Topic: Mavel Mystery Oil Vs tank Lining

[Ace Blackwell]

All,

I'm getting back to my tank restoration after the holidays. I've read lots of approaches to removing rust.  My approach is a combination like most others.  However, I read where some uses the Mystery Oil as a tank coating and others POR-15 tank liner.   Is there a condition where one would be used over the other?  Or is one used until the other could be used?  Or is it just personal preference?

Thanks
Ace 

[seanbarney41]

after you are done removing rust...and there are no leaks, there is absolutely no reason to use a liner.  I f you have pinholes, then you may need a liner.  Personally, I will do everything I can possibly do to avoid using tank liner, as I believe every liner available is a failure waiting to happen.  Even if a liner holds up for 5 years, when it fails you have a huge problem to fix.

[Ace Blackwell]

Thanks for the advice.  I didn't realize the liners were not permanent. Besides I don't have pin holes and I can always go to the liner later if I choose.   I was just thinking long term about rust.

Ace

[seanbarney41]

Liners are "supposed" to be permanent.  The problem is 10 percent ethanol gas.  Your tank will not rust once in regular use and cared for properly.

[mystic_1]

Not to mention that tank liners can be tricky to apply well.  If you don't get the tank completely clean inside, or if you don't apply the liner properly, it won't adhere well and will eventually start peeling off inside.

They're best avoided, I agree. 

Your tank will not rust once in regular use and cared for properly.

Agreed.  In particular, try to keep the tank mostly full, as rust tends to form in the parts of the tank exposed to air.

mystic_1

[carnivorous chicken]

Pinholes are the main reason as stated. That being said, I have a tank that I lined with POR-15 10+ years ago and it's still fine. If you do it right, it won't fail, in my experience. Kreem is terrible, and I have a tank with Redkote in it that's been going strong for 6+ years. If you're repainting, you might want to consider lining as well -- if a pinhole leak develops, you're going to have to line it and repaint it.

[calj737]

To answer your original question, Marvel is used to prevent flash rusting or "fogging" a tank after de-rusting. POR-15 is an applied epoxy liner. Many like liners, many don't. If you don't need a liner, I'd shy away from it until such time as you determine you need a liner.

But if you ever do need a liner, Caswell is the bomb and ethanol doesn't bother it one lick.

[przjohn]

I don't see how Marvel could be considered a tank liner. I have had very good luck with The Caswell Kit and have been lining all my resto tanks for the past 10 years. When you have a good investment in paint it makes sense to line the tank on old bikes IMO. If you follow the Caswell directions you will have no problems.

[mystic_1]

Marvel Mystery Oil is not a tank lining.

It's an oil.

Like any other oil, it leaves a film on surfaces which help inhibit rust, but like any other oil it'll get washed away quickly by gasoline.

mystic_1

[Don R]

 Some guys are using a little synthetic 2 stroke oil mixed in to help protect the tank and original type exhausts too. It burns clean and doesn't smoke when used lightly.  Avoid storing it with gasohol if you can buy straight gas. Race gas or Avaition gas stores well too.
 The marvel may also help ward off rust, in a high performance engine, burning oil can cause detonation. Not likely in our case if everything is in good working order. And of course some guys would never do either in any case.

[dhall57]

Don't know about gas tanks but MMO works great on freeing up stuck engines

[Powderman]

The Marvel Mystery Oil is used to line the tank when it is empty and put in storage for a period to keep the rust from starting. I see no other benefit to it if there is gas sloshing around in the tank from use, the oil will just wash off.

[BobbyR]

If you do a search. you will find many threads on tank cleaning and lining, if necessary. It depends on how much rust there is.  Some people have had good luck with Vinegar which is cheap and safe. Toilet bowl cleaner is good for some conditions. Electrolysis is used for some tanks. It is all there fro you to make an informed decision.

Coatings mentioned can be a problem, even if applied properly. I am not blowing you off reccomending a search. There are step by step tutorials on this site.

[bochnak]

I use vinegar or evaporust to remove as much rust as possible. If I have to coat the tank, I use Caswell epoxy.

I have  a couple of videos on the process here:

https://www.howtomotorcyclerepair.com/restoring-a-rusty-motorcycle-tank/

-Matt

[flybox1]

The Marvel Mystery Oil is used to line the tank when it is empty and put in storage for a period to keep the rust from starting. I see no other benefit to it if there is gas sloshing around in the tank from use, the oil will just wash off.

+1
Only for storing a (good on inside) empty tank.

[Lostboy Steve]

I use vinegar or evaporust to remove as much rust as possible. If I have to coat the tank, I use Caswell epoxy.

I have  a couple of videos on the process here:

https://www.howtomotorcyclerepair.com/restoring-a-rusty-motorcycle-tank/

-Matt

I am doing my tank with the caswell even though I am usually a loyal por15 guy. You like it huh?

[bochnak]

I have done about 6 tanks in the past few years with no issues. I have never tried POR, though.

I have done both clear and black, which actually turns out to be translucent black. I prefer the black kit as it hides all the imperfections and you can see the coverage easier over the clear kit.

[Ace Blackwell]

All

Ok, was able to get the tank rust soaked and found that i have two small pin holes on the flat of the bottom.  I am starting to get mixed feelings about epoxy lining.  Given that the holes are in an unseen area of the tank, would it be easier / wiser to apply epoxy directly to the holes from the outside.   Or is there enough confident in the POR / Caswell process to go that route. I like the idea of coating the tank permanently, not so fond of coating the inside of my carbs/engine permanently .

Thanks
Ace

[calj737]

If your tank is clean inside, etch it with Prep and Etch. Dry overnight. Pour 1/2 of mixed Caswell in and gently rock the tank back forth covering the floor plates and up the side seams. Let sit 6-8 hours. Pour other 1/2 in and invert tank to get underside of top, and side panels. Cure overnight. Done. Permanent. Ride on!

[mystic_1]

Are you sure you only have two pinholes?

Unless the holes are from impact damage or some other mechanical cause, then the holes came from rust, and if it rusted THERE then it probably rusted elsewhere also, maybe not enough to go all the way through, but my point is:  how thin is the metal in that area now?

If you're pretty confident that there's really only two holes and the metal is sound, why not weld them up?  That's a trivial job with a welder, and no worries about crapping up your fuel system. (naturally drain rinse and purge the tank before welding)

If the metal is sound and you can't get it welded up, then after making sure the metal isn't dangerously thin in that area I would apply a small amount of standard two-part epoxy from the outside to close the holes, AND then line it with your liner of choice.  The epoxy from the outside is just to make the internal liner lay down nicely, if just used alone without an internal liner, it would be destined to fail.

All in all though my personal preference is not to line tanks, so get it welded up if possible.  If they're literally pinholes, then you're talking about 5 seconds of actual welding trigger time, with time for prep and cleanup on either side. 



BTW if it were me, before I did any lining, I'd also take the tank, seal up the fill hole, run a small amount of air pressure into the petcock hole, and immerse the tank in water.  Don't rely on visual inspection if you're dealing with pinholes, a bubble test will reveal them for sure.  Mark them by circling with a scribe, then dry off the tank and plug them by welding or with epoxy as per above.  Then you can repeat the test until you're 100% sure the tank is airtight.  THEN worry about the internal liner.

mystic_1

[Ace Blackwell]

Thx, you mean like concrete etch and prep?  Or is there an epoxy etch and prep?

[mystic_1]

Tank liner kits typically come with a mild acid solution to clean out an remaining residue and etch the metal slightly in preparation for the coating.

Get a kit so that you're sure all the component chemicals are compatible with each other, and follow the directions carefully.  As said upthread, this is easy to screw up and there are plenty of stories about failed tank linings out there on the web.

mystic_1

[calj737]

Thx, you mean like concrete etch and prep?  Or is there an epoxy etch and prep?

Just like Concrete Prep 'n Etch. You can use the same product on metal to remove rust, on metal as pre-treatment for paint, or on concrete.

If the floor plates are rusted and thinned as ideated, the Caswell will more than strengthen that area. And the Caswell may bleed through the pinholes, but not likely. Its pretty thick and sets up quickly too. If it does seep through, you'll be assured of having the hole filled anyway. Scrape it smooth or back the hole from the outside with blue tape prior to lining.

[grcamna2]

Pinholes are the main reason as stated. That being said, I have a tank that I lined with POR-15 10+ years ago and it's still fine. If you do it right, it won't fail, in my experience. Kreem is terrible, and I have a tank with Redkote in it that's been going strong for 6+ years. If you're repainting, you might want to consider lining as well -- if a pinhole leak develops, you're going to have to line it and repaint it.

 

[przjohn]

If you have pin holes you have a tank that could definitely benefit from a liner as odds are, there are many more areas ready to pop through. The Caswell kit is a 2 part kit and the POR15 is a single part kit that goes on thinner and is more like paint. You have absolutely no reason to fear applying The Caswell liner. I have done many tanks both metal and fiberglass with no failures. If you follow the simple instructions you will have a leak free tank that lasts.

[carnivorous chicken]

If you have pin holes you have a tank that could definitely benefit from a liner as odds are, there are many more areas ready to pop through. The Caswell kit is a 2 part kit and the POR15 is a single part kit that goes on thinner and is more like paint. You have absolutely no reason to fear applying The Caswell liner. I have done many tanks both metal and fiberglass with no failures. If you follow the simple instructions you will have a leak free tank that lasts.

Not sure what you mean here by one part kit, but the POR-15 process is a 3 step process: rust removal, acid prep, and liner. Each step has to be done perfectly according to instructions (e.g. the tank has to be bone dry before the final step, the liner, is put in). And it has to cure for a few days. I've sealed up pinholes with it before, piece of cake and no problems since.

[grcamna2]

There's a company here local to me that does an expensive liner/treatment that's very involved and takes a while w/ many processes;the job is done and is permanent/guaranteed for life.I had it done and am enjoying that I won't have to 'mess' with it Anymore.  gas-tank.com

[przjohn]

If you have pin holes you have a tank that could definitely benefit from a liner as odds are, there are many more areas ready to pop through. The Caswell kit is a 2 part kit and the POR15 is a single part kit that goes on thinner and is more like paint. You have absolutely no reason to fear applying The Caswell liner. I have done many tanks both metal and fiberglass with no failures. If you follow the simple instructions you will have a leak free tank that lasts.

Not sure what you mean here by one part kit, but the POR-15 process is a 3 step process: rust removal, acid prep, and liner. Each step has to be done perfectly according to instructions (e.g. the tank has to be bone dry before the final step, the liner, is put in). And it has to cure for a few days. I've sealed up pinholes with it before, piece of cake and no problems since.

I mean't that it does not require 2 ingredients mixed together like the Caswell kit.

[carnivorous chicken]

If you have pin holes you have a tank that could definitely benefit from a liner as odds are, there are many more areas ready to pop through. The Caswell kit is a 2 part kit and the POR15 is a single part kit that goes on thinner and is more like paint. You have absolutely no reason to fear applying The Caswell liner. I have done many tanks both metal and fiberglass with no failures. If you follow the simple instructions you will have a leak free tank that lasts.

Not sure what you mean here by one part kit, but the POR-15 process is a 3 step process: rust removal, acid prep, and liner. Each step has to be done perfectly according to instructions (e.g. the tank has to be bone dry before the final step, the liner, is put in). And it has to cure for a few days. I've sealed up pinholes with it before, piece of cake and no problems since.

I mean't that it does not require 2 ingredients mixed together like the Caswell kit.

Ah, gotcha, correctamundo!

[Ace Blackwell]

Thanks all,

I am going to go with a liner.  As you guys suspected I do have more than just the 2 pin holes.  Its more like 4 from what i can tell, though the metal seems pretty solid.  Couple of things I learned doing this.  And unfortunately didn't really have a great solution to either but just thought I'd share.  Maybe someone else my think of a better way before getting knee deep in the middle.

- The 550 tank doesn't have any opening at the lowest point of the tank.  Meaning, flip the tank upside down and the counter sink of the tank cap area becomes a raised platform.   And right side up, the petcock area apparently isn't the lowest point as I couldn't get everything to drain. I have shaken the hell out of the tank today and it took forever to get the vinegar and then the water out of the stupid thing.  I did use alcohol to dry the remaining dampness.  Because I didn't have my liner yet, I just poured in container of Marvel's, then shook it,  and have left it in.  I did use air from a pump for the alcohol, but didn't have access to a compressor to hit with high pressure.

- Sheetrock screws Vs BBs as a shaker media.  As most know, one of the recommendations is to fill the tank with a pound of screws or something to rattle around for a while in the tank to dislodge the loose rust.  I chose BBs.  They sounded like a better idea because they are smaller.  Could get to more areas right?  Well they did a great job but for the reasons listed above, they were a pain to get out of the tank.  It's up to the individual, but for a tank with a counter sink cap I would strongly recommend something larger than BBs.  Something you can reach in and get the last few by hand.

I have come to respect the guys that went through this process on a painted tank.  I had rust filled vinegar and then water all over everything.  In any case I really do appreciate all the good info.  Now to find where I can get the liner.  Advanced Auto here didn't have it.

Thanks
Ace 

[mystic_1]

Cool cool, you'll want to make sure to clean off the Marvel oil really really well before trying to line it, so that you don't get any adhesion problems.

The thing about using drywall screws is that the points of them would help scratch up the inside surfaces of the tank almost like sanding, which will give the liner some mechanical "tooth" to cling to.  The points would also get down into the corners a little better than the BB's would.

Any way sounds like you have a good plan for moving forward.  You'll probably need to order the liner, I've never seen it just on the shelf anywhere.

mystic_1

[Flyin900]

Whenever I do a tank I use a little acetone to roll around in there in the final stage of drying. I fortunately have a shop vac that can also be used as a blower by reversing the hose on the assy.
By using the cone shaped attachment tool that came as any accessory with the shop vac in the gas cap hole I blow the remaining water/acetone out the petcock hole and allow it to sit for a few hours afterwards. It is dry as a bone inside when done and ready for your liner material.

[calj737]

Definitely need to flush that tank with Acetone before using any liner product. With a bit of water residue, you could have just added Prep N Etch as it dehydrates the water anyway.

As for using screws, BBs or whatever, Vinegar (or any other acid) doesn't need mechanical additives to work. And the PnE will scratch the surface to create a liner "bite", so you can abandon that whole nightmare going forward. But, for anyone that wants to use a mechanical fastener, I strongly recommend 12-14MM stainless nuts. They're large enough, heavy enough, and inert to the acids. And they're much easier to extract later. I've got about 2 dozen for helping to beat an old liner from a guys tank that went in wrong.

But definitely thoroughly clean your tank now before installing a liner. Caswell is purchased most easily over the Web. I've not seen a lot of Auto Parts stores stock it. I prefer the "clear" formula personally.

[przjohn]

Yup, I agree, you need to get that Marvel out of there, every bit of it. Acetone is your best bet and is what Caswell says to use. Personally I use sheet rock screws, but anything that gets the rust and loose stuff off should work. A couple of tips that I have learned,

The screws come out easier if your are shaking them out with water, and not just dry. They will follow the flow of the water, just keep filling the tank and emptying.

Get a small piece of garden hose and tape it into the suction hose end of a wet/dry vac to suck out water and a remaining screw or 2.

I use a hair dryer set on low and tape it to the top of the tank and let it blow for hours while I work on something else. The tank will then air dry for a day before lining, it is desert dry by then.



I too am a fan of the clear Caswell, follow the instructions to the letter and you will have excellent end results.

[bochnak]

I had pinholes in a Z50 tank. I placed some masking tape over them before pouring in the caswell. I made sure to have a extra thick coating on the bottom. It's at least 1/8" thk and I don't have any problems with it. You can always double coat it per the instructions.

[Ace Blackwell]

Thx all,

Przjohn good idea on the blow drier.  Sure beat the sin out of shaking the silver off the metal.

Bochnak  The tape thing makes sense. Thanks for the heads up.

Hey does the liners come with the prep stuff? I don't imagine it comes with acetone but I m hoping it comes with the etch .

Ace

[seanbarney41]

Caswell comes with nothing...I spent $50 in extra materials to prep for it, granted, much of that was to protect an original paint job and alot of that stuff a normal household may already have on hand.  POR15, I believe , is the only one that comesas kit, with cleaner and etching compound.

[bochnak]

Bochnak  The tape thing makes sense. Thanks for the heads up.

Hey does the liners come with the prep stuff? I don't imagine it comes with acetone but I m hoping it comes with the etch .

Ace

Caswell does not need as much "prep" as other sealers. I use evaporust or vinegar to derust the tank a bit. If using vinegar, make sure to neutralize with baking soda.

Quick tip on using acetone as a final wash: don't pour directly out of the metal can it comes in. Instead, transfer it to an easy to pour container, otherwise there is a good chance you will spill it all over the place. Ask me how I know and you can imagine what this does to paint. Mask the hell out of it.