later model tank construction.

[matt glascock]

I just scored an 03 roller with awesome forks (yay). In the deal was a really sweaty looking tank. Looking inside in anticipation of the usual rust stalactites and stalagmites I found a pristine, shiny tank. Ditto on the inside of a really punished White tank 250 SL I found a while back. Was there a change in the construction of the later model tanks to account for this or did I just hit the pick-six? Or is this finding typical of painted tanks compared to chrome tanks?

[dcooke007]

I don't have any first hand knowledge but my observations match yours. Maybe a different steel or plating?

Danny

[matt glascock]

You must be right, Danny. I can't imagine that the painting process alone would impart a better rust resistance than chrome plating the tank. I've seen chrome tank after chrome tank looking fairly decent on the outside leaking like a sieve from multiple rust-throughs, but all my painted tanks, no matter how abused they look on the outside, hold fuel well and required only a light cleaning internally. Hmmm...

[Darrell]

Not for me. My 250SL tank didn't look too bad on the outside, but it took a heat gun and a big pair of Channel-Locks to remove the gas cap. That revealed a gas tank of horrors as the rust was holding it together at that point.

[viclioce]

My 03 tank was really clean inside too! The outside looked more like a barn find tank! Victor

[matt glascock]

Interesting, fellas. The mystery deepens. My tank of horrors instances have all been chrome toasters. Hmmm... Oh Captain, enlighten por favor.

[viclioce]

I'm just guessing, but could it be the chrome toaster tanks are thinner than the later Model coffin ranks? Victor

[matt glascock]

Until I read Darrell's post, it seemed like the lining was more rust inhibitory but maybe you're right, Victor. That would lessen the rust-through problem.

[Bullfrog]

Sorry guys, I'm pretty focused on toaster tanks . . . and haven't peered into many of the later painted tanks. I'd have to wonder if the difference might be related to plating operations VS no plating operations?
Ed

[Darrell]

Here's an interesting variable: Painted tank Hodakas are oil-injected so they were most likely retired with straight gas left in the tanks.
It sounds reasonable that the chrome tanks should have been somewhat preserved by having some quantity, or residue, of 20:1 premix as a rust inhibitor.
However, my 94 Wombat's tank was very rusty, but not yet perforated, when I got it. But it had been sitting under a junk pile in an old barn for 35 years before I got it.

[viclioce]

But it appears that the newer painted tanks don't rust up inside as often as the chrome toaster tanks. My Model 99 tanks were painted toasters. One tank had already been sealed but was OK to use! ; D Victor

[matt glascock]

Thanks fellas. Just an interesting ponderable. I could see the potential for some alteration of the base metal during the plating process that would leave it more susceptible to corrosion as the Captain stated. Darrell's point is also interesting, valid, yet would support improved anticorrosion properties which doesn't seem the case. I've noticed what appears to be a layer of copper on toaster tanks with the chrome flaking off. Does anyone know the details on tank construction? Maybe it's things like this that prompt my wife to frequently ask the question "Why are you always in pursuit of the useless minutiae?" My snarky response, of course,"So I can aptly prepare myself to draw the biggest crowd at the dinner parties you lasso me into with my scintillating conversation". This, in turn, begets the eye roll of hopeless futility.

[Bullfrog]

Who would not be thrilled to learn that decorative chrome plating involves smoothing/polishing of the base steel surface, then a plated coat of copper which is also buffed to a achieve a perfect surface . . . then a plated coat of nickel (I think this part is correct, about the nickel that is. But there is some discussion that Hodaka may dropped the nickel step at some point.) Then the nickel is examined, buffed as needed - then the chrome plating step happens. I've been told that "triple chrome plated" actually refers to the three layer process - - - which seems to make some sense. The three layers are metallurgically required for improved bonding between the different metal layers . . . and for better filling/smoothing of defects by the plating.

I'm thinking your wife should "get on board" with the important community service you are providing. (I'll tell YOUR wife that . . . if you'll tell MY wife the same thing. )
Ed

[Bill2001]

I wonder if Hodaka didn't start treating later tanks for rustproofing. For example, you can etch a tank with phosphoric acid, which will cut down on the rusting

[matt glascock]

I'd bet you're right. Bill. We've only seen one exception to the rust resistance of the painted vs toaster tank on this thread. I'm with you Captain. I can't imagine why tank construction and the chrome plating process isn't of interest to anyone with a pulse. I agree with your assessment as it seems the copper coat was immediately deep to the chrome with no intervening nickle stratum. With regard to the "wife reprogramming" you have yourself a deal. Just a quick bit of advice - be strong, Brother. You have your work cut out for you

[Bullfrog]

. . . on thinking my offer through a bit further . . . I suggest that we save the "wife reprogramming" reciprocal actions until such time as all four of us are in attendance at the same cocktail party. This will have the effect of 1) delaying the risky action for quite awhile, and 2) putting you and I in the position of being able to hastily re-negotiate the agreement before we do something stoooopid!
Ed

[matt glascock]

Sage advice, Captain. By acting hastily, we could end up in a situation which leaves us confused and sifting through the flaming wreckage. Trust me, this is a pathway I've indelibly beaten. Then again, we could end up at the bar contrasting and comparing the merits and drawbacks of Caswell vs. Redseal

[Bill2001]

Redcote is an Industry Standard and it works well.
My preference is for Caswell epoxy sealer. It clings tenaciously and is impervious to anything in gasoline. The drawback is that since it cures through a catalytic process, the clock starts once it is mixed and it.is temperature-dependent.

[Darrell]

I second that for the Caswell sealer. I've also used POR 15 before, but it seeped through the thin spots on a real problem (250SL) tank.

I've also learned to use double the stated amount for a motorcycle gas tank because the tank saddle increases the interior surface area remarkably. So, if your sealing a 3-gallon motorcycle tank use up to the equivalent amount of sealant for a typical 6-gallon tank to ensure complete coverage. Don't be cheap about it, like I was before I knew better

[Bullfrog]

Does it take special scheduling to get the Caswell bulk tank truck to stop by when you want to seal up a 250 SL tank?
Ed

[matt glascock]

Captain, the Caswell is packaged incrementally based on the volume of the tank up to and including automotive sizes. I agree with Darrell doubling down on volume size after I short-changed an Sl100 tank. After that misfire, I have used it on four tanks now, including an aluminum alloy early RM tank, and it has performed flawlessly. Amazingly, on the "one-dent wonder" tank I use on my Super Rat only for racing, I put a pretty good ding on it and the Caswell didn't fracture. Design, luck, really hot day? Who knows. It held up. The caveat with the Caswell is that the instructions, which are well-presented, have to be followed precisely for the desired outcome. Also, if you have the option, get in the two compartment "burst pack" format. In that packaging, both components of the epoxy arrive in a single plastic pack separated by a plastic septum. By simply squeezing one side, the separating seal is ruptured and the two components can be squished back and forth to mix. Then, snip off a corner and it can be poured into the tank. No muss, no fuss. This saves having to fart around with a coffee can, paint stirrer and funnel to get the stuff mixed and into the tank.

[Bill2001]

Good directions, Matt. I use rubber stoppers from Ace Hdwr to seal the petcock and filler openings and mix the epoxy in a disposable poly container from the paint store.

My experience is that the Caswell std motorcycle tank sealer is quite enough for a BMW 5.5 gal.tank and will do a 6.5 gal Touring tank if you work quickly.

The basic sealer is clear and the same product with a red pigment is available.
It also works well on plastic and 'glas tanks.

[matt glascock]

Right on, Bill. I forgot to mention the tech for plugging the holes. For blocking the outlets I use junk brass petcocks and saranwrap under the gascap for the filler neck. Have you used it to seal a plastic tank? I have an old, and I mean reeeeeeeaaaally old Clarke tank with a crack at the petcock mounting boss resulting in a slow leak. Like a moron I cracked it while yanking the fuel line off for annual line and filter change. At the time I did what any self respecting nimrod would do - I rammed a bunch of JB weld around the outlet tube. Didn't work. The melange of profanity is still echoing up and down Chateau Court. I used that tank on my Combat Wombat for racing only as the bike has a OEM tank in excellent condition I don't particularly want to bang up.

[Bill2001]

I don't have any first-hand experience with using it on plastic tanks, but I have heard several reports that it works well on plastic. I do know that it does "stick" very well to a polyethylene mixing container (although nothing adheres to poly). The coating is thick and stays flexible. If there is movement around the petcock fitting, I don't know how the epoxy would do. If the tank is polyethylene, it can be heat welded with a soldering iron.

So it's a definite maybe...