand in a spherical pattern would be a better way of getting rid of rust than chemical or electrical means.

You bring up an interesting point, though. No one keeps their tanks full or even mostly so, most of the time, why don't they rust? My old Nighthawk had no rust when the tank was 15 years old, and yet this is a high-humidity area where bare metal can start rusting in a day.

[LongRanger_imp]

I live in an arid region and keep my bikes topped off with fresh gas and Stabil for that very reason, even on the bikes with polyethylene tanks. If nothing else, I feel a full tank reduces the likelihood of ethanol-induced condensation and tank deformation. Plus, it's nice to have a full tank when heading out on a ride.

[postoak_imp]

Well, I should have done some googling before posting as this has been asked and answered before. (Not about whether the tanks are sprayed at the factory but about sand-blasting.) There are two reasons not to, 1) it's too powerful and can go right through the metal and 2) it's almost impossible to get all the sand out.

[736cc_imp]

Ethanol blend fuel absorbs water. The old-school way to store gas was to top off tank w/ gas and add stabil. The new-school way is to add 2 stroke oil and Stabil or Startron to whatever gas is in tank, run the engine a minute or so then it's winterized. Or simply drain tank completely if vehicle is stored indoors. Untreated modern fuels are causing huge problems in boats and classic vehicles w/ carbs and old fuel systems.
Modern gas tanks are not bare metal, they are coated from the factory.

[Ulvetanna_imp]

Ethanol blend fuel absorbs water. The old-school way to store gas was to top off tank w/ gas and add stabil. The new-school way is to add 2 stroke oil and Stabil or Startron to whatever gas is in tank, run the engine a minute or so then it's winterized. Or simply drain tank completely if vehicle is stored indoors. Untreated modern fuels are causing huge problems in boats and classic vehicles w/ carbs and old fuel systems.
Modern gas tanks are not bare metal, they are coated from the factory.

Depends on your location whether ethanol is used, of course.

Where did you get the info about modern gas tanks being coated?

Which marques, any articles or discussions re: this?

All my tanks look to be bare metal (except the F800GS), and given that the fuel nozzle can and does easily contact that metal, which could chip away any coating, that seems implausible.

That's especially true where vapor recovery hoses are not used, and the nozzle can be inserted well into the tank.

The start of the chipped area could then allow corrosion to begin (don't think anyone is using cathodic protection in a fuel tank yet), and create particles and debris that could clog the fuel filter and other parts of the system.

I would need to see some substantiation on this, would appreciate any links/articles/such.

[postoak_imp]

I did some googling and someone said tanks are "terne plated", which is 50% tin 50% zinc.
http://www.tms.org/pubs/journals/jom/960...-9607.html

[pdedse]

A bunch of old nuts, screws and bolts did a decent job on a somewhat rusty xs650 tank, 1983. Shook it by hand for about 30 minutes. Rinsed with Naval Jelly / distilled water mix a couple of times, and it looked clean metal inside. I was going to coat it but had read about coatings peeling off over time, so I left it clean, but a flash rust developed which I didn't worry about. It ran fine for months afterwards and then I sold it...to buy my CB!

[kmoney_imp]

I did the shake and coat thing on my 81 XJ650. I bought the POR 15 kit and filled the tank with the solvent, chains, gravel, and warm water and shook it for about 15 mins. It actually got it really clean inside. The POR 15 lasted for 6 years (at which point the bike was dead) with no problems at all.

The CB tank does look like it's costed (or more likely plated or electrocoated) with something. I've never seen a spec of rust anywhere inside it.