Prep to seal a rusty tank

[mixelpix]

Hi, finally found an '80 standard gas tank with cocks/fuel send cap and keys (and a matching ignition) to fit onto my '79 Special. I have read up on navigating the petcocks/diaphragms and the fitting - I am okay with the swap, couple a questions, however, about preparing a new and, yes, rusty tank.

Irregardless of the items description (ahem...) I received a gas tank with a considerable amount of surface rust inside the tank - from what I can see with a light and a mirror, it doesn't look like there is any significant bubbling. I have ordered and am waiting on the "the Caswell Epoxy Gas Tank Sealer...See http://www.caswellplating.com for details." and was wondering in the meantime
1) what I can do to stop the rust which has started?
2) when the Caswell product arrives, is there anything I should do to prep the tank for the seal?

I am trying to locate some phosphoric acid (not sure where to look) and acetone (should be easy to find), but I am mostly concerned about the manufactured holes in the tank. Should I remove the fuel send unit? (I am assuming yes) Also the petcocks? Prior to cleaning /and/ the epoxy coating, or just for the coating? Is there anything I can do to keep the epoxy from messing up the fit of the petcocks/fuel send? I guess I could sand/scrape any messy bits...

Finally, the drain pipe out the back of the tank - should I stick a wire brush or something in it to keep it from getting sealed over?

Any suggestions or thoughts from those who have followed the advice on the repairs url would be appreciated.

Thanks!

[Pat Kelly]

What I did when I "Caswelled" my tank was:
-rattle some chain around inside the tank to loosen the flakes of rust...
-cleaned with acetone...
-put the old petcocks (towers were missing and I had replacements) in baggies and bolted them back on...
-made a cover for the sender out of thin wood (wood paneling I think) and bolted it on...

Bolting the parts back on allowed the sealer to form around the bolts.

The drain hole in the back of the tank dosen't (shouldn't be) open to the inside of the tank. It goes from the area just outside the filler to the back of the tank. It drains spilled gas (or rainwater, etc).

Very easy to do, I have two more to do myself.

[bikerhawk]

I've researched this topic thoroughly, as I have tanks for both the F and the 750 that need rust removal/coating...here's my .02.

--I tried Kreem first. My honest opinion: s#@t. Didn't work well at all. Works for some, causes even more problems for others.

--The Caswell kit is supposed to be very good. I have a kit on my workbench to be used eventually. But first, I'm going to try...

--Yamaha's own tank rust remover/neutralizer kit. 1 bottle each of rust remover and neutralizer to keep the rust from returning. The F tank will be my guinea pig. I've heard that if done correctly and filled with fuel quickly after completion, the rust will stay away. We'll see.

--A good rust remover/prep is milkstone remover, used in dairy tanks and lines to remove deposits. Less hazardous to work with than acetone or MEK. The only isssue might be finding the stuff, unless you live in a dairy belt. Tractor Supply Co. supposedly carries Sterosol brand milkstone remover, but when I asked about it at my local TSC, they looked at me as if I were tripping on something.

--POR-15 is another product that some have used with good results.

Good luck--please share your results with us.

[MAXIMAN]

Home remedy

A couple "bike restorers" I've talked to said..."DON'T USE ANY LINER!!!" Unless and only unless the tank is leaking. They all indicated that a liner will...sooner or later...flake out of the tank. It may take 10 years but it will eventually release from the tank. They both said if ya keep live fuel in the tank it won't rust.

If the tank is leaking you have no choice in order to stop the leak. However if is not leaking all you need to do is stop the rust....and that is a pretty simple process.

So I did my own treatment. I did not buy a kit. I spent about $10 using a quart of varnish remover and a quart of rust remover found at most hardware stores. It has worked well so far. If it doesn't prove to work well over time I can always go back and "seal" the tank at a later date. The reason I chose this route was to avoid a liner. I had night sweats thinking about that liner coming loose when I was somewhere between Elko and Reno with no cell service.

Here's what I did:

1-Drain the tank and use pieces of flat metal plate to make covers for the petcock and sensor holes using inner tube for a gasket. Cut a piece of innertube to go under the tank filler cap/lid.

2-Poured one quart of liquid paint/varnish stripper into empty tank and shook thoroughly...round and upside down. Be sure not to get any on paint as it will ruin it. Have a running water hose available to wash any off immediately. Let the tank sit for about an hour to allow the chemical to work. Then rinse the heck out of it...several times.

3- Allow the tank to dry completely.

4- Pour a quart of rust inhibitor (not paint primer) in the tank. This can be obtained at almost any hardware or building center. The stuff is usually a green tinted clear liquid. It neutralizes rust from an oxide to a phosphate and leaves no residue. It effervesces as it eats the rust away. The brand I used was "Ospho". There are several. Shake well and upside down since most rust is in the top of the tank where air circulates. Let it sit for about an hour. No "physical" abrasive is needed to remove rust with this stuff. Just get a quart and put some on a rusty piece of metal to see what it does to rust.

5-rinse tank extra thoroughly with hot water...several times...and allow to dry completely. I actually left a water hose running in the tank for a good 30 minutes. At this stage I used a blow drier to facilitate drying.

Put tank back together and fill with gasoline.

So far so good.

[desert1]

bolt holes

You wanna put something in the bolt holes for the petcocks to keep the threads from being filled, but you allready planned for that I'm sure.......also put 2 or even 3 coats of treatment inside the tank, rolling the tank around slowly as you go.......when I did my 78s tank 2 years ago I used 2 part marine epoxy (slow setting type) 3 coats, cost me about $35.00 Canadian and it works fine..........oh, get yourself a small paint brush to touch any areas around the filler or petcock outlets the swirling may have missed........
Bruce


"You cant tell an honest man by the filing of his income tax return.......but you can by the zero-adjust on the batroom scales"

[mixelpix]

Originally posted by Pat Kelly
It goes from the area just outside the filler to the back of the tank. It drains spilled gas (or rainwater, etc).

Thanks Pat! I was wondering about that!
-pat

[mixelpix]

Thanks!

Thanks for all the suggestions and information everyone! This site rocks. No time to read eveything now at work, but I'll let you know how it goes.
-pdk

[Dragonrider]

Plumbers putty works great for sealing threads/stuff from getting epoxy on them. I've used caswells on a couple different projects and have been really pleased. There is not a lot of prep needed, just make sure there is no loose rust/etc . . . the surface rust just promotes good adhesion.

[scoobes]

what i have done in the past is put a load of very small ball bearings in the tank then rap the tank up in bed sheets and a quilt then put it in to one of those little portable cement mixers but with enough packing to keep it in the center of the drumm,after a couple of hours the inside of the tank was like brand new.

[randy]

Whatever method you choose, be careful with the MEK or Acetone. They will remove all types of enamel and laquer paints even faster than brake fluid!

MEK has been called brain cancer in a bottle. Acetone smells just as bad, so VENTILATE or you will cease to ASPIRATE.

HTH

[mixelpix]

Originally posted by scoobes
what i have done in the past is put a load of very small ball bearings in the tank then rap the tank up in bed sheets and a quilt then put it in to one of those little portable cement mixers but with enough packing to keep it in the center of the drumm,after a couple of hours the inside of the tank was like brand new.

Hmm, I wonder if my dryer's tumbler is big enough..... (insert evil smile here)

[don07tncav]

I was thinking the same thing.... would yea old dryer work??

[Ken Talbot]

Sonds like you guys are fans of the Red Green show - one of Canada's contributions to television culture...

"quando omni flunkus moritati"

[DiverRay]

The dryer will work, with a few beach towels around the tank.
I used Berrymans B12 Chemtool, about two quarts, and some stainless 1/4 short bolts to clean a Honda tank. Worked like a charm, and I did NOT put anything else in it. The tank was still nice when I sold the bike after almost a year.
Just get the rust off, and use the tank if it's not leaking. That is best for you and the tank.

[Geezer]

If you're planning to repaint the tank, one thing you can do is send it out and have it tinned. The tank has to be acid dipped first then is dipped in a vat of molten tin. After that the tank is good for life.

Geezer