De-rusting gas tanks with MSR ?

bluebikerblan · Posted: February 26, 2009, 3:05 pm Post subject: De-rusting gas tanks with MSR ?

This tip is from another forum.....I too had mixed results using electrolysis and Kreem and was better pleased with MSR (Milk Stone Remover) and a tank lining product called Red Kote which used to be red but now is blue in color. The tip is written by Bill Lane and posted on a CB 45O forum

"MSR is about 70% phosphoric acid, with an orange dye. Mix it 50% with water, fill the tank, come back later. It will save even the worse tanks. It's hell on rust, won't touch chrome. It will mess up paint if left long enough.
Some tanks will get de-funkified in a few hours, some may take much longer - days or even a week or more, if they're really nasty.

It is also way less dangerous than muriatic (hydrochloric) or sulfuric - if you get some on you, at least you have a chance to make it inside and rinse it off before it burns the livin' snot out of you. No noxious fumes either. I'm a degreed chemist, I've seen what acids can do so I stay with MSR, it's much safer.

Iive had unsatisfactory results with electrolysis. It's "line of sight", meaning that if the sacrificial electrode can't "see" the area nothing will happen . That means that convoluted volumes or parts (like tanks) will yield indifferent results. MSR also works better on flat pieces. I keep a big 60-quart cooler full of MSR solution which I process nearly everything with it.
Some people claim it leaves some sort of protective coating that prevents further rust. I have not found that to be the case at all. In my experience you can see the rust re-forming before your very eyes. So you need to quickly either paint the piece, spray with WD 40 or light oil. For a tank case, fill quickly (or swish around) some heavy 2-stroke gas/oil mixture to coat it while you prepare to do something else with it.

Everyone has a favorite tank "sealer" - I prefer Red-Kote myself, use what you prefer. Although Red-Kote has changed recently, it's now blue, but the same stuff.
If you go with Red-Kote, mix it down a bit with acetone to make it easier to use. The stuff is really viscous out of the can." -endquote-

Another tank lining product is POR 15 which a lot of people like as well. I have no experience with it.

ilk Stone Remover, MSR, is available from a variety of Dairy Service product suppliers. I found and purchased it from a local Tractor Supply store.

Hope this helps with a rather messy and onerous task. It did for me. Blue

rwreed

I've tried to keep my tank full when sitting out the winter. So it's not too bad. Just some light rusting. I do have to rebuild the petcocks this year. Just got the kits from Mikes. Was wondering if I should block the petcock openings and try MSR and liner while I'm rebuilding them.

Did you have to remove your petcocks first and plate them over for this job like with the electrolysis? Just wondering.

Thanks for the info!

JeffM

You can make the plates out of anything... I used some scrap 1/4" aluminium I had, but even plywood would do the job. I cut some rubber out of an inner tube for a gasket.
If you line it, give the liner LOTS of time to cure before you put fuel in it.

Thanks for the tip on the MSR Blue... I have a couple of tanks I picked up recently to play with. I am thinking it would be worth trying on rusty bolts too.

Xumi

I had really good results with Electrolysis. to get around the Line Of Site issue, I made a very wide anode out of a coat hanger in a W pattern, so it should have LOS to the whole tank.

That tank was Really bad inside.. and after 2 days electrolysis was clean as I could see it. After washing it with denatured alcohol to displace the water and letting it air dry for about 20 minutes, I put in some light motor oil and gave it a good swirl, then drained, as I knew I wouldn't be ready to fill 'er up anytime soon.

It's now 1 year since then, and I have 1 small spot on the crest of the center of the tank that is showing VERY little rust - probably didn't get any oil - other than this, the tank is clean, and that with sitting essentially dry for a year.

So... I can't tell anyone else what to do with their bikes, but for me, electrolysis was cheap, easy, and didn't leave stuff on the inside of my tank that may end up peeling off later and clogging everything up.

bluebikerblan · Last edited by bluebikerblan on March 9, 2009, 12:56 pm; edited 1 time in total

I wouldn't recommend leaving anything aluminum in any way in contact with the electrolytic solution with current on. Electrolysis works at varying rates according to metals electrolytic order. Aluminum goes much more quickly than rust (Ferric oxide). I'd remove the petcocks and blank the holes off with rubber and plywood. RTV silicone works well if you let it cure well before adding solutions.

Also, don't leave petcocks on the tank when you line the tank with Red-Kote (or any of the others and make sure that all tank exits coated are cleared and open from lining coating. Stuff is real tought to remove or open up after it's set.

I dissolved a petcock on a Honda tank (electrolysis method) a while back where a rubber stopper would have done nicely instead of thinking that I could leave the petcock on the tank while de-rusting.

Glad you got the hang of it Xumi. I have real good luck with MSR. Maybe as an old Chemist I just have better luck with chemicals than electrolytic deposition or removal. Hmmmm come to think of it I used to loose my sacraficial anode on my sailboat quickly too and it's all chemistry anyway.

Best, Blue

Xumi

True enough, Blue - there are as many ways to fix these bikes as there are people who fix 'em... and in the end, if it gets ya down the road, then it was worth the price.

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