Cleaning, maybe coating the tank

Hi guys,

I have a 1987 VFR700F that I bought recently on eBay. The bike was in riding condition, but there are a few things I want to check out and maybe fix before I put a lot of miles on this bike.

The first thing is the fuel tank. It looks like it's coated inside with something reddish brown (Red-Kote?). The coating is not very thorough, and I think the tank is developing some rust in spots that were missed. I want to clean the inside down to bare metal and figure out where to go from there. I have methylene chloride, which is basically paint stripper. First question: will this remove the brown polymer coating, or do I need a different chemical? Is there anything that could be harmed inside the tank using chemicals like this? (I noticed this tank has a lot of "stuff" going on inside, not the simple empty cavity of the VTR250 or the CB750 I'm familiar with.)

Second question: Assuming I can get that stuff out of there (and not remove the white metallic paint on the outside!), does it even make sense to use a coating inside these tanks? I can see metal screening in there, and I can't imagine how a good thorough coating process (rolling the tank around slowly, etc.) could help but plug the screens up.

Anyone been through this? I'd sure appreciate whatever experience you can share.

Thanks,

Walden

 

Acetone usually works with the other commercial liners, I am not sure if it will work with Red Kote lining, that stuff is pretty tough.
Sounds like some amateur decided to dabble in tank lining.I think these tanks due to the method of construction do not lend themselves to lining procedures too well.

 

:welcome:

Greetings to another VTR 250 rider !!!!

 

Methylene chloride is the main component in paint and epoxy strippers unless they are of the sodium hydroxide type ie. lye. Nasty stuff, but unlike acetone is not flammable. Acetone also evaporates lickety split.

Since the object is to strip the inside of the tank to bare metal, see if a sample of the inner coating can be obtained to use in an empirical test.

Be dammned careful with either solvent on the outside of your tank. Both can do damage right down to bare metal.

Not a clue on the "screen". Some good wrenches here may chime in..

 

One of the at the local bike shop told me they would never put that liner in any tank unless it was repaired or the tank was cleaned after having a lot of rust in it. I was going in to buy a liner after doing a project flush on a Hawk GT I had and explained to him what I did and how the tank looked. He said he would love to sell me stuff but he thinks it would be a waste of money and possibly ruin the tank.

 

This stuff converts rust (iron oxide) to magnetite. Best IMO to scale first. An old time method was to use gravel. I once hooked up a tank from a parts bike to a 5 gallon paint shaker and let er rip.

This brand is made in Seattle. There are others and the price range varies. Same stuff.. Sherwin-Williams has a like product and I think it may be available in rattlecans.

Corroseal Rust Converter | Metal Primer | Rust Paint

 

You mean because of the tubes and other stuff going on inside there? This is my concern. Although in a sense they are easier than other tanks I've coated because you have a large hole at the very bottom to drain the excess out.

 

Thanks! Is that the 1988? Or the 1990? I only know it's not the '89.

 

Billy,

Tanks for the reply. Did that test with some of the coating that easily peeled right off the inside of the fill hole. (Suggests a really inferior prep job.) Yes, indeed, the stuff seems to soften and dissolve in the methylene chloride, so I'm going to go ahead with that.

As for the "careful" part, it says on the instructions that the "meth" won't harm duct tape, so I've wrapped the tank in it. A couple of pix:

 

That's my situation, cleaning the rust out, which leaves the metal vulnerable to more rusting. I have used POR-15 three times successfully. But this tank I believe I will not coat.

 

Good idea to start with the tank cuz rust in there will eventually foul up the carbs. Problems with coating involve the fuel level sender, which needs removal and a block-off plate and the screen on the tube leading out to the petcock.

Personally, i would avoid any use of meth/chloride and find an alternative method as it's a carcinogen and disposing of it after use is an environmental hazard.

 

Well, I went the meth/chloride route and I regret it. Initially I was just duct taping over the openings. What happens is that the chemical reacts with whatever is inside the tank, creates pressure and blows the tape off. Now you've got the stripper possibly under the tape, and you can't see the extent of it. Thought I'd ruined the paint job. Having gone through the emotional stages (anger, denial, grief, etc.) and accepted that my paint was ruined, I pressed ahead with the chemical regimen. Screwed the sender unit in; screwed the cap assembly in; screwed the petcock assembly in, protected by tape. After a few days of adding stripper, rolling around, waiting, adding more as the coating soaked up the stripper (I was adding 1/2 cup at a time), I thought the whole thing was soft and runny inside, and should wash right out. Waited one day, and things started to firm up again! Got some lacquer thinner in there hoping to loosen it all up, and instead the opposite happened. Put some more stripper in there, hoping to loosen it up, and the opposite happened! Walked away in defeat.

Then I read on the Red Cote site that the product "turns to ash" at 250 degrees F. So, after drying it out for a week or so, I "got permission" to put the tank in the oven. Baked it for 10 hours or so. The smell vanished, and the coating that remained inside turned black, but is not exactly "ash". I think of ash as being a powdery mess that you can easily rinse off. This stuff is now more like baked on grease on the inside of the oven. Maybe it's a little crispy, but the parts I tested seemed to still have a rubbery kind of strength left. So all-in-all not going too well.

By the way, I removed all the duct tape before baking. Fortunately, damage to the paint is limited to places that can't be seen when the tank and everything is installed, so I lucked out there.

Next step will be to see if acetone or lacquer thinner or lye or anything else I can think of will now remove what's left. I expect to do a lot of shaking with sharp dyrwall screws and/or chains. God, what a pain trying to remove this stuff. But it has to be done.

 

Reading into whoever told you that methylene chloride would not harm duct tape is full of shit.. It will dissolve the adhesive and it did. Lots of tapes say "duct" or even duck tape even gaffers tape.. I would not slosh even the real thing with meth. Best deal at this point IMO, is to strip the tank on the outside too. "Repaint and thin no more!"

Lots of thing going on with this tank that looks like unknowns.

You might try the abrasion route providing that someone here has some real knowlege of what the innards of your tank in stock condition really is.

BTW "gravel" is a size and not some generic designation. There are many many types of abrasives used for "sandblasting" on the market which IMO may be your best bet overall. I'm thinking if the inside of the tank is corroded (rusted-oxidised) blasting may be the optimum solution. These various materials run the gamut from slag to dry ice to shaped plastic media graded by size, shape and durometer, dry ice ect..

If available you might at this point want to seek out a powdercoater if available. The larger shops have blast capability.
Another route is to seek out some of the sites that speciaize in restoration of vintage and antique bikes.

Whoops! Some of that seepage under the "duct" tape was effected by evaporation and a pressure build up if I am reading your post right. There are mired nomographs of evap rates for many of the "hot" solvents. All the gas laws apply.

Tank me later..

 

I think it was the POR-15 instructions for removing other coatings that said duct tape would not be affected. In fact, the stripper dissolves both the adhesive and the face coating of the tape. I think that selling methylene chloride and advocating its use in this application borders on irresponsible. It would be very difficult, IMO, to do this safely.

The outside of the tank still looks pretty good. I want to keep the original finish if at all possible. If I do end up having to paint or powder coat, does anyone know if the Honda decals can still be found? As for blasting the inside, is that really an option? How can you see what you're doing? I've had good results shaking with drywall screws, acid washing, etc, on four other Honda tanks. It's just a lot of physical work. I'm hoping the polymer bond to the underlying surface (metal and rust) is sufficiently compromised by the stripper and heat treatments. We'll just have to wait and see.

What does "thin no more" mean?

 

I have my doubts that the red tape used was duct tape. The old walks and talks like a duct may not apply here. Never applied meth to either mself. From experience it would be a fools errand anyway.

Indeed meth is some bad shit. Used properly employing safety precautions it's like many chemical compounds and can be effective. Not for everyone? Yes..

Once more in blasting there are many options and in the hands of a skilled and experienced operator, then yes, it would be a viable option. "Sandblasting" is a generic and not a specific. I only mentioned a few of the form of media used and did not include corncobs used to blast log homes the excess being used in planters and flower beds..

Put that tank and whatever you want as an abrasive on a five gallon paint shaker and let er rip.. Or if you are in the South Central of LA strap it to some Crumpers.

Honda grapnics? Sure just Google em.

Old joke...

A painter gets a contract out in the country to paint a church. At the near end of the job he sees that he is going to run out of paint. He figures these are church people and will not know the difference if he thins the paint some.

He cuts the paint and on the last few brushstrokes the sky opens up and washes off all the paint. The poor SOB looks skyward and cries, "God what will I do now!"

Big voice answers back, "Repaint and thin no more".

 

I told ya so ! Nobody mentioned using muriatic acid to etch the tank ?

 

Hi all,

I eventually got through this project. The key was to use heat. After a first baking at 250F, the coating, which had slid mostly to the bottom of the tank when I was using solvents, was black but not brittle enough. I baked again at 325F for close to 12 hours, until there was no more chemical smell coming from the oven. This second baking brittled up the remaining coating and made it possible to remove it by mechanical means: shaking 1/4" nuts and drywall screws inside, dry, and then with detergent solutions. I got most of it out like that, but in the corners where the tank seams form, it was stubborn. Tons of elbow grease, enough to almost give an old fart like me a heart attack. I turned the tank over and hit the bottom just below the seams with a plumber's torch until smoke was produced. Then, letting it cool, I could hear the coating crackling as it let go of the metal. Then a lot of tapping with a hammer right on the seam dislodged most of what was left. Some poking inside with various metal rod scraps and eventually I was convinced that the worst of it was out and whatever remained I would just have to learn to love.

Next step was thorough de-grease wash, followed by thorough rinse, followed by phosphoric acid wash, until the inside was looking nice and bright (no more rust). Then rinse, baking soda rinse, rinse again, and again. Then dry with a heat gun after rinsing with a little acetone. Standard stuff for cleaning a rusty tank.

After the baking, the outside looked like a toasted marshmallow. This was just tape adhesive remaining from the covering I used while in the chemical solvent phase. It polished off pretty nicely.

I hope I never do anything like this again, but if I do, I'll know to skip the paint stripper step altogether and go straight to the heat. My initial fear was that I'd ruin the paint if it got hot enough, but after seeing what a plumber's torch did on the bottom of the tank (where you can't see it), those fears are gone. This paint can stand up to a lot of heat!

I'll post a picture or two of the tank in a little bit. The filler cover I think was painted gray (original or not?), but I stripped that and polished it up bare. Looks pretty nice.

Thanks for the inputs here. It seems like what I did is not a common occurrence with VFR owners. Lucky you! I'm kind of relieved that I don't need a new tank. With this phase done, I'm onto cleaning the carbs now, and then we have some charging system connections that are fried and in need of replacement, and a cooling problem to solve, then maybe I'll eventually git to ride it again.

 

Outside after polishing.


Inside the empty tank.


Close up of inside, a little rust has formed in the empty tank. I had a little bit of gas/oil mix in there, hoping it would inhibit rusting, but looks like not. There's a loose flake of the old coating (now black) in the lower right of this shot. Another acid rinse will be in order before I fill the tank with gas.


Filler cap, polished bright after removing the grayish paint.