[kirkn]

Bill, you're the MSR proponent, so I'll ask:

Does it damage paint?

My CB200 project is still the original paint and it's in very serviceable shape. I'd hate to destroy it. But, the tank is pretty rusty inside. I've done a few iterations of screws-and-diesel-fuel shake-and-rinse, but I'd like to try something more.

I've read Ray's (fasterspider) experience with vinegar, and was thinking about that, but for the follow-up flash rusting.

I've also read your recommendations for MSR, but can't seem to find that definitive answer re: the paint.

Thoughts? Anyone else?

Thanks,

Kirk

 

[fasterspider]

Re: Question for Bill re: Milk Stone Remover

Kirk, just use a POR-15 treatment.
You will have to do a little work but, it will be worth it.

 

[tbpmusic]

Re: Question for Bill re: Milk Stone Remover

Flash rusting is just as bad with MSR as it would be with vinegar.
MSR is only slightly more acidic than vinegar, you just get it in a more concentrated form.
MSR is about 70% phosphoric acid out of the bottle - you mix it down even further, but it's still more concentrated than plain ol' vinegar.

As soon as the piece is exposed to air it will begin to rust, you can almost watch it happen.
So I always rinse heavily, blow dry, and get some primer on it.
In the case of a tank, proceed to coating immediately (or fill with gas).

When doing tanks, I'm pretty careful not to spill any - but for the occasional drip or dribble, I just wipe it up real quick and it seems to be ok.
I would assume that if you left it on the paint for an extended time it would probably mess up the paint.

 

[kirkn]

Re: Question for Bill re: Milk Stone Remover

Hey, guys, thanks for the info. I appreciate it.

Have either of you used a product called Ospho? It's a phosphoric acid solution that coverts iron oxide into iron phosphate, which apparently stops it from being rust. I've used it many times on sandblasted bare metal parts and also on slightly rusty parts. It really does work converting rust into this hard black substance (iron phosphate, I guess...) and it does prevent the bare metal from flash rusting like that. But, I've never used it inside a fuel tank.

I'm still mulling over what approach to take.

POR-15 - it's a leading candidate, too, because I've read a lot of positive testimonials about it. But, boy, their website sure reads like a snake-oil sales site... :lol:

 

[Brown Bomber]

Re: Question for Bill re: Milk Stone Remover

I've used Ospho before, and it works really well, but I haven't used it in a tank. Don't know if any residue left behind would have an adverse effect on the gas, but glad you brought it up, I had forgatten what it was called, and would like to get some more. I also have some MSR, and will put some on a project tank this week end to see if it hurts the paint. I'll reply here later with results.
Allen

 

[KERRY]

Re: Question for Bill re: Milk Stone Remover

It's helpful to wash the tank with boiling hot water. when you drain it out, the hot metal tank just about dries itself, though I use the heat gun, anyway. As far as rust stabilizers are concerned, the effect on the fuel should be negligible or nothing at all - if it isn't soluble, no problem. If some component is soluble, that small an amount - in solution - should be insignificant. it isn't like paint, where petroleum would release the binder and have pigment particles (or chunks) floating around in the fuel. The question would be - is it effective after immersion in fuel? Might be worth treating a rusty nail and leaving it immersed in a container of fuel for a while - or top fuel (nitromethane). If it survives that...

 

[Bird76Mojo]

Re: Question for Bill re: Milk Stone Remover

I've got some nitromethane laying around. What exactly are you trying to explain?

GB :mrgreen:

 

[mopar_man]

Re: Question for Bill re: Milk Stone Remover

If you're concerned about your paint, you could take use some masking tape and plastic shopping bags to cover the paint.

 

[tbpmusic]

Re: Question for Bill re: Milk Stone Remover

Kirk-

Virtually any treatment aggresive enough to remove heavy rust is capable of hurting your paint.

I have no personal experience with POR - anectdotal info suggests it can go on over rust, and that properly applied, it's a Forever kind of thing, it'll never come off.

My only real experience is cleaning and Red-Kote ............

 

[Brown Bomber]

Re: Question for Bill re: Milk Stone Remover

O.K., I dug my future project tank out, and applied a generous amount of MSR (straight up, not diluted) directly to the right rear corner, (First photo) and let stand overnight. After cleaning with simple green, (Second photo) saw no sign of damage to the paint. If left on longer, who knows, but if you get any on the bike, your probably going to wipe it off right away. I would use something like Meguiar's Cleaner wax, and a good coat of caranuba wax prior to doing anything around the paint.

 

[KERRY]

Re: Question for Bill re: Milk Stone Remover

I've got some nitromethane laying around. What exactly are you trying to explain?

GB :mrgreen:

To see whether the rust stabilizer treatment is fuel proof - that is, if you stabilize rust in your fuel tank with it, is the effect permanent or will fuel reverse the treatment. If it survives immersion in top fuel then exposure to water and air without re-rusting, it should withstand ordinary motor fuel for an extended period - sort of an accelerated test. Since I understand it works by chemically altering the rusted surface and not by sealing it, it might work.

 

[kirkn]

Re: Question for Bill re: Milk Stone Remover

OK, I think there's another weapon in the old-bike resurrection arsenal....

If this had not worked, I'd have used the POR-15.

I dumped a large handful of 1" drywall screws in the tank, and used 1/2 gallon of diesel fuel. Shook, drained, repeated 4x. I got out about 1/2 a margarine tub of rust muck!! Flushed with water. By the time I did that, there were almost no rust particles coming out, but the inside was still rough:

Then, I just bought 3 gallons of pure white distilled vinegar at the grocery store ($2.50 / gallon) and filled the tank right up to the top. Put the whole thing in a big tub, up on wood blocks, in case a bottom seam started leaking or anything.

My experience with vinegar was the same as Ray's - worked great, but began to re-rust almost right before my eyes following rinsing... (I let it soak for 24 hours or so).

Next, I dumped / shaked / compressed air'd as much water out as I could, then poured in about a cup of Ospho. I was able to buy the Ospho at my local Ace Hardware store for $9 a quart. Home Depot used to carry it, but they don't anymore. They have something that's "just as good as Ospho...", but I passed on buying it. It was ~ $20/gallon and I didn't know how it'd work. Ospho, for me at least, was already a known entity. I shook the cup of Ospho around in there for about 10 minutes. Wetted everything very well. Dumped it out as best I could, but did NOT rinse with water and it's been drying in the 90* sun for about an hour now. No rusting at all!!

This was a bit of an experiment, but as far as I'm concerned, this was a success. Kinda labor intensive, what with the shaking of screws, dumping, etc. but not impossible.

All this was done with the petcock still in place and using the normal filler lid.

Petcock removal / clean will be next, but that's a whole different story...

 

[tbpmusic]

Re: Question for Bill re: Milk Stone Remover

I dumped a large handful of 1" drywall screws in the tank

Petcock removal / clean will be next, but that's a whole different story...

I tried the same thing on a 200 tank - I didn't see the screws again until after three days soaking in MSR was done - the rust assimilated all the screws, like the Borg - no amount of shaking produced any noise at all, they simply disappeared into the rust.
Admittedly, the tank was the worst rust case I ever tangled with, but jeez.......

Careful with the petcock- it's held on by a single phillips screw, which usually doesn't want to come out. Any attempt to use an impact or something will dent the bottom of the tank.
There's a reason CB200 tanks always have the petcocks still on them when you see them on EBay - if they could get them off they would, to sell separately. Replace that screw with an allen head - plenty of room for it.

 

[kirkn]

Re: Question for Bill re: Milk Stone Remover (Tank Cleaning)

Uh oh... The Ospho might not work after all...

Carbs were clean as a whistle and bike was running good after being tuned/sync'd while using my "I.V. drip" type plastic fuel tank hook-up in the driveway.

I was able to successfully rebuild the petcock (replacing the screw with an allen-head). Put the tank on, put some gasoline in and went for a ride. All seemed well. Filled the tank with premium from the local station. Got about 40 miles or so and it seemed to be running worse and worse. Hmm....

Ultimately, the throttle slides seemed to be sticking in their bores. Then, the throttle slides were DEFINITELY sticking in their bores.

Pulled 'em out, and uh oh... They're coated with a very sticky caramel-looking coating.

Hmmm... Pulled the carbs off, and the whole intake tract is coated with this sticky caramel.


Dunno what it is, and haven't done anything with the tank other than peek inside. Haven't disassembled the carbs, but I hope it just comes off with carb cleaner.

I'm thinking that maybe trace Ospho is reacting with the fuel? or with the aluminum itself? No clogging of the inline fuel filters, though. At least from just a cursory visual.

If anyone is planning to use Ospho in a tank, you might wanna hold off a bit...

Sigh.

 

[KERRY]

I'm surprised it had that much effect - but I wouldn't have left the tank unrinsed. To keep it from rusting, have some very lint free cotton cloth on hand - rinse the tank with boiling hot water and dump it out. The cotton is necessary because you can't quite dump all the water out and the cotton will absorb the small remainder. Because the tank is hot, blowing a heat gun into it will dry it out almost instantly. If any moisture remains, putting an alcohol radical like MEK into it will absorb all the water. The alcohol might be a good idea for drying the seams, anyway.

 

[kirkn]

Yeah, in hindsight, rinsing the tank SOMETIME following the Ospho rinse was probably a mistake. Maybe not immediately following the treatment, but sometime later.

The only update I have so far: this morning, the sticky caramel inside the intake manifold attached to the carb had dried out to a smooth, dry, not-sticky layer. I used a bit of acetone on a rag and, fortunately, it DID dissolve instantly and wipe right out. So, at least I'll be able to easily get rid of it...

I haven't done anything to the tank yet, though, or looked inside the petcock. This weekend...

 

[kirkn]

UPDATE:

The sticky goo in the intake tracts cleaned right out with Acetone on a rag. The carbs cleaned up with a 1/2 hour dunk in Simple Green. I disassembled all the jets, etc. and they were clean, oddly enough. It was only from the throttle slide forward (to the intake valve) that was coated. From the throttle slide back towards the air filters was clean!

One add'l wrinkle was that the goo actually caused an intake valve to hang open!! It was in the open position when I stopped, and it got stuck there! I had to really poke an acetone-soaked rag down the intake port to clean the valve.

I got it running good again on a temporary tank, and had a "spare" CL175 tank from another project that was pristine. So, for now, I'm running the bike with the CL175 tank in place. Got about 40 miles so far with no further problems.


What I think the goo was, based on it's extreme smell, was just "garden-variety" gasoline varnish. I realized the goo had that exact same, very identifiable smell that old varnished carburetors have when you open 'em up. There must have been "puddles" of varnish left in the tank. Hard to know, because there were areas of the tank that you can't get a line of sight on.

I've been told that ethanol in the gasoline (recently made mandatory now in all of FL) will actually dissolve long-hardened deposits in fuel systems and send it on down the line... A co-worker used to work in the local marine industry and he told me that the marine industry has been struggling mightily with ethanol dissolving deposits in marine tanks which have otherwise been stable for years and sending the deposits on down the fuel system where they "plate out" just as they seem to have done for me.

We'll see... I still haven't done anything with the old tank itself. I've just spent the weekend getting the bike back on the road. Now the tank work will come next.

 

[kirkn]

UPDATE:

Well, I'll tell you what, this little tank-cleaning project has been kicking my butt...


I realized that, indeed, the root cause was just still unclean sections of tank. Either the new gasoline or the ethanol IN the new gasoline simply started dissolving what was left behind and sent it on downstream. I guess I should've left the vinegar in there longer the first time around... In the past, I've been able to get away with 'good enough' on tank cleaning and just using an in-line filter to catch anything left. Not this time. That varnish went right on past the filters and didn't plate out until in the intake tract.


So, I decided to use something a little more aggressive than the vinegar next, thinking that the deposits left behind are going to need it. So, I used Muriatic acid (garden-variety swimming pool acid). I diluted what comes from the pool store 3:1. That is, I made 4 gallons of mix from 1 gallon of acid.

All safety gear on, etc. etc. and poured it into the tank. Within 10 MINUTES that diluted acid had eaten right thru the aluminum petcock and was gushing out into the plastic catch pan. :shock: :shock: Fortunately, I had decided to use the plastic tub rather than the galvanized metal tub this time around. Sigh. It ate right thru the aluminum portions of the petcock. The petcock lever got completely dissolved - no evidence left whatsoever. The sediment bowl is 70% dissolved. The copper tubes that poke up into the tank - very clean and shiny, but still OK. Rubber 4-hole gasket? Steel wavy lever spring? Steel bolt? All untouched...

Well, I managed to not harm anyone nor damage the tank any further, but that was the end of the acid experiment.

I wish I had read others' experiences a bit more thoroughly first, because two or three other threads on the subject clearly warn not to mix acid with aluminum...

Bike Bandit to the rescue with a new petcock, but still, a $48 'lesson-learned'! :shock:


So, back to vinegar... I fabricated a steel blank-off plate with gaskets for over the petcock & bolt hole. This time, I let it sit for 48 hours! By the time I dumped it out, I had liberated a whole new handful of gravel from my dad's previous attempts at tank cleaning!! I hadn't even realized it was IN there!! This time, the tank was very nearly perfect! Using a bright light and a dental mirror, I could get a line-of-sight on the entire inside. It was very nearly perfect. Still a few stubborn deposits along the seams.

So, a THIRD batch of clean fresh vinegar went in, and this evening will mark the 48 hour mark for THAT batch. I'm thinking the tank will be very clean this time around. I checked on it yesterday, but other than a slight layer of scum on top of the vineger, I couldn't tell much. Fortunately, nothing has started leaking - no seams nor rust holes.


What a learning experience. That's the only thing that makes it all OK.

I'll re-do the Ospho treatment when it's all over, because the Ospho does/did a great job on stopping the flash rusting that occurs after rinsing out the vinegar.

 

[Rampage1967]

I wonder how well E-85 would clean out fuel deposites. After all it is 85% ethanol.

 

[kirkn]

Well, the trouble is, it just allows them to migrate downstream to the NEXT spot - intakes, valves, piston tops, etc.

But, it DOES loosen 'em up...

Here in FL, in the last few months, 10% ethanol has been MANDATED in the gasoline. So, there's no getting away from it. It does unpleasant things to the marine industry, too. I've got a whole article on the subject, by West Marine, but it's in .pdf format so I can't post it. It can attack fuel hoses, soft parts, and even the resin in many kinds of fiberglass.

Sigh.